Fifteen out of the forty-five patients with long-standing diabetes mellitus type I were characterised by the presence of TNFalpha in the sera when examined on several occasions over a period of five years. TNFalpha-producing patients had a better control of the disease and a smaller percentage of them suffered from diabetic complications as compared with those not producing this cytokine. TNFalpha-producing patients had lower levels of the proinflammatory markers - IL6 and CRP, and higher concentrations of ACTH and cortisol than those not producing this cytokine. We suggest that TNFalpha released systemically in diabetic patients stimulates the hypophysis-adrenal axis, and in that way indirectly ameliorates autoimmune response occurring during the advanced phase of the disease.