Characterization of a new HLA-C allele in a Caucasian Italian family by sequence-based typing: HLA-Cw*0730.
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Adult↗
Biomedical subjects
L Delfino
Publications and source records attributed to L Delfino.
Characterization of a new HLA-DRB1*01 allele (HLA-DRB1*010203) in a Caucasian Italian family by using sequence-based typing.
We report the identification of an HLA-DRB1*01 nucleotide sequence variant in three members of a Caucasian Italian family by using sequence-based typing. The nucleotide sequence of exon 2 observed in the new allele is identical to that of HLA-DRB1*010201 except in position 189 (codon 34) where the adenine of the consensus was replaced by a guanine and it was designated officially as HLA-DRB1*010203* by the WHO Nomenclature Committee.
Alleles↗
HLA-C sequence based typing: nucleotide analysis from exon 1 through exon 8. Identification of a new allele: Cw*0718.
At present, 128 HLA-Cw alleles have been described. Twenty-four of 128 display critical polymorphisms in contributing to allele identification outside exons 2 and 3. As a matter of fact, complete resolution of Cw*030201, Cw*030202, Cw*0409N, Cw*0501, Cw*0503, Cw*070101, Cw*070102, Cw*070401, Cw*0706, Cw*0711, Cw*0718, Cw*120201, Cw*120202, Cw*150501, Cw*150502, Cw*1701, Cw*1702, Cw*1703, Cw*1801 and Cw*1802 alleles requires nucleotide analysis of exons 1, 4, 5, 6 and 7. Moreover, some alleles (Cw*04010101, Cw*04010102, Cw*07020101 and Cw*07020102) showing nucleotide differences outside the coding regions of HLA-C gene (intron 2) have been reported. High resolution sequence based typing (SBT) developed in this study involves two DNA amplifications and 12 direct sequencing reactions and allows the analysis of HLA-C polymorphisms from exon 1 through exon 8, including intron 2. This typing procedure identifies all 128 Cw alleles described so far. Nevertheless, a number of ambiguous heterozygous typing results may be expected, this being the major drawback of SBT methods. A total of 201 samples were HLA-C typed using SBT strategy here described. The sequence of exons 6, 7 and 8 of HLA-Cw*070102 allele was elucidated. A novel HLA-Cw*07 allele, Cw*0718, was identified in two samples. Cw*0718 differs from the Cw*070101 allele by a unique nucleotide position within exon 6, resulting in an amino acid substitution at codon 324 (Ala-->Val) in the cytoplasmic region of the molecule.
HLA-C Antigens↗
Bone marrow transplantation from unrelated donors: the impact of mismatches with substitutions at position 116 of the human leukocyte antigen class I heavy chain.
The hypothesis was tested that amino acid substitutions in specific positions within human leukocyte antigen class I heavy chain would have different impacts on transplant-related mortality (TRM) in patients receiving transplanted bone marrow from unrelated donors. One hundred patients and their unrelated donors were typed by sequence-based typing for the human leukocyte antigen (HLA)-A, -B, and -C loci. All pairs were matched for DRB1, DRB3, DRB4, DRB5, DQA1, and DQB1 loci. Forty pairs were also matched at class I, and 60 pairs had one or more mismatches at class I loci. It was found that substitutions at positions 116 and 114 of class I heavy chain significantly increased the risk for TRM in univariate and bivariate Cox analyses. Conversely, no association between number of multiple mismatches or number of amino acid substitutions and TRM was seen when positions 116 and 114 were adjusted for. Variables predictive of TRM in multivariate Cox analysis were number of cells infused, diagnosis (chronic myeloid leukemia [CML] or non-CML), and amino acid substitution at position 116 or 152. The only variable predictive of severe acute graft-versus-host disease (GVHD) in multivariate Cox analysis was substitution at position 116. Actuarial risk for acute GVHD grade III-IV, TRM, and relapse in pairs with substitutions at position 116 (n = 37) compared to other pairs (n = 63) was, respectively, 36% versus 14% (P =.01), 59% versus 28% (P =.001), and 25% versus 31% (P =.4). In conclusion these data suggest that substitutions at position 116 of class I heavy chain increase the risk for acute GVHD and TRM in patients who receive transplanted bone marrow from unrelated donors.
