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.

Sensitivity and specificity of a syphilis rapid diagnostic test in blood donors' samples.

Rapid Diagnostic Tests (RDT) are useful to identify syphilis cases, particularly for hard-to-reach populations and if laboratory services are scarce. However, RDT performance may be suboptimal. We aimed to assess the sensitivity and specificity of a syphilis RDT using well-characterized blood donors' samples. We categorized samples from 811 blood donors into five groups: 1 - Samples with reactive Chemiluminescence (QML), FTA-Abs, and VDRL; 2 - Samples with reactive QML and FTA-Abs, and nonreactive VDRL; 3 - Samples with reactive QML, and nonreactive for other markers (false-positives); 4 - Controls with nonreactive QML; and 5 - Samples reactive for HIV, with nonreactive QML. Sensitivity was tested in groups 1 (overall and according to VDRL titers) and 2; specificity was tested in groups 3‒5. The RDT had high specificity, even in samples reactive for HIV. The sensitivity was high (91.9%) in samples with reactive VDRL but varied between 75.0%‒100% according to VDRL titers. The overall sensitivity was lower (81.3%) in samples with reactive FTA-Abs and nonreactive VDRL. The RDT is a useful tool to detect active syphilis but may be more limited for cases with very early or remote infection, or those with prior treatment. When higher sensitivity is needed, additional strategies including recurrent testing or laboratory-based tests may be required.

Infectious diseases and the impact on transfusion medicine: A historical review and lessons for the future.

Blood transfusion saves millions of lives each year. It is a well-established treatment, and many procedures are applied to avoid transmitted infections. However, throughout the history of transfusion medicine, many infectious diseases arose or were recognised, bringing up an impact on the blood supply, as the difficulties in diagnosing new diseases, the decrease in blood donors, the challenges for the medical team, the risks for the receptor and the related costs. This study aims to review historically the principal infectious diseases transmitted through the blood that circulated worldwide in the 20th and 21st centuries, considering the impact on the blood banks. Despite the current blood bank control of transfusion risks and the hemovigilance improvements, transmitted and emerging infections can still compromise the blood bank supply, as we have witnessed during the first waves of the COVID-19 pandemic. Moreover, new pathogens will continue emerging, and we must be prepared for the future.

Sensitivity and specificity of a syphilis rapid diagnostic test in blood donors' samples

Abstract Rapid Diagnostic Tests (RDT) are useful to identify syphilis cases, particularly for hard-to-reach populations and if laboratory services are scarce. However, RDT performance may be suboptimal. We aimed to assess the sensitivity and specificity of a syphilis RDT using well-characterized blood donors' samples. We categorized samples from 811 blood donors into five groups: 1 - Samples with reactive Chemiluminescence (QML), FTA-Abs, and VDRL; 2 - Samples with reactive QML and FTA-Abs, and nonreactive VDRL; 3 - Samples with reactive QML, and nonreactive for other markers (false-positives); 4 - Controls with nonreactive QML; and 5 - Samples reactive for HIV, with nonreactive QML. Sensitivity was tested in groups 1 (overall and according to VDRL titers) and 2; specificity was tested in groups 3‒5. The RDT had high specificity, even in samples reactive for HIV. The sensitivity was high (91.9%) in samples with reactive VDRL but varied between 75.0%‒100% according to VDRL titers. The overall sensitivity was lower (81.3%) in samples with reactive FTA-Abs and nonreactive VDRL. The RDT is a useful tool to detect active syphilis but may be more limited for cases with very early or remote infection, or those with prior treatment. When higher sensitivity is needed, additional strategies including recurrent testing or laboratory-based tests may be required.

The relevance of a bank with genotyped platelets donors

ABSTRACT Objective: Describe the clinical and laboratory characteristics and the transfusion strategy of patients at Hospital Israelita Albert Einstein with platelet refractoriness and identify their etiological characteristics. Standardize the platelet immunofluorescence technique by flow cytometry as a test for platelet compatibility in immune platelet refractoriness in transfusion support. Methods: Review of medical records of refractory platelet patients followed at HIAE from January 2011 to May 2017. Clinical-demographic data, laboratory data and identification of the use of compatible genotyped platelets for patients in need of transfusion therapy were collected. The analyzed patients were classified according to the etiology of their platelet refractoriness. To standardize the FC-PIFT technique, blood group O platelets were incubated with serum from blood group AB donors and anti-IgG monoclonal antibody to determine the negative control. In order to verify the influence of the ABO system, monoclonal anti-IgG antibodies were incubated with blood group A or B platelets and with blood group O donor serum with isohemagglutinins below and above 1/64. Results: A total of 47 patients were evaluated, a 51% (24/47) preponderance of associated immune and non-immune factors (NIPR + IPR). The most common causes of NIPR + IPR were splenomegaly (54%) and the development of HLA antibodies (88%), consistent with the literature. For patients who required therapeutic transfusion, only a small portion received compatible genotyped platelets. Conclusion: Although 60% of patients could benefit from the therapeutic transfusion of genotyped platelets, only 10% were actually transfused with this type of blood component. This reaffirms the need for investments in a bank of genotyped platelet donors.

HLA-DRB1 and cytokine polymorphisms in Brazilian patients with myelodysplastic syndromes and its association with red blood cell alloimmunization.

