Early onset Pneumocystis carinii pneumonia after allogeneic peripheral blood stem cell transplantation

Pneumocystis carinii (P. carinii) is one of the major opportunistic pathogens responsible for hematopoietic stem cell transplantation (HSCT)-related pneumonias. Although trimethoprim-sulfamethoxazol (TMP/SMX) prophylaxis has been shown to prevent almost all P. carinii infections, 1%-2% of patients may still experience this complication. P. carinii pneumonia (PCP) is usually a late complication in patients receiving TMP/SMX prophylaxis, with most cases occurring later than 2 months post-transplant. We report a patient who developed early onset PCP after allogeneic peripheral blood stem cell transplantation (PBSCT) from an HLA-identical sibling donor. On day 12, the patient complained of dyspnea and cough. A chest X ray showed infiltrates in right upper lobe with bilateral pleural effusion. By the findings of Grocott stain on bronchoalveolar lavage fluid obtained on day 14, he was diagnosed as having PCP. Intravenous TMP/SMX failed to improve the lesion. This is the earliest onset PCP in the literature after HSCT despite the prophylactic administration of TMP/SMX before transplant.