Adult↗
Noninvasive prediction of sudden death and sustained ventricular tachycardia after acute myocardial infarction using a neural network algorithm.
BACKGROUND: The early and accurate noninvasive identification of postinfarction patients at risk of sudden death and sustained ventricular tachycardia (arrhythmic events) still remains an unsolved problem. The aim of the present study was to identify the combination of clinical and laboratory noninvasive variables, easy to obtain in most patients, that best predicts the occurrence of arrhythmic events after an acute myocardial infarction. METHODS: Four hundred and four consecutive patients with acute myocardial infarction were enrolled and followed for a median period of 21.4 months. In each patient, 61 clinical and laboratory noninvasive variables were collected before hospital discharge and used for the prediction of arrhythmic events using an artificial neural network. RESULTS: During follow-up, 13 (3.2%) patients died suddenly and 11(2.5%) had sustained ventricular tachycardia. The neural network showed that the combination best predicting arrhythmic events included: left ventricular failure during coronary care stay, ventricular dyskinesis, late potentials, number of ventricular premature depolarizations/hour, nonsustained ventricular tachycardia, left ventricular ejection fraction, bundle branch block and digoxin therapy at discharge. The neural network algorithm allowed identification of a small high-risk patient subgroup (12% of the study population) with an arrhythmic event rate of 46%. The sensitivity and specificity of the test were 96 and 93% respectively. CONCLUSIONS: These results suggest that, in postinfarction patients, it is possible to predict early and accurately arrhythmic events by noninvasive variables easily obtainable in most patients. Patients identified as being at risk are candidates for prophylactic antiarrhythmic therapy.
Aged↗
Novel associations among HLA-DQA1 and -DQB1 alleles, revealed by high-resolution sequence-based typing (SBT).
Althought it is a valuable tool for the identification of HLA alleles, sequence-based typing (SBT) presents difficulties when used to determine HLA-DQA1 and -DQB1 alleles. Specifically, some HLA-DQA1 alleles have a three-base deletion at codon 56 of exon 2 that interferes with the sequencing read. Moreover, the frequently used primers for HLA-DQB1 may co-amplify the HLA-DQB2 pseudogene. To overcome these problems, we amplified DQA1 exon 2 using five group-specific polymerase chain reactions (PCRs) which allowed separation of deleted from non-deleted DQA1 alleles. DQB1 exon 2 was amplified using two group-specific amplifications. To increase typing resolution, we also analyzed DQA1 exons 1, 3 and 4 and DQB1 exon 3 by PCR using sequence-specific primers (PCR-SSP) or SBT analysis. Using this method we found some important associations between DQA1 and DQB1 alleles: DQA1*05011 and DQB1*0201, DQA1*0505 and DQB1*03011, DQA1*01021 and DQB1*06, DQA1*01022 and DQB1*0502.
Alleles↗
Identification of a new DRB3*02 allelic variant (DRB3*0209) by high-resolution sequence-based typing.
The HLA-DRB3/B4/B5 sequence-based typing method developed in this study in combination with PCR-SSP, enabled us to identify a new DRB3*02 allele, that was named as DRB3*0209 (GenBank accession number AF148518). This name has been officially assigned by the WHO Nomenclature Committee in May 1999. The new allele differs from DRB3*0207 by one substitution in codon 51 from AGG to ACG and another in codon 60 from TAC to TCC, resulting in aminoacid changes from Arg-->Thr (codon 51) and from Tyr-->Ser (codon 60). The DRB3*0209 allele was discovered in two related North Italian families. The fact that it was present in an hemizygous situation in three members of the paternal family and in one member of the secondary related family enabled us to isolate and sequence the new DRB3 allele without cloning, to identify its association with the DRB1 locus, and to generate an Epstein-Barr virus (EBV)-transformed cell line, now present in our ECBR (European Collection for Biomedical Research) Cell Line Bank.
