Monoclonal Gammopathy and Risk of Lymphoma and Multiple Myeloma in Patients With Primary Sj ogren s Syndrome

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1 ARTHRITIS & RHEUMATOLOGY Vol. 68, No. 5, May 2016, pp DOI /art VC 2016, American College of Rheumatology BRIEF REPORT Monoclonal Gammopathy and Risk of Lymphoma and Multiple Myeloma in Patients With Primary Sj ogren s Syndrome Anne-Laurence Tomi, Rakiba Belkhir, Gaetane Nocturne, Frederic Desmoulins, Elisabeth Berge, Stephan Pavy, Corinne Miceli-Richard, Xavier Mariette, and Raphaèle Seror Objective. To assess the link between monoclonal gammopathy (MG), disease activity, and incidence of malignant hematologic disorders (MHDs), including and multiple myeloma (MM), in patients with primary Sj ogren s syndrome (SS). Methods. Screening for the presence of MG was performed in 352 primary SS patients. Each patient with MG was paired with 2 age- and sex-matched primary SS controls without MG. Their characteristics were compared for the presence of risk factors for MG and for the relationship between MG and MHD. Results. Twenty-six of the 352 primary SS patients (7.4%) had MG; 88% were women, with a median age of 62.7 years (interquartile range [IQR] years) and a median disease duration of 7.8 years (IQR years). The parameters associated with MG on multivariate analysis were higher disease activity, as measured by either the European League Against Rheumatism Sj ogren s Syndrome Disease Activity Index (ESSDAI; adjusted odds ratio [OR] 9.7, P ) or the Clinical ESSDAI (adjusted OR 6.7, P ), and low C4 level (adjusted OR 3.4, P ). After a median follow-up of 6.3 years (IQR years), 10 patients with MG had developed an MHD (38.5%; 4 had s and 6 had MM), as compared with 4 patients in the control group (7.7%; all had s) (OR 7.5, P ). The only factor associated with the risk of MHDs was the presence of MG (adjusted OR 5.5, P ), which was principally Anne-Laurence Tomi, MD, Rakiba Belkhir, MD, Gaetane Nocturne, MD, Frederic Desmoulins, MD, Elisabeth Berge, MD, Stephan Pavy, MD, Corinne Miceli-Richard, MD, PhD, Xavier Mariette, MD, PhD, Raphaèle Seror, MD, PhD: Universite Paris-Sud, AP-HP, H^opitaux Universitaires Paris-Sud, INSERM U1184, and Centre Hospitalier Universitaire de Bic^etre, H^opital Bic^etre, Le Kremlin Bic^etre, France. Drs. Mariette and Seror contributed equally to this work. Address correspondence to Xavier Mariette, MD, PhD, or Raphaèle Seror, MD, PhD, Service de Rhumatologie, H^opital Bic^etre, 78 Rue du General Leclerc, Le Kremlin Bic^etre, France. xavier.mariette@bct.aphp.fr or raphaele.seror@bct.aphp.fr. Submitted for publication May 28, 2015; accepted in revised form November 24, associated with an increased risk of MM (23% versus 0%; P ), but not (15% versus 8%; P 5 0.3). Conclusion. The presence of MG was associated with higher disease activity and an increased risk of MHD in primary SS. In the presence of MG, the risk of MM was even higher than the risk of. These results suggest that regular monitoring of primary SS patients with MG for the emergence of both and MM is necessary. Primary Sj ogren s syndrome (SS) is an autoimmune epitheliitis characterized by lymphocytic infiltration of the exocrine glands, resulting in functional impairment of the salivary and lacrimal glands (1). The spectrum of disease manifestations includes sicca syndrome as well as systemic manifestations. The pathogenesis of primary SS is characterized by major B cell activation, as demonstrated by an increase in BAFF levels in the serum and in organs targeted by the disease (2). This continuous B cell activation may lead to the emergence of clonal proliferation and malignant, with an estimated 6 18-fold increased risk of in patients with primary SS (3 5). Monoclonal gammopathy (MG) of undetermined significance is a premalignant state characterized by a limited benign clonal proliferation of bone marrow plasma cells without organ-specific involvement (6). In the presence of MG of undetermined significance, the estimated annual risk of developing a malignant hematologic disorder (MHD), principally multiple myeloma (MM), is 1% (7). However, in primary SS, the presence of MG has been shown to be primarily associated with the risk of (8), particularly low-grade marginal zone localized to the mucosa (9). In the present study, our aim was to study factors associated with the presence of MG and to examine the relationship between MG and the incidence of MHDs, both non-hodgkin s and MM, in a cohort of patients with primary SS at a single study center. 1245

