The Role of PPARgamma Ligands as Regulators of the Immune Response.

A major challenge in medical research is to break the traditional compartmentalization that frequently separates different fields. Unexpected linkages between different areas of medicine are often of particular interest. An unsuspected "bridge" across clinical cardiology and basic immunology, as presented in this review, is a good example of such a linkage. Peroxisome proliferator-activated receptor gamma (PPARgamma) plays a role in glucose homeostasis and adipocyte differentiation and has been implicated in diabetes mellitus, a metabolic disorder predisposing to atherosclerosis. In addition, PPARgamma ligands of the antidiabetic thiazolidinediones group exert beneficial effects on atherosclerosis. Expression of major histocompatibility complex class II (MHC class II), a key molecule in the immune response, has recently been observed in atherosclerotic plaques. In recent years, important effects of PPARgamma ligands on MHC class II expression, activated T lymphocytes and macrophage activation have been described. Using atherosclerosis as a model of an immune-mediated disease, we summarize in this review the recent exciting observations that link PPARgamma to the immune response. (c) 2002 Prous Science. All rights reserved.