Protective Antibody Responses to Pneumococcal Conjugate Vaccine after Autologous Hematopoietic Stem Cell Transplantation

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1 Biology of Blood and Marrow Transplantation 11: (2005) 2005 American Society for Blood and Marrow Transplantation /05/ $30.00/0 doi: /j.bbmt Protective Antibody Responses to Pneumococcal Conjugate Vaccine after Autologous Hematopoietic Stem Cell Transplantation Joseph H. Antin, 1 Eva C. Guinan, 1 David Avigan, 2 Robert J. Soiffer, 1 Robin M. Joyce, 2 Victoria J. Martin, 3 Deborah C. Molrine 3 1 Departments of Adult Oncology and Pediatric Oncology, Dana-Farber Canter Institute, Boston, Massachusetts; 2 Hematologic Malignancy Bone Marrow Transplant Program, Beth Israel Deaconess Medical Center, Boston, Massachusetts; 3 Massachusetts Biologic Laboratories, University of Massachusetts Medical School, Jamaica Plain, Massachusetts Correspondence and reprint requests: Deborah C. Molrine, MD, Massachusetts Biologic Laboratories, University of Massachusetts Medical School, 305 South St., Jamaica Plain, MA ( deborah.molrine@umassmed.edu). Received June 29, 2004; accepted December 16, 2004 ABSTRACT Patients undergoing autologous hematopoietic stem cell transplantation (autohct) are at increased risk for infection with Streptococcus pneumoniae and have impaired antibody responses to pneumococcal polysaccharide vaccines. We performed this study to examine the ability of autohct patients to respond to a heptavalent pneumococcal conjugate vaccine (PCV7) given after transplantation and to determine whether there was a potential benefit of immunizing these patients before stem cell collection. Sixty-one patients scheduled for autohct were randomized to receive either PCV7 or no vaccine before stem cell collection. After stem cell reinfusion, all study patients were immunized with PCV7 at 3, 6, and 12 months. Pneumococcal immunoglobulin G antibody concentrations were measured at the time of each immunization and 1 month after the 12-month dose. Serotype-specific pneumococcal antibody concentrations were significantly higher in patients immunized with PCV7 before stem cell collection compared with patients not immunized before their stem cells were collected for 6 of 7 serotypes at 3 months, 6 of 7 serotypes at 6 months, 4 of 7 serotypes at 12 months, and 3 of 7 serotypes at 13 months. After the 3-dose series of PCV7 after autohct, >60% of study patients had protective concentrations of antibody to all 7 vaccine serotypes regardless of immunization before stem cell collection. Pneumococcal conjugate vaccine is immunogenic in autohct patients and may be an effective strategy to prevent invasive disease after transplantation American Society for Blood and Marrow Transplantation KEY WORDS Hematopoietic cell transplantation Pneumococcal conjugate vaccine Immunization Autologous INTRODUCTION Patients undergoing autologous hematopoietic cell transplantation (autohct) are at increased risk for infection with Streptococcus pneumoniae and other polysaccharide-encapsulated organisms [1-4]. After autologous and allogeneic stem cell transplantation, there is a decline in specific antibodies, and the recovery of B-cell and T-cell function is delayed [5-8] Current recommendations to prevent pneumococcal disease in hematopoietic cell transplant (HCT) recipients include the use of 23-valent pneumococcal polysaccharidevaccineat12and24monthsafterhct[9]. However, most HCT patients respond poorly to immunization with unconjugated polysaccharide vaccines, because immune responses to T cell independent antigens are slow to mature after transplantation even when immunization is delayed until 12 months [10-13]. Polysaccharide conjugate vaccines link capsular polysaccharides to protein carriers and enhance polysaccharide antibody responses through T cell dependent mechanisms [14,15]. Polysaccharide conjugate vaccines to Haemophilus influenzae type b (HIB) and BB&MT 213

2 J. H. Antin et al. S pneumoniae have been shown to be effective in providing protection from invasive disease in infant populations unable to respond adequately to polysaccharide vaccines [16-18]. We and others have shown that HIB conjugate and, more recently, pneumococcal conjugate vaccines are immunogenic in non T cell depleted allogeneic bone marrow transplantation (BMT) patients [19-21]. In this study, the ability of autohct patients to respond to pneumococcal conjugate vaccine was examined. We also sought to determine whether immunization of these patients before stem cell collection enhanced antibody responses to vaccine administered after transplantation. MATERIALS AND METHODS Patient Population Patients were recruited during ambulatory visits to the oncology centers at Brigham and Women s Hospital, Dana-Farber Cancer Institute, Children s Hospital, and Beth Israel Deaconess Medical Center (all in Boston, MA). Eligible patients were those older than 2 years of age with an underlying diagnosis of a hematologic malignancy and who were scheduled to receive an autologous stem cell transplant. Patients who gave a history of immunization with 23-valent pneumococcal polysaccharide vaccine within the previous 6 years were excluded from study participation. Informed consent was obtained from the patient or his or her parent or guardian. The study protocol was approved by the institutional review boards of all participating institutions. Eligibility