2 1246 TOMI ET AL PATIENTS AND METHODS Patients. Since 2000, our Rheumatology Department has organized standardized multidisciplinary sessions for outpatients with sicca symptoms or other signs suggestive of primary SS. All patients who were referred to this session gave their informed consent for collection of their data in the H^opitaux Universitaires, Paris-Sud prospective cohort. At inclusion, clinical and biologic characteristics were recorded in a standardized manner in a database. This cohort was approved by the Local Ethics Committee. From this cohort, all patients with primary SS according to the American European Consensus Group criteria (10) were monitored prospectively. All patients included before 2009 were included in the present study. We chose this time point so that the study patients would have had at least 5 years of follow-up. Clinical and biologic assessments. At inclusion in the cohort, the following clinical, biologic, and histologic features were systematically recorded: symptoms of dry eyes and mouth, objective evidence of ocular dryness (Schirmer s test showing #5 mm of wetting in 5 minutes or keratoconjunctivitis sicca with a Van Bijsterveld score of.4), objective evidence of oral dryness (unstimulated salivary flow,0.1 ml/minute), and enlargement of the parotid glands. Extraglandular complications of primary SS were defined as arthritis, myositis, Raynaud s phenomenon, purpura, lymphadenopathy, splenomegaly, pulmonary involvement, renal involvement (glomerulonephritis, interstitial nephritis), peripheral neuropathy, or involvement of the central nervous system. A medical history of MHD was also analyzed. Biologic features, such as a complete blood cell count, erythrocyte sedimentation rate, and levels of C-reactive protein, lactate dehydrogenase, and b 2 -microglobulin, were recorded. Immunologic data included antinuclear antibodies (detected by indirect immunofluorescence), anti-ro/ssa anti- La/SSB antibodies, and rheumatoid factor (RF) as determined by nephelometry. Complement components (C3 and C4) were measured by nephelometry. Serum cryoglobulins were measured after centrifugation and incubation at 48C for 7 days after collection. The histologic findings of minor salivary gland biopsies were classified according to the Chisholm and Mason classification system, and a focus score was determined (considered positive if the focus score was $1). Quantification of gamma globulin and monoclonal component levels. At inclusion into the cohort, gamma globulin and monoclonal component levels, when detectable, were measured by serum protein electrophoresis in agarose gel. Serum immunofixation was also systematically performed on agarose gel with specific antisera to IgG, IgM, IgA, and k and l chains. The technique of electrophoresis and immunofixation was the same in all patients. In patients with MG, a corrected gamma globulin level was calculated after subtraction of the monoclonal component in order to estimate the level of polyclonal gamma globulin. Selection of cases and controls. At inclusion in the cohort, all patients who had MG were defined as cases. For each case, 2 age- and sex-matched primary SS patients without MG were randomly selected from the remainder of the cohort. These patients served as controls. Assessment of disease activity. Disease activity was assessed retrospectively from information in the patient s medical record at the time of inclusion in the cohort; the European League Against Rheumatism Sj ogren s Syndrome Disease