Identification of the novel allele, HLA-A*02:653, in an Italian patient.

HLA-A*02:653 differs from A*02:01:01:01 by a C to T substitution in exon 2.

A new allele, HLA-A*03:275N.

The novel allele HLA-A*03:275N differs from HLA-A*03:01:01:01 by 1 nucleotide substitutions in exon 2.

Identification of the new HLA-DQA1*01:15N allele in an Italian patient.

The novel allele DQA1*01:15N differs from DQA1*01:03:01:01 by 1 nucleotide substitutions in exon 2.

Identification of the new C*07:555 allele in an unrelated donor for HSCT.

HLA-C*07:555 differs from C*07:01:01:01 by a C to G substitution in exon 2.

Characterization of the novel HLA-C*02:106 allele in a hematopoietic stem cell volunteer donor.

HLA-C*02:106 allele differs from C*02:02:02:01 by a C to T substitution in exon 4.

HLA-A-B-C-DRB1-DQB1 phased haplotypes in 124 Nigerian families indicate extreme HLA diversity and low linkage disequilibrium in Central-West Africa.

The simultaneous typing of five-HLA loci at high resolution and the availability of pedigree data allowed us to characterize extended five-locus phased haplotypes in 124 Nigerian families and to compare the observed frequencies with those expected by an expectation-maximization algorithm for unphased data. Despite the occurrence of some frequent alleles at each locus (e.g. B*53:01, which is assumed to protect against Plasmodium falciparum), as many as 82% of the sampled individuals carry two unique five-locus haplotypes and only three extended haplotypes with frequency above 1% exhibit significant linkage disequilibrium. Although preliminary, these results reveal an extreme level of HLA diversity in the Nigerian population, which reflects both its multi-ethnic composition and the very ancient demographic history of African populations.

Sequence-based typing characterization of the novel HLA-DRB3*01:16 allele, identified in an Italian family.

The novel DRB1*01:16 allele differs for G to T substitution at position 595 from DRB3*01:01P.

Influence of the HLA characteristics of Italian patients on donor search outcome in unrelated hematopoietic stem cell transplantation.

The information regarding the probability of finding a matched unrelated donor (MUD) within a relatively short time is crucial for the success of hematopoietic stem cell transplantation (HSCT), particularly in patients with malignancies. In this study, we retrospectively analyzed 315 Italian patients who started a search for a MUD, in order to assess the distribution of human leukocyte antigen (HLA) alleles and haplotypes in this population of patients and to evaluate the probability of finding a donor. Comparing two groups of patients based on whether or not a 10/10 HLA-matched donor was available, we found that patients who had a fully-matched MUD possessed at least one frequent haplotype more often than the others (45.6% vs 14.3%; P = 0.000003). In addition, analysis of data pertaining to the HLA class I alleles distribution showed that, in the first group of patients, less common alleles were under-represented (20.2% vs 40.0%; P = 0.006). Therefore, the presence of less frequent alleles represents a negative factor for the search for a potential compatible donor being successful, whereas the presence of one frequent haplotype represents a positive predictive factor. Antigenic differences between patient and donor observed at C and DQB1 loci, were mostly represented by particular B/C or DRB1/DQB1 allelic associations. Thus, having a particular B or DRB1 allele, linked to multiple C or DQB1 alleles, respectively, might be considered to be associated with a lower probability of a successful search. Taken together, these data may help determine in advance the probability of finding a suitable unrelated donor for an Italian patient.

Detection of the new HLA-DRB1*14:129 allele in a voluntary stem cell donor.

The new allele, officially named HLA DRB1*14:129, differs from HLA DRB1*14:54 in exon 2.

The novel HLA-A*03:143 allele, identified by sequence-based typing in an Italian family.

HLA-A*03:143 has one nucleotide change from A*03:01: 01:01 at nt 406 from G to C, resulting in an amino acid change at codon 112 of exon 3 from Gly to Arg.

Characterization of the novel HLA-C*07:195 allele in an Italian hematopoietic stem cell volunteer donor, detected by sequence-based typing.

The new allele shows one nucleotide change from C*07:02:01:01 at 351 nt from C to A, resulting in an amino acid change at codon 93 of exon 3 from H to Q.

Identification of the new HLA-A*31:48 allele in an Italian patient.

Human leukocyte antigen (HLA) class I sequence-based typing (SBT) for hematopoietic unrelated donor searching in an Italian Caucasian patient showed the presence of a novel HLA-A allele defined as A*31:48. HLA-A*31:48 has one nucleotide change from A*31:01:02 at nt 727 from C to T, resulting in an amino acid change at codon 219 of exon 4 from Arg to Trp.

Identification of a novel HLA-B*07 allele in an Iranian family: B*0769.

New allele B*0769 showed one nucleotide difference with B*0732 at codon 272 (TTC-->TGC).

A new HLA-DRB1*11 allele, DRB1*1144, identified by cloning and sequencing.

We report here the identification of a novel DRB1*11 allele, DRB1*1144, identified during sequence-based HLA-DRB1 typing. Molecular cloning and direct sequencing confirmed that the new allele is identical to DRB1*110401 at exon 2, except for a single nucleotide substitution (GTG-->GCG) changing codon 38 from Valine to Alanine.