EN
Since serological methods used in the diagnosis of pneumocystosis may be helpful to a various extent, depending on the stage of a diagnosed infection, it was decided to evaluate the usefulness of some the methods in the course of infection. Wistar rats were used in the experiments. The animals were administered hydrocortisone infections for 12 weeks to induce immunosuppression and activate naturally occurring asymptomatic infections with Pneumocystis carinii. Blood samples and specimes of lung tissues were collected, then they were examined for the presence of specific IgG and IgM antibodies, circulating antigen of Pneumocystsis carinii and circulating immune complexes using immunoenzymatic assays. The results of the above experiments indicated, that in an early stage of infection, the examinations of serum samples for circulating immune complexes were helpful, particularly for these with IgM antibodies.