Thyroid Autoantibodies as a Marker of Immunologic Disorder in Women with Unexplained Recurrent Spontaneous Abortion

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1 Med. J. Cairo Univ., Vol. 79, No. 2, September: , Thyroid Autoantibodies as a Marker of Immunologic Disorder in Women with Unexplained Recurrent Spontaneous Abortion EL-DESOUKI FOUDA, M.D.*; GAMAL A. BADR, M.D.*; AHMED FATA, M.D.**; MAHMOUD HADAD, M.D.* and MONA ALRAYES, M.D.*** The Departments of Internal Medicine*, Obstetrics & Gynaecology** and Clinical Pathology***, International Islamic Center for Population Studies and Research**, Faculty of Medicine Al-Azhar University Abstract Background: Recurrent spontaneous abortion (RSA) is one of the most frustrating and difficult areas in reproductive medicine, because the etiology is often unknown and there are few evidence-based diagnostic and treatment strategies. This study was undertaken to estimate the incidence & potential role of thyroid autoantibodies in patients with unexplained recurrent spontaneous abortion. Patients and Methods: This is a clinical based cross sectional study of 7 months duration. 70 women were recruited and divided into two groups; clinically euthyroid 50 women with history of unexplained recurrent spontaneous abortion with mean age 27.5 years (group I), and 20 women with no history of abortion but they have living birth as a control and their mean age was 26.8 years (group II). Both groups subjected to history, clinical examination and CBC, liver and renal function tests, serum free T3 & T4 and TSH, anti-thyroid peroxidase, anti-thyroglobulin and anti-cardiolipin (IgM & IgG). Results: Based on thyroid function profile, both groups proved to be in euthyroid state. Group (I) with RSA expressed 34/50 (68%) positive anti-peroxidase antibody (antitpo) versus 9/20 (45%) control, and 29/50 (58%) with RSA were found to be positive for anti- thyroglobulin antibody (anti- TG) versus 3/20 (15%) control respectively. Also the results demonstrated significant positive correlation between the serum levels of anti TG and Anti TPO in women with RSA. However the anti-tg level was positively associated with RSA irrespective to number of abortion. Conclusion: There was association between RSA and serum anti-thyroglobulin antibody with potential underlying pathogenic mechanisms may be suggested even in presence of normal thyroid functional profile. Key Words: Thyroid IgM IgG AntiTPO Abortion. Introduction RECURRENT spontaneous abortion (RSA) classically refers to the occurrence of three or more Correspondence to: Dr. El-Desouki Fouda, The Department of Internal Medicine, Faculty of Medicine, Al-Azhar University consecutive losses of clinically recognized pregnancies prior to the 20th week of gestation (ectopic, molar, and biochemical pregnancies are not included) [1]. RSA can be considered a primary or secondary process. Primary Recurrent spontaneous abortion refers to repeated miscarriages in which a pregnancy has never been carried to viability. The secondary one, a live birth has occurred at some time. The prognosis for successful pregnancy is better with secondary recurrent spontaneous abortion [1]. Several factors have been implicated in the etiology of RSA as genetic, anatomic, infectious, endocrine, and immunologic. Immunologic factors are important in 30-80% of cases according to different studies [2]. The current understanding of the immunology of pregnancy points at to separate etiologies for RSA. Alloimmune causes refer to antibodies and organ specific like antithyroid and antiovarian antibodies [3]. The failure of normal immune recognition of the fetus by the maternal body can be detected by the failure of maternal immune system to mount an appropriate response to paternal antigens contained in the fetal tissue [4]. Autoimmune causes refer to presence of the spectrum of autoantibodies that has been linked with increased spontaneous abortion. They are broadly divided into two categories non organ specific such as antiphospholipid, anti-dna and ANA. Potential theories that have been proposed for the RSA in women carry thyroid autoantibodies include: There may exist a subtle degree of hypothyroidism. Thyroid antibodies directly cause RSA. 139

