A novel HLA-B*18:80 allele identified by SBT typing in an Italian bone marrow volunteer donor.

A novel allele, officially named B*18:80, was detected in a Caucasoid individual by polymerase chain reaction-sequence-specific primers and SBT. The new allele differs from B*18:01:01 at two nucleotidic positions in codon 24 at exon 2.

Molecular modelling of HLA-B*35:132.

Here we describe the molecular modelling of the new variant HLA-B*35:132. This allele shows one mismatch with B*35:01:01:01 in exon 3 at position 575 where a T is substituted by a C, which implies an amino acidic change from Leucine to Proline. This seems not to alter the molecular structure and not to compromise the HLA complex and T-cell receptor interaction.

Description of the novel HLA-DPB1*137:01 allele found in an Italian subject.

In this report, we describe the identification and sequencing of a novel HLA-DPB1 allele, found in an Italian haematological patient. This allele is identical to DPB1*17:01 except for a single nucleotide substitution (GAC→GAG) at position 57, which changes the encoded amino acid from Asp to Glu.

Description of two new HLA-C alleles: C*08:63 and C*14:44.

Here, we present two new HLA allelic variants at C locus: HLA-C*08:63 and HLA-C*14:44 detected by sequence-based typing. In both cases, a single-nucleotide mutation in exon 3 is responsible for a change in aminoacid translation. The extremely high polymorphism of human leucocyte antigen (HLA) system in human genome is responsible for the capability to recognize different antigens, including non-self-MHC (Major Histocompatibility Complex) molecules. This very high polymorphism and the improving accuracy of genomic HLA typing methods lead to an exponential increasing of known HLA alleles. Here, we describe the characterization of two new HLA-C alleles identified by sequence-based typing (SBT): HLA-C*08:63 and HLA-C*14:44.

Identification of two novel HLA-A alleles: A*24:199 and A*02:324.

Here, we describe two new HLA-A alleles: A*24:199 and A*02:324. The two new variants are attributed to a single nucleotide mutation namely A→C for A*24:199 and G→A for A*02:324. Both point mutations are responsible for a change in translated amino acids.

Two novel alleles at HLA-B locus identified in two volunteer bone marrow donors by sequence-based typing.

Two novel human leucocyte antigen (HLA) class I alleles have been identified in two Italian individuals. HLA-B*27:07:02 is identical to HLA-B*27:07:01 except for a nucleotide substitution at position 846 (A->G) resulting in a silent mutation. HLA-B*35:206 differs from the most similar allele, HLA-B*35:08:01, because of a single base mutation at position 149 (G->C) causing an aminoacidic change at codon 26 from Gly to Ala.

Description of the new allele HLA-DQB1*04:03:02.

A new variant of HLA-DQB1*04:03 allele officially designated as HLA-DQB1*04:03:02 was detected in two unrelated Caucasoid individuals by polymerase chain reaction-sequence-specific primers and SBT. The new allele nucleotide sequence differs from HLA-DQB1*04:03:01 for a single silent point mutation in exon 2 at position 159, codon 21.

Sequence of a novel HLA-B*51 allele in a volunteer haematopoietic stem cell donor.

We describe a novel HLA-B*51 allele detected by DNA direct sequencing. The sequence of this allele has been officially named B*51:78 as a confirmatory sequence. This new allele nucleotide sequence differs from HLA-B*51:01:01 for two point mutations in exon 2 where codons 79-80 change from CGG-ATC to CGC-ACC (p.Ile80Thr).

A discrepancy between serological and molecular typing results led to identification of a novel HLA-B*57 allele: HLA-B*5728N.

Summary Here, we describe the characterisation of a new allelic variant of HLA-B*57. The novel allele, HLA-B*5728N, was identified with sequence-based typing in a Caucasoid family. HLA-B*5728N, differs from HLA-B*5701 because of a nucleotide substitution at position 420 (C->G) resulting in a coding change from Tyrosine to a stop codon.

Identification of two new HLA-DRB1 alleles, DRB1*040405 and DRB1*1190.

We describe here two novel DRB1 alleles, officially named *040405 and *1190. DRB1*040405 differs from DRB1*0404 for one point mutation at codon 72 with no coding changes. DRB1*1190 is identical to DRB1*110101 except for a nucleotide substitution at codon 24 which causes an aminoacidic mutation from valine to methionine. Over time we have been witnessing the identification of a great number of new HLA alleles. DRB1 allelic variability is mostly present in the second exon and more that 760 alleles have been so far identified. Here, we report the description of two novel DRB1 alleles, named *040405 and *1190, and identified in two Caucasoid subjects.

A silenced allele in the Colton blood group system.

