Characterizing Pneumocystis jirovecii Pneumonia in patients with Primary Immunodeficiency Disorders, Data from the US Immunodeficiency Network (USIDNET) Registry

Abstract

Pneumocystis jirovecii pneumonia (PJP) is a life-threatening infection that affects immunocompromised individuals, including those with primary immunodeficiencies (PID). The US Immunodeficiency Network (USIDNET) registry was utilized to perform retrospective analysis of PID patients who developed PJP. The cohort was categorized into those who developed PJP before or at PID diagnosis versus those who developed PJP after PID diagnosis. Frequency of PJP in PID patients within USIDNET was 63/5204 (1.2%). Forty-nine patients developed PJP prior to history of transplantation and were included in final analysis. This cohort was 22% female (11/49), 78% male (38/49). The majority developed PJP before/at PID diagnosis (40/49,82%). Median age at PID diagnosis in the PJP before/ at PID diagnosis group was 0.65 years [IQR 0.40,2.08]. PID diagnoses varied, including Hyper IgM syndromes (17/49,34.7%), Severe Combined Immunodeficiency (SCID) (15/49,30.6%) and Common Variable Immunodeficiency (CVID) (8/49,16.3%), among others. Hyper IgM patients with PJP before/ at diagnosis of PID median first CD4 count was 1233/uL [IQR 929,4100]. All other patients with PJP before/at diagnosis of PID median first CD4 count was 197/uL [IQR 12,560], though for CVID patients, median first CD4 was 580/uL. Of patients with phytohemagglutinin data, 16/27 (59%) had normal PHA response. This characterization of PJP in PID from the USIDNET registry demonstrates the importance of considering the particular PID defect when contemplating PJP prophylaxis. However, PJP often precedes or is part of the initial consideration of a PID diagnosis. T cell lymphopenia and poor mitogen response may not adequately identify PID patients at risk of PJP.