T-cell activity in HLA-associated autoimmune diseases

Abstract

Background: The existence of T-helper-1 (Th1) and T-helper-2 (Th2) subsets has been implicated in the regulation of several immune responses, and alterations in the Th1/Th2 balance have been involved in autoimmunity. The present study investigates the relative influence of Th1 and Th2 patterns in autoimmune responses in patients with HLA-associated autoimmune diseases.

Methods: This study concerns 849 patients of both sexes, suffering from several autoimmune diseases. Tissue typing for HLA antigens of Class I (A, B, C) and Class II (DR, DQ) was carried out in all patients by conventional serologic methods, comparing results with frequencies detected in a normal population. Many immunological tests were also done. In particular, lymphocyte subsets (CD4+, CD8+, CD3-HLA-DR+, NK cells, sIg + B cells) were detected with monoclonal antibodies by a fluorescent cytometer. The changes in frequencies of T cell subsets were used to calculate the possible incidence of two effector phenotypes (TE-1; TE-2).

Results: The results of the immunogenetic analysis confirmed the significant HLA-associations in several diseases. The essential T-cell changes were also exposed, thus defining the incidence of T-cell phenotypes (TE-1 = 56.3%; TE-2 = 34.8%). This finding suggested a major impact of cell-mediated immunity, as compared with that of antibody-mediated immunity.

Conclusions: The anomalies of Th1/Th2 balance can impact autoimmune disease, and in many cases a Th2 response can prevent Th1-mediated autoimmunity, which is the most evident phenomenon in several HLA-associated diseases.