Circulating Antinuclear and Rheumatoid Factors in Coal Miners

Serums from 207 coal miners were examined for the presence of rheumatoid factor and antinuclear antibodies. The population included miners with simple and complicated pneumoconiosis, miners without pneumoconiosis, and also a few subjects in whom Caplan's syndrome was suspected. Of the 156 miners with pneumoconiosis, serums from only 9 were positive for rheumatoid factor, although 34% of them had antinuclear antibodies. There was a regional variation in the prevalence of antinuclear antibodies; it was highest in the anthracite miners with complicated pneumoconiosis. A geographic association of antinuclear antibodies in coal workers' with pneumoconiosis was observed, that is, miners from those geographic regions in which the disease was most prevalent were most likely to have antinuclear antibodies. In contrast to other reports, serums from miners with complicated pneumoconiosis did not contain rheumatoid factor more often than those serums from subjects with the simple form of the disease.