Presensitization revisited: pitfalls of vascular allografts in transplant candidates
A 44-year-old woman previously immunized by several pregnancies developed ESRD and started hemodialysis in 2009. The first arteriovenous fistula soon occluded. Neither surgical revisions nor prosthetic grafts resulted in long-term patency. Menometrorrhagia led to blood transfusions in 2009 and 2011. Antibodies to several HLA class I molecules were detected in a Luminex single antigen assay before the first blood transfusions, but by August 2010 only reactivity to HLA-A24 was observed (a mean fluorescence index >1000 defined as positive). Overweight delayed by 2 years acceptance to the renal transplant ‘waiting list’. Meanwhile, graft thrombosis impaired dialysis access, necessitating insertion of a fresh arterial allograft from a deceased donor in September 2010. Antibodies to a broad range of HLA class I and II molecules were detected by Luminex single antigen assay in January 2012, but the panel reactive antibodies (PRAs), as determined by CDC cell screening, remained negative. Menometrorrhagia precluded anticoagulation. The arterial allograft was found obliterated at removal in February 2012 and replaced by another fresh arterial allograft. By April 2012, the PRA reactivity was 80% and Luminex analyses in June 2012 identified strong antibodies to almost all HLA class I and II molecules, including HLA-A1, -B60, -DR4 and -DQ8 present in the allograft.