Infrequent patterns in cerebrospinal fluid isofocusing test: Clinical significance and contribution of IgG index and Reiber diagram to their interpretation.

Cerebrospinal fluid (CSF) isoelectrofocusing (IEF) is considered as the gold standard for detecting an intrathecal synthesis of IgG, which is a hallmark of multiple sclerosis (MS). This corresponds to the presence of CSF-restricted IgG oligoclonal bands (OCB) (typically type 2 pattern). Moreover, this technique can also detect a systemic immune reaction with passive transfer of IgG (type 3 and 4 patterns) for which the clinical relevance is less understood. The aim of our study was to determine the frequency and disease associations of IEF type 3 and 4 patterns and to investigate the potential usefulness of including quantitative data (IgG index and Reiber Diagram) in interpreting such IEF profiles. Among 544 patients who underwent CSF IEF (Hydragel CSF isofocusing kit, Sebia®, France) in our Laboratory during a six-year-period, those who presented type 3 or 4 patterns were selected. Clinical data and results of other immunological tests were analyzed for 27 patients followed in the Neurological Department. Frequencies of type 3 and type 4 patterns were relatively low (2.3 % and 3.4 % respectively). Among patients with type 3 pattern included in our study (n = 10), 5 were diagnosed with MS. For the 5 other patients, the diagnosis was a clinically isolated syndrome (CIS) (2 cases), a probable auto-immune encephalitis (2 cases) and a possible genetic neurodegenerative disease (1 case). MS patients had an IgG index >0.7 and fell into area 4 of Reiber diagram while non-MS patients had an IgG index <0.7 and fell into area 1, except the last case. Regarding type 4 pattern (n = 17), the diagnoses were as follows: MS (3), CIS (4), Neuromyelitis optica spectrum disorders with positive anti-AQP4 antibodies (3) and anti-NMDAR autoimmune encephalitis (1). The remaining cases had central nervous system impairment related to vascular, metabolic or tumoral etiologies (3) or peripheral nervous system impairment (3). In this group (type 4 pattern), IgG index was <0.7 in 15/17 cases. Interpretation using Reiber diagram showed an abnormal blood-brain barrier for 8/17 patients. Type 3 and 4 IEF patterns are infrequently observed in routine neurology practice. It is important for the diagnostic laboratory professional as well as for the neurologist to understand their clinical relevance. Our findings highlight the contribution of quantitative evaluation of CSF (IgG index, Reiber diagram) for the interpretation of such situations. Despite the small size of our study population, our results emphasize the importance of reporting the exact type of IEF pattern and not only the positivity or not of OCB.

Vitamin D deficiency in relation with the systemic and central inflammation during multiple sclerosis.

Background: During the last decade, vitamin D (VitD) has become a topic of interest in immune regulation, especially in multiple sclerosis (MS) disease. Amongst the wide range of effects reported for this vitamin on the immune system, a regulatory role on cytokines production has been described. Our aim is to analyze the status of VitD and its correlation with the circulating inflammation and the intrathecal humoral response during MS. Methods: We analyzed samples of 318 individuals: 108 MS patients and 210 controls. Determination of 25-(OH) VitD3 level in serum was made using electrochemiluminescence method. Circulating inflammatory cytokines (IL-6, IL-8, IL-10, TNF-a, IL12p70 and IL-1b) were investigated using Cytometer Bead Array Technology. The central humoral response was characterized using CSF isofocusing test and IgG Index calculation. Results: As expected, mean value of VitD was significantly lower in MS group (26 nmol/L) than in control group (34.75 nmol/L) (p=0.002), with a severe deficiency in 67% of MS patients. Mean value of VitD was significantly lower in MS female patients. Regarding cytokines, mean value of TNFa was significantly higher in MS patients with oligoclonal bands of IgG in the CSF. IL6 was positively correlated with IgG level in serum of MS patients. Conclusions: Our results support the association of VitD deficiency with MS, especially in female patients of our region. However, the vitamin level seems to not correlate with inflammatory cytokines nor with disability. Interestingly, TNFa and IL6 levels were correlated with the intrathecal synthesis of IgG and the circulating IgG level, respectively.

Juvenile Dermatomyositis Without Skin Lesions in an Antinuclear Matrix Protein 2 Antibody Seropositive Pediatric Case.

