Serum Sulfhydryl Determinations and Significance in Connective Tissue Diseases

Abstract

Serum sulfhydryl levels were determined by amperometric titration on normals and patients with a variety of connective tissue disorders. Patients were studied for a 6-months whenever possible, and serum sulfhydryl concentrations were correlated with the clinical course of the patient. Rheumatoid factor, total proteins, and albumin-globulin ratios were also studied at periodic intervals in an attempt to correlate these parameters with sulfhydryl concentrations. Sulfhydryl levels did not seem to correlate with albumin-globulin ratios, but suggested a more fundamental biochemical disturbance. Abnormal sulfhydryl concentrations were correlated with a high incidence of sera positive for rheumatoid factor as determined by the latex fixation method (Singer-Plotz method). Normal or low normal serum sulfhydryl levels were present in chronic gouty arthritis, rheumatoid spondylitis, and osteoarthritis. Decreased serum sulfhydryl levels were present in active rheumatoid arthritis. Individuals within this group showed much wider fluctuation on serial determinations than did those in the normal group. The lowest sulfhydryl concentrations were found in rheumatoid arthritis complicated by necrotizing vasculitis and in active lupus erythematosus and polyarteritis. The values in these diseases fell into the range previously reported for Waldenstrom''s macroglobulinemia. These levels also corresponded to the values for the Waldenstrom''s macroglobulinemia patients included in this study. It is suggested that decreased sulfhydryl levels are indicative of a biochemical disturbance which could result in protein denaturation through disulfide interlinkage. The importance of this disturbance in the pathogenicity of the diseases under study is yet to be established.