criteria, outcome variables, and the analysis plan were determined before study initiation. Patients were conditioned for transplantation according to diagnosis and current protocols. Patients enrolled in the study were randomized to receive a dose of heptavalent pneumococcal conjugate vaccine (PCV7, Prevnar; Wyeth Lederle Laboratories, Pearl River, NY) approximately 7 to 10 days before stem cell collection or no vaccine before stem cell collection. Randomization of patients was stratified according to age (pediatric versus adult) and used a permuted block design. Prelicensure lots of PCV7 containing serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F individually conjugated to a nontoxic variant of diphtheria toxin (CRM 197 ) were used. After reinfusion of stem cells (transplantation), all study patients were immunized with PCV7 at 3, 6, and 12 months. Blood samples were collected at the time of each immunization and a mean of 5 weeks (range, 2-11 weeks) after the 12-month dose of vaccine (designated as the 13- month sample). For patients randomized to receive a dose of vaccine before stem cell collection, a blood sample for baseline pneumococcal antibody concentrations was collected on the day of immunization. The baseline sample was collected a mean of 10 days (range, 6 to 25 days) before stem cell collection. A second sample was obtained from these patients at the time of stem cell collection to evaluate the antibody response to the single dose of PCV7 given before stem cell collection. For the patients randomized to receive no vaccine before stem cell collection, a blood sample for baseline pneumococcal antibody concentrations was collected near the day of initial stem cell collection (mean of 2.4 days before stem cell collection; range, 18 days before to 9 days after the initial collection). The serum from these samples was stored at 80 C until assay. Laboratory assays were performed on coded samples by personnel blinded to a patient s immunization group assignment. Adverse Event Monitoring All study patients completed standardized vaccination report cards at 24, 48, and 72 hours after each immunization. Local injection site reactions of redness, swelling, and arm tenderness were scored as mild, moderate, or severe according to the size of the reaction and restriction of arm movement. Systemic reactions that were monitored consisted of fever, headache, malaise, joint pain, or other. Fever was defined as an oral temperature of 37.2 C. Antibody Assays Immunoglobulin (Ig)G antibodies to serotypespecific pneumococcal capsular polysaccharides were measured by a C-polysaccharide (CPS)-absorbed enzyme-linked immunosorbent assay [21]. IgG antibody concentrations were measured for the 7 vaccine serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), with a lower limit of detection of 10 ng/ml for each serotype. The reference standard of the assay was US standard reference serum lot 89-SF from the Center for Biological Evaluation and Review (Food and Drug Administration, Bethesda, MD). Statistical Analysis Antibody results were log-transformed for statistical analyses. The primary outcome of the study was a comparison of the serotype-specific antibody concentrations of patients immunized before stem cell collection with those of patients not immunized before stem cell collection after receipt of 3 doses of PCV7 after transplantation. Comparisons of geometric mean antibody concentrations were also performed at 3, 6, and 12 months after HCT between the 2 immunization groups. Antibody concentrations below the limit of assay quantitation were assigned values of one half the lower limit. Comparisons of geometric mean antibody concentrations between immunization groups were performed by 2-tailed t tests. The proportion of patients in each immunization group with protective concentrations of antibody (defined as a concentration 0.35 g/ml to all 7 vaccine sero- 214

3 Pneumococcal Conjugate Immunization in Autologous HCT types) was compared by Fisher exact test. Assessment of the effect of immunization group, sex, age at transplantation, underlying diagnosis, source of stem cells, baseline pneumococcal antibody concentrations, conditioning regimen, total body irradiation, and ex vivo manipulation on posttransplantation serotype-specific antibody concentrations was determined by multivariate stepwise linear regression analyses. RESULTS Patient Population Sixty-one patients were enrolled in the study, of whom 45 were evaluable after transplantation. Evaluable patients were defined as those who had survived disease free to at least 3 months after transplantation. Of the 16 patients excluded from analysis, 11 were randomized to the group unimmunized before stem cell collection and never received study vaccine. Of these 11 patients, 4 died from disease or complications of transplantation before 3 months, 4 relapsed before 3 months, 1 patient had the type of transplantation changed after study enrollment, 1 patient had persistent thrombocytopenia and could not receive 3-month immunizations, and 1 patient moved away and withdrew from the study. Five patients in the group immunized before stem collection were excluded from analysis: 2 patients had their transplantation postponed, 1 patient was subsequently enrolled on another protocol and withdrew from participation, 1 patient missed 3-month immunizations, and 1 patient was removed for the protocol violation