Activity Index (ESSDAI) (11) was used. Since this score includes the presence of MG and MHDs in the biologic and hematologic domains, respectively, sensitivity analyses were performed using the Clinical ESSDAI (ClinESSDAI; to avoid identifying an association with MG that was due only to its presence in the biologic domain) (12) and using the ESSDAI without rating in its calculation (to avoid overestimation of disease activity in patients with or lymphadenopathies). When information in the medical record was insufficient to distinguish 2 different levels of activity, the lower one was used. The ClinESSDAI includes all ESSDAI domains, except the biologic domain; each domain has a weight different from that of the original ESSDAI. Active disease was defined as an ESSDAI of $5. The same threshold was used for the ClinESSDAI and for the ESSDAI without. Biologic assessment of BAFF levels. Serum levels of BAFF were measured by enzyme-linked immunosorbent assay (R&D Systems) of frozen serum samples from some of the primary SS patients (15 of the 26 cases and 39 of the 52 controls). Patient outcome. The medical records of all patients were systematically retrieved to collect data on the occurrence of an MHD and its eventual histologic type. For patients no longer being monitored in our department, the general practitioners and/or rheumatologists of the cases and controls were systematically contacted to collect data on their outcomes. In case of MHD, confirmation of the diagnosis, pathology reports, and/or laboratory findings (bone marrow examination, complete blood cell count, analysis of lymphocyte subpopulations) was obtained from the hematology departments where patients have been followed up. Statistical analysis. Quantitative data are presented as the median and interquartile range (IQR) and were compared using the nonparametric Kruskal-Wallis test. Categorical variables are presented as the number and percentage and were compared using the chi-square test or Fisher s exact test when appropriate. To search for factors associated with MG, clinical and biologic characteristics were compared between the cases and the controls. The other known risk factors for MHDs (i.e., purpura, cryoglobulinemia, lymphopenia, low C4 level, and high b 2 -microglobulin level) were compared between patients with and those without MHDs. Parameters associated with MG or MHDs in univariate analyses (P # 0.10) were entered into a multivariate logistic regression to identify independent factors for MG or MHD, respectively. For all analyses, SAS statistical software (release 9.3; SAS Institute) was used. P values less than 0.05 were considered significant. RESULTS Identification of primary SS cases and controls. Between 2000 and 2009, 352 patients with primary SS according to the American European Consensus Group criteria were recruited in the Paris-Sud cohort. Among them, 26 (7.4%) had MG detected by immunofixation at inclusion and were selected as cases for the present study.

3 MONOCLONAL GAMMOPATHY AND HEMATOLOGIC MALIGNANCY/DISORDER RISK IN PRIMARY SS 1247 Table 1. of MG* Characteristics of the 78 primary SS patients according to the presence of MG and baseline parameters associated with the presence Primary SS patients P Baseline characteristic With MG (n 5 26) Without MG (n 5 52) Univariate analysis Multivariate analysis Clinical features Female 23 (88) 46 (88) 0.29 Age at screening, median (IQR) years 62.7 ( ) 64.8 ( ) 0.50 Disease duration, median (IQR) years 7.8 ( ) 6.1 ( ) 0.74 Duration of follow-up, median (IQR) years 6.3 ( ) 6.3 ( ) 0.62 Sialadenitis (focus score $1) 23 (88) 44 (85) 0.25 Parotidomegaly, no. (%) 10 (38) 14 (27) 0.12 Lymphadenopathy, no. (%) 2 (8) 1 (2) 0.22 Splenomegaly, no. (%) 2 (8) 0 (0) 0.11 Purpura, no. (%) 5 (19) 4 (8) 0.1 Biologic features Hemoglobin, median (IQR) gm/dl 13.3 ( ) 13.3 ( ) 0.65 Neutrophils, median (IQR)/mm 3 4,120 (2,790 5,290) 3,400 (2,550 4,420) 0.28 Lymphocytes, median (IQR)/mm 3 1,310 (1,050 1,880) 1,540 (1,210 1,770) 0.35 ESR, median (IQR) mm/hour 28 (10 