SERUM TITERS OF PNEUMOCYSTIS-CARINII ANTIBODY IN HEALTH-CARE WORKERS CARING FOR PATIENTS WITH AIDS

Background-Pneumocystis carinii pneumonia was thought to occur from re activation of latent infection, but recent studies with the polymerase chain reaction have failed to detect P carinii in normal subjects. If pneumocystis pneumonia is therefore caused by new infection the sourc e and mode of transmission of P carinii remains unknown. Methods-Natur al exposure to P carinii was detected by measuring antibodies by indir ect immunofluorescence in 24 health care workers working continuously with patients with AIDS and 24 control health care workers exclusively treating elderly patients. Results-P carinii antibody titres were sig nificantly higher in the health care workers exposed to AIDS than in t he control group (median titre 1:32 v 1:16 respectively). Three contro l subjects had no antibodies compared with none of the subjects expose d to AIDS, and 10 of the 12 highest titres came from the exposed group . Conclusions-Raised P carinii antibody titres in health care workers caring for patients with AIDS suggest that patients infected with HIV may be a potentially infectious source of P carinii for susceptible su bjects.