Kidney transplantation in a recipient with anti-HLA antibody IgM positive

In general, anti-HLA antibody belongs to the IgG subclass, but there are very few reports of detection of anti-HLA IgM antibodies. In the present study, we report a renal transplant recipient with a positive NIH-complement dependent cytotoxicity (NIH-CDC) test. The patient was a 24-year-old male with focal segmental glomerulosclerosis (FSGS) as the underlying kidney disease. He had been on maintenance hemodialysis since December 2003 and finally received a living-donor allograft from his mother in October 2008. Pre-transplantation, the NIH-CDC test was positive for both B and T cells, but the flow-cytometric crossmatch test (FCXM) was negative for both cells. The result of the panel-reactive antibody assay (PRA)-single beads test using anti-IgM antibody as the second antibody demonstrated that the positive NIH-CDC test was due to the presence of anti-HLA IgM antibody against the donor-specific antigen A24. Biopsy specimens showed thrombus formation in a small number of glomeruli immediately after the transplantation, but this finding was no longer seen at three months postoperatively. We report successful renal transplantation in a case with anti-HLA IgM antibody.