of having received pneumococcal vaccine 2 years before stem cell collection. Of the 45 evaluable patients, clinical characteristics were similar between the 2 immunization groups, as shown in Table 1. Most patients mobilized for peripheral blood stem cell (PBSC) collection received high-dose cyclophosphamide followed by granulocyte colony-stimulating factor (G-CSF). There were no significant differences between groups in terms of age at time of transplantation, sex, underlying diagnosis, source of stem cell infusion at transplantation, conditioning regimen, receipt of total body irradiation, or ex vivo manipulation. Antibody Responses of Patients Immunized with Pneumococcal Conjugate Vaccine before Stem Cell Collection Twenty-five of the 45 eligible patients had been randomized to receive a single dose of PCV7 before stem cell collection. Immunization was given a mean of 9.3 days (range, 6-17 days) before the start of stem cell collection. Twenty-two of the 25 patients immunized before stem cell collection had serum samples both from before immunization (baseline) and from the time of stem cell collection. Fold increases in BB&MT Table 1. Characteristics of Autologous Stem Cell Transplantation Study Patients Characteristic Immunized before Stem Cell Collection (n 25) Group Not Immunized before Stem Cell Collection (n 20) Median age, y (range) 44 (4-69) 46 (13-69) Male/female 14/11 10/10 Diagnosis, n (%) NHL 19 (76) 11 (55) HD 4 (16) 4 (20) CLL 1 (4) 2 (10) AML 0 (0) 2 (10) ALL 1 (4) 1 (5) Source of stem cell infusion (n) PBSCs 8 5 Bone marrow PBSCs and bone marrow 6 5 Conditioning regimen, n (%) CTX 10 (40) 9 (45) CTX/VP-16 1 (4) 1 (5) CTX/BCNU/VP-16 13* (52) 8 (40) CTX/busulfan 0 (0) 2 (10) CTX/thiotepa/ carboplatin 1 (4) 0 (0) Total body irradiation, n (%) 11 (44) 10 (50) Ex vivo manipulation, n (%) CALLA 1 (4) 1 (5) B1B5J5 BRC 10 (40) 9 (45) Subjects evaluable at Study time points (n) 3mo mo mo mo NHL indicates non-hodgkin lymphoma; HD, Hodgkin disease; CLL, chronic lymphatic leukemia; AML, acute myelogenous leukemia; ALL, acute lymphatic leukemia; PBSCs, peripheral blood stem cells; CTX, cyclophosphamide; BCNU, carmustine; CALLA, common acute lymphoblastic leukemia antigen; VP- 16, etoposide; B1B5J5 BRC, monoclonal antibody treatment of stem cells with anti-b1 (CD20), anti-b5 and J5 (anti-cd10) plus baby rabbit complement. *Two patients in the group immunized before stem cell collection were also conditioned with dexamethasone/ifosfamide/carboplatin/vp-16. Five patients had a relapse of underlying malignancy, and 1 patient had refractory thrombocytopenia. One patient had a relapse of underlying malignancy. One patient had a relapse of underlying malignancy. Two patients had a relapse of underlying malignancy, and 1 patient had a protocol violation. One patient did not return for the final blood draw. geometric mean antibody concentrations ranged from 0.77 for serotype 19F to 1.8 for serotype 14. After immunization, geometric mean antibody concentrations were higher for all serotypes except for serotype 215

4 J. H. Antin et al. Figure 1. Effect of immunization with heptavalent pneumococcal conjugate vaccine (PCV7) before stem cell collection on antibody responses to PCV7 administered after autohct. Geometric mean IgG antibody concentrations to the serotypes of PCV7 of patients immunized with PCV7 before stem cell collection ( ) were compared with those of patients not immunized before stem cell collection (- - -). As indicated by the arrowheads, all study patients received PCV7 3, 6, and 12 months after autohct. *Geometric mean antibody concentrations were significantly higher for the group immunized before stem cell collection compared with those not immunized before stem cell collection (P.05; t test). 19F, which declined from 3.30 to 3.06 g/ml (P.023 by paired t test). The increases for the other 6 serotypes were not statistically significant, with geometric mean antibody concentrations of 0.86 g/ml for serotype 4, 2.43 g/ml for serotype 6B, 0.99 g/ml for serotype 9V, 3.23 g/ml for serotype 14, 1.16 g/ml for serotype 18C, and 2.29 g/ml for serotype 23F at the time of stem cell collection. Antibody Responses to Pneumococcal Conjugate Vaccine Administered after Stem Cell Transplantation by Immunization Group The primary outcome of the study was a comparison of antibody concentrations between the immunization groups after receipt of PCV7 vaccine at 3, 6, and 12 months after autohct. Patients who were immunized with PCV7 before stem cell collection had consistently higher pneumococcal antibody concentrations to vaccine serotypes after HCT compared with patients not immunized before stem cells were collected (Figure 1). At 13 months, after receipt of 3 doses of PCV7 at 3, 6, and 12 months after HCT, geometric mean IgG pneumococcal antibody concentrations were higher in patients immunized before stem cell collection compared with those immunized after transplantation only, and this reached significance for serotypes 18C, 19F, and 23F. Significant differences in serotype-specific pneumococcal IgG antibody concentrations between the immunization groups were also seen earlier after HCT after receipt of 1 and 2 doses of PCV7. Geometric mean antibody concentrations in patients immunized before stem cell collection were significantly higher for 6 of the 7 vaccine serotypes at 6 months and for 4 of the 7 serotypes at 12 months after HCT (Table 2). Of note, geometric mean IgG pneumococcal antibody concentrations at 3 months before administration of posttransplantation doses of pneumococcal conjugate vaccine were significantly higher for all vaccine serotypes except serotype 9V in patients immunized before stem 216

