Increased production of soluble HLA-G molecules in stimulated peripheral blood mononuclear cells following extracorporeal photopheresis: Is it a mechanism involved in the therapeutic effect of the procedure?

• Published in: Journal of clinical apheresis 2005-12, Vol.20 (4), p.222-224
• Main Authors: Rizzo, Roberta, Melchiorri, Loredana, Tazzari, Pier Luigi, Tassi, Cristina, Soli, Maurizio, Lunghi, Monica, Belloni, Maurizio, Conte, Roberto, Baricordi, Olavio R.
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Cells, Cultured; Emergency and intensive care: renal failure. Dialysis management; extracorporeal photopheresis; Graft vs Host Disease - metabolism; Graft vs Host Disease - therapy; Histocompatibility Antigens Class I - biosynthesis; HLA Antigens - biosynthesis; HLA-G; HLA-G Antigens; Humans; IL-10; Intensive care medicine; Interleukin-10 - biosynthesis; Leukocytes, Mononuclear - metabolism; Lipopolysaccharides - pharmacology; Medical sciences; mononuclear cells; Pharmacology. Drug treatments; Photopheresis; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Urinary system
• ISSN: 0733-2459; 1098-1101
• DOI: 10.1002/jca.20070

We hypothesized that the effects of extracorporeal photopheresis (ECP) are mediated by induction of immunosuppressive cytokines like IL‐10, which enhances synthesis of HLA‐G molecules. HLA‐G products are expressed by CD14+ peripheral blood mononuclear cells (PBMC) and play an important role in inhibition of cell mediated immunity. ECP induces apoptosis in lymphocytes but not in CD14+ cells. We, therefore, investigated the concentrations both of IL‐10 and of soluble HLA‐G5/sHLA‐G1 molecules in supernatants from cultures of lipopolysaccharide‐stimulated PBMC obtained from leukocyte collection bags of 10 patients receiving ECP for graft versus host disease both before (pre‐irradiation) and after (post‐irradiation) exposure to 8‐methoxypsoralen and UVA irradiation. Levels of both IL‐10 and HLA‐G5/sHLA‐G1 molecules were increased in the post‐irradiation cultures. This suggests that therapeutic effects of ECP could be mediated by increased production of IL‐10 and tolerogenic HLA‐G molecules. J Clin Apheresis 2005. © 2005 Wiley‐Liss, Inc.