Pneumocystis Jirovecii Pneumonia In Recipients Of Autologous Hematopoietic Stem Cell Transplantation: A 10-Year Cohort Study

Pneumocystis jirovecii pneumonia (PJ), previously known as Pneumocystis carinii (PCP), is a potentially life-threatening disease in immunocompromised patients. The at-risk population includes patients with HIV infection and low CD4 counts, hematological malignancies, hematopoietic stem cell (HSC) and solid organ transplant recipients, and patients receiving glucocorticoids or other immunomodulatory agents. The highest-risk group of immunocompromised patients tends to be those with HIV (human immunodeficiency virus) infection, where PJ follows an indolent course. However, in non-HIV immunocompromised patients, such as HSC transplant recipients, the infection tends to present with respiratory failure. The incidence of Pneumocystic jirovecii pneumonia (PCP) in autologous BMT (bone marrow transplant) has not been clearly determined, and the indication for prophylaxis in this setting remains unclear. In this study we evaluate the incidence of PJ infection over a 10-year period in recipients of autologous transplants.

Retrospective analysis of 1191 consecutive autologous HSC transplants performed between 1/1/2000 and 6/30/2011 at the University of Michigan Blood and Marrow Transplantation Program. The data was obtained from the BMT Program Database at The University of Michigan Comprehensive Cancer Center. The diagnosis of PJ pneumonia was established by both bronchoscopy with brochoaveolar lavage (BAL) with polymerase chain reaction (PCR). We analyzed the following risk factors for the development of PJ pneumonia: diabetes, glucocorticoid use (in the setting of primary disease relapse, chemotherapy-induced pneumonitis, or idiopathic thrombocytopenic purpura), infections (Pseudomonal urinary tract infection, candidiasis, herpes simplex virus), cutaneous T-cell lymphoma, hypertension, and seizure disorder.

A total number of 5 PJ infections were diagnosed during study period, resulting in a cumulative incidence incidence of 0.42% (95%CI [0.136449% -- 0.976969%]) over the 10 year period. All cases occurred between 2001 and 2006, and 3 months or later following transplantation. Most patients (n=4) were older than 50 years old, and all of them were on steroids. Diagnoses included non-Hodgkin’s lymphoma (n=3), Hodgkin’s lymphoma (n=1) and multiple myeloma (n=1). Conditioning regimen was BEAM (BCNU, etoposide, cytarabine, melphalan, n=4) and high dose melphalan (n=1). Only 2/5 patients were neutropenic at the time of the pneumonia, and this did not correlate with the CD34+ cell infused, which was ≥2.2x10E6/kg for all patients. Four patients were on corticosteroids for relapsed lymphoma (n=2), ITP (n=1), BCNU pneumonitis (n=1). The remainder patient was on florinef and was coinfected with candida and herpes virus. There were no particular comorbidities associated with the diagnosis of PJ pneumonia. One patient died of PJ, the remainder were treated successfully.

This is the largest cohort of patients undergoing autologous transplantation evaluated for PJ pneumonia over a long period of time. Our low incidence and successful therapy suggest that PJ prophylaxis is not routinely warranted in patients undergoing autologous HSCT. Special consideration may be given to patients with additional risk factors such as corticosteroids.

No relevant conflicts of interest to declare.