5 Pneumococcal Conjugate Immunization in Autologous HCT Table 2. Comparison of Serotype-Specific Pneumococcal Antibody Concentrations* after Immunization with Pneumococcal Conjugate Vaccine (PCV7) after AutoHCT between Patients Immunized before Stem Cell Collection with PCV7 and Patients Not Immunized before Stem Cell Collection Months after Transplantation Serotype Group Unimmunized 0.35 ( ) 0.25 ( ) 0.44 ( ) 1.06 ( ) Immunized 0.87 ( ) 0.89 ( ) 1.39 ( ) 2.85 ( ) P value B Unimmunized 1.12 ( ) 0.57 ( ) 2.10 ( ) 2.36 ( ) Immunized 3.74 ( ) 2.80 ( ) 1.75 ( ) 8.09 ( ) P value V Unimmunized 0.51 ( ) 0.42 ( ) 0.83 ( ) 1.08 ( ) Immunized 1.12 ( ) 1.29 ( ) 1.75 ( ) 2.77 ( ) P value Unimmunized 1.74 ( ) 1.61 ( ) 1.76 ( ) 3.35 ( ) Immunized 5.39 ( ) 4.54 ( ) 4.05 ( ) 6.54 ( ) P value C Unimmunized 0.50 ( ) 0.43 ( ) 0.57 ( ) 0.81 ( ) Immunized 1.84 ( ) 2.04 ( ) 2.09 ( ) 3.27 ( ) P value F Unimmunized 1.36 ( ) 1.04 ( ) 1.15 ( ) 2.16 ( ) Immunized 2.89 ( ) 2.76 ( ) 3.66 ( ) 7.61 ( ) P value F Unimmunized 0.59 ( ) 0.59 ( ) 0.83 ( ) 1.23 ( ) Immunized 2.70 ( ) 3.04 ( ) 3.44 ( ) 6.66 ( ) P value < *Data are geometric mean antibody concentrations ( g/ml) (95% confidence interval). Patients in both immunization groups were immunized with PCV7 at 3, 6, and 12 months after autohct. Serum samples for antibody measurement were collected at the time of each immunization and a mean of 5 weeks after the 12-month dose. cell collection. Geometric mean IgG pneumococcal antibody concentrations at 3 months ranged from 0.87 g/ml (serotype 4) to 5.39 g/ml (serotype 14) in the group that was immunized before stem cell collection, compared with 0.35 g/ml (serotype 4) to 1.74 g/ml (serotype 14) for the group that was not immunized before stem cell collection (Table 2). The proportion of patients in each immunization group with protective IgG concentrations to all 7 vaccine serotypes was also compared at 3, 6, 12, and 13 months after transplantation. An IgG serotype specific antibody concentration of 0.35 g/ml is a calculated threshold concentration considered protective on the basis of analyses of recent clinical trials [22,23]. As shown in Table 3, the proportion of patients with protective concentrations to all 7 vaccine serotypes was higher at each of the measured time points in patients immunized before stem cell collection; this reached significance at 6 months after transplantation (68% versus 32%; P.03). Regardless of preharvest immunization, 60% of patients who received 3 doses of PCV7 after autohct had protective concentrations at 13 months. Factors Affecting Pneumococcal Antibody Concentrations after Transplantation To determine whether other clinical factors affected pneumococcal antibody concentrations after autohct, multiple stepwise linear regression analyses were performed. The effects of immunization before stem cell collection, age at transplantation, sex, diagnosis, baseline pneumococcal antibody concentrations, source of stem cell infusion (PBSCs or bone marrow), receipt of total body irradiation, type of conditioning before transplantation, and ex vivo stem cell manipulation on serotype-specific antibody concentrations at 3, 6, 12, and 13 months were determined. In the stepwise selection process, only variables with a significance level.05 were allowed to enter into the model, and variables were removed if Table 3. Comparison of the Percentage of Patients Protected to All 7 Vaccine Serotypes* after AutoHCT Months after AutoHCT No. Vaccine Doses Received after AutoHCT Immunized before Stem Cell Collection, % (n) Not Immunized before Stem Cell Collection, % (n) P Value (15/25) 40 (8/20) (13/19) 32 (6/19) (11/17) 47 (9/19) (13/15) 61 (11/18).13 *IgG concentration 0.35 g/ml to serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. Serum not available on 1 patient. BB&MT 217

6 J. H. Antin et al. Table 4. Final Multivariate Stepwise Regression Analyses* for Serotype-Specific Pneumococcal Antibody Concentrations Measured after AutoHCT Serotype Variable 3 mo 6 mo 12 mo 13 mo 4 Baseline 1.85 ( ) 1.91 ( ) 2.11 ( ) 1.83 ( ) Group 1.53 ( ) 2.19 ( ) 6B Baseline 1.75 ( ) 1.85 ( ) 1.72 ( ) Group 1.96 ( ) 2.81 ( ) Age Tx 0.96 ( ) CTX only 0.36 ( ) 9V Baseline 1.79 ( ) 1.80 ( ) 1.83 ( ) 1.74 ( ) CTBCVP 2.21 ( ) 14 Baseline 1.92 ( ) 2.37 ( ) 1.82 ( ) 1.43 ( ) Group 2.87 ( ) 2.92 ( ) 2.35 ( ) PBSC 2.88 ( ) 18C Baseline 1.84 ( ) 1.80 ( ) 1.78 ( ) 1.45 ( ) Group 2.00 ( ) 2.70 ( ) 2.15 ( ) 2.91 ( ) 19F Baseline 1.86 ( ) 2.36 ( ) 2.12 ( ) 2.05 ( ) Alt cond 2.32 ( ) 2.91 ( ) Age Tx 0.97 ( ) 0.97 ( ) 0.95 ( ) 23F Baseline 1.67 ( ) 1.89 ( ) 2.05 ( ) 1.81 ( ) Group 2.32 ( ) 2.69 ( ) CTX only 0.47 ( ) Data are odds ratio (95% confidence interval). *Variables considered for entry into the model were group (0, not immunized before stem cell collection; 1, immunized before stem cell collection); baseline pneumococcal antibody concentration measured before stem cell collection (baseline); sex (male/female); age at transplantation (age Tx); type of stem cell infusion (PBSC/marrow); total body irradiation (yes/no); diagnosis (leukemia/lymphoma); and conditioning regimen (cyclophosphamide [CTX] only, CTX/carmustine/VP-16 [CTBCVP], or