Increased Serum IgA Levels in Rats after Portacaval Shunt but not after Portacaval Transposition

Abstract

Groups of rats were submitted to end-to-side portacaval shunt, portacaval transposition or a control sham operation. There was an 18-fold increase of the IgA level in the serum of portacavally shunted rats (n = 7) at 3-6 wk after surgery. Gel filtration revealed that this increase was predominantly due to dimeric and polymeric IgA. The serum IgM of these shunted rats, but not the IgG, was also significantly increased (2-fold) above their control values. In rats subjected to portacaval transposition (n = 6), there was no significaint increase of serum IgA, IgM or IgG when compared with their control values. The data confirm the active transfer, by the healthy rat liver, of IgA and, to a lesser extent, of IgM from the blood into bile. Impairment of this function, leading to the accumulation of polymeric IgA and IgM in the serum, in portacavally shunted but not portacavally transposed animals, may be related to impairment of hepatic blood flow and hepatic atrophy, shown to occur in portacavally shunted but not transposed rats. Such reduction in liver cell mass could also explain the fall in transferrin levels in shunted rats.