46) 20 (10 28) 0.09 C-reactive protein, median (IQR) mg/liter 5.0 ( ) 5.0 ( ) 0.25 Gamma globulin, median (IQR) gm/liter 12.4 ( ) 10.8 ( ) 0.04 Corrected gamma globulin, median (IQR) gm/liter 11.1 ( ) 10.8 ( ) 0.27 b 2 -microglobulin, median (IQR) mg/liter 2.17 ( ) 1.77 ( ) 0.12 Low C3 9 (34.6) 12 (23.1) 0.28 Low C4 15 (57.7) 11 (21.2) Cryoglobulins, no. (%) 5 (19) 0 (0) Anti-SSA, no. (%) 18 (69) 37 (71) 0.86 Anti-SSB, no. (%) 5 (19) 20 (38) 0.09 NS Rheumatoid factor, no. (%) 15 (58) 29 (56) 0.87 BAFF, median (IQR) pg/ml 703 (444 1,340) 1,018 (821 1,348) 0.11 Disease activity ESSDAI, median (IQR) 7 (3 10) 2 (0 4), ESSDAI without, median (IQR) 5.5 (3 8) 2 (0 4), ESSDAI $5 without 19 (73.1) 12 (23.1), ClinESSDAI, median (IQR) 6.5 (3 10) 2 (0 4.5), * The multivariate analysis included a low C4 level, the European League Against Rheumatism Sj ogren s Syndrome Disease Activity Index (ESSDAI), and anti-ssb antibodies. P values less than 0.05 were considered significant. SS 5 Sj ogren s syndrome; MG 5 monoclonal gammopathy; IQR 5 interquartile range; ESR 5 erythrocyte sedimentation rate; NS 5 not significant; ClinESSDAI 5 Clinical ESSDAI. Of the 26 patients with MG, 23 (88%) were women (Table 1). Their median age at screening was 62.7 years (IQR years) and median disease duration was 7.8 years (IQR years). The median ESSDAI score at inclusion was 7 (IQR 3 10). The MG isotypes in the 26 patients were as follows: IgGk in 8 patients (31%), IgGl in 6 (23%), IgMk in 4 (15%), IgMl in 3 (12%), IgAk in 1 (4%), and biclonal gammopathy in 4 (15%). Factors associated with the presence of MG. In the 26 patients with MG (compared with the 52 matched controls) cryoglobulinemia (P ), low C4 levels (P ), the ESSDAI and ClinESSDAI scores (P, ), and high gamma globulin levels (P ), but not the corrected gamma globulin, were significantly associated with the presence of MG in univariate analysis (Table 1). The multivariate model showed significant differences between these 2 groups for low C4, anti-ssb antibodies, and the ESSDAI, but not cryoglobulinemia, since all patients with mixed cryoglobulinemia also had a MG. In multivariate analysis, only a low C4 level (adjusted OR 3.4 [95% confidence interval (95% CI) ], P ) and an ESSDAI score of $5 (adjusted OR 9.7 [95% CI ] for an ESSDAI score $5 versusanessdaiscore,5, P ) were retained as being associated with the presence of MG. Sensitivity analyses revealed similar results using the ClinESSDAI (adjusted OR 6.7 [95% CI ], P ) or the ESSDAI $5 without (adjusted OR 9.9 [95% CI ], P ). Association of MG with the risk of an MHD. The median follow-up duration did not differ between patients with MG and controls (6.3 years [IQR years] versus 6.3 years [IQR years]; P ). During the follow-up period, 10 patients in the MG group (38.5%) had an MHD (Table 2). Four of them had a (mantle cell in 1, marginal zone in 1, lymphocytic in 1, and mucosa-associated lymphoid tissue (MALT) with hepatic localization in 1) and 6 had MM (stage III in 4 and stage I in 2). At screening, the MHD

4 1248 TOMI ET AL Table 2. Sex/age at inclusion, years Characteristics of Sj ogren s syndrome patients with MG who developed an MHD* Disease duration at inclusion, years Time from MG detection to MHD Systemic signs at inclusion Immunologic biomarker F/ years after Cough RF, Cryos, b 2 m F/66 14 Concomitant Myalgia, urticaria F/ years before Parotid gland inclusion swelling, RP, b 2 m urticaria M/44 1 Concomitant Parotid gland swelling, splenomegaly, purpura F/ years after Myalgia, cough RF, Cryos, F/ years after Cough F/61 0 Concomitant Parotid gland swelling, bronchiectasis, purpura F/ years after None RF, Cryos, b 2 m F/ years before inclusion M/ year before inclusion Parotid gland swelling Parotid gland swelling, cough RF1, Cryos1, b 2 m Ig isotype Hematologic neoplasia MHD diagnostic elements IgGk MM stage III MG level increase; bone lesions IgGl MM stage I 35% BM plasma cells IgMl Mantle cell Lymphadenopathy IgGk Hepatic MALT Hepatomegaly IgAk MM stage III MG level increase; cytopenia; 