Samy Haddouk

Clinical and diagnostic value of ribosomal P autoantibodies in systemic lupus erythematosus

OBJECTIVE To analyse prospectively the diagnostic sensitivity and specificity as well as the clinical relevance of ribosomal P (anti-P) autoantibodies in a large cohort of SLE patients. METHODS The anti-P autoantibodies were evaluated in the serum of 200 Tunisian SLE patients at disease onset and 130 various control subjects by a sensitive immunodot assay. A complete laboratory evaluation and clinical examination were performed in each SLE patient. During the follow-up, the patients were regularly monitored for clinical parameters. Global SLE activity was measured by the ECLAM. RESULTS The sensitivity and specificity of anti-P testing for SLE were 23.5 and 98.4%, respectively. The anti-P-positive samples 14/47 (29.8%), 27/47 (57.4%) and 5/47 (10.6%) were negative for anti-dsDNA, anti-Sm or both antibodies, respectively. The anti-P-positive patients showed more active disease activity and a much higher prevalence of arthritis. An association between IgG aCLs and anti-P antibodies was also found. However, anti-P antibodies were not associated with neuropsychiatric manifestations or lupus nephritis. CONCLUSION This study does not seem to confirm the described association of anti-P antibodies with neuropsychiatric manifestations of SLE. However, it supports the anti-P antibody association with arthritis and disease activity as well as the presence of aCL. Based on our study and other related studies, we propose that, akin to anti-Sm and anti-dsDNA, anti-P antibodies detected by one agreed method may be considered for inclusion as a criterion for the classification of SLE.

Clinical significance of antinucleosome antibodies in Tunisian systemic lupus erythematosus patients

The aim of this study was to investigate the clinical significance of antinucleosome antibodies in Tunisian systemic lupus erythematosus (SLE) patients. IgG antinucleosome antibodies were detected by a qualitative enzyme immunoassay (immunodot) in the sera of SLE patients at onset of disease. The patients were divided into two groups according to the result of the antinucleosome antibodies test: positive (group A) and negative (group B). The two groups were also evaluated for clinical and biological parameters. Of 84 patients with SLE, 66 (78.6%) had antinucleosome antibodies. Among 21 patients negative for anti-double-stranded DNA (anti-dsDNA), 5 (23.8%) were antinucleosome positive. The most common initial features were haematological disorders (80.1%) and arthritis or arthralgias (79.8%). Renal disorders, observed in 59.5% of SLE patients, were more common in group A compared to group B (65 vs 38%) (p=0.04). The European Consensus Lupus Activity Measurement (ECLAM) mean score was higher in group A (6.42) than in group B (4.44) (p=0.002). Antinucleosome antibodies were positive in nearly one-fourth of SLE patients negative for anti-dsDNA. We found a correlation between antinucleosome antibodies, nephritis and SLE disease activity. Therefore, the determination of circulating antinucleosome antibodies could be a useful parameter for early diagnosis and follow-up of SLE patients.

Inflammatory Bowel Disease: Susceptibility and Disease Heterogeneity Revealed by Human Leukocyte Antigen Genotyping

This study aimed to investigate the association between HLA DR/DQ and inflammatory bowel diseases (IBD) in Tunisian patients and to determine the relationship between HLA DR/DQ alleles with the clinical disease patterns. DNA typing of human leukocyte antigen (HLA) genes was performed in 70 ulcerative colitis (UC) patients, 40 Crohns disease (CD) patients, and 123 healthy controls (HC) using a polymerase chain reaction sequence specific primer technique. Data were analyzed using Cochran-Mantel-Haenszel test and binary logistic regression. Compared with HC, IBD patients showed an increased frequency of the homozygous DRB1*07 genotype. This positive association was maintained when UC and CD were separately compared to HC. In UC patients, DQB1*03:02 was predictive of colonic extension whereas DRB1*13 and DQB1*03:01 were associated limited disease localization (left-sided colitis and proctitis). The DRB1*15 allele increased in patients with extraintestinal manifestations. In CD, female patients showed an increased frequency of DRB1*13, DRB1*15, and DQB1*06 alleles and DRB1*13-DQB1*06 haplotype, whereas a significant increase of DRB1*07, DQB1*02 alleles, and DRB1*07-DQB1*02 haplotype was noted in male patients. These results show a significant association of the homozygous HLA-DRB1*07 genotype with UC and CD and of several HLA DR/DQ alleles and haplotypes with the clinical phenotypes of these diseases in Tunisian patients. Because of limited statistical power, our study findings are subject to further investigation.

