[Could lymph node microangiopathy play a part in the immunodeficiency of diabetes? Histological and immunohistochemical study of lymph nodes from 4 patients with long-term insulin-dependent diabetes mellitus subjected to autopsy examination].

The reason of increased susceptibility to frequent and protracted infections in diabetic patients is still unclear, although a multitude of "in vitro" studies have focused on the metabolic and functional modifications of the immune cells. From the literature immune abnormalities have been demonstrated "in vitro models" in genetic (type 1), autoimmune (type 2) and metabolic (type 1 and type 2) insulin-dependent diabetes mellitus (IDDM), and concisely referred in this paper. Diabetes microangiopathy, which is a peculiar alteration of the disease has been extensively described on many sites such as retina, renal glomeruli, skin etc, but as far as we know, not yet in the lymph-nodes. Therefore we report our histological and immunohistochemical observations in lymph-nodes removed from four patients with long-term IDDM, submitted to autoptic examination. On the clinical history all had shown, in the last years, lymphocytopenia and several infective diseases. The peculiar microangiopatic modifications appear joint to lymphodepletion of B and T cell dependent areas with marked reduction of follicular dendritic reticulum cells. The microangiopathy of thin intranodal capillaries besides compromise the diapedesis and traffic of the T and B lymphocytes could prevent the transformation of endothelial cells into dendritic reticulum cells. Indeed from the recent literature the dendritic reticulum cells should appear derived from transformed endothelial cells. This histological and immunohistochemical report could thence provide some additional knowledge about the complex problem of the immunodeficiency in diabetic patients.