ABSTRACT: We report a 5-year-old boy who presented with progressive weakness in 4 limbs and gait disorders over 7 months. No skin rash was observed on admission. A symmetrical proximodistal weakness was found. The creatine kinase level was normal with a slightly elevated lactate dehydrogenase level. Biopsy specimens showed infiltration of mononuclear cells, few necrotic fibers, and perifascicular atrophy. Screening for myositis-specific antibodies was positive for the antinuclear matrix protein 2 antibody, which is mainly associated with dermatomyositis. Symptoms improved on receiving corticosteroids. Our findings suggest that in cases where inflammatory muscle disease is suspected, antinuclear matrix protein 2 antibody analyses should be considered for precise diagnosis, even with the absence of dermatological symptoms. The case suggests consideration of juvenile dermatomyositis in children with no associated skin manifestations or elevated creatine kinase levels and highlights the importance of screening for myositis-specific antibodies in helping with the diagnosis, given the possible heterogeneity of its clinical presentations.

Recent advances in selective allergies to mammalian milk proteins not associated with Cow's Milk Proteins Allergy.

Cow's milk proteins allergy (CMA) is an atypical immune system response to cow's milk and dairy products. It's one of the most common food allergies in children affecting 8% of the total pediatric population pediatric population. This comprehensive review examines recent studies in CMA, especially regarding mammalian milk allergies such as goat's, sheep's, buffalo's, camel's, mare's and donkey's milk allergies in order to increase awareness of these selective allergies and to reduce allergy risks for those who have them. The consumption of other mammalian milk types is not recommended because of the significant homology between milk proteins from cow, sheep, goat and buffalo resulting in clinical cross-reactivity. However, camel's, mare's or donkey's milk may be tolerated by some allergic patients. Selective mammalian milk allergies are unusual and rare disorders characterized by severe symptoms including angio-oedema, urticaria, respiratory manifestations and anaphylaxis. Based on the reported allergic cases, cheese products including Ricotta, Romano, Pecorino and Mozzarella, are considered as the most common source of allergens especially in goat's, sheep's and buffalo's milk allergies, while the major allergens in donkey's and mare's milk seems to be whey proteins including lysozyme, α-lactalbumin and ß-lactogloblin due to the low casein/whey proteins ratio in equine's milk.

The presence of two light chain bands on immunofixation is associated with poor outcomes in newly diagnosed multiple myeloma patients.

We aimed to describe the clinical and biological characteristics and the prognosis of patients presenting with an additional light chain (LC) band along with a complete monoclonal protein on immunofixation (IF).An 8-year descriptive study was conducted to assess all cases with confirmed monoclonal gammopathies (MG). We studied those with an entire M-protein with 2 bands of LC of the same isotype based on the results of IF. Data were collected from patients' files.Among 548 cases of MG, we found 32 cases (5.8%) with an additional LC band. We included 28 patients (5%) with a confirmed diagnosis of multiple myeloma (MM). The m/f ratio was 2.5 with a median age of 63 years [32-80 years]. All MM patients had anemia, 16 (57%) had renal failure, 14 (50%) had lytic lesions, 9 (32%) received hemodialysis, and 7 (25%) had hypercalcemia. The free-kappa-lambda ratio was abnormal in all cases: median = 0.07 [0.002-58.57]. The mean overall survival (OS) was 22 months ± 38.76.Fifteen MM patients (48%) received chemotherapy, and 7 (22%) autologous stem cell transplants (SCT). Patients who received SCT had an OS higher than those who received other treatments (p = 0.038). OS was low in patients with high ß2microglobulin levels (rho = -0.791; p = 0.001), and abnormally low free-kappa-lambda ratio (rho = -0.852;p = 0.04).The presence of an additional LC band with a complete monoclonal protein seems to identify newly diagnosed MM patients with poor outcomes and frequent renal impairment.

Biclonal Gammopathies in South Tunisia: Clinical and Biological Characteristics.

