Immunological findings in human beings with autoimmune uveitis

Thirty-four adult patients suffering from uveitis of unknown origin were submitted to an immunological protocol where specific and non-specific parameters were checked. Serum IgA, IgG and IgM appeared within normal values meanwhile IgE-PRIST was undoubtedly increased in 27 out of 34 patients. The presence of autoantibodies such as antimitochondrial and antismooth muscle were detected in a few patients with Harada's syndrome; high serum levels of immune complexes were also detected in this little group of patients with posterior uveitis. Serum complement fractions showed no significant changes. Antirretinal IgG antibodies were present in almost 40% of the patients especially in those who also have autoantibodies and immunocomplexes. The histoimmunofluorescent technique revealed positive images at the retinal membrane agreeing with the histopathological lesions obtained in the experimental model. The positive cross reactivity between bovine tissue sections and the sera from patients with uveitis reinforced the idea of the presence of common epitopes in the S-antigen of both origins. LT-CD4 and LT-CD8 serum lymphocytes showed contradictory results though both subpopulations appeared diminished. The ratio between them kept within the normal range or slightly increased (2.3-2.8). Sensitized lymphocytes to the S-antigen were detected by the MIF technique in one-third of the patients. The presence of IgG antiretinal antibodies led us to speculate about the possibility that an ADCC mechanism could also participate in the etiopathogenesis of the autoimmune uveitis. On the other hand the presence of a specific antiretinal IgE antibody must play a paramount role in increasing the vascular permeability and thus enhancing the humoral and cellular events in the inflammatory focus.(ABSTRACT TRUNCATED AT 250 WORDS)