RESUMO
BACKGROUND AND OBJECTIVES: Detection of anti-platelet antibodies is required for the diagnosis of foetal/neonatal alloimmune thrombocytopaenia. The most commonly used methods for anti-platelet antibody detection are the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) and the Luminex bead assay (PakLx). However, for economic reasons, the use of the PakLx assay is limited. MATERIALS AND METHODS: In the present study, we evaluated the performance of an optimized protocol based on a half-volume of PakLx reagents. We compared two alternative procedures: one with a half-volume of all components including patient samples, and another based on a half-volume of reagents but a standard volume of patient sample. RESULTS: Our results obtained with a panel of 67 samples demonstrate improved sensitivity when using a standard sample volume. CONCLUSION: In the event of an inconclusive result with this optimized protocol (e.g., incomplete panel of positive Luminex beads), we recommend testing the sample with an alternative protocol (e.g., MAIPA or the original PakLx protocol).
Assuntos
Antígenos de Plaquetas Humanas , Recém-Nascido , Humanos , Análise Custo-Benefício , Isoanticorpos , Testes Imunológicos , Anticorpos Monoclonais , PlaquetasRESUMO
Acute graft-versus-host disease (GVHD) is a rare but frequently lethal complication after solid organ transplantation. GVHD occurs in unduly immunocompromised hosts but requires the escalation of immunosuppression, which does not discriminate between host and donor cells. In contrast, donor-targeted therapy would ideally mitigate graft-versus-host reactivity while sparing recipient immune functions. We report two children with end-stage renal disease and severe primary immune deficiency (Schimke syndrome) who developed severe steroid-resistant acute GVHD along with full and sustained donor T cell chimerism after isolated kidney transplantation. Facing a therapeutic dead end, we used a novel strategy based on the adoptive transfer of anti-HLA donor-specific antibodies (DSAs) through the transfusion of highly selected plasma. After approval by the appropriate regulatory authority, an urgent nationwide search was launched among more than 3800 registered blood donors with known anti-HLA sensitization. Adoptively transferred DSAs bound to and selectively depleted circulating donor T cells. The administration of DSA-rich plasma was well tolerated and notably did not induce antibody-mediated rejection of the renal allografts. Acute GVHD symptoms promptly resolved in one child. This report provides a proof of concept for a highly targeted novel therapeutic approach for solid organ transplantation-associated GVHD.
Assuntos
Doença Enxerto-Hospedeiro , Transplante de Rim , Criança , Doença Enxerto-Hospedeiro/etiologia , Humanos , Imunização Passiva , Transplante de Rim/efeitos adversos , Esteroides , Condicionamento Pré-TransplanteAssuntos
Antígenos de Plaquetas Humanas , Trombocitopenia Neonatal Aloimune , Feminino , Humanos , Recém-Nascido , Masculino , Antígenos de Plaquetas Humanas/imunologia , Plaquetas/imunologia , Plaquetas/metabolismo , Isoantígenos/imunologia , Complexo Glicoproteico GPIb-IX de Plaquetas , Trombocitopenia Neonatal Aloimune/sangue , AdultoRESUMO
Matching for HLA-A, -B, -C, and -DRB1 loci (8/8 match) is currently the gold standard for unrelated donor hematopoietic cell transplantation (HCT). In Europe, patients are also matched at the HLA-DQB1 loci (10/10 match). However, there is increasing evidence that matching at HLA-DRB3/4/5 loci may help to lower transplant-related morbidity and mortality. We therefore investigated the impact of HLA-DRB3/4/5 mismatches on outcomes in 1975 patients who received a first 10/10 matched unrelated donor (MUD) HCT in France from 2000 to 2012 for a hematological malignancy. High-resolution typing was performed at HLA-A, -B, -C, -DRB1, -DQB1, -DPB1, and -DRB3/4/5 loci for all donor/recipient pairs. Compared with DRB3/4/5-matched pairs, patients who received a MUD HCT from a DRB3/4/5 mismatched donor had a significantly increased risk of grade II-IV acute graft-versus-host disease (aGVHD) (Adjusted Hazard Ratio (HR) 1.43 (1.07 to 1.90)) associated with lower graft-versus-host disease-free and relapse-free survival (GRFS) (Adjusted HR 1.20 (1.02 to 1.42)). Conversely, we observed no differences in terms of chronic GVHD, nonrelapse mortality, relapse and overall survival. However, we believe that patients stand to benefit from DRB3/4/5 loci being considered for unrelated donor selection to improve GRFS and then quality of life after unrelated HCT.