OBJECTIVE: Biclonal gammopathies (BGs) are rare situations characterized by the production of 2 monoclonal proteins. There are no available data on BGs in North Africa. We aimed to estimate the prevalence of BGs in our population and describe their clinical and laboratory features. METHODS: We conducted a 31-year retrospective study including patients with persistent double monoclonal bands based on the results of immunofixation/immunoelectrophoresis. RESULTS: A total of 35 patients with available clinical data (sex ratio, M/F = 1.53; mean age, 70 ±â€…10.87 years [range, 45-90 years]) were included. The main associated conditions were multiple myeloma (MM) (40%), BG of undetermined significance (BGUS) (34%), and lymphoproliferative diseases (23%). Only one-third of the patients had 2 monoclonal spikes on serum protein electrophoresis. The most common paraprotein combinations were immunoglobulin (Ig)G-IgG (25%) and IgG-IgA (23%) with different light chains in one-half of the cases. The mean follow-up was 25.6 months (median, 12 months). No BGUS evolved into a malignant disease. CONCLUSION: BGs are rare in clinical laboratory routine but must be accurately identified by the pathologist. Our cohort is characterized by a high prevalence of BGUS compared with MM.

Anti-mitochondrial antibodies detection assays for diagnosis of primary biliary cholangitis in southern Tunisia population / Techniques de détection des anticorps anti-mitochondries pour le diagnostic de cholangite biliaire primitive : étude dans une population sud-tunisienne

Anti-mitochondrial antibodies (AMA) represent serological markers of primary biliary cholangitis (PBC). Investigation of these autoantibodies can be performed by indirect immunofluorescence (IIF) on tissue sections or immunodot using M2 and M2-3E antigens. We aimed to evaluate the concordance of these immunological tests and their performance in PBC diagnosis. We reviewed sera which were tested for autoimmune liver disease anti-bodies by IIF (EUROIMMUN®) and immunodot (EUROIMMUN®). Results of IIF (AMA) and immunodot (anti-M2 and anti-M2-3E) were analyzed. A focus was given on positive results for AMA and/or anti-M2 and/or anti-M2-3E. According to available clinical data, patients were divided into two groups "PBC" and "Non PBC". Three-hundred-nineteen sera were tested by both techniques. Results of AMA, anti-M2 and anti-M2-3E were concordant in 296 cases (92.8%). Indeed, the three biomarkers were negative in 237 cases (74.3%) and positive in 59 cases (18.5%). Eighty-two sera were tested positive for AMA and/or anti-M2 and/or anti-M2-3E. Clinical data were available for 30 patients. In "PBC" group (n = 15), AMA, anti-M2 and anti-M2-3E antibodies were positive in 14/15 cases. PBC diagnosis was made in 12/15 patients without requiring liver biopsy. In "non PBC" group (n = 15), AMA, anti-M2 and antiM2-3E antibodies were positive in 9/15 cases. However, PBC diagnosis was not reached in the absence of other diagnostic criteria. IIF represents a first-line technique for AMA detection while immunodot is useful to confirm antigenic specificity in IIF-AMA positive cases. Anti-M2 and/or anti-M2-3E can be detected in some IIF-AMA negative cases. Interpretation of these tests'results relays mainly on clinical context.

Les anticorps anti-mitochondries (AAM) peuvent être recherchés par immunofluorescence indirecte (IFI) ou immunodot en utilisant les Ag M2 et M2-3E. Afin d'évaluer la concordance de ces tests et leur intérêt dans le diagnostic de cholangite biliaire primitive (CBP), nous avons comparé les résultats de recherche des AAM (IFI), anti-M2 et anti-M2-3E (immunodot) de 319 sérums. Selon les données cliniques disponibles, les patients avec au moins un marqueur positif ont été classés en deux groupes « CBP ¼ et « non CBP ¼. Les résultats des trois marqueurs étaient concordants dans 296 cas (92,8 %). Au moins un marqueur était positif dans 82 cas. Dans le groupe « CBP ¼ (n = 15), les trois marqueurs étaient positifs dans 14 cas. Dans 12 cas, le diagnostic était retenu sans recours à la biopsie hépatique. Dans le groupe « non CBP ¼ (n = 15), les trois marqueurs étaient positifs dans neuf cas, mais les autres critères de CBP n'étaient pas remplis. L'IFI demeure la technique de première intention pour la recherche des AAM ; l'immunodot permet de confirmer la spécificité antigénique. L'interprétation, notamment des cas discordants, repose surtout sur le contexte clinique.

Intrathecal B cell-related markers for an optimized biological investigation of multiple sclerosis patients.

