Impact of lymphocyte differential count in BALF on the mortality of patients with acute exacerbation of idiopathic chronic fibrosing interstitial pneumonia

Abstract

Background: Idiopathic chronic fibrosing interstitial pneumonia (CFIP) has been recognized to have a potential risk of acute exacerbation (AE). However, regarding the therapeutic response and prognosis of AE of CFIP, the usefulness of cellular analyses of bronchoalveolar lavage fluid (BALF) has never been analyzed. Objectives: This study aimed to evaluate the impact of lymphocyte differential count in BALF on the mortality of patients with AE of CFIP. Methods: Retrospective analysis of 37 patients who satisfied the criteria for AE of CFIP and underwent BAL on admission. The patients studied were divided into two groups: one group had a lymphocyte differential count >15%, the other had a lymphocyte differential count ≤15%. We compared the 30-day mortality between the two groups as the primary outcome, and the 90-day mortality and overall survival as the secondary outcomes, using two-tailed log-rank test. Results: Median age was 75 years (range, 72 to 78); thirty-one patients were men. Twenty-four patients had a lymphocyte differential count greater than 15% and 13 patients had counts equal or less than 15%. The 30-day mortality was significantly higher in the group with lymphocyte differential count ≤ 15% compared to the group with lymphocyte differential count > 15% (p=0.002). The 90-day mortality and overall survival were also worse in the group with lymphocyte differential count ≤ 15% compared to the group with lymphocyte differential count > 15% (p=0.003 and p Conclusions: The lymphocyte differential count in BALF may be associated with favorable outcomes in patients with AE of CFIP.