Alleles↗
Continuous renal replacement therapy and charcoal plasmaperfusion in treatment of amanita mushroom poisoning.
Hemoperfusion has been used in the treatment of mushroom poisoning for many years. The aim of this study was to study the efficacy of charcoal plasmaperfusion (CPP) and continuous renal replacement therapy (CRRT) in 2 patients severely poisoned by the amanita mushroom. Both patients arrived at the ICU from another hospital with a diagnosis of amanita phalloides mushroom poisoning. The patients were precociously treated with CRRT for 20 h and CPP for 3 h every day. The treatments were effected for 3 and 5 days, respectively. Both patients recovered completely and were discharged asyntomatic after 7 and 10 days.
Aged↗
Low prevalence of selective human leukocyte antigen (HLA)-A and HLA-B epitope losses in early-passage tumor cell lines.
The down-regulation of human leukocyte antigen (HLA) class I molecules, especially the selective down-regulation of certain allelic products, is believed to represent a major mechanism of tumor escape from immune surveillance. In the present report, an original approach is described to precisely evaluate and classify HLA class I epitope losses in 30 cancer patients with malignant melanoma and lung, breast, endometrium, ovary, and colon carcinoma tumors. Early-passage tumor cell lines were established in culture from the corresponding metastatic tumor lesions obtained in each patient. Both the cell lines and the tumor lesions were compared, in their HLA-A and -B expression, to the peripheral blood mononuclear cells (PBMCs) obtained from the same patient (autologous PBMCs). On the basis of HLA-genotyping data, the appropriate monoclonal antibodies identifying mono- and poly-morphic HLA-A and HLA-B epitopes were selected from a panel of 34 antibodies for a total of 24 testable alleles. The selected antibodies were used not only in immunohistochemical assays on cryostatic tumor sections and cytospins of PBMCs but also in quantitative, sensitive flow cytometry assays on early-passage tumor cells and PBMC suspensions. With this latter method, a low overall HLA expression was detected in 26 tumor cell explants and a complete, generalized HLA-A, HLA-B, HLA-C loss in the remaining 4 cases. However, no complete, selective loss of any of the 45 tested HLA-A and HLA-B allomorphs was observed. Sequences from all of the HLA class I alleles could be detected at the genomic DNA level in tumor cells and tissues. At variance from the literature and the results of immunohistochemical experiments performed in parallel on the corresponding tumor lesions, the relative proportions of the various HLA epitopes were relatively preserved in each early-passage cell line/PBMC pair, and selective increases, rather than decreases, in the expression of polymorphic HLA epitopes had the highest prevalence and greatest magnitude. Our data suggest an alternative tumor stealth strategy in which up- and down-regulation are equally important. This alternative model of tumor-host interaction better fits the available models of tumor cell recognition by CTLs and natural killer cells bearing activatory and inhibitory receptors for HLA-A, HLA-B, HLA-C molecules.
Antibodies, Monoclonal↗
Stromal damage as consequence of high-dose chemo/radiotherapy in bone marrow transplant recipients.
Bone marrow transplant (BMT) relies on the engraftment of donor hemopoietic precursors in the host marrow space. Colony forming units-fibroblasts (CFU-f), the precursor compartment for the osteogenic lineage, are essential to hemopoietic stem cell survival, proliferation and differentiation. We have studied CFU-f in donors (aged 5 months to 62 years) and in patients who had received allogeneic BMT (aged 2 months to 63 years). In donor marrows we found an inverse correlation between CFU-f frequency and age. In BMT recipients CFU-f frequencies were reduced by 60%-90% (p < 0.05) and the numbers did not recover up to 12 years after transplant. Stromal reconstitution to normal levels was found only in patients < 5 years old. In all patients studied CFU-f post-BMT were of host origin. Patients with low CFU-f levels displayed also a decreased bone mineral density (p < 0.05) and significantly reduced levels of long-term culture-initiating cells (LTC-IC) (p < 0.05). Our study demonstrates that the marrow stromal microenvironment is seriously and irreversibly damaged after BMT. Donor cells do not contribute to reconstitute the marrow microenvironment, whose residual CFU-fs remain of host origin.