In multiple sclerosis (MS) disease, the importance of the intrathecal B cell response classically revealed as IgG oligoclonal bands (OCB) in cerebrospinal fluid (CSF) was reaffirmed again in the recently revised diagnostic criteria. We aimed to optimize Laboratory investigation by testing the performance of new B cell-related molecules in CSF (Ig free light chains (FLCκ and λ) and CXCL13 (B-Cell Attracting chemokine1)) for MS diagnosis. 320 paired (CSF-serum) samples were collected from 160 patients with MS (n = 82) and non-MS diseases (n = 78). All patients benefited from IgG index determination, OCB detection, CSF CXCL13 and FLC (κ and λ) measurement in CSF and serum for metrics calculation (κ/λ ratio, FLC-related indexes, and κFLC-intrathecal fraction (IF)). CXCL13 and FLC metrics in CSF were higher in patients with MS and positive OCB. As expected, κFLC metrics-in particular, κFLC index and κFLC IF-had the highest accuracy for MS diagnosis. κ index showed the best performance (sensitivity 83% and specificity 91.7%) at a cut-off of 14.9. Most of the FLC-related parameters were positively correlated with IgG index and the level of CXCL13. In conclusion, the quantitative, standardizable, and technically simple CSF FLCκ metrics seem to be reliable for MS diagnosis, but could not replace OCB detection. CXCL13 appears to be an effective parameter reflecting the intrathecal B cell response. An optimized way for CSF testing combining the conventional and the new B cell-related parameters is proposed in this study.

Autoantibodies to Zinc Transporter 8 and SLC30A8 Genotype in Type 1 Diabetes Childhood: A Pioneering Study in North Africa.

Background: Type 1 diabetes (T1D) occurs as a result of insulin deficiency due to destructive lesions of pancreatic ß cells. In addition to classical autoantibodies (Abs) to islet cell antigens, antizinc transporter 8 Abs (ZnT8-Ab) have been recently described in T1D. Objective: As no data on ZnT8-Ab in Tunisian patients has been reported, we aim to evaluate the relationships between ZnT8-Ab, ZnT8 coding gene (SLC30A8) promoter polymorphism, and T1D risk in newly diagnosed children. Methods: ZnT8-Ab were measured in the serum of T1D newly affected children (n = 156) who were admitted to the pediatric department of the Hedi Chaker University Hospital of Sfax. Rs13266634 was genotyped in T1D children and 79 of their first-degree parents. The SPSS software was used to analyze the serological data. Allelic association analysis was conducted with family-based association tests implemented in the FBAT program v1.5.1. Results: ZnT8-Ab was detected in 66/156 (42.3%) of T1D newly diagnosed children. Among them, 6 (9%) presented ZnT8-Ab as the only humoral marker. The inclusion of ZnT8-Ab increased the number of Ab-positive patients to 90% and reduced the negative ones by 27%. There was no evidence of any overtransmission of any allele of the rs13266634 C/T polymorphism from parents to affected T1D children, nor of any correlation with any clinical or serological parameter. After the T1D disease onset age adjustment, a significant association was observed with the C allele suggesting that it could have a susceptibility role. Conclusion: ZnT8-Ab appears as a relevant diagnostic marker for T1D in Tunisian children, especially at the onset of the disease as teenagers.

Traditional risk factors and combined genetic markers of recurrent ischemic stroke in adults.

BACKGROUND: The involvement of traditional risk factors and combined genetic markers of recurrent arterial ischemic stroke (AIS) in adults remains unclear. OBJECTIVE: This study aims to determine significant clinical and genetic factors of AIS recurrence, and to investigate the combined effect of genotypes on the occurrence of a second cerebral ischemic attack. METHODS: We investigated a cohort study of AIS patients (18-50 years old) followed in the neurology department over 5 years. Traditional and genetic risk factors were carried through a multivariable logistic regression model. We used a Cox proportional hazard model for identifying predictors of recurrence. RESULTS: Two hundred and seventy patients were enrolled in our study. The risk of AIS recurrence was 36.2% within 5 years. The potential risk of recurrence of AIS increased with traditional and genetic risk factors such as hypertension, diabetes mellitus, heart failure, and family history of cerebrovascular diseases. This risk increased with increasing number of genetic factors. The hazard ratio (HR) was 0.66 (95% confidence interval [CI] 0.97-2.67) for the subject with one genetic factor, 1.61 (95% CI 0.97-2.25) for combined methylenetetrahydrofolate reductase (MTHFR) polymorphisms, and 2.57 (95% CI 1.32-4.99) for combined factor V Leiden (FVL) and MTHFR polymorphisms (677 or 1298). The HR for the three polymorphisms combined was 6.04 (95% CI 2.40-15.16). CONCLUSIONS: Our findings suggest that cumulative effect of both traditional and common genetic risk factors was associated with recurrence of ischemic stroke. We demonstrated for the first time that a combined genotype FVL/MTHFR profile increase the risk of a second cerebral ischemic attack.

