Prédisposition aux maladies auto-immunes thyroïdiennes au sein d’une famille tunisienne multiplexe

New insights into childhood Vernal keratoconjunctivitis-associated factors

The purpose of this study was to test for detectable serum levels of antibodies usually associated with immune-related diseases in children with Vernal keratoconjunctivitis (VKC) and seek for their family history of allergies and autoimmune disorders. The association of human leukocyte antigens (HLA) with VKC was also investigated. We enrolled 181 VKC children and assessed total and specific IgE, antithyroglobulin (AbTG), antithyroidperoxidase (AbTPO), antitransglutaminase (tTG), and antinuclear antibodies (ANA) by standard procedures. Class I and II HLA typing was also carried out following standard protocols, and it was compared with that of healthy subjects. Patients were positive for AbTG (22%), AbTPO (14.6%), and ANA (15.8%), and AbTG positivity was associated with VKC severity (mean ocular score ± SD positive vs. negative: 6.56 ± 2.1 vs. 4.82 ± 2.1; p = 0.03). We found that 12.2% of VKC cases had a positive family history for psoriasis, 6.4% for other cases of VKC, and 5.2% for thyroiditis, while 50.2% of them were atopic. The expression of HLA class I B37 was significantly higher in VKC patients than in controls (7.1% vs. 2.1%, p = 0.04), although not confirmed after multiple antigens testing analysis. Our study suggests a role of common components associated with immune-based diseases in the clinical expression of VKC.

Autoantibody heritability in thyroiditis: IgG subclass contributions

Using a simple screening technique called regression of offspring on mid-parent (ROMP) to examine the role of IgG subclasses in affected and unaffected siblings of children and adolescents with autoimmune thyroid disease and their parents, both total-restricted and subclass-restricted autoantibodies to thyroglobulin (Tg) were assayed quantitatively for each of the IgG subclasses. There was a significant correlation of anti-Tg titer of probands with parental titers in thyrotoxicosis (TT), (R(2) = 0.569, p = 0.001), but not in chronic lymphocytic thyroiditis. The most striking correlation was in TT patients of African-American ancestry, (R(2) = 0.9863, p = 0.0007). Additional insight is provided by examining the contributions of the IgG subclasses individually, particularly those whose concentrations appear not to have direct influence on the total IgG titers. Thus, using small numbers of patients, and assaying the IgG subclass distributions, as well as any other immunoglobulin isotypes that are significantly altered in autoantibody assays, ROMP can be performed rapidly to ascertain which quantifiable parameters may be usefully extended to predict disease onset and progression.