Almeida, Natalia Castillo

e20057 Background: T-cell lymphomas (TCL) are a heterogeneous group of rare, but aggressive non-Hodgkin lymphomas. CD4+ and CD8+ T-cell function plays a vital role in the immunologic response to P.jirovecii infection. Our study aims to define the prevalence of Pneumocystis jirovecii pneumonia (PJP) in HIV-uninfected TCL patients. Methods: All patients at Mayo Clinic, Rochester MN diagnosed with TCL and a positive Pneumocystis PCR assay from either bronchoalveolar lavage (BAL) fluid or other respiratory specimens were identified from March 2005 until November 2019. Patients with TCL and a diagnosis of PJP made outside of our medical center were identified through Advanced Cohort Explorer, a query building tool. Results: A total of 922 patients with TCL were identified, and only 14 cases (1.5%) had confirmed PJP. In confirmed PJP cases, the median age of TCL diagnosis was 62 years (IQR 51-70 years), 79% were male, and the median number of chemotherapy lines was 1.5 (IQR of 1-3). Half of the cases (6/12) received CHOP as first-line of therapy, followed by CHOEP (25%, 3/12). The median time to PJP diagnosis relative to chemotherapy was 18 days (IQR 14-27 days). Peripheral TCL, not otherwise specified was the most common TCL, followed by angioimmunoblastic TCL, and CD30+ T-cell lymphoproliferative disorders (64%, 29% and 7%, respectively). The primary specimen type sampled for PJP diagnosis was BAL fluid (n = 9, 64%), followed by sputum (n = 3, 22%), induced sputum (n = 1, 7%), and transbronchial lung biopsy (n = 1, 7%). Three patients had a prior autologous stem cell transplant (ASCT), and all three cases had relapsed TCL one year after ASCT. 77% of cases received oral prednisone equivalents (median dose of 25 mg, IQR 20-40 mg) 30 days prior to PJP diagnosis. Two patients developed PJP despite anti- Pneumocystis prophylaxis with aerosolized pentamidine. At the time of PJP diagnosis, most patients had lymphopenia (88%, 8/9), and CD4+ T-cells measurement was obtained only in one patient (CD4+ of 100 cells/mL). 71% of the cases were treated with trimethoprim/sulfamethoxazole (TMP/SMX). After the initial PJP episode, 36% of the cases were transitioned to TMP/SMX for secondary prophylaxis. All cause 30-day and 90-day mortality was 7% and 29%, respectively. Mortality attributed to PJP was 7% (n = 1). Conclusions: In our TCL cohort, the occurrence of PJP was low. Primary prophylaxis should be individualized in this population.