Vitamin D status and CYP27B1-1260 promoter polymorphism in Tunisian patients with systemic lupus erythematosus.

AIM: An association between serum vitamin D (Vit D) levels and systemic lupus erythematosus (SLE) has been reported by several studies that suggested the involvement of genetically determined characteristics of enzymes of vitamin D metabolism. Our study aimed to evaluate the relationship between 25 hydroxyvitamin D (25[OH]D) level, the most representative metabolite of VitD status, and polymorphism of the cytochrome P450, CYP27B1 gene, which influence vitamin D metabolism, and serum levels, in SLE Tunisian patients. MATERIAL AND METHODS: A cross-sectional study has been conducted in SLE patients (supplemented and not supplemented patients), matched to healthy controls by age and gender. The 25[OH]D serum level was measured by chemiluminescence assay and CYP27B1-1260 genetic polymorphism was carried out using PCR-RFLP methods. Statistical analysis was made using Shesis and SPSS.20 Software. RESULTS: Controls and Vit D not supplemented patients' groups presented the highest percentage of hypovitaminosis D. A significant difference in the mean level of circulating 25[OH]D between Vit D supplemented SLE patients and controls was observed (23.91 ng/ml and 7.18 ng/ml, respectively p = 3.4 105 ). Our results showed a correlation of high 25[OH]D level with complement component 3 levels and prednisolone drug. Moreover, the analysis of CYP27B1-1260 polymorphism in SLE patients and controls revealed a nonsignificant allelic or genotypic association. CONCLUSION: Despite the sunny climate, the high prevalence of Vit D deficiency is common in Tunisia. This hypovitaminosis D feature may affect the Vit D levels in our SLE patients but a direct association with the disease or with the genetically determined features remains unclear. More studies are needed to establish thresholds and susceptibility genes according to the characteristics of each population.

Antinuclear antibodies in children: clinical signification and diagnosis utility.

BACKGROUND: Antinuclear antibodies (ANA) test is used to screen adults as well as children for connective tissue diseases (CTD) and autoimmune hepatitis. However, interpretation of ANA positivity can be delicate. AIM: to determine clinical significance and diagnosis utility of ANA positivity in children. METHODS: Patients from a general pediatric department with ANA positive results were included (follow-up period of 2 years). ANA screening was performed by indirect immunofluorescence (IIF) on HEp-2 cells substrate (BioSystems®). In case of ANA positivity (cut-off: 1:80), the specificity was determined by IIF on Crithidia luciliea substrate (BioSystems®) and immunodot (Euroimmun®). RESULTS: Among 102 ANA tests, 55 (53,9%) were positive. We recorded the data of 38 patients (age average: 9,5 years - sex ratio: 0.72). The most frequent signs were join pain (55,3%). ANA titer varied between 1:80 (39,5% of cases) and 1:1280 (2,6% of cases). Typing was negative in 89,5% of cases. The majority (42,1%) of children with positive ANA test had musculoskeletal diseases. The others (57,9%) had systemic lupus erythematosus(n=2),  overlap syndrome(n=1), rheumatoid purpura(n=2), idiopathic thrombocytopenic purpura(n=1), coeliac disease(n=1) or non-autoimmune diseases/no confirmed diagnosis(n=15). CONCLUSIONS: ANA prevalence in children was relatively high. When the pretest probability is low, the positive predictive value for CTD or autoimmune hepatitis is low. However, depending on the clinical context, ANA detection can represent a supplement diagnostic tool for these diseases and/or can lead to a clinico-biological monitoring.

Autoantibodies against Desmoglein 1 and 3 in South Tunisian pemphigus.