alternative conditioning [Alt cond], defined as all other conditioning regimens noted in Table 1). All variables in the final model had P values.05. their significance level was All patients who received total body irradiation had ex vivo manipulation of their stem cells; therefore, we chose to use total body irradiation as the variable in the regression model. Higher baseline pneumococcal antibody concentrations and being in the group immunized before stem cell collection were the 2 variables consistently independently associated with higher serotype-specific pneumococcal antibody concentrations after autohct (Table 4). For all 7 serotypes, higher baseline antibody concentrations measured before stem cell collection were significantly associated with posttransplantation concentrations at all measured time points except for serotype 6B at 12 months. Being in the group immunized before stem cell collection was independently significantly associated with higher pneumococcal antibody concentrations for serotypes 4, 6B, 14, 18C, and 23F at 3 months; serotypes 4, 6B, 14, 18C, and 23F at 6 months; serotypes 14 and 18C at 12 months; and serotype 18 at 13 months (Table 4). No other variable was consistently independently associated with higher pneumococcal antibody concentrations for multiple serotypes after autohct. Given the significant association of baseline pneumococcal antibody concentrations with posttransplantation concentrations, we compared the baseline concentrations between the 2 immunization groups. Baseline geometric mean IgG pneumococcal antibody concentrations of patients immunized before stem cell collection were significantly higher compared with those from patients in the group not immunized before stem cell collection for serotypes 4 (0.59 versus 0.26 g/ml; P.049), 6B (1.55 versus 0.60 g/ml; P.046), 9V (0.85 versus 0.31 g/ml; P.028), 18C (1.37 versus 0.50 g/ml; P.020), 19F (3.30 versus 0.93 g/ml; P.009), and 23F (1.43 versus 0.41 g/ml; P.009). Baseline geometric mean IgG concentrations for serotype 14 were not significantly different between the 2 immunization groups (1.40 versus 1.25 g/ml; P.80). This difference in baseline pneumococcal antibody concentrations between the 2 immunization groups was unexpected, although the study protocol did not specify that the samples for baseline pneumococcal antibody concentrations from the 2 groups should be obtained on the same day before stem cell collection. The mean SD time interval of serum sample collection for baseline pneumococcal antibody concentrations relative to the date of stem cell collection was days for the group immunized before stem cell collection and was days in the group not immunized before stem cell collection, and this interval difference was significant between groups (P.0001). Therefore, univariate linear regression analyses were performed to examine the effect of immunization group assignment, the interval of time between the baseline sample collection date and the date of stem cell collection, age, sex, and diagnosis on baseline serotype-specific pneumococcal antibody concentrations. Being randomized to the group immunized before stem cell collection and having an increased interval between the time of baseline serum sample 218

7 Pneumococcal Conjugate Immunization in Autologous HCT collection and the date of stem cell collection were significantly associated with higher baseline antibody concentrations for 6 of 7 and all 7 serotypes, respectively. However, after controlling for the timing of baseline sample collection in a multivariate linear regression analysis, the immunization group variable was no longer statistically significantly associated with higher baseline pneumococcal antibody concentrations. Safety and Tolerability of Pneumococcal Conjugate Vaccine The heptavalent pneumococcal conjugate vaccine was well tolerated in patients both before stem cell collection and after autohct. Of the 35 study patients who had completed vaccine report cards at 3, 6, and 12 months, 28 (80%) reported a reaction at the 3-month immunization. Eighteen (64%) of these 28 reported reactions at 6 and 12 months, and 10 (36%) reported a reaction at 6 or 12 months. The reactions reported were often similar to the 3 month reaction in type and degree of severity. Seven patients (20%) had no reaction to the 3-month immunization; 3 of the 7 reported no reactions after receipt of the 6- and 12- month doses of vaccine, whereas 4 had a reaction at either 6 or 12 months. There was no trend for reactions to increase in severity with an increasing number of doses. The most frequent local adverse event reported within 72 hours of immunization was pain in the arm that received vaccine injections. Forty-three percent of patients immunized before stem cell collection reported pain, as did 68%, 64%, and 69% of all study patients at 3, 6, and 12 months, respectively, after autohct. Severe pain restricting arm movement was reported by 7% to 13% after each immunization. Redness and swelling at the injection site was reported by 10% to 40% of patients after each immunization and did not increase in frequency with an increasing number of doses. Fever was reported by 30% of patients after each injection; all temperatures recorded except 1 were F. One patient reported a temperature of F at 72 hours after his 3-month immunization, with concurrent symptoms of chills, malaise, joint pain, and cough. He