Positive Crossmatch Need Not Stop Tx

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Successful renal transplantation can occur with an appropriate pre- and post-transplant protocol.

 

SAN FRANCISCO—Many renal transplant candidates who have a positive AHG-CDC crossmatch can undergo successful transplantation, a new study suggests. The study showed that only 41% of recipients with weak AHG-CDC positive crossmatches have HLA-specific donor-specific antibody (DSA).

 

“With our treatment protocol, the 41% who have a higher risk of rejection because they have donor-specific antibody have the same one-year graft survival as those who didn't have donor-specific antibody to begin with,” said Michael Goldstein, MD, assistant professor of surgery at Weill Cornell Medical College in New York. The remaining 59% “don't require any treatment at all and have very low risk of rejection,” he observed.

 

The treatment protocol used at his institution requires pre-treatment of the recipients before transplantation, and some post-treatments. For optimal outcomes, he stressed that flow-bead antigen analysis and flow-cytometric donor-specific crossmatch should be used to guide therapy.

Dr. Goldstein and his colleagues analyzed the records of all deceased donor renal transplant recipients who received an allograft with a heat-inactivated AHG-CDC positive preoperative crossmatch over a 22-month period. All recipients with a positive AHG-CDC crossmatch received preoperative intravenous immunoglobulin (IVIg) and were screened by flow-bead antigen analysis and flow-cytometric donor-specific crossmatch to determine the presence of DSA. Patients with DSA were treated post-transplantation with a second dose of IVIg and rituximab. For this analysis, the outcomes of the DSA-positive patients were compared with those of the DSA-negative recipients.

 

Of the 290 renal transplant patients, 27 (9.3%) had a heat-inactivated positive AHG-CDC crossmatch. Twenty-five of these (93%) were AHG-CDC B-cell positive and two (7%) were both T-cell and B-cell positive. Eleven patients tested positive for DSA and were treated post-transplantation.

 

Dr. Goldstein said the median peak panel reactive antibody (PRA) for positive and negative DSA recipients were 87.5% and 15.5%, respectively. The groups were similar with respect to delayed graft function (DGF), length of hospital stay, and early graft function at three and six months. The one-year graft survival rates were 91% and 100% for the sensitized and non-sensitized recipients, respectively. 

 

Study findings were presented here at the 2007 American Transplant Congress.

 

“There are many transplant patients who are not being transplanted with specific deceased donor organs because of a potential risk of antibody rejection due to a weakly positive crossmatch. I think that the majority of the transplant programs in the country may turn away or shy away from transplanting that patient because of a potential risk for early rejection. What is suggested here is that the majority, 59%, do not have a higher risk of rejection and the 41% who do have potentially higher risk for rejection can be easily treated,” Dr. Goldstein told Renal & Urology News. “We are pushing the envelope, but the results show that these donors should be used and more transplants of this type should be done.”

 

Roy Bloom, MD, medical director of the Kidney Transplant Program at the University of Pennsylvania in Philadelphia, said the new findings are interesting. “They suggest we don't need to be as strict in our criteria for determining who should be transplanted and with what kind of crossmatch.”                                                                        

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