BACKGROUND: Desmoglein (Dsg) 1 and 3 are the 2 major autoantigens in pemphigus foliaceus (PF) and pemphigus vulgaris (PV). AIM: We aimed to determine anti-Dsg1 and 3 Abs'usefulness in the diagnosis of pemphigus and to assess the correlation of these antibodies (Abs) with clinical phenotype and disease activity in south Tunisian patients. METHODS: We retrospectively analyzed 131 samples from 82 patients (52 with PF and 30 with PV) during follow-up. Anti-Dsg1 and 3 Abs were measured by ELISA. Consecutive anti-Dsg1 and 3 Abs were correlated with disease activity. Receiver operating characteristics (ROC) curve were calculated to determine anti-Dsg1 and 3 Abs'cut-offs with optimal sensitivity and specificity for disease activity. RESULTS: Anti-Dsg1 and 3 levels were associated to in PF and PV patients respectively (p<0,001). Anti-Dsg1 and 3 Ab were associated with skin (95%) and mucosal (60%) lesions, respectively. A significant decrease of anti-Dsg1 Abs was observed in patients with PF in clinical remission (36 ± 62 U/mL; (p=0,04). No correlation was found between anti-Dsg3 Abs and the course of mucosal lesions in PV (p=0,3). During follow-up, anti-Dsg1 Abs correlated with relapses (177 ±60 U/mL ; p=0,04). The 161,5 U/mL cut-off for anti-Dsg1 Abs provided 100% specificity and 86,4% sensitivity in PF disease activity. The 30,7U/mL cut-off for anti-Dsg3 provided 89,5% sensitivity and 100% specificity in PV. CONCLUSIONS: High anti-Dsg3 Abs values are not always associated with PV disease activity. Anti-Dsg1 Abs showed a closer relationship with skin activity in PS and should be therefore taken into account in management of pemphigus patients.

Pemphigus herpetiformis in South Tunisia: a clinical expression of pemphigus foliaceus?

BACKGROUND: Pemphigus herpetiformis (PH) is a rare subtype of pemphigus combining clinical features of dermatitis herpetiformis and the immunopathologic characteristics of pemphigus. We aimed to analyze the epidemiological, clinical, and immunological presentation and management of the disease in a cohort of south Tunisian patients with a long-term follow-up. METHODS: We included all patients with confirmed PH followed from January 1987 to December 2015 in the dermatology department. RESULTS: We included 24 south Tunisian female patients with a mean age of 36 years (20-63), mainly from rural origin (84%). All patients had exclusive skin lesions. Clinical features combined erythematous, vesicular, or bullous lesions, with circinate borders mainly on the trunk and limbs associated with severe pruritus (91%). Peripheral hypereosinophilia was noted in 31% of cases. Histological examination demonstrated no intraepithelial (50%), suprabasal (35%), or subcorneal cleavage (15%). Eosinophilic spongiosis was seen in 42% of cases. On direct immunofluorescence, there was an intercellular staining in 96% of cases composed mainly of IgG and C3 (79%). Indirect immunofluorescence was positive in 71% of cases. Reactivity was mainly directed against Dsg1. Dapsone alone was inefficient. All patients received systemic corticosteroids. Most patients (64%) relapsed. Iatrogenic complications and cutaneous infections were noted in 40% and 16% of cases, respectively. CONCLUSION: PH is characterized by the occurrence of exclusive skin lesions in young women with a good response to corticosteroids but not to Dapsone. Reactivity mainly against Dsg1 suggests that PH in south Tunisia is a particular variant of nonendemic pemphigus foliaceus.

The intrathecal polyspecific antiviral immune response (MRZ reaction): A potential cerebrospinal fluid marker for multiple sclerosis diagnosis.

We tested the performance of MRZ-reaction, an intrathecal humoral immune response against-Measles (M), Rubella (R) and Varicella Zoster (Z) viruses, in multiple sclerosis (MS) diagnosis. The MRZ-reaction was significantly more positive in MS than in non-MS group with a specificity of 91.9%. In MS group, the RZ-profile was the most prevalent and the R-specific antibody-index was correlated to the number of oligoclonal bands (OCB) in CSF. Interestingly, the MRZ-reaction was detected in 53% of OCB-negative-MS patients. The MRZ-reaction seems to be a relevant CSF diagnostic marker of MS disease. The likely relation between its positivity and the vaccination status deserves to be investigated.

HLA Class III: A susceptibility region to systemic lupus erythematosus in Tunisian population.

