Immune reactions in pulmonary fibrosis.

Two groups of fibrosing lung disorders have been studied, namely connective tissue disorders and fibrogenic inorganic dust diseases. Antinuclear factors (ANA) are frequently raised in both, but to varying extents and having markedly different characteristics when analysed in detail. The evidence for immune complex deposition in the lung in human disease is summarized and the relationship between ANA and the radiographic extent of fibrogenic inorganic dust disease is described. The evidence of lymphocyte responsiveness is incomplete, but holds interesting potential. Preliminary studies of histocompatibility antigens are summarized and warrant further investigation.