HUMORAL AND CELLULAR IMMUNE-RESPONSE TO ELASTIN IN PATIENTS WITH SYSTEMIC-SCLEROSIS

The humoral immune response against elastin and collagen was studied i n parallel with the delayed type hypersensitivity (DTH) reaction to el astin and the percentage of lymphocyte subpopulations in peripheral bl ood in 20 patients with systemic sclerosis (SSc), An increase of anti- elastin antibodies of all subclasses was found with a significant prev alence of IgE and IgA antibodies. The profile of anti-collagen type I and type IV antibodies showed an increase of IgE isotypes, In 25% of t he patients (5 out of 20) positive DTH reactions to elastin were obser ved as compared to the negative skin reactions in all control individu als. At the same time a significant hyporeactivity to common bacterial and mould antigens was found in 40% of the patients (versus 16% in th e control group) which could be an explanation for the low incidence o f positive anti-elastin DTH reaction, The DTH hyporeactivity in SSc ca ses was in contrast with the increased percentage of CD4 T cells (58.4 vs. 42.0) and increased CD4/CD8 ratio (2.5 vs, 1.5) in the peripheral blood of the patients. This finding together with the increased IgE a ntibodies to elastin and collagen type I and type IV might suggest a p ossible shift of the immune balance towards the Th2 type of immune res ponse, This is in line with the increased CD8+CD57+ cells which correl ated with the highest number of other parameters studied - disease dur ation, total skin score, IgE anti-elastin antibodies, IgG anti-collage n type I antibodies, CD4/CD8 ratio and CD19 B cells. The results of th is study demonstrated the existence of both humoral and cell-mediated immune response against elastin in SSc patients, However, we could not define whether this was an essential part of pathogenetic mechanisms or a secondary phenomenon reflecting the extent of the damage of conne ctive tissue.