THE SYNDROME OF PRESUMED OCULAR HISTOPLASMOSIS IN MEXICO - A PRELIMINARY-STUDY

A study to screen for the syndrome of presumed ocular histoplasmosis ( SPOH) among native populations from three Mexican states was performed . Two of these states, Guerrero and Queretaro, were selected as histop lasmosis is endemic there, whereas Tlaxcala was considered a control, due to the absence of reported cases. A total of 253 individuals were submitted to ocular fundus examination to obtain evidence of SPOH. A h igh percentage of positive reactors to histoplasmin skin test (ST) was observed in Guerrero (83%) and Queretaro (53%), whereas in Tlaxcala p ositive ST were almost absent (2.04%). Only five individuals had retin al lesions, although these lesions were not characteristic of the synd rome. Stimulation of these individual's cells showed different pattern s in the histoplasmin-induced lymphocyte transformation response, and two out of five individuals with retinal lesions presented a stimulate d response, as well as three controls without lesions. Histocompatibil ity antigens (HLA) were determined in a sample of each population and no particular allele, including HLA-B7, was found to be related to SPO H as reported in the USA; however, HLA-B22 was found in three individu als who developed pulmonary histoplasmosis. Results do not provide cli nical evidence or data on specific HLA risk factors, for the presence of SPOH in the population studied.