Angioimmunoblastic lymphadenopathy: an ultrastructural and immunologic study with review of the literature.

Six cases of angioimmunoblastic lymphadenopathy (AIBL) are presented, detailed ultrastructural and immunohistologic studies of several involved organs are described, and the literature is reviewed. The features of the lesion are of normal immune reactive cells containing polyclonal cytoplasmic immunoglobulin. Large numbers of dying and degenerating cells result in accumulations of cell debris, corresponding to the characteristic interstitial material seen by light microscopy. Our studies confirm that the vascular changes are unique to lymph nodes, appear confined to postcapillary venules, and consist of endothelial cell hypertrophy and expansion of the vessel wall by basement membrane-like material, cellular debris and collagen fibers. No deposits of amyloid or antigen-antibody complexes were noted by ultrastructural or immunologic techniques. Our data reveal morphologic and laboratory features of a hyperimmune state but with paradoxical cutaneous anergy and decrease in blood (T) lymphocytes. We postulate that AIBL is an abnormal, but non-neoplastic immune reaction related to the autoimmune disorders, resulting from a loss of suppressor T cells with hyperfunction of the B lymphocyte system.