A SEQUENTIAL STUDY IN THE SCREENING OF COELIAC DISEASE AMONG FIRST DEGREE RELATIVES?

Abstract

Aim: The prevalence of coeliac disease (CD) among the relatives (from 5.5% to 8.5%) and the complications of an undiagnosed CD prompted us to identify the best strategy to screen these subjects. Methods: We studied 441 first degree relatives of 208 CD patients by IgA EMA and RIA immunoglobulin A anti-transglutaminase autoantibodies (TGAA). 364 subjects were typed for HLA-DRB1, -DQA1 and -DQB1 genes by PCR-SSP method using commercial kits. Endoscopic intestinal biopsies were proposed to the serology positive subjects. Results: Two immunodeficient fathers (one IgA deficient, the other on steroid therapy) both with duodenal villous atrophy, were excluded from serological evaluation. The TGAA revealed a higher sensitivity (100%) than IgA EMA (90%) (table). On the whole, CD prevalence in our series resulted 9.5%. 231/364 relatives (63.4%) and 38/40 biopsy proved coeliac subjects (95%) carried the DQ2/DQ8 haplotypes. 3 DQ2 positive parents, previously negative, became positive to the serology during the follow-up.TABLEConclusion: CD prevalence in our series resulted very high. These data suggest an accurate algorithm to select candidates for intestinal biopsy among CD high risk subjects: as a first step an evaluation of the sensitive and non-expensive RIA TGAA and of total IgA (if IgA deficiency, RIA IgG anti-tTG assay); a second evaluation of the TGAA and the genetic study should be performed 2-3 yrs later to the negative subjects. The relatives carrying the DQ2/DQ8 haplotipes should continue the serological follow-up, while the others need only a clinical follow-up.