IgM Turnover in Chronic Liver Disease

The turnover of radioiodine‐labelled homologous IgM was studied on 16 occasions in 15 patients with chronic liver disease (e.g. cryptogenetic cirrhosis, chronic hepatitis, alcoholic cirrhosis). Nine were untreated, 5 received prednisone, and 2 azathioprine at the time of investigation. Serum IgM varied from 0.55 to 4.02 g per 1. Four patients had normal IgM turnover. In 6 studies the serum IgM concentration was elevated owing to an increased synthesis rate; however, in 5 of them the fractional catabolic rate, too, was accelerated. In 3 studies a normal serum concentration was combined with a high normal synthesis rate and increased degradation rate. One patient who was reinvestigated after 11 months of azathioprine treatment showed a decrease in serum IgM due to lowered synthesis. The IgM turnover pattern was not correlatable0 to the type of cirrhosis or to the treatment.