was evaluated and placed on antibiotics for his respiratory symptoms, and he subsequently recovered. Other systemic complaints such as headache, malaise, joint pain, and muscle aches were reported by approximately 25% of patients after each immunization. No serious adverse event related to immunization was reported. DISCUSSION Infections with polysaccharide-encapsulated bacteria such as S pneumoniae are not uncommon after BB&MT hematopoietic stem cell transplantation, even though the risk after autohct seems to be less than the risk after allogeneic HCT. A recent prospective survey assessed the incidence of invasive pneumococcal infection after autologous BMT and PBSC transplantation to be transplantations, compared with transplantations after allogeneic BMT and PBSC transplantation [2]. These rates of invasive disease support measures to prevent pneumococcal infections after HCT. Until recently, unconjugated pneumococcal polysaccharide vaccines were the only vaccines available for recommended use in HCT patients, even though responses to these vaccines are impaired in most patients. Data from a recent study conducted in non T-cell depleted allogeneic BMT patients demonstrated that a pneumococcal conjugate vaccine was immunogenic in this high-risk group: most patients achieved protective concentrations after a 3-dose series [21]. In addition, immunization of healthy donors with pneumococcal conjugate vaccine before bone marrow harvest significantly enhanced recipients antibody responses to posttransplantation doses of vaccine. Thus, in this study, we examined the effect of immunization with a pneumococcal conjugate vaccine before stem cell collection on patients ability to respond to pneumococcal conjugate vaccine administered at 3, 6, and 12 months after autohct. Pneumococcal antibody concentrations produced after 1, 2, and 3 posttransplantation doses of PCV7 were compared between patients immunized before stem cell collection and patients not immunized before stem cell collection. Patients who received pneumococcal conjugate vaccine before stem cell collection had significantly higher antibody concentrations to 6 of the 7 vaccine serotypes at 3 and 6 months after autohct compared with patients who received vaccine after transplantation only beginning at 3 months. After the third dose of PCV7 at 12 months, IgG geometric mean antibody concentrations were still significantly higher for serotypes 18C, 19F, and 23F in the group immunized before stem cell collection. The proportion of patients with a protective antibody concentration to all vaccine serotypes was also higher in the group immunized before stem cell collection; 60% to 87% of patients were protected between 3 and 13 months after transplantation. In contrast, protective concentrations to all 7 serotypes were not achieved in most patients immunized after transplantation only until 13 months, after completion of the 3-dose series. These results suggest that immunization before stem cell collection benefits patients in the early months after autohct. These findings confirm results seen in a previous study conducted in autobmt patients [24]. In that small, nonrandomized study of similar design, significantly higher antibody concentrations were seen after autohct to HIB-conjugate vaccine at 3 months and 219

8 J. H. Antin et al. to tetanus toxoid vaccine at 3 and 6 months in patients immunized with these vaccines before bone marrow harvest compared with patients who were not immunized before harvest. These data suggest that a strategy to immunize autologous stem cell donors before stem cell collection with PCV7 followed by additional doses of pneumococcal conjugate vaccine after transplantation should be considered. For both autologous and allogeneic stem cell transplantation patients, an approach to immunize with multiple doses of pneumococcal conjugate vaccine is likely to produce more consistent antigen-specific antibody responses by expanding the number of carrier-specific T-helper cells, which in turn enhance the production of antibody from polysaccharide-specific B cells [25]. The ability of multiple doses of PCV7 to prime for increased antibody responses and reduce invasive pneumococcal disease has been demonstrated in infants, a population whose immature immune system also places them at high risk for pneumococcal disease [18]. Our findings also expand the immunization literature on patients who receive autologous PBSC transplants (autopbsct). At least half of the enrolled patients underwent PBSC transplantation with or without BMT. Transplantation with PBSC results in more rapid reconstitution of hematopoiesis compared with BMT [26,27]. Functional immune recovery may also be enhanced in recipients of autopbsct compared with autobmt, although findings from previous studies have not shown this consistently. In 1 prior study, vaccine-specific antibody concentrations were shown to be higher in autopbsct patients compared with autobmt patients after receipt of multiple doses of HIB-conjugate and tetanus toxoid vaccines within the first 2 years after transplantation [28]. In contrast, a study that compared influenza, pneumococcal, and tetanus toxoid antibody responses after a single dose of each vaccine found no significant differences between autopbsct patients and autologous BMT patients [29]. The difference in the findings from these studies could be related to the timing of immunization