Association between diabetes mellitus type 1 and celiac disease : case-control study among Sudanese patients 2009-2011

Background: Gluten sensitive enteropathy (celiac disease (CD)) has a strong association with diabetes mellitus (type 1DM). Since, 2-3% of CD patients have selective IgA deficiency, the majority of the available tests may fail to show the auto-antibodies (the IgA endomysial antibody (EMA). To prevent such a false negativity, a new Enzyme Linked Immune Sorbent Assay (ELISA) test has been introduced to detect both IgG and IgA antibodies reactive with tissue transglutaminase (tTG), an autoantigen in CD patients. Objectives: This study has been conducted to detect celiac disease among Sudanese patients with type 1 autoimmune diabetes using anti-tissue transglutinamase antibodies as a diagnostic tool. Patients and Methods: Samples were collected from sixty nine randomly selected patients (38 males and 31 females) and their age ranged between 3-22 years with DM type 1 who were attending the outpatient clinics in Gabir Abu Eliz diabetic Center and Omdurman Pediatric Emergency Hospital. Blood samples were collected from 25 healthy individuals as controls. Levels of tTG specific IgA, tTG specific IgG and anti-endomysial antibodies of IgA class were measured in sera collected from both cases and from controls. All the results were analyzed using Statistical Packages of Social Sciences (SPSS) version 17 and MicroSoft office excel. Results: Seven out of 69 patients with DM type 1 (10.1%) were identified as having CD using IgG anti-tTG and 5 (7.2%) of them were positive for IgA anti-tTG and IgA anti-endomysial antibodies. The mean of both anti-tTG IgA and IgG titers were higher in diabetic patients (M±SD = 12.30±41.0 and 7.2±13.1 respectively) when compared with the control group (M±SD =1.8±1.1 and 1.8±0.9 respectively), however, only anti-tTG IgG antibodies titer achieved statistical significance. Discussion and conclusion: The present study revealed that patients with DM type I have an increased tendency to develop CD. The increased association of CD and selective IgA deficiency is a potential source of false-negative IgA, therefore testing for IgG class autoantibodies is recommended if celiac disease is suspected. Antibodies to tTG antigen fall once a gluten-free diet has begun, thus facilitating monitoring of dietary compliance. Thus, anti-tTG antibodies are highly sensitive marker for celiac disease with 95- 100 % sensitivty, and specificity of 90 to 97 %.