2 140 Thyroid Autoantibodies as a Marker of Immunologic Disorder in Women The presence of thyroid antibodies represent an epiphenomenon that reflects an underlying overall autoimmune imbalance, resulting in more frequent rejection of the fetus [5]. In view of the discrepancies the objective of this work was to evaluate the thyroid autoantibodies as a marker of autoimmune disorder and predictor of abortion in women with unexplained recurrent spontaneous abortions. Patients and Methods This was a clinical based, cross sectional study of 7 months duration, the patients were selected from outpatient clinic at Al Hussein University Hospital and Allergy and Immunology Center, Al- Azhar University. This study was carried out on 70 non pregnant women, 50 patients with history of unexplained recurrent spontaneous abortion (negative for TORCH test) and their age ranged from 20 and mean 35 and the mean age 27.5 year (group I) and 20 women with living birth with no history of recurrent abortion as a control and their age ranged from 20 to 35 and the mean age 26.8 (group II). Patients and controls were clinically euthyroid and subjected to history, clinical examination and the following investigations: Complete Blood Count, liver and renal function tests, serum FT3, FT4 & TSH, antithyroid peroxidase, anti thyroglobulin antibodies. Other causes of RSA have been excluded after investigations, including hysterosalpingography complete endocrine profile (screening for glucose intolerance and luteal phase defect), viral and bacterial screening, screening for antiphospholipid syndrome (anti Cardiolipin IgM & IgG) and presence of non organ specific antibodies as ANA. Serum were analyzed for thyroid peroxidase antibody and thyroid thyroglobulin antibody concentrations using a chemiluminescent immunoassay (immulite 2000 analyzer, diagnostic products corporation, Los Anglos, CA) the analytical sensitivity of thyroid anti TPO >4.1 iu/ml assay and for thyroid anti TG >64.2 iu/ml. Statistical analysis: The data were evaluated using descriptive statistical methods (mean ± SD, ranges). For comparison of two independent variables the non parametric Mann-Whitney U-test was used. p<0.05 was considered significant. Correlations were assessed by Spearman s test. Statistical calculations were performed using SPSS Version 12 for Windows. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy at the best cut-off value selected was don by the receiver operating characteristic curve (ROC). Results The mean maternal age in group (I) was 27.5 ± 4.5 years old versus 26.8 ±4.05 years old in group (II), however this difference was not statistically significant. The mean overall basal levels of serum FT3, FT4 and TSH were measured in women in both groups and showed their levels in the normal reference rang with no significant changes. Patients were considered to be positive for either anti TG or anti TPO or both antibodies when their serum titer exceeds the upper range of cut off point which was 64.2 iu/ml and 4.1 Iu/ml respectively and accordingly, 29/50 (58%) women of group (I) were found to be positive for anti TG versus 3/20 (15%) of control group, and 34/50 (68%) women of group (I) were found to be positive for anti TPO versus 9/20 (45%) control group (II) Tables (1,2). Table (3) and Fig. (1) showed significant positive correlation between the serum levels of Anti TG and Anti TPO in women in group (I) and (22/50 (44%) were positive for both antibodies). However, patients in group (I) were positively associated with presence of anti TG antibody but not with anti TPO, and in spit that, insignificantly correlated with the number of abortion Table (4). Analysis of sensitivity and specificity for anti- TPO and antitg was done and we found sensitivity 66%, 58%, and specificity 60%, 90% respectively and the positive and negative predictive values was 80%, 93% and 41%, 46.2% respectively Tables (5,6). Table (1): Comparison between group (I) and group (II) as regard mean anti TG. Group Mann-Whitney test Range Median Mean rank Z p-value Group I S Group II There was significant increase in anti TG levels in group I in comparison to group II. Significance