and the number of vaccine doses administered after transplantation, because these factors have been shown to affect antibody responses [30,31]. Therefore, we speculate that the ability to detect significant differences in pneumococcal antibody concentrations between the 2 immunization groups within the first year after transplantation may be partly related to enhanced recovery of humoral immunity after auto- PBSCT compared with autologous BMT. Clinical factors associated with higher pneumococcal antibody concentrations to vaccine serotypes after transplantation included being in the group immunized before stem cell collection and having higher baseline pneumococcal antibody concentrations. The significant differences in baseline serotype-specific antibody concentrations between patients immunized 7 to 10 days before stem cell collection compared with patients not immunized before stem cell collection were not expected, because the groups were randomized. The most likely explanation for this finding is the significant interval difference between the groups in the timing of the baseline sample collection relative to the date of stem cell collection. The mean interval difference between the groups was 7.6 days; patients in the group not immunized before stem cell collection had their baseline sample drawn closer to the date of stem cell collection. Linear regression analyses, stratified by immunization group, of baseline antibody concentrations relative to the time of their collection before stem cell harvest showed a decline in antibody concentrations for both groups as the date of stem cell collection approached. The reason for the decline in antibody concentrations when measured close to or at the time of stem cell collection is not clear. Possible explanations may be the effect of prior chemotherapy used to treat underlying disease on antibody concentrations over time or the effect of mobilization techniques before stem cell collection. Most patients who underwent PBSC collection were mobilized with cyclophosphamide followed by G-CSF before stem cell collection. G-CSF has been shown to have immunomodulatory effects on cytokine secretion and to affect immune responses [32,33]. Despite the limitation in our study design of obtaining baseline serum samples for the 2 immunization groups at different times before stem cell collection, the variable of being in the group immunized before stem cell collection was independently associated with higher pneumococcal antibody concentrations after transplantation, particularly at 3 and 6 months. In summary, findings from this study support a positive effect of immunization before stem cell collection on antigen-specific antibody responses elicited with posttransplantation immunization. These results also demonstrate that autohct patients can tolerate and respond to multiple doses of vaccine given within the first year after transplantation. An approach to immunize autohct patients before stem cell collection and/or within a year of transplantation may be useful for other infectious diseases or tumor vaccine strategies. A significant reduction in the occurrence of herpes zoster within 12 months after transplantation was seen in auto- HCT patients immunized with an inactivated varicella vaccine within 30 days of HCT regardless of apheresis followed by additional doses of vaccine at 30, 60, and 90 days after HCT [34]. Investigations of early immunization after stem cell reinfusion with autologous dendritic cells pulsed with tumorspecific antigens or tumor proteins conjugated to an adjuvant are ongoing, and findings from initial studies are promising [35,36]. Our data suggest that a more immunogenic strategy to prevent pneumococ- 220

9 Pneumococcal Conjugate Immunization in Autologous HCT cal disease after autohct includes immunization with pneumococcal conjugate vaccine beginning at 3 months after transplantation and that immunization before stem cell collection should be considered. Future studies will need to address the utility and timing of subsequent immunization with 23- valent pneumococcal polysaccharide vaccine to expand serotype coverage. ACKNOWLEDGMENTS Supported in part by Wyeth Lederle Vaccines. REFERENCES 1. Kulkarni S, Powles R, Treleaven J, et al. Chronic graft versus host disease is associated with long-term risk for pneumococcal infections in recipients of bone marrow transplants. Blood. 2000; 95: Engelhard D, Cordonnier C, Shaw PJ, et al. Early and late invasive pneumococcal infection following stem cell transplantation: a European Bone Marrow Transplantation survey. Br J Haematol. 2002;117: Sable CA, Donowitz GR. Infections in bone marrow transplant recipients. Clin Infect Dis. 1994;18: Hoyle C, Goldman JM. Life-threatening infections occurring more than 3 months after BMT. Bone Marrow Transplant. 1994; 14: Lum LG. The kinetics of immune reconstitution after human marrow transplantation. Blood. 1987;69: Kiesel S, Pezzutto A, Moldenhauer G, et al. B-cell proliferative and differentiative responses after autologous peripheral blood stem cell or bone marrow transplantation. Blood. 1988;72: Miller RA, Daley J, Ghalie R, Kaizer H. Clonal analysis of T-cell deficiencies in autotransplant recipients. Blood. 1991;77: Hammarstrom V, Pauksen K, Bjorkstrand B, Simonsson B, Oberg G, Ljungman P. Tetanus immunity in autologous bone marrow and blood stem cell transplant recipients. Bone Marrow Transplant. 