Low incidence of anti-Gal α 1-3Gal and anti-porcine antigens antibodies in xenotransplanted type-1 diabetic patients after 6 years of follow-up (B160)

Abstract

We have reported the clinical follow-up of diabetic patients xenotransplanted with islet cells. Here, we report the antibody response elicited against the xenograft after 6 years. Samples were screened by ELISA for anti-Gal IgM, IgG and IgG subclasses. Anti-pig antigen antibodies were tittered by means hemolytic antibody assay. Anti-Gal IgM and IgG titers of pretransplant sera were 90 and 115 respectively with no statistical differences in comparison with sera titers from healthy subjects. After first transplant the mean for anti-Gal IgG was 918 and increased with second and third transplants. After that the levels diminished to basal line. IgM titers were no different. IgG subclasses titers were not different, except for IgG2. Hemolytic anti-pig pretransplant antibodies mean was 320 however at this time the mean is 190. There is a classical humoral response against Gal antigen after each transplant with high levels of IgG but with very lower levels of IgM. However, these levels go backward 6 weeks after each transplant. During this assay we have observed an upsurge of IgG2 over the other subclasses. Low anti-pig levels elicited suggest an immune accommodation induced by this procedure.