Vijay Kumar (1,2), J.E. Valeski (1,2) and Jacobo Wortsman (3)
IMMCO Diagnostics, Inc.,1 Departments of Microbiology and Dermatology, State University of New York at Buffalo,2 Buffalo, New York, and Department of Internal Medicine, School of Medicine, Southern Illinois University, Springfield, Illinois. Celiac disease (celiac disease) is a gluten-sensitive enteropathy characterized by the presence of serum antibodies to endomysial reticulin and gliadin antigens. celiac disease has been associated with various autoimmune endocrine disorders, such as diabetes. We report a rare case of idiopathic hypoparathyroidism with coexistent celiac disease characterized by the presence of serum autoantibodies.
Studies were conducted to determine the specificities of these autoantibodies and to localize the antibody binding sites by indirect immunofluorescence and immunoelectron microscopy.
Sera from a patient with idiopathic hypoparathyroidism and celiac disease and from two patients with celiac disease alone were tested by indirect immunofluorescence for autoantibodies to parathyroid and endomysial antigens. The specificities of the antibody reactions were determined by testing the sera before and after absorption with monkey stomach tissue. In addition, immunoelectron microscopic studies were performed to determine the localization of the endomysial antigen.
Indirect-immunofluorescence studies on the patients serum were positive with a parathyroid as well as the endomysial substrate. Similar reactions were also observed with the sera of endomysial antibody-positive patients with celiac disease. Absorption of the sera with monkey stomach powder, which is known to have the endomysial antigen, abolished the antibody activities on both the endomysial substrate and the parathyroid tissue. Immunoelectron microscopic studies showed that endomysial antibody activity was associated with antigens localized on the myocyte plasma membrane and in the intercellular spaces. Thus, reactions of the patient s serum with the parathyroid tissue were due to endomysial antibodies and were not parathyroid specific as in patients with idiopathic hypoparathyroidism who did not have coexistent celiac disease.
In conclusion, indirect-immunofluorescence tests on parathyroid tissue detect not only tissue-specific antibodies but also cross-reactive antibodies, and this should be taken into consideration when these tests are performed.