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


CONCLUSIONS
These results emphasize the familial risk to develop CD and the value of serological screening as an instrument for identifying this disease.
Laboratory of Immunopathology, Clinical Hospital, Federal University of Paraná, Curitiba, Brazil.
Flávia Raphaela
FR
Nass
Lorete Maria da Silva
LM
Kotze
Renato Mitsunori
RM
Nisihara
Iara José
IJ
de Messias-Reason
Shirley
S
Ramos da Rosa Utiyama
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D001938:Brazil / Q000453:epidemiology; D002446:Celiac Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005190:Family; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D008875:Middle Aged; D011503:Transglutaminases / Q000276:immunology; D055815:Young Adult
D001323:Autoantibodies; D007070:Immunoglobulin A; D011503:Transglutaminases