Abstract
Certain human hypermacroglobulinemic sera contain a 22 S component in addition to the usual 19, 27 and 35 S macro-globulins. This material differs from the 22 S component seen in the sera of some patients with rheumatoid arthritis in being a 19 S dimer. It can undergo reversible transitions that are both pH and temperature dependent. Macroglobulin systems containing the 22 S component give complex precipitin reactions in gels.