3 El-Desouki Fouda, et al. 141 Table (2): Comparison between group (I) and group (II) as regard mean (anti TPO). Group Anti TPO Iu/ml Mann-Whitney test Range Median Mean rank Z p-value Significance Group I N.S Group II There was no significant differenc between group I and group II. Table (3): Correlation between Anti TG and all other studied parameters in group (I). 100 r p-value Anti TPO Iu /ml <0.001 * F.T3 pg/ml F.T4 ng/dl * TSH u Iu/ml (IgM) MPL/ml (IgG) GPLu/ml PLT x1000 /L Age (years) No. of Abortion There was significant positive correlation between Anti TG and Anti TPO while there was significant negative correlation between Anti TG and free T4. Other studied parameters revealed no significant correlation. Table (4): Correlation between Anti TPO and all other studied parameters in group (I). Sensitivity Anti-TG Anti-TPO Specificity Fig. (1): Correlation between Anti-TG & Anti-TPO. Difference between areas = Standard error = % Confidence interval = to Significance level p=0.390 r p-value F.T3 pg/ml F.T4 ng/dl TSH u Iu/ml (IgM) MPL/ml (IgG) GPLu/ml Age (years) No. of Abortion No significant correlation was detected between Anti TPO and any of the studied parameters in the diseased group Table (5): Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of anti TG at the best cut-off value selected by the receiver operating characteristic curve (ROC). Cutoff Sens. Spec. PPV NPV Accuracy > % 90.0% 93.5% 46.2% Iu/ml Table (6): Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of anti TPO at the best cut-off value selected by the receiver operating characteristic curve (ROC). Cutoff Sens. Spec. PPV Accuracy >4.1 Iu/ml 66.0% 60.0% 80.5% Discussion Much attention has been focused on the role of immune system in recurrent spontaneous abortion. And a significant association between thyroid antibodies and risk of abortion has been shown by various studies [6,7]. reported that the presence of serum thyroid antibodies reflect a generalized activation of immune system and suggesting that autoantibodies are secondary markers of autoimmune risk rather than specific causative factors. The results of this study showed that there was statistically significant increase in the level of anti thyrogloulin in women with history of recurrent spontaneous abortion in comparison with the control group (p=0.02). On the other hand anti peroxidase revealed non significant increase in the recurrent spontaneous abortion group ( p>0.05). According to [8] there are two working hypothesis concerning the roles of anti TPO, anti TG antibodies in pregnancy loss. TG and TPO antibodies are considered to be secondary markers of autoimmune disease rather than the actual cause of pregnancy loss.

4 142 Thyroid Autoantibodies as a Marker of Immunologic Disorder in Women Bio chemical interaction between hormones of pregnancy and elevated thyroid antibodies that is could be result in pregnancy loss. As observed in this study all women in group I had normal thyroid function and in spite of that, there was elevated TG, and TPO antibodies. However thyroid Antibodies are known to occur in normal healthy population and these auto antibodies are five times more common in women than men. But in spite of that presence of these antibodies may reflect a generalized activation of the immune system particularly of T cells which are ultimately responsible for fetal loss [9]. This study showed also that, there was non significant relationship between the presence of Anti TPO, Anti TG and RSA (r.097 p-value and 0.057, respectively). This result was concordant with some other studies in this field [10]. One of interesting study done by [11] showed that patients with thyroid antibodies treated with thyroid replacement therapy had lower rate of RSA compared with those treated with IVIG. These finding suggest that, pregnancy loss in such patient is related to thyroid dysfunction rather than a generalized over reaction of immune system. In this study we have measured both of Anti TPO and Anti TG antibodies and we found a significant positive correlation between Anti TG and Anti TPO while there was significant negative correlation only between anti TG and FT4. In the study of Caroliset et al., 5.9% of patients had only anti TPO and 16.7% had both anti TPO and anti TG. In other study by [12] done on 700 women with RSA 6.6% had positive Anti TPO, and Anti TG were detected in 7.7% of them. Also by setting the TG cut off value at >_64.2 Iu/ml. in our study to detect the high level of Anti TG, we have got specificity of 90.0% and positive predictive value of 93.5%. While the cut off value of TPO antibody at >_4.1 Iu/ml. and specificity of 60.0%, sensitivity 66%and positive predictive value of 80.5%. However no correlation had been found between anti TG and RSA, the cause might be related to small sample size of our study [13]. used cut of value >40 u/ml to report Positive Anti TPO in their study and found a correlation between detection of serum thyroid antibodies