Adolescent↗
Biosynthesis of HLA-C heavy chains in melanoma cells with multiple defects in the expression of HLA-A, -B, -C molecules.
Recent investigations have shown that malignant transformation may down-regulate the expression of class I HLA molecules, beta2-microglobulin (beta2m) and members of the antigen-processing machinery. In the present study, we HLA-genotyped and identified at a biochemical level the three (HLA-A25, -B8, -Cw7) class I alleles expressed by the previously described [D'Urso CM et al (1992) J Clin Invest 87: 284-292] beta2m-defective human melanoma FO-1 cell line and tested their ability to interact with calnexin, calreticulin and the TAP (transporter associated with antigen processing) complex. All these alleles were found to bind calnexin, but not calreticulin or the poorly expressed TAP complex, both in parental and beta2m-transfected FO-1 cells, demonstrating a complex defect of class I expression in FO-1 cells. In these conditions, Cw7 heavy chains interacted with calnexin more strongly than A25 and B8, and preferentially accumulated in the endoplasmic reticulum, in both a calnexin-associated and a calnexin-free form. In addition, they could be transported to the cell surface at low levels even in the absence of beta2m, without undergoing terminal glycosylation. These results establish a parallel between HLA-C and the murine Db and Ld molecules which have been found to be surface expressed and functional in beta2m-defective cells. They also demonstrate distinctive features of HLA-C molecules. We propose that the accumulation of several assembly intermediates of HLA-C might favour the binding of peptide antigens not readily bound by HLA-A and -B molecules in neoplastic cells with suboptimal class I expression.
Alleles↗
HLA-A, -B, -C genotyping and expression in human nonlymphoid tumor cell lines.
A combination of molecular genotyping and protein biochemistry methods was used to assess the HLA-A, -B, -C genotyping and expression of six tumor cell lines. Four cell lines had been previously HLA typed by conventional serologic methods. Two could not be typed by serology because deficient in the surface expression of HLA-A, -B, -C molecules. As shown herein, all the 25 alleles carried by the six tested cell lines were typed at the DNA level. In addition, discrepancies between the previous serologic and the present DNA typing results were detected in 9 of the 21 tested serologic specificities. Typing at the protein level by isoelectric focusing and allele-specific monoclonal antibodies confirmed the DNA typing data. Our results exemplify the limits of the serologic typing procedures and demonstrate that molecular methods are highly desirable to conduct functional experiments and identify HLA losses in neoplastic cells at single allele level.
Alleles↗
HLA-C high resolution typing: analysis of exons 2 and 3 by sequence based typing and detection of polymorphisms in exons 1-5 by sequence specific primers.
HLA-C high resolution sequence based typing developed in this study involves a unique DNA amplification encompassing exon 1 to intron 3 and four fluorescent sequencing reactions covering exon 2 and 3. Both dye primer and dye terminator sequencing techniques were performed and results compared. This approach allowed the identification of all of the 50 HLA-C allelic variants so far described, except for two allele pairs that are distinguished by non-coding nucleotide changes (Cw*12021 = 12022, Cw*15051 = 15052) and three allele pairs (Cw*0701 = 706, Cw*1701 = 1702 and Cw*1801 = 1802) that share the same nucleotide sequence in exon 2 and 3. For complete subtyping of these allelic variants, an amplification based on sequence specific primers (PCR-SSP) was used. No ambiguous heterozygous combinations of alleles were detected in our panel so far. HLA-C typing data obtained by this method were compared with data from serological and low resolution PCR-SSP typing, which had been performed previously on the samples sequenced.
