The aim of this study was to assess the role of mesenteric blood in polymeric IgA (p-IgA) and IgA2-transport from the intestinal mucosa into plasma and the role of the liver in the clearance of these molecular forms of IgA. The concentrations of IgA, p-IgA and IgA2 were measured in mesenteric, splenic, portal, and hepatic veins of 7 control subjects without liver disease and in portal and peripheral veins of 4 patients with alcoholic cirrhosis. In control subjects, the concentration of the different molecular forms of IgA were not significantly different in mesenteric and in splenic vein. No significant decrease of IgA concentrations was observed in hepatic vein, as compared with portal vein. In cirrhotic patients IgA concentrations were significantly higher than in control subjects, but concentrations of IgA, p-IgA and IgA2 were not different in portal and peripheral blood. These results show that mesenteric vein is not a major way for p-IgA and IgA2 from the gut lamina propria to plasma, and suggest that the origin of a significant part of these molecular forms of IgA could be peripheral lymph-nodes more than gut-associated-lymphoid-tissue. The absence of significant clearance of p-IgA by the liver in normal subjects suggests that abnormalities of hepato-biliary transport of p-IgA is not responsible for the increased IgA levels observed in cirrhotic patients.