INTERNATIONAL CELL EXCHANGE–CORRELATION OF SEROLOGIC EQUIVALENTS TO RARE AND NOVEL ALLELES IDENTIFIED IN CELLS CONTRIBUTED TO THE 13TH IHWS

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TITLE: INTERNATIONAL CELL EXCHANGE–CORRELATION OF SEROLOGIC EQUIVALENTS TO RARE AND NOVEL ALLELES IDENTIFIED IN CELLS CONTRIBUTED TO THE 13TH IHWS

Marie Lau,¹ Min S. Park,¹ Paul I. Terasaki,² Elaine F. Reed.¹

¹UCLA Immunogenetics Center, University of California, Los Angeles, Los Angeles, California; ²Terasaki Foundation Laboratory, Los Angeles, California

For a 33–month period (September 1999 through May 2002), the International Cell Exchange contributed 108 cells to be typed on the 13th IHWS trays in the Serology and Null Alleles Component (Project 6). The cells were isolated from normal donors representing different ethnic groups, including Hispanics (25%), Black (21%), Caucasian (21%), Asian (15%), Filipino (15%), and mixed (3%). Related donors were typed, resulting in 5 family studies. 37 HLA–A–locus, 79 HLA–B–locus, and 29 Cw–locus alleles were identified, for a total of 145 Class I alleles, which were correlated to serologic equivalents. A high percentage of them were determined to be rare or new, 45% of the A–locus (n = 17), 54% of the B–locus (n = 43), and 69% of the Cw–locus (n = 20) alleles. The serologic expression for 2 new B–locus alleles, B*4416 and B*5204, was evaluated. For the novel B*4416, its serologic expression as B47 was explained by the 2 amino acid changes at 163 (L to E) and 167 (S to W) due to 3 nucleotide substitutions in exon 3 (pos 559, 560, 572) which then makes the encoding sequence identical to the B*4701–03 sequences.¹ Unusual and short anti–B52 serologic reactivity patterns were reported for B*5204, which differs from B*52011 at pos 200 (C to A).²

For over 28 years, the International Cell Exchange has provided a process to standardize HLA typing, as well as to reveal new and rare antigens, on a collaborative basis among laboratories worldwide. By sending 4 cells from peripheral blood on a monthly basis to be typed for Class I antigens by serology and DNA methods, invaluable information is obtained for the growing number of new alleles. The typing data from the exchange cells contributed useful information to the 13th Workshop Project 6 component, to attain its goal of assigning serologic specificity equivalents to alleles previously defined by DNA only. This data is routinely added to the HLA dictionary³ that offers allele–serologic equivalents to be used in matching searches for unrelated donors.

¹Lau M et al. Report of the 255th Cell Exchange, November 10, 1999.

²Lau M et al. Report of the 270th Cell Exchange, June 6, 2001.

³Schreuder G.M.Th. et. al (2001) Tissue Antigens 58, 109–40.