ECTASIAS OF THE SUBCAPSULAR SINUS IN LYMPH-NODES OF ATHYMIC AND EUTHYMIC RATS - A RELATION TO IMMUNODEFICIENCY

This paper describes a morphologically unusual feature occurring in ly mph nodes of some aged euthymic animals but mostly athymic animals. It initially consists of small alveole-like excrescences of the cortical wall of the subcapsular sinus. With dilatation, an excrescence become s an ectasia which expands into the cortex. Observations suggest that ectasias enlarge under the influence of an increased pressure of the a fferent lymph of a node. Such condition conceivably results from a gre ater lymph formation due to inflamation of the drained tissue site, co mbined with an impairment to the flow of lymph from the subcapsular si nus into medullary sinuses. A probable relation of ectasia formation t o immunodeficiency is discussed. This formation results in the atrophy of the affected lymphoid cell populations of a node which likely cont ributes to aggravate the deficiency of the immune system.