Autoantibodies in coalminers: their relationship to the development of progressive massive fibrosis.

Sera from 2421 coalminers, representing all the radiological categories of pneumoconiosis, and from 260 healthy blood donors, as controls, were examined for antinuclear factor and rheumatoid factor. Antinuclear factors were present in 21.5% of sera from the controls and in 23.1% from the coalminers' group. Rheumatoid factor was present in 5.3% of coalminers and as expected occurred particularly in the few men with progressive massive fibrosis who also had rheumatoid disease. The combined prevalence of both factors showed an increase with age at all disease levels and a significant association with pneumoconiosis category only in men older than 60 years. This study provides no evidence that autoantibodies are likely to be of value in detecting men predisposed to the development of massive fibrosis other than those with rheumatoid disease.