The CREM gene is involved in genetic predisposition to inflammatory bowel disease in the Tunisian population

The identification of susceptibility genes for inflammatory bowel disease (IBD) is key to understanding pathogenic mechanisms. Recently, the results of genetic association studies have highlighted many loci that are shared among several autoimmune diseases. We aimed to study the genetic epidemiology of polymorphisms in specific genes previously associated with other autoimmune diseases, namely the CREM, STAT4, STAT5a, Stat5b, and IRF5 genes. Twelve polymorphisms in the CREM, STAT4, STAT5a, Stat5b, and IRF5 genes were genotyped in a cohort of 107 IBD patients (39 Crohns disease [CD] and 68 ulcerative colitis [UC]) and 162 controls from southern Tunisia. One CREM single nucleotide polymorphism (SNP) displayed evidence for genetic association with IBD (p=8.7×10(-4), odds ratio [OR]=2.84 [1.58; 5.09]). One STAT4 SNP (p=0.026; OR=1.65 [1.06; 2.58]) exhibited a marginal association with UC but not with CD. No significant association was observed with the SNPs in STAT5a, IRF5, and STAT5b. These results suggest that common variants of the CREM gene are involved in the genetic component conferring general susceptibility to IBD, whereas STAT4 appears to be more specifically associated with UC. This work provides motivation for studies aiming to replicate these findings in larger populations.

Non-HLA autoimmunity genetic factors contributing to Autoimmune Polyglandular Syndrome type II in Tunisian patients

Autoimmune Polyglandular Syndrome Type II (APSII) is characterized by the co-occurrence of clinical insufficiency of at least two endocrine glands. Although, HLA determinants of APSII predisposition have been identified, little attention has been paid to non-HLA genes. Here, we used SNP genotyping in a Sequenom platform and genetic association tests to study a cohort of 60 APSII Tunisian patients presenting highly frequent co-occurrence of Autoimmune Thyroid Disease (AITD) and Type 1 Diabetes (T1D) and lower frequency of Addisons disease (AD). We tested the high a priori possibility that well-established non-HLA autoimmunity loci were involved in APSII and confirmed five association signals to APSII, namely: (1) two T1D-associated SNPs, in CTLA4 and IL2RA, suggest their involvement in T1D pathogenesis in this cohort; (2) two SNPs in STAT4 and IL15 not previously associated to endocrinopathies, are possibly involved in co-occurrence of organ autoimmunity in APSII, and; (3) one SNP in TNF alpha showed association to APSII irrespective of AD. While this work was performed in a relatively small cohort, these results support the notion that the non-HLA genetic component of APSII include genetic factors specific of particular autoimmune manifestations as well as genetic factors that promote the co-occurrence of multiple autoimmune endocrinopathies.

Association of ZAP70 and PTPN6, but Not BANK1 or CLEC2D, with inflammatory bowel disease in the Tunisian population.

Inflammatory bowel diseases (IBDs), consisting of ulcerative colitis (UC) and Crohns disease (CD), are complex disorders with multiple genes contributing to disease pathogenesis. We aimed to identify the associations of genetic variations in the ZAP70, PTPN6, BANK1, and CLEC2D genes encoding for intracellular signaling molecules with IBDs. One hundred seven patients (39 CD and 68 UC) with IBD and 162 healthy control subjects from the Southern Tunisia were recruited. We genotyped 4 single-nucleotide polymorphisms (SNPs) in ZAP70 (rs1020396, rs11686881, rs13420683, and rs17695937), 2 SNPs in PTPN6 (rs7310161 and rs759052), 3 SNPs in BANK1 (rs10516487, rs17266594, and rs3733197), and 1 SNP in CLEC2D (rs3764021). ZAP70 displayed a strong genetic association with CD for rs13420683 [allele C, p=0.003, P(corr)=0.006, odds ratio (OR)=2.25 (1.32; 3.85); genotype CC, p=0.016, P(corr)=0.048, OR=2.57 (1.22; 5.41)]. However, in UC, a weak association with PTPN6 was observed [TT (p=0.01; P(corr)=0.03; OR=2.11 (1.18; 3.76)]. No significant association in the BANK1 and CLEC2D genes was observed. These results suggest the involvement of the ZAP70 and PTPN6 genes in the genetic component conferring a general susceptibility to CD and UC, respectively. This work provides motivation for studies aiming to replicate these findings in larger populations.

Spectrum of autoantibodies other than anti-desmoglein in pemphigus patients

Background  Pemphigus is a life‐threatening autoimmune blistering disease mediated by autoantibodies against adhesion molecule of the skin. Its concurrence with systemic and organ‐specific autoimmune disease was described in case reports.

