Occurrence of Pneumocystis carinii DNA and anti-Pneumocystis antibodies in the sera of infants during a period of of physiologic decreased immune response

The polymerase chain reaction (PCR) and indirect immunofluorescent test (IF) were used for examination of serum samples obtained from infants with respiratory tract infections. Sixty (11.9%) out of the 503 examined infant samples were positive for anti-P. carinii IgM and 354 (70.4%) contained anti-Pneumocystis IgG. P. carinii DNA was found in 6 (6.7%) sera from 90 of infected infants. Five out these 6 samples were for anti-Pneumocystis antibodies positive; 4 contained both IgG and IgM classes and one had only IgG. The sixth sample had neither IgG nor IgM, despite of P. carinii DNA presence. The results of the studies indicated that for diagnosis Pneumocystis carinii pneumonia (PCP) in infants on serum specimens detection of antibodies by IF test is of greater value than Pneumocystis DNA amplification by PCR method.