The immunopathology and clinical relevance of lymphocyte cultures in liver transplantation.

Lymphocytes infiltrating human liver allograft biopsies were expanded in vitro for 3 to 5 days in recombinant IL-2 and then uniformly quantified and phenotypically characterized. The extent of proliferation was correlated with the degree and pattern of lymphocyte infiltration of the source biopsy as well as with the subsequent clinical outcome. Each of the 117 cases was assigned to one of three primary clinical outcome groups based on a retrospective evaluation of the clinical course before and after biopsy. The groups consisted of cases involving viral infection (n = 21), rejection (n = 40), or nonrejection-related allograft dysfunction (n = 56). The rejection group showed significantly greater in vitro expansion of lymphocytes (4201 +/- 685) compared to the nonrejection group (2720 +/- 408, P < 0.05). However, cases from the viral infection group showed the highest overall average lymphocyte growth (6655 +/- 2595, P < 0.05). Immunohistologic evaluation of the source liver transplant biopsy demonstrated increased T-cell infiltration of portal triads primarily by CD8+ T-cells in rejection compared to nonrejection cases (semiquantitative grade 1.3 +/- 0.1 versus 1.0 +/- 0.1, P < 0.05). The viral infection group demonstrated more significant T-cell infiltration (again predominantly CD8+) of the lobules compared to cases without viral infection (1.9 +/- 0.3 versus 1.3 +/- 0.1, P < 0.05). Immunohistologic evaluation of the cultured lymphocytes from the biopsies demonstrated a marked predominance (75% of cultures) of CD8+ T-cells compared to CD4+ T-cells.(ABSTRACT TRUNCATED AT 250 WORDS)