Histochemical Studies of Rheumatic Conditions: II. The Nodule of Rheumatoid Arthritis

Abstract

Histochemical studies show that the nodules of rheumatoid arthritis consist of a core of degenerating collagen fibers plus granular material related to fibrin encased in a fibrous "corona" which merges into normal skin. Using stains specific for collagen, mucopolysaccharide, reticulin and one which stains both collagen and fibrin, together with enzymes which removed some elements unmasking others, it was shown that the granular material is of 2 sorts. Large, pepsin-resistant granules stain with phosphotungstic acid, while small granules present are digested by pepsin. Polysaccharide and large amounts of tyrosine suggest the core is a synthetic product of the activity of the corona, rather than exclusively degeneration products of pre-existing tissue.