Lymphocyte status in endomyocardial biopsies and blood after heart transplantation.

We performed immunological phenotyping of mononuclear cells in tissue sections of 84 endomyocardial biopsies (EMB) showing infiltrates, which were taken from 21 patients after heart transplantation. Data were correlated with histology (grading following Billingham) and cyto-immunologic monitoring (CIM) on blood samples (grading into negative, rejection, or infection, based on leukocyte morphology and T-cell phenotype). Few T lymphocytes were observed in 35 biopsies, and many in 49 biopsies. The semi-quantitative estimate of T cells and CD4/CD8 ratio did not correlate with EMB histology but was related to CIM data. For example, 31 out of 42 cases with a CIM indicative of infection (14 of which showing no rejection on histology) manifested large numbers of T cells. In most cases, the CD4/CD8 ratio was less than 1. The presence of activated cells (bearing interleukin-2 receptors or the CD30 antigen) was not related to EMB histology or to CIM data. The number of T cells (subsets) in EMB was not related to relative or absolute numbers in the blood.