TRIMETHOPRIM-SULFAMETHOXAZOLE PROPHYLAXIS FOR PNEUMOCYSTIS-CARINII INFECTIONS IN HEART-LUNG AND LUNG TRANSPLANTATION - HOW EFFECTIVE AND FOR HOW LONG

Pneumocystis carinii pneumonia (PCP) is a common clinical problem in the setting of organ transplantation, particularly in heart-lung and lung allograft recipients. Without prophylactic measurements, the incidence of P carinii pneumonia can reach up to 88% of heart-lung transplant recipients. We conducted a retrospective analysis of the Stanford heart-lung and lung transplant experience in order to assess the efficacy of the prophylactic therapy and to try to define the duration of therapy necessary for prevention. During a 9-year period 82 heart-lung and 13 single-lung transplants were performed. Of the patients not on prophylaxis therapy 27% (13 patients) developed P carinii infection as compared with 0% of patients on trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. The incidence of PCP infection peaked between 3 and 6 months posttransplantation. No case of infection was observed before the 7th week posttransplant. PCP was more common following induction immunosuppression with OKT3 as compared with RATG (P < 0.05). All cases of infections later than one year posttransplant were associated with recent increase in the immunosuppression regimen with high-dose corticosteroids for treatment of acute or chronic (obliterative bronchiolitis) rejection. Although our study is retrospective and based on various immunosuppressive and diagnostic technique periods, it seems that TMP-SMX is highly effective in preventing PCP infections in heart-lung and lung transplant recipients. Twelve months of therapy is probably a sufficient length of therapy if immunosuppressive therapy is stable. However, whenever augmentation in the immunosuppression regimen is indicated, prophylactic therapy should promptly be restarted.