Pneumocystis carinii pneumonia in heart transplant recipients

Objectives: In spite of the high prevalence of Pneumocystis carinii (PC) pn eumonia in immunocompromised patients. little is known about the epidemiolo gical characteristics of this infection, and whether the cases of PC pneumo nia in immunosuppressed patients are the result of a reactivation of a late nt infection or a due to a recent infection is unknown. The aim of this stu dy was to provide information about the epidemiological characteristics of PC pneumonia in a cohort of heart transplant (HT) recipients when compared with the epidemiology of PC infection in a cohort of chronic sputum produce rs (CSP) representative of the general population of the same geographical area. Methods: We identified all the cases of PC pneumonia in the cohort of 72 subjects who underwent cardiac transplantation at our institution betwe en January 1991 and December 1996 and compared them with the cases of PC in fection identified in a non-selected cohort of 34 CSP. This second group wa s included to obtain an approximation of the frequency of PC carriers in th e general population. Identification of PC was accomplished through customa ry stain techniques and immunofluorescence with monoclonal antibodies. Resu lts: Of the 72 HT recipients four (5.5%) developed PC pneumonia, but one ha d two episodes. Only one had received primary chemoprophylaxis, but develop ed PC pneumonia 2 months after discontinuing prophylactic therapy. PC pneum onia episodes were produced 53, 102, 230, 181 and 772 days after the moment of transplant, respectively. PC was identified in two (5.8%) of the 34 CSP . No significant differences were found when the accumulative incidences of PC pneumonia in HT patients and PC infection in CSP were compared (P = 0.7 ). Conclusions: The frequency of PC pneumonia among HT patients is the same as the frequency of PC infection in the general population. This observati on and the long interval between transplantation and the development of PC pneumonia observed in the study support the hypothesis that the occurrence of PC pneumonia in immunocompromised patients might be from a new infection rather than from the reactivation of latent organisms. Therefore, continuo us prophylaxis might be indicated in areas with a high prevalence of PC for patients at highest risk. (C) 2001 Elsevier Science B.V. All rights reserv ed.