Virtual platelet cross-matching as transfusion management for patients with immune platelet refractoriness.

BACKGROUND AND OBJECTIVES: This study describes the use of the Epvix platform for virtual cross-matching (VC) of human leucocyte antigen (HLA)-compatible platelets for patients with immune platelet refractoriness, and demonstrates effectiveness of the selected platelets. MATERIALS AND METHODS: A prospective cohort of haematological patients was evaluated from 2018 to 2022. HLA-typed donor bank profile was previously uploaded to the Epvix platform. Each patient's antibody reactivity panel (PRA) was included in the platform. Then, search, selection and VC were performed, and 24-h-corrected count increment (CCI) platelet transfusion was calculated (reference ≥2500). RESULTS: Six patients were included (four female, two male), with mean age of 61 years. HLA antibodies were detected as the cause of immunity for all patients, whereas four patients also had non-immune causes. High percentage of alloimmunization was detected in all studied patients (mean PRA: 85.7%). Thirty different donors were able to schedule and perform platelet donations. The mean 24-h CCI count was 9882. All platelet transfusions achieved a satisfactory CCI count except for two transfusion events. Presence of non-immune causes identified in these two cases could account for the unsatisfactory CCI. CONCLUSION: Epvix is a free application hosted on the Web and uses the HLAMatchmaker algorithm to generate histocompatibility reports. This study demonstrates the efficiency of VC performed by Epvix. However, physical cross-matching will still be necessary in some instances, as the platform does not support human platelet antigen polymorphism.

Genetic contribution and functional impairment of inflammasome in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD), one of the most common single-gene disorders, is caused by mutations in the hemoglobin ß-chain gene. Clinical presentation is heterogeneous, and inflammation is a common condition. Thereby, we hypothesized that inflammasome and related cytokine IL-1ß could represent significant SCD pathogenesis contributors. MATERIAL AND METHODS: 161 SCD (SS/Sß) patients were enrolled for the study. Seven single nucleotide polymorphisms (SNPs) in 5 inflammasome genes (NLRP1, NLRP3, NLRC4, CARD8, IL1B) were selected based on minor allele frequency. Total peripheral blood mononuclear cells (PBMC) and monocytes were isolated from 10 out of 161 SCD patients (HbSS) and 10 healthy donors (control group, Ctrl) for inflammasome analysis. RESULTS: SCD patients presented a functional impairment of inflammasome, with monocytes and peripheral blood mononuclear cells (PBMC) exhibiting a different NLRP3 inflammasome activation rate. Gain-of-function variants in NLRP1 and IL1B genes resulted associated with a mild SCD clinical presentation. DISCUSSION: Our results can contribute to the understanding of SCD inflammation. SCD patients showed possible exhaustion of monocytes due to chronic inflammation, moreover others cells in PBMC can contribute to the NLRP3 inflammasome activation. NLRP1 gain-of-function was associated with mild clinical presentation, suggesting that other inflammasome receptors can be involved in SCD. This is the first study reporting a significant contribution of inflammasome SNPs in SCD.

miRNA profile and disease severity in patients with sickle cell anemia.

Identification of biomarkers associated with severity in sickle cell anemia is desirable. Circulating serum microRNAs (miRNA) are targets studied as diagnostic or prognostic markers, but few studies have been conducted in sickle cell anemia. The purpose of this study is to identify specific signatures of miRNAs in plasma samples from sickle cell anemia patients according to severity indexes. Screening of the miRNAs expression was performed in 8 patients, classified by tricuspid regurgitation velocity (TRV) measure: 4 with TRV ≥ 2.5 m/s and 4 with TRV < 2.5 m/s. The samples were analyzed by real-time PCR using Megaplex RT Human Pool A and Pool B comprising 667 distinct miRNAs. Seventeen miRNAs were differentially expressed between the two groups (p < 0.05). Five differentially expressed miRNAs (miR15b, miR502, miR510, miR544, miR629) were selected for validation in a cohort of 52 patient samples, 26 with TRV ≥ 2.5 m/s. Another two severity scores were also used: organ injury score (OIS) and Bayesian score (BS). Univariate binary logistic regressions were performed to analyze the data. Five out of 17 differentially expressed miRNAs were selected for validation in 52 patient samples: miR15b, miR502, miR510, miR544, and miR629. Two miRNAs (miR510 and miR629) were significantly decreased in cases of greater severity. Whereas miR510 expression discriminated the patients according to TRV and OIS, miR629 expression did it according to BS. This is the first study investigating plasma miRNAs as possible biomarkers for SCA severity. Our data suggest that low levels of miR510 and miR629 expression are associated with greater SCA disease severity. Further studies are still necessary to elucidate mechanism of these miRNAs and their related proteins.

The inflammasomes: crosstalk between innate immunity and hematology.

BACKGROUND: The inflammasome is a cytosolic multi-protein complex responsible for the proteolytic maturation of pro-inflammatory cytokines IL-1ß and IL-18 and of gasdermin-D, which mediates membrane pore formation and the cytokines release, or eventually a lytic cell death known as pyroptosis. Inflammation has long been accepted as a key component of hematologic conditions, either oncological or benign diseases. OBJECTIVES: This study aims to review the current knowledge about the contribution of inflammasome in hematologic diseases. We attempted to depict the participation of specific inflammasome receptors, and the possible cell-specific consequence of complex activation, as well as the use of anti-inflammasome therapies. METHODS: We performed a keyword-based search in public databases (Pubmed.gov, ClinicalTrials.gov.). CONCLUSION: Different blood cells variably express inflammasome components. Considering the immunosuppression associated with both the disease and the treatment of some hematologic diseases, and a microenvironment that allows neoplastic cell proliferation, inflammasomes could be a link between innate immunity and disease progression, as well as an interesting therapeutic target.

Anti-A and SARS-CoV-2: an intriguing association.

BACKGROUND: Blood groups and anti-A isohemagglutinin may be involved in susceptibility to SARS-CoV-2 infection. MATERIALS AND METHODS: We retrospectively studied 268 COVID-19 convalescent plasma donors and 162 COVID-19 inpatients (total 430 subjects, confirmed by RT-PCR) and 2,212 healthy volunteer first-time blood donors as a control group. These were further divided into two groups: those with anti-A (blood types O and B) and those without it (types A and AB). Titres of nucleoproteins, and neutralizing SARS-CoV-2 antibody were measured in the convalescent plasma donors and inpatients. Multivariate logistic regression and non-parametric tests were applied. RESULTS: Persons having types O or B showed less infection prevalence than those of types A or AB (OR = 0·62, 95% CI 0·50-0·78; P < 0·001), but there was no difference when COVID-19 inpatients were analysed. Immunoglobulins M, G and A were lower in COVID-19 subjects of types O or B group than those of A or AB (0·16 vs. 0·19; P = 0·03, 2·11 vs. 2·55; P = 0·02, 0·23 vs. 0·32; P = 0·03, respectively). CONCLUSION: In this retrospective cohort, COVID-19 individuals were less likely to belong to blood types O and B, and also had lower SARS-CoV-2 antibody titres than A and AB individuals. COVID-19 severity did not associate with the blood groups.

Identification of the novel HLA-A*68:250 allele in a volunteer bone marrow donor from Sao Paulo, Brazil.

The allele HLA-A*68:250 differs from HLA-A*68:27:01 by three nucleotides.