Under endotoxin-free conditions, peripheral blood mononuclear cells and purified monocytes isolated from healthy control subjects and patients with alcoholic cirrhosis disclose elevated tumor necrosis factor α messenger RNA level and produce tumor necrosis factor α in response to stimulation by either soluble polymeric IgA or monomeric IgA bound to the surface of culture dishes but not by soluble monomeric IgA. Polymeric IgA induces tumor necrosis factor α secretion in a dose-dependent fashion. These results suggest that cross-linking of Fcα receptors on human monocytes induces the messenger RNA accumulation and the secretion of the cytotoxic and immunoregulatory cytokine tumor necrosis factor α. Furthermore, it is shown that lipopolysaccharide-induced tumor necrosis factor α secretion by peripheral blood mononuclear cells is synergistically enhanced in the presence of solid phase monomeric IgA but not in the presence of either soluble monomeric or polymeric IgA. Although increased lipopolysaccharide-induced tumor necrosis factor α secretion is observed at baseline in alcoholic cirrhotic patients, this synergism is also expressed in this group of patients. These observations could be of pathophysiological relevance in alcoholic cirrhosis because monomeric IgA deposits along the liver sinusoids and increased serum levels of polymeric IgA are common even in the early stages of this disease. (HEPATOLOGY 1991;13:670–675.)