RESUMO
Graft rejection is a critical risk in solid-organ transplantation. To decrease such risk, an understanding of the factors involved in low immunogenicity of liver allografts could potentially make it possible to transfer this tolerogenic property to other transplanted organs. HLA-G, a natural physiological molecule belonging to the Human Leukocyte Antigen class (HLA) Ib family that induces tolerance, is associated with fewer rejections in solid-organ transplantation. In contrast to HLA-G, HLA antigen incompatibilities between donor and recipient can lead to rejection, except in liver transplantation. We compared HLA-G plasma levels and the presence of anti-HLA antibodies before and after LT to understand the low immunogenicity of the liver. We conducted a large prospective study that included 118 patients on HLA-G plasma levels during a 12-month follow-up and compared them to the status of anti-HLA antibodies. HLA-G plasma levels were evaluated by ELISA at seven defined pre- and post-LT time points. HLA-G plasma levels were stable over time pre-LT and were not associated with patient characteristics. The level increased until the third month post-LT, before decreasing to a level comparable to that of the pre-LT period at one year of follow-up. Such evolution was independent of biological markers and immunosuppressive treatment, except with glucocorticoids. An HLA-G plasma level ≤ 50 ng/ml on day 8 after LT was significantly associated with a higher rejection risk. We also observed a higher percentage of rejection in the presence of donor specific anti-HLA antibodies (DSA) and an association between the increase in HLA-G plasma levels at three months and the absence of DSA. The low immunogenicity of liver allografts could be related to early elevated levels of HLA-G, which lead, in turn, to a decrease in anti-HLA antibodies, opening potential new therapeutic strategies using synthetic HLA-G proteins.
Assuntos
Transplante de Fígado , Humanos , Antígenos HLA-G , Estudos Prospectivos , Isoanticorpos , Fígado , Antígenos HLA , Aloenxertos , Rejeição de Enxerto , Sobrevivência de EnxertoRESUMO
DQB1*05:235N differs from DQB1*05:03:01:01 by one nucleotide substitution at position 123 in exon 2, resulting in a premature stop codon.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Éxons/genética , Cadeias beta de HLA-DQ/genética , HumanosRESUMO
B*51:296 differs from B*51:01:01:01 by one nucleotide substitution at position 1030 in exon 6.
Assuntos
Antígenos HLA-B , Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Éxons/genética , Antígenos HLA-B/genética , Humanos , Mutação de Sentido IncorretoRESUMO
B*40:450 differs from B*40:01:02:01 by one nucleotide substitution at position 5 in exon 1.
Assuntos
Genes MHC Classe I , Antígenos HLA-B , Alelos , Éxons/genética , Antígenos HLA-B/genética , Sequenciamento de Nucleotídeos em Larga Escala , HumanosRESUMO
B*18:181 differs from B*18:01:01:02 by one nucleotide substitution at position 1043 in exon 6.
Assuntos
Genes MHC Classe I , Antígenos HLA-B , Alelos , Éxons/genética , Antígenos HLA-B/genética , Sequenciamento de Nucleotídeos em Larga Escala , HumanosRESUMO
DQA1*05:13 differs from DQA1*05:05:01:04 by one nucleotide substitution at position 37 in exon 1.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Cadeias alfa de HLA-DQ/genética , Humanos , Análise de Sequência de DNARESUMO
DQA1*01:19 differs from DQA1*01:02:01:04 by one nucleotide substitution at position 731 in exon 4.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Cadeias alfa de HLA-DQ/genética , Humanos , Análise de Sequência de DNARESUMO
DRB1*11:260 differs from DRB1*11:03:01 by one nucleotide substitution at position 484 in exon 3.
Assuntos
Cadeias HLA-DRB1 , Alelos , Éxons/genética , Cadeias HLA-DRB1/genética , Sequenciamento de Nucleotídeos em Larga Escala , HumanosRESUMO
DQB1*03:417 differs from DQB1*03:01:01:01 by one nucleotide substitution at position 179 in exon 2.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Éxons/genética , Cadeias beta de HLA-DQ/genética , HumanosRESUMO
B*44:476 differs from B*44:03:01:01 by one nucleotide substitution at position 934 in exon 5.
Assuntos
Genes MHC Classe I , Antígenos HLA-B , Alelos , Éxons/genética , Antígenos HLA-B/genética , Sequenciamento de Nucleotídeos em Larga Escala , HumanosRESUMO
DRB1*01:107 differs from DRB1*01:01:01:01 by one nucleotide substitution at position 484 in exon 3.
Assuntos
Cadeias HLA-DRB1 , Alelos , Éxons/genética , Cadeias HLA-DRB1/genética , Sequenciamento de Nucleotídeos em Larga Escala , HumanosRESUMO
DRB1*08:97 differs from DRB1*08:03:02:01 by one nucleotide substitution at position 485 in exon 3.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Éxons/genética , Cadeias HLA-DRB1/genética , Teste de Histocompatibilidade , HumanosRESUMO
B*44:452 differs from B*44:02:01:01 by one nucleotide substitution at position 527 in exon 3.