July 13, 2022
PJP Prophylaxis Paradigms: Time to Broaden?By Nirav Patel, MD
Efficacy of primary prophylaxis for Pneumocystis jirovecii pneumonia (PJP) in patients with cell-mediated immunodeficiency has been well established, historically in HIV-infected patients with low CD4 counts, but also non–HIV-infected patients after solid-organ transplantation or other similar situations. However, this retrospective review by Park and collaborators highlights a potential gap in prophylaxis for patients with induced B-cell deficiency.
The article, published in Chest, reviewed more than 3,500 patients at a referral center in South Korea who were treated with rituximab from 2002 to 2018 for a variety of conditions, including hematological diseases, rheumatic diseases, or organ transplant. Comparing the 1,001 patients in the prophylaxis group compared to the 2,500 patients in the control group who did not receive prophylaxis, the hazard ratio was 0.2 (95% confidence interval, 0.1-0.42). Based on a time-varying analysis, there was only one case of PJP per 509 person-years while on treatment vs. 95 cases per 2,472 person-years without.
Traditionally, PJP has been associated with cell-mediated immune defects, either from disease or after therapy. Rituximab leads to B-cell depletion. However, this article demonstrates a significant impact on PJP incidence. As a retrospective study, there are likely unaccounted variables that would lead to an individual patient receiving prophylaxis compared to not, including treating clinician concerns or prior/comorbid history. Further limitations of retrospective studies apply as well, though the extensive dataset as well as early, wide divergence of the incidence curves suggests a true effect. Likely a deeper understanding of immunological containment of this pathogen as well as a new paradigm for prophylaxis are necessary to reduce patient risk.