BACKGROUND: The antigens of the Colton blood group system, Co(a) and Co(b), are encoded by a single gene that produces the aquaporin-1 (AQP1) protein, a water channel-forming protein, and are characterized by a single nucleotide polymorphism (SNP). A healthy Caucasoid blood donor originally typed as Co(a-b-) with commercial anti-Co(b) typed Co(a-b+) when retested with another anti-Co(b). Retyped with two different molecular biology methods, the sample came out Co(a)/Co(b). With the aim of understanding these discrepancies, serological, cytometric and molecular biology tests were carried out. METHODS: Absorption/elution studies with propositus red cells and controls were performed. The region spanning exon 1 to exon 4 of the Colton gene was sequenced, and flow cytometry analyses were carried out. RESULTS: Absorption/elution studies showed the absence of Co(a) and a weak expression of Co(b). DNA sequencing confirmed a CT heterozygosity at nucleotide position 134 (i.e. Co(a)/Co(b)), and an additional heterozygous CT was found at position 112. The presence of the Co(b) allele that encodes for the Co(b) antigen was confirmed. The new allele has the base cytosine at nucleotide 134 (Co(a)), in cis with the new nucleotide 112T. The nucleotide substitution 112C>T causes a missense mutation leading to an amino acid change from proline (CCG) to serine (TCG) at codon 38. CONCLUSION: The substitution found at codon 38 results in a modified AQP1 protein which explains the Co(a-b+) phenotype and possibly the weak expression of Co(b).

Characterization of two novel HLA class I alleles: HLA-A*310103 and HLA-B*9531.

Two novel human leucocyte antigen (HLA) class I alleles were characterized by means of sequencing-based typing techniques. HLA-A*310103 was identified in a cord blood unit from a Caucasoid individual. The sequence of this allele is identical to that of HLA-A*310102 except for a silent mutation in exon 3 at position 480 (G --> A). HLA-B*9531 was found in a Caucasoid female patient registered on the heart transplantation waiting list in the North Italy Transplant programme. This new variant differs from HLA-B*1503 at position 572 (G --> C) in exon 3. This nucleotide change leads to an amino acidic substitution at codon 167 from tryptophan to serine.

Identification of two novel HLA-DRB1*11 alleles (DRB1*110404 and DRB1*1161) in two Italian cord blood units.

We describe the isolation and characterization of two novel HLA-DRB1*11 alleles, officially named DRB1*1161 and 110404. These two new variants were both identified in two Caucasoid individuals. The exon 2 sequence of DRB1*1161 is identical to that of DRB1*110101 except at codon 41, where a nucleotide substitution (GAC>AAC) is responsible for an amino-acidic change from Asp to Asn. The exon 2 sequence of the second novel allele described here, DRB1*110404, differs from that of DRB1*110401 only at codon 34 where the nucleotidic change CAA>CAG gives rise to a silent mutation.

Characterization of a novel HLA-DRB1*04 allele (DRB1*0460) in the Italian population.

We report the identification of a novel HLA-DRB1*04, officially named DRB1*0460. It was detected during performing HLA-DRB1 high resolution typing by DNA sequencing-based method. The exon 2 nucleotide sequence of DRB1*0460 is identical to that of DRB1*040301 except at codon 63 (AGC-->AAC), changing the encoded serine to asparagine.

Distribution of killer cell immunoglobulin-like receptors genes in the Italian Caucasian population.

BACKGROUND: Killer cell immunoglobulin-like receptors (KIRs) are a family of inhibitory and activatory receptors that are expressed by most natural killer (NK) cells. The KIR gene family is polymorphic: genomic diversity is achieved through differences in gene content and allelic polymorphism. The number of KIR loci has been reported to vary among individuals, resulting in different KIR haplotypes. In this study we report the genotypic structure of KIRs in 217 unrelated healthy Italian individuals from 22 immunogenetics laboratories, located in the northern, central and southern regions of Italy. METHODS: Two hundred and seventeen DNA samples were studied by a low resolution PCR-SSP kit designed to identify all KIR genes. RESULTS: All 17 KIR genes were observed in the population with different frequencies than other Caucasian and non-Caucasian populations; framework genes KIR3DL3, KIR3DP1, KIR2DL4 and KIR3DL2 were present in all individuals. Sixty-five different profiles were found in this Italian population study. Haplotype A remains the most prevalent and genotype 1, with a frequency of 28.5%, is the most commonly observed in the Italian population. CONCLUSION: The Italian Caucasian population shows polymorphism of the KIR gene family like other Caucasian and non-Caucasian populations. Although 64 genotypes have been observed, genotype 1 remains the most frequent as already observed in other populations. Such knowledge of the KIR gene distribution in populations is very useful in the study of associations with diseases and in selection of donors for haploidentical bone marrow transplantation.

Description of a new HLA-DRB1*1104, DRB1*110403.

We report here the exon 2 sequence of the novel HLA-DRB1*110403 which differs from DRB1*110401 by a single synonymous nucleotide substitution at codon 78, where TAC is substituted by TAT. The variant originally identified in a Caucasoid individual was confirmed by cloning and sequencing.

HLA-A*2626, a new allele identified through external proficiency-testing exercise.

A new allele, officially named HLA-A*2626, has been detected in a blood sample belonging to a Caucasian subject human leucocyte antigen typed for Lombardy Region external proficiency-testing exercise. The DNA sequences of exons 2, 3 and 4 of this new allele are identical to those of HLA-A*2601 except at codon 259 of exon 4 (CCT-->CTT). This variation modifies the encoded protein from proline to leucine.

Identification of a new HLA-B variant, HLA-B*5615.

A new HLA-B allele, B*5615, has been identified in a Caucasian individual by sequence-based typing. This allele shows a sequence identical to that of HLA-B*5601 except for two nucleotide substitutions that cause a change from TTA to TAC at codon 116 and an amino acidic change from Leucine to Tyrosine in the mature protein.