Occurrence of different immunoglobulin isotypes in horses with equine recurrent uveitis (ERU)

We investigated 30 healthy eyes and 41 eyes with ERU from 57 horses. The to tal immunoglobulin titers and titers of IgGa, IgGb, IgM were measured in aq ueous humour, vitreous and serum using different ELISA techniques. Every sa mple investigated contained detectable amounts of immunoglobulins. Compared to control eyes significantly increased titers were found in the aqueous h umour and vitreous of the ERU eyes for all immunoglobulin isotypes studied (p less than or equal to 0,01). While IgM was detected in only 2 out of thi rty aqueous humour and in none of the thirty vitreous samples of healthy ey es, 79.6 % of samples of ERU eyes revealed considerable IgM titers. Changes of the IgGa / IgGb ratio in the eye as compared to that in the autologous serum was more frequent in affected than in healthy eyes. In contrast to th e intraocular immunoglobulins there were no significant differences in immu noglobulin serum titers in healthy horses and those affected with ERU (p > 0,05). In conclusion, the results argue for a physiological appearance of i mmunoglobulins in the healthy eye. The increased titers of immunoglobulins in eyes stricken with ERU might be signs either of a local ocular productio n of antibodies and / or an increased permeability of intraocular barriers.