EVALUATION OF THE PEL-FREEZ Cw HIGH RES SSP UNITRAY®FOR HIGH RESOLUTION HLA-Cw TYPING.

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EVALUATION OF THE PEL-FREEZ Cw HIGH RES SSP UNITRAY®FOR HIGH RESOLUTION HLA-Cw TYPING.
Edward S. Campbell , Patrick W. Adams and Charles G. Orosz . Columbus OH, the Ohio State University Medical Center, 43210, Surgery .

Our bone marrow transplant program requires allele-level typing for HLA-Cw. The PEL-FREEZ Cw High Res SSP UNITRAY® is a combination of 63 primer pairs designed to identify the HLA-Cw loci at the allele level. We have evaluated whether this product can provide a quick, inexpensive, and reliable allele-level HLA-Cw typing methodology. To do this, 249 bone marrow recipients and matched, unrelated donors were typed using the Cw High Res SSP UNITRAY®. The PEL-FREEZ Cw High Res SSP UNITRAY® unambiguously assigned 460 of the 479 alleles (96.03%) identified in this group of patients. Most of the 19 ambiguous HLA-Cw allele assignments fall into two groups. Group 1: the HLA-Cw*0401/04 ambiguity, accounted for 5 of the 19 ambiguities (26.32%) and could be attributed to shared sequences with a rare second HLA-Cw allele. This represented only 9.26% of all HLA-Cw*04 encountered. Group 2: the typings which yield ambiguities for both HLA-Cw alleles, accounted for 12 of the19 ambiguities (63.16%). These 6 samples were the only cases in which no allele-level assignments could be made for the patient and represents only 2.38% of all typings performed. The performance of this tray was further evaluated for the number of weak/failed reactions and how often the Cw High Res SSP UNITRAY® required repeat testing. Only 100 of the 15,876 PCR reactions (0.63%) were weak or failed. Only 3 of these failed reactions were relevant to the analysis and required the test to be repeated. All three repeat tests resolved the allele assignment. A repeat test rate of 1.19% is exceptional and indicates a high quality product. The PEL-FREEZ Cw High Res SSP UNITRAY® provides us with a quick, inexpensive, and nearly unambiguous method for HLA-Cw high resolution typing, and represents a significant quality improvement to our typing strategy.