Abstract
Serum α2-macroglobulin levels were measured in normal subjects and in patients with various diseases by an immunochemical method. The values for normal men were 284 mg./100 ml. (±89·6 mg./100 ml.) and for normal women 350 mg./100 ml. (±94·5 mg./100 ml.). Men with rheumatoid arthritis had normal levels, but the levels in women were depressed. There was no relationship to the concentrations of the acute phase reactive proteins, haptoglobin, and C-reactive protein. In chronic liver disease, the levels in men were significantly higher than normal and were slightly higher than normal in women. A small group of patients with nephrotic syndrome had very high levels. No significant variations from the normal were found in sera from a group of patients with miscellaneous diseases.