Base Sequence↗
Bone marrow transplantation for chronic myeloid leukemia (CML) from unrelated and sibling donors: single center experience.
This is a report on 60 consecutive patients with chronic myeloid leukemia (CML) who received an allogeneic bone marrow transplant (BMT) in this Unit. Donors were HLA-identical siblings (SIB) (n = 36) or unrelated donors (MUD) (n = 24) matched by serology for HLA A and B and by molecular biology for HLA DR. All patients were prepared with cyclophosphamide 120 mg/kg and fractionated total body irradiation 10-12 Gy. GVHD prophylaxis consisted of cyclosporin A (CsA) starting on day -7 and short-course methotrexate. Bone marrow was unmanipulated in all cases. Cytomegalovirus prophylaxis consisted of acyclovir for SIBs and foscarnet for MUDs. When compared to SIB transplants, MUD patients were younger (29 vs 36 years; P = 0.002), had younger donors (31 vs 39; P = 0.001), had a longer interval between diagnosis and BMT (1459 vs 263 days; P < 0.001) and received a smaller number of nucleated cells at transplant (3.3 vs 4.4 x 10(8)/kg; P = 0.003). More MUDs had advanced disease (50 vs 17%, P = 0.005). The median day to 0.5 x 10(9)/l neutrophils was similar in both groups (18 days for SIBs vs 17 days for MUDs; P = 0.06); the median platelet count on days +30, +50, +100 was significantly (P < 0.01) higher in SIB than in MUD patients (122 vs 38, 113 vs 50 and 97 vs 45 x 10(9)/l, respectively). Acute GVHD was scored as absent-mild, moderate, or severe, in 36, 58 and 6% of SIBs vs 25, 42 and 33% in MUD patients (P = 0.01). Chronic GVHD was comparable (P = 0.1). The actuarial risk of CMV antigenemia at 1 year was 60% in both groups. There were six deaths in SIB patients (two leukemia, two infections, one GVHD, one pneumonitis) and four deaths in MUD patients (three acute GVHD and one infection). Fifty patients survive with a median follow-up of 656 days for SIBs and 485 for MUDs. The actuarial 3-year transplant-related mortality is 12% in SIBs and 17% in MUDs (P = 0.5); the actuarial relapse is 18% in SIBs vs 6% in MUDs (P = 0.4) and 3-year survival 78% in SIBs vs 82% in MUDs (P = 0.7). This study suggests that survival of CML patients after marrow transplantation from unrelated or sibling donors is currently similar, provided the former are well matched. The increased incidence of GVHD in MUD patients is possibly compensated by a lower risk of relapse.
Acyclovir↗
HLA-A typing: comparison between serology, the amplification refractory mutation system with polymerase chain reaction and sequencing.
In this study we typed HLA-A polymorphisms by a new sequence-based typing (SBT) method, which involved one PCR reaction and four sequencing reactions covering exon 2 and exon 3. This method allowed complete identification of all known HLA-A alleles and revealed the presence of a new allele, named HLA-A*2608. We also introduced sequencing of exon 4 for some samples in order to discriminate the allelic pairs that are identical in exon 2 and 3, thus improving SBT resolution. Finally, we compared the results obtained by SBT with data obtained by serological typing and the amplification refractory mutation system (ARMS-PCR). Together, our results suggest that the SBT here described provides an optimal HLA-A typing technique that may be useful in selecting donor-recipient pairs in bone marrow transplantation between unrelated individuals.
Adult↗
HLA-C heavy chains free of beta2-microglobulin: distribution in normal tissues and neoplastic lesions of non-lymphoid origin and interferon-gamma responsiveness.
Lacking monospecific antibodies to HLA-C, the expression and synthesis of these molecules have been difficult to evaluate. Using biochemical and flow cytometry approaches, the present report demonstrates that the reactivity of the murine monoclonal antibody L31 is restricted to naturally occurring HLA-C (HLA-Cw1 through -Cw8), HLA-B8 and HLA-B51 heavy chains not associated with beta2-microglobin (beta2m). This is due to two properties of HLA-C heavy chains: (a) they share the L31 epitope which distinguishes them from all the HLA-A and most HLA-B molecules; (b) they accumulate intracellularly, in a beta2m-free form, in much greater amounts than most L31-reacting HLA-B heavy chains. On the basis of this restricted reactivity, a representative panel of normal and neoplastic human tissues and cells derived from HLA-B8- B51- individuals was selected and employed to assess the tissue distribution, surface expression and IFN-gamma responsiveness of beta2m-free HLA-C heavy chains. At variance from antibody W6/32 to beta2m-associated heavy chains, L31 stains normal and neoplastic tissues with a ground-glass pattern and weakly binds to the surface of viable cells, even after treatment with interferon gamma (IFN-gamma). Thus, beta2m-free HLA-C heavy chains are, for the most part, located intracellularly. In spite of their distinct cellular localization, L31- and W6/32-reacting molecules have an overlapping tissue distribution, undergo concordant changes upon transformation and are upregulated in their synthesis by IFN-gamma to a similar extent. These observations demonstrate a coordinate regulation of HLA-C with HLA-A and -B molecules. In addition, they indicate that the assembly of HLA-C is impaired in most body districts and IFN-gamma is unable to completely reverse this impairment. The present results are consistent with a low surface expression of HLA-C and with a privileged role of these molecules in signaling class I loss to cytotoxic effectors in pathological conditions.
Adult↗
DNA typing of DQ and DR alleles in IgA-deficient subjects.
IgA deficiency (IgA-D) represents the most common immunodeficiency syndrome of infancy. In most cases IgA-D represents an isolated immunological disorder, while sometimes it is associated with IgG subclass deficiency or with the presence of autoantibodies. We investigated the pattern of association of IgA-D with DRB1 and DQB1 loci of the HLA region by DNA molecular typing, which allows the identification of previously serologically undefined specificities. We also compared the gene frequency of DRB1 and DQB1 allelic variants between IgA-D subjects with or without serum autoantibodies. Our results indicate that the gene frequency of the DRB1*0102 subtype and of the DRB1*0102, DQB1*0501 haplotype is significantly higher in IgA-D than in the general population. Furthermore, the IgA-D subjects with autoantibodies showed a positive association with DR4 and DR13 subtypes, thus supporting the hypothesis that genetic factors are also involved in the association between IgA-D and autoantibodies.
Alleles↗
HLA polymorphism in a Mataco South American Indian tribe: serology of class I and II antigens. Molecular analysis of class II polymorphic variants.
In the present study, HLA-A, B, C, DR, DQ, and DP loci were analyzed in a group of Mataco Amerindians of Argentina. Using reagents from the 11th International Histocompatibility Workshop (11th IHW), class I specifities such as Bw70, Bw75, and Bw48 were found in this population, other than the HLA determinants commonly described in South American Indians. The class II antigens found were DR4, DRw14, and DRw8 at the DR locus, and DQw4 and DQw7 at the DQ locus. The analysis of DRB1-DR4 related alleles, performed by PCR amplification and oligonucleotide probe hybridization, showed the presence of DRB1*0403, *0404, *0405, and *0411 in individuals from this ethnic group. By the analysis of DRB1-DRw14 related alleles, two variants were found: DRB1*1402 and DRB1*1406, the latter provisionally called DRB1 14.6 in 11th IHW. The DRw8-related allele present was DRB1*0802. The analysis of DRB3 gene revealed only the presence of DRB3*0101 allele in DRw14 individuals. DPB1 locus was also analyzed in unrelated individuals of the same population. Only five DPB1 alleles were found: DPB1*0201, *0301, *0402, *0501, and *1301 over the 19 previously described in the literature. These findings emphasize the restricted HLA class I and II variation observed in this ethnic group as it has been previously shown in other American groups. Some particular haplotypes in this Mataco tribe are described in this work.
Alleles↗