Contribution of immunofluorescence to identification and characterization of antineutrophil cytoplasmic antibodies in inflammatory bowel disease

We evaluated the combined use of different fixatives for the identification of atypical perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) in patients with inflammatory bowel diseases (IBD) by indirect immunofluorescence (IIF). Sera from 59 ulcerative colitis (UC) and 37 Crohn’s disease (CD) patients, and from 64 healthy controls were studied. The IIF on ethanol-, formalin-, and methanol-fixed neutrophils was used for the detection of ANCA. Enzyme linked immunosorbant assay (ELISA) was performed to identify the antigens recognized by ANCA. ANCAs were present in 35 of 59 (59.3%) UC patients and in 10 of 37 (27.02%) CD patients. Atypical p-ANCA positivity was strongly associated with UC disease (44.1% in UC vs. 8.1% in CD; p = 0.0002). The combined application of different fixatives contributed to make easy the differentiation between typical p-ANCA and atypical p-ANCA. Atypical p-ANCA determination appears to be a useful parameter for the distinction between UC and CD.

HLA-DRB1/DQB1 susceptibility for autoimmune polyglandular syndrome type II and III in south of Tunisia

OBJECTIVES The aim of our study was to investigate the association of HLA-DRB1 and HLA-DQB1 alleles with autoimmune polyglandular syndromes (APS) type II and III in a southern Tunisian population. PATIENTS AND METHODS Sixty-two unrelated patients with APSII (n=20) and APSIII (n=42) and 146 healthy controls were genotyped for HLA class II alleles (DRB1*, DQB1*) by PCR-SSP technique. RESULTS An increased frequencies of HLA-DQB1*03:02 (P=0,02; OR=2.98) in APSII patients, HLA-DRB1*03 (P=310(-6); OR=4.28) and HLA-DQB1*02:01 (P=0.04; OR=1.95) in APSIII patients were found compared to healthy controls. Study of the HLA-DRB1*;DQB1* haplotype frequencies showed a higher occurrence of DRB1*04;DQB1*03:02 and DRB1*03;DQB1*02:01 in APSII patients (P=410(-3); OR=3.31 and P=0.03; OR=2.74 respectively) whereas APSIII was only associated with DRB1*03;DQB1*02:01 (P=7.210(-8), OR=4.71). CONCLUSION Our data suggest that the variation in class II HLA alleles and haplotypes could be a genetic factor involved in the susceptibility of APS syndrome.INTRODUCTION The mosaicism 45, X/46, XY is a gonosomal abnormality characterized by a broad phenotypic spectrum, ranging from women with or without Turner syndrome stigmata, to men apparently normal, passing by the ambiguous phenotypes with variable virilisation of external genitalia. From the histological point of view, several situations may arise. PATIENTS AND METHODS We analyzed the clinical, hormonal, sonographic, and genitographics data, as well as peroperative and histological findings for five cases of mosaicism 45, X/46, XY, and we discussed treatment performed. RESULTS The mean age of patients was 6.6 years, two had a female phenotype with clitoral hypertrophy (one of them had Turner syndrome stigmata), one had a normal male phenotype with bilateral cryptorchidism and two had an ambiguity of external genitalia assigned to male. Short stature was noted for four patients. Surgical exploration concluded to the diagnosis of mixed gonadal dysgenesis for four of our patients. No cases of gonadoblastoma have been reported, for girls a prophylactic gonadectomy was performed, for boys the streak gonad was resected and the dysgenetic testis biopsied and preserved, subject for constant monitoring. CONCLUSION This heterogeneity indicate the importance of an accurate clinical and histological evaluation of any patient presenting with 45, X/46,XY mosaicism.

Genetic Factors Contributing to Systemic Lupus Erythematosus in Tunisian Patients

Systematic lupus erythematosus (SLE) is a multi system autoimmune disease characterized by autoantibodies production, multi-organ damage and complex genetic inheritance. Multiple genetic and environemental factors contribute to the pathogenesis of this disease. Recent genome-wide studies, have added substantially to the number of genes associated with SLE. We performed a case control study using 138 SNPs in 93 Tunisian patients affected with lupus and 162 healthy controls. All SNPs were genotyped in a Sequenom platform. To confirm some associations, associated SNPs were analyzed using logistic regression which allows the test of association with a given SNP by adjusting for the effect of confounding variables. Association was especially reported with rs3733197 (P=0.0026, OR=2.04), rs17266594 (P=0.046, OR=1.56) in BANK1 gene, rs2070197 (P=0.0016, OR=2.31), rs2004640 (P=0.024, OR=1.54), rs10954213 (P=0.035, OR=1.53) in IRF5 gene and rs7574865 (P=0.017, OR=1.77) in STAT4 gene: previously confirmed SLE susceptibility genes. rs1800629 (P=0.00036, OR=2.26), rs4147359 (P=0.026, OR=1.55) and rs11575812 (P=0.037, OR=1.57) of TNF-α, IR2RA and IL2 genes respectively were also associated with SLE. Haplotypic analysis reported 2 susceptibility haplotypes: TGG (P=0.00421, OR=1.87) in BANK1 and TCA (P=0.00177, OR=2.34) in IRF5 genes. Our results show that numerous genes, some with known immune related function predispose to lupus.