Detection of serum Pneumocystis carinii DNA in the course of P.carinii pneumonia in experimental animals and HIV-infected patients

A nested PCR which amplified a part of the mitochondrial gene encoding the large subunit of rRNA of Pneumocystis carinii was used to detect P. carinii DNA in sera obtained from HIV-infected patients and immunosuppressed rats. P. carinii DNA was found in sera from nearly 52% of rats between 6th and 9th week of immunosuppressive treatment and in 12 serum samples out of 51 collected from HIV-infected patients, including 4 from clinically suspected and laboratory confirmed cases of PCP. The results of the studies indicated that DNA of P. carinii is most likely to appear in the blood in the advanced infection, however, the test for serum DNA may be of little value for the diagnosis of PCP since negative results do not exclude active infections and positive ones may be encountered in asymptomatic carriers.