Characterization of renal tissue lymphocytes in patients with interstitial nephritis.

Five patients with interstitial nephritis who presented with a variety of clinical profiles were studied with particular emphasis on documentation of the cellular types of potentially immunocompetent lymphocytes and mononuclear cells present within interstitial renal infiltrates. Immunohistologic studies coupled with conventional light and electron microscopic observations indicated that most mononuclear cells making up renal interstitial infiltrates were T cells. Some chronic inflammatory cell foci within renal interstitium were characterized by clusters of Ia antigen-positive T cells considered to be markers for activated lymphocytes. B cells were present in very small proportions (5 percent or less). The profile of immunocompetent cells present in lesions of interstitial nephritis suggests a major role for cell-mediated immunity in this disorder. Increase in tissue lymphocytes of the T gamma subclass with receptors for the Fc portion of immunoglobulin G (IgG) also suggests local activation of intrinsic suppressor cell mechanisms.