Raised immunoglobulin concentrations in bronchoalveolar lavage fluid of healthy granite workers

Immunoglobulin concentrations and lymphocyte counts were determined in bronchoalveolar fluid obtained from nine symptomless, healthy, non-smoking granite workers (mean age 45.6, range 22-56 years) and nine normal, non-smoking, non industrial controls (mean age 22.8, range 21-32 years). The proteins were measured in unconcentrated lavage fluid by means of a solid phase, enzyme linked immunosorbent assay. IgG and IgA concentrations were three times greater in lavage fluid from granite workers than the samples from non-industrial controls (p less than 0.02). Eight of nine normal volunteers (89%) had no detectable IgM (less than 30 ng/ml) in the lavage fluid whereas eight of nine (89%) granite workers had detectable IgM (chi 2 = 8, p less than 0.01). Lymphocyte counts in lavage fluid from the workers were significantly greater (15.5%) than control counts (5.6%; p less than 0.05). The normal albumin concentration suggests that differences in permeability do not account for all of the increased immunoglobulin concentrations found in granite workers' lavage fluid and that some immunoglobulin is locally synthesised. It is concluded that occupational exposure to granite dust is associated with an increased proportion of lymphocytes and an increased concentration of immunoglobulin in lavage fluid that may reflect a subclinical immune inflammatory response.