Immunophenotyping in presumed ocular histoplasmosis like retinopathy

Four cases of presumed ocular histoplasmosis like retinopathy are presented. A detailed immunological assessment was carried out on the patients and a control group: lymphocyte immunophenotyping; flow cytometric analysis; HLA typing and T cell receptor variable region (TCR V region) expression were assessed. Analysis of TCR V region expression revealed no significant preferential expression. HLA typing also failed to reveal any links. All lymphocyte markers analysed were unremarkable, with the exception of CD38 which was significantly raised compared with controls (p < 0.01). This finding was confirmed by the use of two different CD38-specific monoclonal antibodies. The raised CD38 in our cases was shown to be persistent when the patients were retested after an interval of several months. Significantly, this may correlate with poor T cell function, as in Common Variable Immunodeficiency, making these patients more susceptible to various stimuli.