21% BM plasma cells IgGl MM stage III MG level increase; cytopenia; 27% BM plasma cells IgGk MM stage III 15% BM plasma cells IgGl MM stage I MG level increase; 12% BM plasma cells IgMk Marginal zone IgGk and IgMk Lymphocytic Lymphocytosis *MG5 monoclonal gammopathy; MHD 5 malignant hematologic disorder; RF 5 rheumatoid factor; Cryos 5 cryoglobulins; b 2 m 5 b 2 -microglobulin; MM 5 multiple myeloma; BM 5 bone marrow; RP 5 Raynaud s phenomenon; MALT 5 mucosa-associated lymphoid tissue. in 6 of these 10 patients had already been diagnosed (the 4 with s and 2 of the 6 with MM). The MM in the 4 remaining patients occurred during follow-up and was diagnosed after an increase in the MG in 2 of them, after the appearance of cytopenia in 1, and after the occurrence of bone lesions in 1. Three of the 4 patients (75%) had IgM MG, whereas no IgM MG was detected in the 6 MM patients. We did not observe any change in the MG isotype in the 10 patients with MG. In the control group, 4 patients presented with an MHD, all of whom had (marginal zone in 2, ocular MALT in 1, and Hodgkin s disease of the jaw in 1). MHDs had previously been diagnosed in 3 control group patients. No MM occurred in this group. One patient in the control group developed MG during follow-up, but without MHD. The overall risk of an MHD in the MG group (10 patients [38.5%]) compared to the control group (4 patients [7.7%]) was increased (OR 7.5 [95% CI ], P ). Other parameters associated with MHD in univariate analyses were a low C4 level (P ) and an ESSDAI of $5 (10 of 14 patients [71.4%] compared to 21 of 64 patients [32.8%]; P ). After exclusion of the domain, an ESSDAI of $5 tended to remain associated with the Figure 1. Serum levels of BAFF in patients with primary Sj ogren s syndrome (pss), according to the presence or absence of monoclonal gammopathy (MG). Each symbol represents a single subject; horizontal lines with bars show the mean 6 SD.

5 MONOCLONAL GAMMOPATHY AND HEMATOLOGIC MALIGNANCY/DISORDER RISK IN PRIMARY SS 1249 presence of MHDs (8 of 14 patients 57.1%] compared to 21 of 64 patients [32.8%]; P ). Multivariate analysis (including low C4 level, presence of MG, and ESSDAI $5 without ) retained MG only as an independent predictor of an MHD (OR 5.5 [95% CI ], P ). The presence of MG was principally associated with an increased risk of MM (23.1% versus 0%; P ), but not with an increased risk of (15.4% versus 7.8%; P 5 0.3). Serum BAFF levels. The median serum BAFF levels in primary SS patients with MG was 703 pg/ml (IQR 444 1,340), which was not significantly different from the value in the controls of 1,018 pg/ml (IQR 821 1,348) (P ) (Table 1 and Figure 1). Very high serum levels of BAFF were found in 3 patients with MG, 1 of whom had active cryoglobulinemic vasculitis and 2 had. DISCUSSION In the present study, we found a 7.4% prevalence of MG in patients with primary SS. The presence of MG was associated with higher levels of disease activity and low levels of C4, as well as with a significantly increased risk of MHDs. Interestingly, this increased risk concerned mainly MM, which in contrast to, has rarely been studied in large cohorts of primary SS patients. The prevalence of MG in this study is in the lowest range but is consistent with previously reported observations in primary SS patients, ranging from 4% to 25% (5,13). This relatively low prevalence might be explained by our finding of a low prevalence of cryoglobulinemia in this cohort. Nevertheless, this prevalence is much higher than that in the general population of the same age, which is estimated to be 3% (14). The main factor associated with MG was active disease (defined as an ESSDAI of $5). This association between MG and disease activity has not previously been reported. This association remained significant even after excluding the biologic domain of ESSDAI (which includes MG) and the hematologic domain (which includes ). In comparison to previous studies (4,8), we did not find any association between the presence of MG and singleorgan