This paper reviews the immunological aspects of silica and silicosis. Since crystalline silica by itself is nonantigenic, emphasis is placed on how silica can effect immunological consequences, on what immunological abnormalities are observed in both spontaneous and experimental forms of silicosis, and on how these immunological activities may influence silicosis.

The effect of silica on immunoglobulin levels, interferon induction, lymphocyte function, and macrophages in the afferent limb of the immune response is critically examined. The toxic and adjuvant effects of silica are discussed in relation to how these effects influence humoral and cellular immune responses to extrinsic and intrinsic antigens.

Finally, the relationship between the immunological effects of silica and immune reactions involving connective tissue antigens is explored in relation to its possible role in the pathogenesis of disease.