Pronase-treatment (PT) is a procedure used in the Cryptococcal antigen (CA) latex agglutination test for the removal of nonspecific factors such as rheumatoid factor. Routinely, if a specimen is positive by the qualitative screen procedure (i.e. no PT) it will be retested after PT in order to confirm the validity of the positive result. Two observations have prompted us to further assess the usefulness of PT on all specimens irrespective of the qualitative screen result. 1. Kovan et al. reported that 3 serum specimens from AIDS patients with active cryptococcal infection displayed negative results with conventional CA-Latex agglutination test but had detectable CA-antibody by radioimmunoassay. 2. In 2 patients (1 known crypto patient, 1 patient with lymphadenopathy), PT converted original negative screen results into positive with titers ranging from 1:8 to 1:64. Based on these 2 findings, it is speculated that PT may have dissociated the AG-AB complex present in the specimen. The purpose of the project is to assess the usefulness of PT in the early detection of cryptococcal infection among AIDS patients.