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PRE-TRANSPLANT DONOR REACTIVE CLASS II ANTIBODIES ARE AS PATHOGENIC AS CLASS I ANTIBODIES IN PRIMARY RENAL ALLOGRAFTS.
Denise Pochinco RT , Howard Gebel PhD , Robert Bray PhD , Ian Gibson MD , David Rush MD , Martin Karpinski MD , John Jeffery MD and Peter Nickerson MD . Winnipeg MB, Canada, University of Manitoba, R3E 3R4, Faculty of Medicine and Atlanta GA, Emory University, Dept of Pathology .

There is much debate as to the significance (i.e. risk for acute humoral rejection and/or early graft loss) of donor reactive Class II antibodies detected pre-transplant in primary renal allografts, relative to the risk that donor reactive Class I antibodies portend. In the current study we compared the clinical outcomes of patients transplanted in the presence of donor reactive Class I or II HLA antibodies.
Of 303 primary renal allografts transplanted between 1992-2003 (negative AHG-CDC T-cell and negative CDC B-cell crossmatch), 46 were retrospectively found to have Class I or Class II antibodies present in the pre-transplant sera by FlowPRA assessment. These 46 patients had the specificity of the HLA antibodies determined by flow using donor cells, as well as specificity and/or single antigen beads. The patients were segregated into 3 groups: Donor reactive Class I (n=17), Class II (n=10) or Controls (HLA antibodies present but none donor reactive (n=19)).
There was no difference in outcome between patients with donor reactive Class I or II antibodies; both had earlier and higher rates of rejection as well as graft loss compared to patients with pre-transplant antibodies that were not donor reactive (table; * p<0.05 vs. Control).

GroupRejection <28daysDay of RejectionHumoral Graft LossDay of Graft Loss
Class I (n=17)15 (88%)*6 (1-19)*5 (29%)*3 (1-12)
Class II (n=10)7 (80%)*5 (2-9)*3 (30%)*5 (2-9)
Control (n=19)4 (21%)13 (8-19)0 (0%)na


In conclusion, detection and specificity analysis of Class II antibodies should be pursued just as aggressively as Class I antibodies in the pre-transplant evaluation in order to optimize transplant management.