BACKGROUND AND OBJECTIVES: Short tandem repeats (STR) are usually used as informative polymorphic markers for genetic mapping and for disease susceptibility analysis. The involvement of these microsatellite markers localized in the MHC region was reported in many auto-immune diseases. In this study we analyzed for the first time eight polymorphisms of microsatellite loci at the HLA region: D6S291, D6S273, TNFa, b and c, MICA, D6S265 and D6S276, in Tunisian systemic lupus erythematosus (SLE) patients. MATERIALS AND METHODS: We performed a case control study in which the microsatellite loci were amplified using specific primers labeled with NED, VIC, PET or 6-FAM and analyzed using GeneScan software 3.7. For the statistical analysis, we used SPSS software and we performed a sub-haplotype scoring test using the haplo.stats software developed in the R language. RESULTS: We found that two mean associated regions existed; the most statistically significant encompassed the 3 TNF markers (p = 0.0003, OR = 19.34); the latter covered the DR region. In fact, when scoring haplotypes in 3 marker- sliding windows, the p value increased as we moved away from the TNF region and decreased again when we approached the DRB1 locus. We also established for the first time the negative association between alleles of D6S291 and SLE. The majority of clinical and serological correlations were noted with TNF alleles. CONCLUSION: Our results confirm the association between TNF and DRB1 polymorphisms and SLE. The association between alleles of D6S291 and SLE needs however to be verified by the analysis of other markers beyond this region.

Human leukocyte antigens-DRB1*03 is associated with systemic lupus erythematosus and anti-SSB production in South Tunisia.

INTRODUCTION: Systemic lupus erythematosus (SLE) is an autoimmune disease with various presentations. This variation is due to the interaction of hormonal, environmental, and genetic factors. Associations between human leukocyte antigens and SLE have long been recognized in different ethnic populations and have been suggested to represent the most important association. OBJECTIVES: The objectives of this paper were to determine susceptibility and protection human leukocyte antigens (HLA) Class II markers for SLE and to highlight, for the first time, associations between HLA alleles and clinical and serological features in South Tunisia. METHODS: We conducted a case-control study on 75 SLE patients and 123 healthy controls. The HLA Class II DRB1/DQB1 of all patients and controls was genotyped using polymerase chain reaction-sequence specific primer technique. Statistical analysis was performed using SPSS software. RESULTS: HLA-DRB1*03 was the principal Class II allele associated with the genetic susceptibility to SLE (pc = 0.02; OR = 2.57; CI = [1.39-4.75]; this allele was also associated with anti-SSB production (P = 0.016; OR = 4.00; CI = [1.24-12.96]). HLA-DRB1*01 was significantly more expressed in SLE patients with neurologic disorders (P = 0.013; OR = 20.25; CI = [1.87-219.21]). No allele was found to be protective against SLE in our study group. CONCLUSION: Our results show that in South Tunisia SLE is associated with HLA-DRB1*03 and that some clinical features of SLE may be influenced by specific DRB1 and DQB1 alleles.

[Positivity of antineutrophil cytoplasmic antibodies in children: prevalence and etiologies]. / Positivité des anticorps anti-cytoplasme des polynucléaires neutrophiles chez l'enfant : prévalence et étiologies.

In adults, anti-neutrophil cytoplasmic antibodies (ANCA) are considered as serological markers of several diseases, especially vasculitis and glomerulonephritis. Since ANCA are rarely positive in children, few data about the clinical relevance of these auto-antibodies in pediatric population have been reported. Therefore, our study aims to describe the spectrum of disorders associated with positive ANCA in Tunisian children. This study had been carried out over a period of 12 years and a half. All patients under the age of 15 for whom ANCA screening was performed in our laboratory were included. Clinical data were collected retrospectively. Indirect immunofluorescence (IFI) technique for ANCA detection was performed using PNN smears fixed with ethanol, formalin and, if necessary, methanol. Positive results were tested using immunodot to characterize the antigenic targets (myeloperoxydase (MPO) and proteinase 3 (PR3)). Our results showed that 410/5,990 (6.8%) laboratory requests for ANCA screening were for children. Forty (9.7%) requests were positive (24 children). Clinical data were available for 19 patients only. Sex-ratio (F/M) was 1.25. The mean age was 9 years and a half (3-15 years). The most frequent IIF patterns were x-ANCA (n=12) and p-ANCA (n=7). In our patients, the most frequent conditions associated to ANCA were treatment with benzylthiouracil for hypothyroidism (n=6), inflammatory bowel disease (n=4) and hemolytic anemia (n=4). In conclusion, the positivity of ANCA in children seems to be a rare event. Associated conditions include clinical disorders specific to the pediatric population. Treatment with benzylthiouracil is an etiology to be taken into consideration.