Identification of a novel HLA-B*2722 allele from a Filipino cell

We present the novel HLA-allele B*2722 amplified and sequenced from a Filipino individual. This DNA was included several times in the International Cell Exchange, UCLA, and typed at the time as B*27 or B*2706 by the majority of the participating laboratories. The second HLA-B allele of this person is B*3802. B*2704/06 or B*2704/06/10 were suggested by approximately one-third of the laboratories. As we were investigating the intron 3 sequences of B*27 alleles, we also sequenced exon 4 of this Filipino DNA and found a single nucleotide exchange in exon 4 (pos. 704) which was not in concordance with the previous B*2706 typing. Our sequencing results showed that the coding sequence of B*2722 is identical to B*2706 in exon 1, 2 and 3. In exon 4 the B*2722 sequence is identical to B*2704. HLA-B*2704 differs from B*2706 in one base at position 704, a G in B*2704 and a C in B*2706, respectively.