T AND B CELL PATTERNS IN IRREVERSIBLY REJECTED HUMAN RENAL-ALLOGRAFTS - CORRELATION OF MORPHOLOGY WITH SURFACE MARKERS AND CYTOTOXIC CAPACITY OF ISOLATED LYMPHOID INFILTRATES
To define the composition and proliferative and functional activity of the rejection infiltrates, subpopulations of lymphoid cells invading 16 nonfunctioning, excised renal allografts were enumerated in tissue sections using cytologic criteria derived from studies of T [thymus-derived] and B [bone marrow-derived] cell lymphomas. Each lymphoid subpopulation was then correlated with the percentage of mononuclear cells (harvested from these same grafts) which formed sheep erythrocyte [E] rosettes (T cells), expressed surface Ig [immunoglobulin] (B cells) or Fc receptors and specific lymphocyte-mediated cytotoxic activity. Small clumped lymphocytes (48.8 .+-. 18.9%) and plasma cells (18.8 .+-. 10.9%) were most common and correlated negatively (P < 0.01). Percentages of surface Ig-bearing and small clumped lymphocytes correlated directly (P < 0.05) as did the percentages of E rosette-forming and plasma cells (P < 0.05). The percentages of surface Ig-bearing B cells correlated negatively with E rosette-forming T cells (P < 0.05). Within this spectrum of rejection, three patterns could be identified. In the 1st pattern, humoral rejection (by immunofluorescence) was intense and cellular infiltration was primarily by surface Ig and Fc receptor-positive small clumped B lymphocytes. The 2nd and most common pattern consisted of a mixed T and B cell infiltrate with intermediate to high lymphocyte-mediated cytotoxic activity and variable humoral rejection. In the 3rd pattern, in vitro studies showed primarily E rosette-forming T cells with paradoxically low lymphocyte-mediated cytotoxic activity. Morphologic studies also revealed the highest percentages of plasma cells but only mild humoral rejection. The degree of lymphocytic invasion of renal tubules and blood vessels may provide an estimate of lymphocyte-mediated cytotoxic activity.