THE PLASMA DISAPPEARANCE TIME AND CATABOLIC HALF-LIFE OF I131-LABELED NORMAL HUMAN GAMMA GLOBULIN IN AMYLOIDOSIS AND IN RHEUMATOID ARTHRITIS*

Abstract

A study of the disappearance of I131 labeled isologous gamma-globulin from the serum of 3 patients with amyloidosis revealed an accelerated rate of disappearance in two instances in which the nephrotic syndrome was also present. The disappearance rate in the third subject was comparable to that of the controls. Of 3 patients with rheumatoid arthritis, only one, who also exhibited a high titre of rheumatoid factor, revealed an accelerated rate of disappearance of the labeled protein. The catabolic half life of gamma-globulin measured as the rate of urinary radioiodide excretion closely approximated the half time of disappearance from the serum. These data suggest that in amyloidosis per se and in rheumatoid arthritis, a disease showing a high incidence of complicating amyloidosis, there is not an accelerated rate of serum gamma globulin utilization.