Factors involved in decreased detection of class II histocompatibility antigens on blood mononuclear cells from transplanted patients receiving immunosuppressive drugs.
Class II histocompatibility antigens were assessed by complement-dependent cytotoxicity on B enriched mononuclear cells and on purified monocytes isolated from the peripheral blood of renal patients before and after transplantation. After transplantation, a significant decrease of detection of DR alloantigens (cytotoxicity score before transplantation 3 +/- 0.1; after transplantation 0.95 +/- 0.1; p less than 0.001) was found. A similar defect was observed both on B enriched frozen cells and on purified monocytes isolated during the post-transplant period. Nevertheless, antigens could be adequately detected by a sensitive microabsorption method and by a procedure involving preincubation of mononuclear cells at 37 degrees C for 3 h followed by B cells enrichment by rosetting. The 37 degrees C induced reexpression could be inhibited by 10 micrograms/ml cycloheximide and by 50 microM monensin. No difference was found in the magnitude either of decreased expression or of temperature-induced reexpression between patients treated by CyS-Pred and those receiving Aza-Pred. It is concluded that transplanted recipients disclose a reversible defect of the expression of class II histocompatibility antigens probably related to perturbation of various steps of intracellular biosynthesis and traffic of these molecules.
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D001379:Azathioprine / Q000494:pharmacology; D001402:B-Lymphocytes / Q000276:immunology*; D003524:Cyclosporins / Q000494:pharmacology; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D007165:Immunosuppression Therapy; D016030:Kidney Transplantation; D009000:Monocytes / Q000276:immunology*; D011239:Prednisolone / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D013696:Temperature
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D003524:Cyclosporins; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D011239:Prednisolone; D001379:Azathioprine