Assessed by IARC on November 18, 2019 during meeting 45 and on December 2, 2019 during meeting 46.

The committee considered IGHV2-70*04_S4496 (C6T) of submission S00010 of Genotype B16, which was previously evaluated as IGHV2-70D*04_S2803 of submission S00006 at Meeting 11. It was affirmed as a Level 0 sequence at that time.

The sequence was seen in just 0.09% of all unmutated rearrangements, with 687 sequences including 252 perfect matches to the inferred allele. There was abundant variation in the CDR3 regions of the aligned sequences. One other IGHV2-70 sequence was present in the genotype, and haplotype data suggests that both these sequences are carried on a single chromosome, one of them possibly located to IGHV2-70D. The rearrangement frequency was above the agreed threshold (0.05%), but In light of the very low frequency of rearrangements seen and the complicated haplotype profile, it was affirmed as a Level 0 sequence. The sequence was affirmed up to and including nucleotide 319 even though alleles of IGHV2-70/IGHV2-70D in general extend up to and including base 322. However, the nucleotide composition of the subsequent three bases of genes associated with this inferred allele did not support their inference. It is however likely that three additional 3’ nucleotides are present in the sequence, and this is indicated in IARC and OGRDB publications by three dots at the end of the sequence.