1998;22: Centers for Disease Control and Prevention. Guidelines for preventing opportunistic infections among hematopoietic stem cell transplant recipients: recommendations of CDC, the Infectious Diseases Society of America, and the American Society of Blood and Marrow Transplantation. MMWR Recomm Rep. 2000;49(RR-10):9-10, Winston DJ, Ho WG, Schiffman G, Champlin RE, Feig SA, Gale RP. Pneumococcal vaccination of recipients of bone marrow transplants. Arch Intern Med. 1983;143: Guinan EC, Molrine DC, Antin JH, et al. Polysaccharide conjugate vaccine responses in bone marrow transplant patients. Transplantation. 1994;57: Avanzini MA, Carra AM, Maccario R, et al. Antibody response to pneumococcal vaccine in children receiving bone marrow transplantation. J Clin Immunol. 1995;15: Spoulou V, Victoratos P, Ioannidis J, Grafakos S. Kinetics of antibody concentration and avidity for the assessment of immune response to pneumococcal vaccine among children with bone marrow transplants. J Infect Dis. 2000;182: Insel RA, Anderson PW. Oligosaccharide-protein conjugate vaccines induce and prime for oligoclonal IgG antibody responses to the Haemophilus influenzae b capsular polysaccharide in human infants. J Exp Med. 1986;163: Eskola J. Immunogenicity of pneumococcal conjugate vaccines. Pediatr Infect Dis J. 2000;19: Black SB, Shinefield HR, Fireman B, et al. Efficacy in infancy of oligosaccharide conjugate Haemophilus influenzae type b (HbOC) vaccine in a United States population of children. Pediatr Infect Dis J. 1991;10: Santosham M, Wolfe M, Reid R, et al. The efficacy in Navajo infants of a conjugate vaccine consisting of Haemophilus influenzae type b polysaccharide and Neisseria meningitidis outer-membrane protein complex. N Engl J Med. 1991;324: Black S, Shinefield H, Fireman B, et al. Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Pediatr Infect Dis J. 2000;19: Molrine DC, Guinan EC, Antin JH, et al. Donor immunization with Haemophilus influenzae type b (HIB)-conjugate vaccine in allogeneic bone marrow transplantation. Blood. 1996;87: Barra A, Cordonnier C, Preziosi MP, et al. Immunogenicity of Haemophilus influenzae type b conjugate vaccine in allogeneic bone marrow recipients. J Infect Dis. 1992;166: Molrine DC, Antin JH, Guinan EC, et al. Donor immunization with pneumococcal conjugate vaccine and early protective antibody responses following allogeneic hematopoietic cell transplantation. Blood. 2003;101: Jodar L, Butler J, Carlone G, et al. Serological criteria for evaluation and licensure of new pneumococcal conjugate formulations for use in infants. Vaccine. 2003;21: Consultative meeting on WHO guidelines for production and quality control of pneumococcal conjugate vaccines, Geneva, 2003, June 4-5. Available: Pneumococcal_Conjugate_Vaccines_Recomm_Nov_2003.pdf. 24. Molrine DC, Guinan EC, Antin JH, et al. Haemophilus influenzae type b (HIB)-conjugate immunization before bone marrow harvest in autologous bone marrow transplantation. Bone Marrow Transplant. 1996;17: Siber GR. Pneumococcal disease: prospects for a new generation of vaccines. Science. 1994;265: Henon PH, Liang H, Beck-Wirth G, et al. Comparison of hematopoietic and immune recovery after autologous bone marrow or blood stem cell transplants. Bone Marrow Transplant. 1992;9: To LB, Roberts MM, Haylock DN, et al. Comparison of hematological recovery times and supportive care requirements of autologous recovery phase peripheral blood stem cell transplant, autologous bone marrow transplant and allogeneic home marrow transplants. Bone Marrow Transplant. 1992;9: Chan CY, Molrine DC, Antin JH, et al. Antibody responses to tetanus toxoid and Haemophilus influenzae type b conjugate vaccines following autologous peripheral blood stem cell transplantation (PBSCT). Bone Marrow Transplant. 1997;20: Gandhi MK, Egner W, Sizer L, et al. Antibody responses to vaccinations given within the first two years after transplant are similar between autologous peripheral blood stem cell and bone marrow transplant recipients. Bone Marrow Transplant. 2001;28: Nordoy T, Husebekk A, Aaberge IS, et al. Humoral immunity to viral and bacterial antigens in lymphoma patients 4-10 years BB&MT 221

10 J. H. Antin et al. after high-dose therapy with ABMT. Serological responses to revaccination according to EBMT guidelines. Bone Marrow Transplant. 2001;28: Vance E, George S, Guinan EC, et al. Comparison of multiple immunization schedules for Haemophilus influenzae type b-conjugate and tetanus toxoid vaccines following bone marrow transplantation. Bone Marrow Transplant. 1998;22: Pan L, Delmonte J, Jalonen CK, Ferrara JLM. Pretreatment of donor mice with granulocyte colony-stimulating factor polarizes donor T lymphocytes toward type-2 cytokine production and reduced severity of experimental graft-versus-host-diseases. Blood. 1995;86: Anderlini P, Przepiorka D, Champlin R, Korbling M. Biologic and clinical effects of granulocyte colony-stimulating factor in normal individuals. Blood. 1996;88: Hata A, Asanuma H, Rinki M, et al. Use of an inactivated varicella vaccine in recipients of hematopoietic-cell transplants. N Engl J Med. 2002;347: Davis TA, Hsu FJ, Caspar CB, et al. Idiotype vaccination following ABMT can stimulate specific anti-idiotype immune responses in patients with B-cell lymphoma. Biol Blood Marrow Transplant. 2001;7: Arai S, Klingemann HG. Role of immunotherapy in stem cell transplantation. Int J Hematol. 2003;77: