The novel HLA-A*02:1152 and HLA-B*40:566 alleles identified in Russian bone marrow donors.

Identification of two novel HLA alleles in Russian bone marrow donors.

Full-length sequences of 3 HLA-B alleles, B*40:01:01, B*40:03 and B*40:40, confirmed by cloning and sequencing.

Full-length sequences of HLA-B*40:01:01, B*40:03 and B*40:40, confirmed by cloning and sequencing in Chinese donors.

Identification of an HLA class I allele closely involved in the autoantigen presentation in acquired aplastic anemia.

To identify HLA alleles closely involved in the autoantigen presentation in acquired aplastic anemia (AA), we studied the HLA allelic loss frequencies of 312 AA patients, including 43 patients with loss of heterozygosity of 6p chromosome (6pLOH). An analysis of the HLA alleles contained in the lost haplotype revealed HLA-B*40:02 to be the most frequently lost allele. When we examined 28 AA (12 6pLOH[+] and 16 6pLOH[-]) patients with HLA-B*40:02 for the presence of leukocytes lacking HLA-B4002 (B4002-) using a new monoclonal antibody specific to this allele, B4002- granulocytes were detected not only in all 6pLOH(+) patients but also in 9 (56%) of the 16 6pLOH(-) patients. Furthermore, 10 (83%) of the 12 6pLOH(+) patients possessed 1.0% to 78% B4002- granulocytes that retained the HLA-A allele on the same haplotype (B4002-A+), suggesting the frequent coexistence of granulocytes that underwent mutations restricted to HLA-B*40:02 with 6pLOH(+) (B4002-A-) granulocytes. Deep sequencing of the HLA-B*40:02 of sorted B4002-A+ granulocytes revealed various somatic mutations, such as frameshift, nonsense, and splice site mutations, in all 15 patients studied. Surprisingly, missense mutations in the α-3 domain of HLA-B*40:02 that are not involved in the antigen presentation were detected exclusively in the B4002+ granulocytes of 3 patients possessing B4002- granulocytes. The markedly high prevalence of leukocytes lacking HLA-B4002 as a result of either 6pLOH or structural gene mutations, or both, suggests that antigen presentation by hematopoietic stem/progenitor cells to cytotoxic T cells via the HLA-B allele plays a critical role in the pathogenesis of AA.

Identification of a novel HLA-B*40 allele, HLA-B*40:332, in a Korean individual.

HLA-B*40:332 differs from B*40:01:02 by 1 nucleotide difference at nucleotide position 439.

HLA-B*40:329, a novel HLA-B*40 variant, identified in a Taiwanese individual.

One nucleotide substitution at codon 254 of HLA-B*40:01:01 results in a new allele, HLA-B*40:329.

HLA-B*40:01:44, a novel variant of HLA-B*40:01, discovered in a Taiwanese hematopoietic stem cell donor.

One nucleotide replacement at residue 147 of HLA-B*40:01:01 results in a new allele, HLA-B*40:01:44.

HLA-B*40:306, a novel variant of HLA-B*40, discovered in a Taiwanese bone marrow hematopoietic stem cell donor.

One nucleotide substitution at residue 308 of the HLA-B*40:06:01:01 results in a new allele, HLA-B*40:306.

Identification of a novel HLA-B*40 allele, HLA-B*40:229, in a Chinese individual.

The novel HLA-B*40:229 allele shows one nucleotide difference from B*40:02:01 in exon 2 at nucleotide position 97 (C → T).

HLA-B*58:63, a novel allele identified by sequence-based typing in a Chinese bone marrow voluntary donor.

HLA-B*58:63 differs from HLA-B*58:01:01 by one nucleotide at position 248 resulting in a single amino acid change.

Identification of a novel HLA-B*40 allele, HLA-B*40:210, in a Chinese individual.

The newly detected HLA-B*40:210 allele has two nucleotide changes in exon 2 compared to B*40:49 allele.

Increased diversity of the HLA-B40 ligandome by the presentation of peptides phosphorylated at their main anchor residue.

Human leukocyte antigen (HLA) class I molecules bind peptides derived from the intracellular degradation of endogenous proteins and present them to cytotoxic T lymphocytes, allowing the immune system to detect transformed or virally infected cells. It is known that HLA class I-associated peptides may harbor posttranslational modifications. In particular, phosphorylated ligands have raised much interest as potential targets for cancer immunotherapy. By combining affinity purification with high-resolution mass spectrometry, we identified more than 2000 unique ligands bound to HLA-B40. Sequence analysis revealed two major anchor motifs: aspartic or glutamic acid at peptide position 2 (P2) and methionine, phenylalanine, or aliphatic residues at the C terminus. The use of immobilized metal ion and TiO2 affinity chromatography allowed the characterization of 85 phosphorylated ligands. We further confirmed every sequence belonging to this subset by comparing its experimental MS2 spectrum with that obtained upon fragmentation of the corresponding synthetic peptide. Remarkably, three phospholigands lacked a canonical anchor residue at P2, containing phosphoserine instead. Binding assays showed that these peptides bound to HLA-B40 with high affinity. Together, our data demonstrate that the peptidome of a given HLA allotype can be broadened by the presentation of peptides with posttranslational modifications at major anchor positions. We suggest that ligands with phosphorylated residues at P2 might be optimal targets for T-cell-based cancer immunotherapy.

Identification of 4 novel HLA-B*40:01 restricted minor histocompatibility antigens and their potential as targets for graft-versus-leukemia reactivity.

BACKGROUND: Patients with hematologic malignancies can be successfully treated with donor lymphocyte infusion after HLA-matched allogeneic hematopoietic stem cell transplantation. The effect of donor lymphocyte infusion is mediated by donor T cells recognizing minor histocompatibility antigens. T cells recognizing hematopoietic restricted minor histocompatibility antigens may induce selective graft-versus-leukemia reactivity, whereas broadly-expressed antigens may be targeted in graft-versus-host disease. DESIGN AND METHODS: We analyzed in detail CD8(+) T-cell immunity in a patient with relapsed chronic myelogenous leukemia who responded to donor lymphocyte infusion with minimal graft-versus-host disease of the skin. CD8(+) T-cell clones specific for 4 HLA-B*40:01 restricted minor histocompatibility antigens were isolated which were identified by screening a plasmid cDNA library and whole genome association scanning. Detailed T-cell reactivity and monitoring experiments were performed to estimate the clinical and therapeutic relevance of the novel antigens. RESULTS: Three antigens were demonstrated to be expressed on primary leukemic cells of various origins as well as subtypes of non-malignant hematopoietic cells, whereas one antigen was selectively recognized on malignant hematopoietic cells with antigen presenting cell phenotype. Skin derived fibroblasts were only recognized after pre-treatment with IFN-γ by two T-cell clones. CONCLUSIONS: Our data show evidence for different roles of the HLA-B*40:01 restricted minor histocompatibility antigens in the onset and execution of the anti-tumor response. All antigens may have contributed to a graft-versus-leukemia effect, and one minor histocompatibility antigen (LB-SWAP70-1Q) has specific therapeutic value based on its in vivo immunodominance and strong presentation on leukemic cells of various origins, but absence of expression on cytokine-treated fibroblasts.