involvement, and its association with overall disease activity confirms its association with more severe and systemic disease. The other factor associated with MG was a low C4 level, which is a known risk factor for in primary SS (5). Although primary SS is a clear model of the close relationship between autoimmunity and, the clinical significance and prognosis of circulating MG in primary SS patients has been assessed only in 2 large studies. Both studies, which were from the same group of investigators, found an increased risk of MHD associated with the presence of MG, with an estimated OR of 8.13 (95% CI ) in the first study, which included patients with primary SS and patients with hepatitis C virus associated SS-like syndromes (15), and an estimated OR of 4.13 (95% CI ) in the second one (16), which included only patients with primary SS. In these studies, all MHDs were s, with no cases of MM. In the general population, the risk of MHDs in the presence of MG has been estimated to be increased by 7.3-fold (95% CI ) (7), resulting in an 8% prevalence of MHD in patients with MG, which is much lower than what we observed in our primary SS patients (38%). Interestingly, in the present study, we observed a large number of patients with MM. This association has rarely been described. As expected, only the IgG or IgA isotype, but not IgM, was associated with the risk of MM, the latter being associated with risk of. In 2 large cohorts of primary SS patients in whom the link between MG and MHDs was studied, no cases of MM were observed after a mean follow-up of 10 years (16) and 2.5 years, respectively (15). Only 1 previous study focused on MM in primary SS, and that study found a prevalence of ;2% (13). Also, a Taiwanese study of a large health insurance database found an increased risk of MM of almost the same range as the risk of in primary SS patients as compared to the general population, with a standardized incidence ratio (SIR) of 6.1 (95% CI ) for MM and 7.1 (95% CI ) for non-hodgkin s (17). Another study conducted in a tertiary care center in China also found an increased risk of MM that was comparable to the risk of, with SIRs of 37.9 (95% CI ) for MM and 48 (95% CI ) for non- Hodgkin s (18). The overall risk of MHDs in this cohort was much higher than that in others, probably because the patients recruited in the tertiary reference center had much more severe disease and therefore had a higher risk of MHD than did other cohorts. Given the fact that the mechanism purported to explain the increased risk of in primary SS is a continuous stimulation of autoimmune B cells by the autoimmune process, it is not surprising to find an increased risk of MM aside from the increased risk of. Indeed, the B cell stimulation in primary SS is not restricted to B cells and continues until the final differentiation; plasmablasts and plasma cells are increased in blood and salivary glands, respectively, and primary SS is the autoimmune disease in which the increase in polyclonal IgG is the most important (19). Several groups of investigators, including our group, have stressed the fre-

6 1250 TOMI ET AL quency of RF activity of membrane Ig of B cell s occurring in primary SS patients. It would be very interesting to assess whether the monoclonal Ig secreted by myeloma cells could also have RF activity (20). In conclusion, the findings of this study confirm that the prevalence of MG is increased in patients with primary SS. The presence of MG was associated with an overall higher level of disease activity. In addition, the presence of MG was associated with an increased risk of MHD. Of interest, we found that in patients with MG, the risk of MM was even higher than the well-known risk of. These results might affect how clinicians monitor not only primary SS patients who have MG, which should therefore include both signs of,but also primary SS patients who have MM when MG is of the IgG or IgA isotype and is not associated with cryoglobulinemia. 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