HYPERGLYCEMIA DUE TO INSULIN-RESISTANCE CAUSED BY INTERFERON-GAMMA

Marked hyperglycaemia (30.9 mmol l(-1)) during interferon-gamma (IFN-g amma) therapy for asymptomatic recurrent renal cancer as multiple lung metastases in a 52-year-old man is described. Although the involvemen t of IFN-gamma has been reported in the development of autoimmune diab etes, in this case, antibodies against pancreatic beta-cells including anti-islet cell antibody (ICA) and anti-glutamic acid decarboxylase ( CAD) antibody were negative. Moreover, serum level of immunoreactive i nsulin (IRI) (11 mu U ml(-1) at fasting) and urinary excretion of C-pe ptide (108 mu g day(-1), reference range: 20-130) suggested insulin re sistance, supported by results of insulin tolerance tests. With insuli n therapy and cessation of IFN-gamma, fasting blood glucose concentrat ion returned to 6.2 mmol l(-1), and insulin therapy was discontinued. The injection of IFN-gamma may cause hyperglycaemia because of insulin resistance, rather than beta-cell injury. (C) 1998 John Wiley & Sons, Ltd.