Insulitis in type 1 (insulin‐dependent) diabetes mellitus in man—macrophages, lymphocytes, and interferon‐γ containing cells

This study sought to determine, firstly, the relative frequency of lymphocytes and macrophages and, secondly, the percentage of lymphocytes containing interferon-gamma in inflamed islets (insulitis) of patients with type 1 (insulin-dependent) diabetes. Autopsy pancreases of 12 patients who had died of recent-onset type 1 diabetes and one pre-diabetic patient who had died of cardiomyopathy were examined immunohistochemically. In the 87 islets that were studied, the lymphocyte macrophage ratio was 9.7:1 and approximately 40 per cent of the lymphocytes contained interferon-gamma. Interferon-gamma release in the insulitis process may be involved in the pathogenesis of type 1 diabetes.