Eosinophilic granulocytes and interleukin-6 level in bronchoalveolar lavage fluid are associated with the development of obliterative bronchiolitis after lung transplantation

In a prospective cohort study, we assessed whether changes in total cell co unts and differentiation and interleukin-6 (IL-6), IL-8, and monocyte chemo attractant protein-1 (MCP-1) concentrations in bronchoalveolar lavage fluid (BALF) are associated with a higher risk to develop obliterative bronchiol itis (OB). We investigated 60 lung transplant patients (follow-up of 2 to 8 yr) with either histologic evidence of OB within 1 yr after lung transplan tation (n = 19) or no pathology, good outcome (CO) for at least 24 mo and w ell-preserved lung function, i.e., FEV greater than or equal to 80% of base line (n = 41). Median time between lung transplantation and the first BAL w as 42 d for the GO group and 41 d for the OB group (p > 0.05). in the bronc hial fraction, median total cell counts (0.06 x 10(3)/ml versus 0.04 x 10(3 )/ml), lymphocyte (9 x 10(3)/ml versus 2 x 10(3)/ml), and eosinophilic gran ulocyte counts (1 x 10(3)/ml versus 0) were significantly higher in the OB group than in the CO group (p < 0.05). In the alveolar fraction, this was t he case for the median value of neutrophilic granulocyte counts (19 x 10(3) /ml versus 4 x 103/ml), respectively. Median values of IL-6 and IL-8 concen trations in both bronchial (IL-6: 23 versus 6 pg/ml, IL-8: 744 versus 102 p g/ml) and alveolar fractions (IL-6: 13 versus 3 pg/ml, IL-8: 110 versus 30 pg/ml) of the BALF were significantly higher in the OB group than in the GO group. By means of logistic regression, we showed that higher total cell, neutrophilic granulocyte, and lymphocyte counts, the presence of eosinophil ic: granulocytes, and higher concentrations of IL-6 and IL-8 were significa ntly associated with an increased risk to develop OB. We conclude that moni toring cell counts, neutrophilic and eosinophilic granulocytes, IL-6, and I L-8 in BALF within 2 mo after lung transplantation in addition to the trans bronchial lung biopsy (TBB) pathology will contribute to a better identific ation and management of the group of patients at risk for developing OB wit hin a year.