and RSA. Another study was carried out by [14] they found that 6 of 12 (50%) of women with history of recurrent abortion with high level of anti TG and 7 of 12 (58%) of women with history of recurrent abortion with high level of anti TPO. While there was only 4 of 12 (33%) with history of recurrent abortion with negative for thyroid antibodies. They also emphasized the usefulness of thyroid antibodies as marker for risk of recurrent abortion. In contrast, another study was carried out by [5] they found that 4.9% of women with history of recurrent abortion with level of anti TG more than 67 IU/ml. and 5.5% of women with history of recurrent abortion with level of anti TPO more than 40 IU/ml. They considered that there was a lack of association between thyroid antibodies and pregnancy outcome. It has been found that women with untreated subclinical hypothyroid were 3 time more likely to develop placental abruption and 1.8 times more likely to experience preterm labor. Three randomized Controlled trials have studied the effects of T4 replacement in early pregnancy in women with euthyroid state but with positive TPO and TG antibodies, which showed marked reduction in miscarriage rate [10]. It has been found in this study a positive correlation between serum FT4 and TG antibody in spite of normal serum TSH and patients were not subclinical hypothyroid. This emphasize that women with RSA with Positive thyroid antibodies could undergo thyroid hormone therapy even when their TSH is within the upper end of the reference rang and special care is necessary in women with increased thyroid antibodies because these women more often develop thyroiditis. In the present study (66%) of the women, their age range between years old and we didn t find any correlation between RSA and the patients age, however it was reported in some studies, an increasing risk of RSA, with increasing maternal age [11]. Also we didn t find any correlation between patient s age and presence of Anti TPO Anti TG. Conclusion: Based on these findings an association between RSA and serum anti-thyroglobulin antibody may be suggested with a potential underlying pathogenic mechanisms despite normal thyroid functional profile. References 1- ANSARI A.H. and KIRKPATRICK B.: Recurrent pregnancy loss: An update. J. Reprod. Med., 49: 806, DOSIOU C. and GIUDICE L.C.: Natural killer cells in pregnancy and recurrent pregnancy loss: Endocrine and immunologic perspectives. Endocr. Rev., 26: 44, 2005.

5 El-Desouki Fouda, et al TONG S., MARJONO B. and BROWN D.A.: Serum concentrations of macrophage inhibitory cytokine 1 (MIC 1) as a predictor of miscarriage. Lancet, 363: 129, KALLEN C.B. and ARICI A.: Immune testing in fertility practice: Truth or deception? Curr. Opin. Obstet. Gynecol., 15: 225, ROBERTS J., JENKINS C. and WILSON R.: Recurrent miscarriage is associated with increased numbers of CD%/20 positive lymphocytes and an increased incidence of thyroid antibodies. Eur. J. Endocrinol., 134: 84-6, CUNNINGHAM F.G., LEVENO K.J., BLOOM S.L., HAUTH J.C., GILSTRAP L.C. and WENSTROM K.D.: Williams Obstetrics. 22 nd ed. New York: McGRAW-Hill, , STAGNARO-GREEN A. and GLINOER D.: Thyroid autoimmunity and the risk of miscarriage. Best Pract Res. Clin. Endocrinol. Metab., 18 (2): , MAHANZ A., SALMAN R.Y., MADANI T. and BA- ZRAFSHAN A.: Anti-Thyroid Peroxidase and Risk of Recurrent Spontaneous Abortion. Royan Institue Iranian Journal of Fertility and Sterility, Vol. 1 (3): , JOHN C.: High anti thyroid antibody associated with adverse pregnancy outcome. Pubmed, 8: 1-3, GAYATHRI R., LAVANYA S. and RAGHAVAN K.: Subclinical hypothyrodism and autoimmune thyroiditis in pregnancy. JAPI, 10: 7, VAQUERO E., LAZZARIN N., DE CAROLIS C., VALENSISE H., MORETTI C. and RAMANINI C.: Mild thyroid abnormalities and recurrent spontaneous abortion: Diagnostic and therapeutical approach. Am. J. Reprod. Immunol., 43: , KUTTEH W.H., YETMAN and DL CARR A.C.: Increased prevalence of antithyroid antibodies identified in women with recurrent pregnancy loss but not in women undergoing assisted reproduction. Fertil Steril, 71: , SIERO NETTO L., MEDINA COELI C. and MICMA- CHER E.: Influence of thyroid autoimmunity on risk miscarriage Am. J. Reprod. Immunol., 52: , PRATT D.E., KABERLEIN G., DUDKIEWICZ A., KARANDE V. and GLEICHER N.: The association of antithyroid antibodies in euthyroid non pregnant women with recurrent first trimester abortions in the next pregnancy Fertil Steril, 60: , 1993.