Low Lymphocyte Proportion in Bronchoalveolar Lavage Fluid as a Risk Factor Associated with the Change from Trimethoprim/sulfamethoxazole used as First-Line Treatment for Pneumocystis jirovecii Pneumonia.

Background: Trimethoprim/sufamethoxazole (TMP/SMX) is the recommended treatment for Pneumocystis jirovecii pneumonia (PCP). However, the efficacy and the safety of alternative salvage treatments are less guarauteed especially when patient experiences treatment failure and/or an adverse drug reactions (ADR). The purpose of this study is to recognize potential risk factors imitating successful treatment with TMP/SMX among PCP patients.

Materials And Methods: Ninety one adult patients diagnosed with PCP were included after searching electronical medical records from January 2013 through July 2015 at Asan Medical Center Seoul, Korea. We compared clinical characteristics and laboratory findings including bronchoalveolar lavage (BAL) fluid analysis in patients who experienced TMP/SMX treatment failure or ADR (the case group) versus those who did not (the control group).

Results: Among the enrolled PCP patients, 39 (42.9%) required salvage treatment owing to either treatment failure (28, 28.6%) and/or ADR (17, 18.7%). The BAL lymphocyte percentage (25% [IQR, 8-40%] vs. 47% [IQR, 15-62%]; P = 0.005) was lower in the case group. Diabetes mellitus (adjusted odds ratio [aOR] 4.98, 95% confidence interval [95% CI] 1.20-18.58), glomerular filtration rate ≤50 mL/min (aOR 4.48, 95% CI 1.08-18.66), and BAL lymphocyte percentage ≤45% (aOR 9.25, 95% CI 2.47-34.58) were independently associated with the case group in multivariate analysis.

Conclusion: This study suggests that BAL lymphocyte count may play some role during PCP treatment. Further studies should be followed to reveal what the role of BAL lymphocyte is in the PCP treatment.