Liver damage in mice and rats causes tenfold increase of blood immunoglobulin A

Average serum concentrations of IgA and IgM of the SDK rats were 0.27 and 0.43 mg/ml, respectively. Subtotal hepatectomy had no detectable effect on the concentration of IgM but IgA increased in 4 days to a level of 4.9 mg/ml. Thereafter the concentration fell back to normal in 21 days. Serum concentrations of IgA, IgM and IgG2a in (C57BL X CBA)F1 mice were 0.41, 0.35 and 1.67 mg/ml, respectively. Neither hepatectomy nor carbon tetrachloride poisoning had an effect on the concentrations of IgM or IgG2a but IgA increased to 3.0 mg/ml (hepatectomy) or 3.6 mg/ml (carbon tetrachloride poisoning). Again the increase was reversible. IgA of normal rat serum was mostly monomeric (7S) and of normal mouse serum a mixture 7S and 9S (dimeric) IgA. After liver damage of either type the majority of the serum IgA had a sedimentation constant higher than 7S. It thus resembled the IgA that is brought to the circulation by the thoracic duct of rats and mice.