The relationship of circulating IgA titers and multiple parameters of cell-mediated immunity was examined in 97 patients with head and neck cancer. In 26% of the patients, IgA titers were above one standard deviation of controls, with highest levels noted in patients with advanced disease. In 40 patients for whom multiple immune parameters were tested in vitro, increasing concentrations of IgA were associated with an enhanced immunologic helper state defined by a generalized hypergammaglobulinemia, increased percentage of T4+ lymphocytes, higher T4/T8 ratio, and an increased lymphocyte blastogenesis response to mitogens. IgA concentrations were inversely related to percentages and absolute number of Leu 11+ natural killer cell subsets, and also to disease-free survival (p less than 0.005 by Cox proportional hazards model). The immune correlations identified here are similar to those noted in many autoimmune diseases. Head and neck cancer patients are an immunologically heterogeneous population, among whom elevated IgA blood levels may reflect the autoimmune nature of cancer, an immunologic state defined by its tumor-promoting capacity.