Elevated levels of α-defensins in plasma and BAL fluid of patients with active pulmonary tuberculosis

Study objectives: To investigate the role of neutrophil peptides named alpha-defensins in patients with pulmonary tuberculosis (TB). Patients: Thirty-seven patients with TB and 25 healthy subjects. Measurements and results: Concentrations of alpha-defensins (human neutrophil peptide [HNP]-1, HNP-2, and HNP-3) were measured by radioimmunoassay in plasma and BAL fluid (BALF). Concentrations of alpha-defensins were significantly higher in plasma and BALF of patients with TB than in healthy subjects. In BALF of patients with TB, the concentration of alpha-defensins correlated positively with the levels of interleukin 8, and higher concentrations of alpha-defensins in BALF were also detected in patients with cavitary lesions. There was an inverse relationship between plasma alpha-defensins and FEV1/FVC ratio before treatment, and between plasma concentrations of alpha-defensins before treatment and the improvement in percentage of vital capacity after treatment. Plasma alpha-defensin concentrations returned to the normal range after treatment. Conclusion: Our data suggest that alpha-defensins released from neutrophils may play an important role in the pathogenesis of TB, and that plasma alpha-defensin concentration may be a useful marker of disease severity and deterioration of pulmonary function.