PubMed1993
The mode of formation and role of rheumatoid factors (RF) in transplantation were reviewed. RF might be produced through stimulation with altered transplantation antibody, which undergoes conformational changes resulting from the reaction with a graft. Some recipients might have such sources of infection as cytomegalovirus or human herpes virus 6 (HHV-6), because almost all patients were treated with immunosuppressive agents. Many bacteria and viruses have IgG Fc receptors on their surface. Herpes virus infection, such as herpes simplex virus, has been demonstrated to be capable of expressing Fc receptor on the infected cells. These Fc receptors could produce RF through the response of antibody production to anti-idiotype of Fc receptors. Also, IgG, which binds to Fc receptors, changes conformationally to produce RF. RF can also be produced as a result of graft versus host reaction. Although IgG RF reacting with homologous IgG is believed to have the most important role in pathogenic conditions, they have not been studied because of difficulties in their measurements. We developed an enzyme immunoassay for detection of IgG RF combining with homologous IgG. The wells of an assay plate were coated with Fc fragment of human IgG, and after incubation with tested serum, binding of IgG RF to the Fc was detected by means of goat anti-human IgG F (ab')2 antibodies followed by alkaline phosphatase conjugated rabbit anti-goat IgG and substrate. IgG RF were increased significantly more in transplantation sera of patients who rejected grafts than in those of patients who had satisfactory graft function. Some evidence for the role IgG RF in rejection, even if only circumstantial, has been provided.