Serological and clinical follow-up of relatives of celiac disease patients from southern Brazil.

BACKGROUND/AIMS: In this study, a clinical and serological follow-up of 8-10 years was performed in relatives of celiac disease (CD) patients from southern Brazil. The occurrence of new CD cases in the families and the use of two different IgA-tTG enzyme-linked immunosorbent assay (ELISA) kits were also evaluated.

METHODS: Serum samples of 233 relatives, 186 recruited between 1997 and 2000 (phase I) and 138 between 2006 and 2007 (phase II: 91 of the follow-up group and 47 newly tested), were analyzed. As a comparison group, 100 unrelated healthy individuals were evaluated. IgA-EmA was tested by indirect immunofluorescence and IgA-tTG by ELISA.

RESULTS: A significant increase in IgA-EmA/IgA-tTG was detected in relatives of patients with CD when compared to controls (p ≤ 0.001). The positivity of antibodies was higher in females (2.4:1 in phase II; p = 0.039), and its high frequency amongst siblings (∼18.81%) highlights the risk of CD in these individuals. The distribution of antibodies by age suggested that CD can occur at any age in relatives, calling attention to the newly tested relatives >60 years of age (p = 0.0657). A better performance of ELISA kits with human tTG was observed. The confirmation of 13 biopsy-proven new CD cases (5.6%; 13/233) at present points out the predisposition to CD in these individuals and the high specificity of concurrently positive antibodies in relatives, especially when both are present in high titers.

CONCLUSION: These results emphasize the familial risk to develop CD and the value of serological screening as an instrument for identifying this disease.