Human Cardiac Allograft Rejection: Correlation of Grading with Expression of Different Monocyte/Macrophage Markers

Abstract

Endomyocardial biopsies from human cardiac allografts were investigated with the use of immunohistochemical methods. A correlation between the different degrees of rejection reaction and subtypes of monocyte/macrophage infiltrates was established. Early and mild rejection is characterized by recently immigrated monocytes/macrophages positive for the monoclonal antibody Ki-M1. In contrast, the cellular infiltrates in severe and resolving rejection show strong expression of antigens recognized by Ki-M6 and Ki-M8, indicating increased phagocytotic function of monocytes/macrophages. The immunohistochemical assessment of monocytes/macrophages can thus be used, in addition to conventional histology, in the diagnosis of cardiac allograft rejection.