Identification of the DRB4*01:03:01:02N null allele with HLA‐DRB1*04 in a Spanish donor

Abstract

The association between the DRB4*01:03:01:02N null allele and the HLA‐DRB1*07~DQB1*03:03 haplotype has often been reported. Nevertheless, more unusual associations have also been found in other countries, such as its association with HLA‐DRB1*04. HLA class I and II antigen typing is currently performed using DNA‐based methods, making it more difficult to identify null alleles than if serological methods were used. Furthermore, the DRB3/4/5 loci are not usually studied. However, the identification of non‐expressed HLA alleles is of great importance for transplantation so it is necessary to identify HLA antigen associations with null alleles and report these findings. In this paper, we describe the association of DRB4*01:03:01:02N null allele with DRB1*04 for the first time in Spain.

Identification of a DRB1*04:07–DRB4*01:03:01:02N haplotype in a native American individual

“…The DRB4*01:03:01:02N allele, first described in 1989, is characterized by a point mutation in the acceptor splice site at the 3′ end of the first intron (AG > AA), leading to incorrect processing of the mRNA transcript and resulting in a non‐expressed allele 5,6 . DRB4*01:03:01:02N is predominantly associated with the DRB1*07:01 – DQB1*03:03 haplotype, 8 although several reports have demonstrated a less frequent association of this allele with DRB1*04 carrying haplotypes in European populations, specifically with DRB1*04:01 , DRB1*04:02 , DRB1*04:03 , and DRB1*04:04 9–12 . A list of the reported DRB1*04 – DRB4*01:03:01:02N – DQB1 associations is provided in Table 2.…”