Clinical significance of in situ detection of T lymphocyte subsets and monocyte/macrophage lineages in heart allografts.

Seventy fresh frozen biopsies of 22 human heart allografts were stained with mouse antihuman monoclonal antibodies (OKT-4, OKT-8, and OKM-1) using the immunoperoxidase method. The numbers of infiltrating cell phenotypes were correlated with patients' clinical status and histopathological diagnoses of the biopsies. At the clinically stable stage the number of OKT-4-positive cells (T-4 cells, helper/inducer), OKT-8-positive cells (T-8 cells, suppressor/cytotoxic), OKM-1-positive cells (M-1 cells, monocyte/macrophage) and T4/T8 ratio were lowest. During the early stage of rejection T-4 cells increased to the highest values. T-8 cells also increased significantly and T4/T8 ratio increased to the peak level as well. During the later stage of rejection, T-8 and M-1 cells increased to the highest values and T-4 cells and T4/T8 ratio decreased. After the treatment of rejection T-4 cells continued to decrease and T-8 cells and M-1 cells decreased to intermediate levels, but T4/T8 ratio still remained level. The numbers of T-4 cells, T-8, cells and M-1 cells were closely associated with the histopathologic severity of rejection. These results were also correlated with the allografts' prognoses. Interestingly, high T4/8 ratios with high number of T-4 cells in biopsies during the quiescent period were often followed by rejection episodes within 7 days, even though the pathological diagnoses were mild rejection. Another important finding was that after the treatment of rejection, persistent M-1 cells and low T4/T8 ratios in situ were frequently accompanied by recurrent rejections. Thus, monitoring of infiltrating cell phenotypes may be beneficial in the management of clinical cardiac transplantations.