Late-onset Pneumocystis jirovecii pneumonia (PJP) in patients with ANCA-associated vasculitis

Immunosuppression in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is complicated by increasing risk of infections including opportunistic infections like Pneumocystis jirovecii pneumonia (PJP). Available evidence on risk factors and indications for prophylaxis in AAV is derived from PJP occurring early in the course of AAV. In this retrospective study, we characterized the profile of PJP in patients with AAV. PJP cases were identified retrospectively based on positive polymerase chain reaction test from electronic record followed by confirmation from medical records over a 10-year period. AAV patients without PJP over the same period were used as control group. Sixteen PJP+AAV+ were identified; in 14 of them, we were able to confirm they received PJP prophylaxis during induction therapy, while in two cases, data were missing. The onset of the infection was after 6 months from AAV diagnosis in 80% of cases. Escalations in immunosuppression prior to PJP were observed in six cases within 3 months prior to PJP onset. Overall mortality was 12.5%. By univariate analysis, renal involvement at AAV diagnosis was associated with PJP. These results indicate that PJP is not limited to the first 6 months following AAV diagnosis. Late-onset infection can occur in context of augmented immunotherapy, particularly with concurrent lymphopenia. Other risk factors that can independently predict late-onset PJP remain to be identified.