Immunocytological and mineralogical study of bronchoalveolar lavage in a group of subjects exposed to asbestos

Twenty-five subjects (24 males and 1 female, mean age 57.4 years) who have been exposed to asbestos underwent chest radiography, high resolution computed tomography (HRCT) of the chest, lung function tests and bronchoalveolar lavage (BAL) for evaluation of cell components (total cell count, percentages of macrophages, lymphocytes, neutrophil and eosinophil granulocytes and the lymphocyte subpopulations CD3+, CD4+, CD8+, CD19+ and HLADR+), soluble factors (IL-8, IL-10, IL-12 and MCP-1 in the supernatant) and concentration of asbestos fibre. The subjects were subdivided according to the degree of their exposure, to the concentration of asbestos fibres in the BAL and to chest X-ray findings using the I.L.O. classification (0/0pl, 0/1 and 1/0 and above). According to the exposure index, we showed statistically significant (p < 0.05) higher lymphocytes percentage in the BAL of subjects with moderate exposure and significantly higher levels of IL-10 (p < 0.05) in the supernatant of subjects showing an absence of asbestos fibres in their BAL. In the group of subjects with a 0/0 and 0/1 radiological profile, the cellular component of the BAL was characterised by a higher percentage of lymphocytes (p < 0.02), whereas a trend toward an increase in the number of neutrophils was noted in subjects with obvious pulmonary fibrosis. The percentage of neutrophils was inversely correlated with some parameters of respiratory function such as vital capacity (p = 0.03) and the partial pressure of oxygen (p = 0.05) in the blood. Investigating the cytokines in the supernatant of the BAL, we found a trend toward lower concentration of IL-10 in the group showing the worst radiological picture (I.L.O. > or = 1/0), and a statistically significant negative correlation between this cytokine and pO2 (p = 0.048). Concerning the other cytokines and chemokines studied (MCP-1, IL-8 and IL-12), no significant differences were found to be associated with the radiological profiles. There were, however, positive correlations between the concentration of IL-8 and the percentage of neutrophils (p = 0.038) and between the concentration of MCP-1 and the percentage of lymphocytes (p = 0.006). A negative relationship between the concentrations of IL-12 and IL-10 has been also observed (p = 0.028). This research allows us to hypothesise that IL-10 may have a pathogenetic role in the evolution of asbestosis.