OBJECTIVE(S): This study aimed investigate association of HLA-DRB1 and cytokine polymorphisms with red blood cell(RBC) alloimmunization in Brazilian Myelodysplastic syndrome(MDS) patients with prior exposure to RBC transfusion. BACKGROUND: MDS patients are at risk RBC alloimmunization due to chronic RBC transfusion. However, differences in immune response of MDS transfused patients are not completely known. METHODS/MATERIALS: A retrospective cohort of 87 polytransfused patients with MDS including 28 alloimmunized (PA) and 59 non-alloimmunized (PNA) was evaluated in three Brazilian reference hospitals. HLA-DRB1genotype was performed by polymerase chain reaction (PCR)-SSOP (Luminex platform) and cytokine polymorphisms analysed by PCR and TaqMan assays. RESULTS: While HLA-DRB1 allele frequencies did not differ between groups, IL17A 197G > A SNP and IL4 polymorphisms showed significant correlation with RBC alloimmunization. IL17A 197A allele A and AA genotype were significantly more frequent in PA than PNA(A, 46.4% versus 27.1%, p = 0.012; OR = 2.3; 95%CI = 1.1-4.9; AA, 25% versus 6.8%, p = 0.041; OR = 6.2; 95%CI 1.3-30.8). Moreover, significant association of alloimmunization to Rh antigens with IL17A 197A allele and AA genotype was also identified in PA group(A, 45% versus 27.1%, p = 0.036; OR = 2.5; 95% CI 1.1-5.7; AA, 30% versus 6.8%, p = 0.042; OR = 7.9; 95%CI 1.5-42.3). Genotype A1A2 of IL4 intron 3 was overrepresented in PA(50% versus 16.9%, p = 0.009; OR = 4.97; 95%CI 1.6-15.5). Similarly, IL4-590 CT genotype was overrepresented in PA(53.6% versus 28.8%, p = 0.049; OR = 3.3; 95%CI 1.2-9.3). CONCLUSIONS: This study showed no association regarding HLA-DRB1 alleles for RBC alloimmunization risk or protection, however the IL17A 197G>A, IL4 intron 3 and IL4 590C>T SNP was significantly associated to RBC alloimmunization risk in this cohort of Brazilian MDS patients.

The relevance of a bank with genotyped platelets donors.

OBJECTIVE: Describe the clinical and laboratory characteristics and the transfusion strategy of patients at Hospital Israelita Albert Einstein with platelet refractoriness and identify their etiological characteristics. Standardize the platelet immunofluorescence technique by flow cytometry as a test for platelet compatibility in immune platelet refractoriness in transfusion support. METHODS: Review of medical records of refractory platelet patients followed at HIAE from January 2011 to May 2017. Clinical-demographic data, laboratory data and identification of the use of compatible genotyped platelets for patients in need of transfusion therapy were collected. The analyzed patients were classified according to the etiology of their platelet refractoriness. To standardize the FC-PIFT technique, blood group O platelets were incubated with serum from blood group AB donors and anti-IgG monoclonal antibody to determine the negative control. In order to verify the influence of the ABO system, monoclonal anti-IgG antibodies were incubated with blood group A or B platelets and with blood group O donor serum with isohemagglutinins below and above 1/64. RESULTS: A total of 47 patients were evaluated, a 51% (24/47) preponderance of associated immune and non-immune factors (NIPR + IPR). The most common causes of NIPR + IPR were splenomegaly (54%) and the development of HLA antibodies (88%), consistent with the literature. For patients who required therapeutic transfusion, only a small portion received compatible genotyped platelets. CONCLUSION: Although 60% of patients could benefit from the therapeutic transfusion of genotyped platelets, only 10% were actually transfused with this type of blood component. This reaffirms the need for investments in a bank of genotyped platelet donors.

Demographics and serological profile of blood donors who opt for the confidential unit exclusion in a blood bank in Sao Paulo, Brazil.

Blood transfusion is still an irreplaceable therapeutic modality, widely applied to medical care. Clinical interviews and laboratory testing for transfusion-transmitted infections (TTI) are routinely performed to prevent TTI among the recipients. However, there is still a residual risk of TTI, and some blood banks have adopted the confidential unit exclusion (CUE) as an additional safety strategy. In this study, we investigated the demographic characteristics and laboratory results of the screening of TTI among blood donors who opted for the CUE, compared to blood donors who did not opt for the CUE. In this study, we included 32,261 blood donations collected in a single blood bank in Sao Paulo, Brazil. A very small proportion of donors (0.25%) opted for the CUE. They were mainly single males and were more likely to have HBV, syphilis, and other positive results in the combined screening for TTI, in comparison with those who did not opt for the CUE. This difference was statistically significant in both the univariable and the multivariable analysis adjusted for age, gender , marital status and years of schooling. Our findings highlight that CUE may be a useful tool to improve the safety for blood recipients, but its efficiency is context-dependent.

COVID-19 convalescent plasma cohort study: Evaluation of the association between both donor and recipient neutralizing antibody titers and patient outcomes.

BACKGROUND: Current evidence regarding COVID-19 convalescent plasma (CCP) transfusion practices is limited and heterogeneous. We aimed to determine the impact of the use of CCP transfusion in patients with previous circulating neutralizing antibodies (nAbs) in COVID-19. METHODS: Prospective cohort including 102 patients with COVID-19 transfused with ABO compatible CCP on days 0-2 after enrollment. Clinical status of patients was assessed using the adapted World Health Organization (WHO) ordinal scale on days 0, 5, and 14. The nAbs titration was performed using the cytopathic effect-based virus neutralization test with SARS-CoV-2 (GenBank MT126808.1). The primary outcome was clinical improvement on day 14, defined as a reduction of at least two points on the adapted WHO ordinal scale. Secondary outcomes were the number of intensive care unit (ICU)-free days and the number of invasive mechanical ventilation-free days. RESULTS: Both nAbs of CCP units transfused (p < 0.001) and nAbs of patients before CCP transfusions (p = 0.028) were associated with clinical improvements by day 14. No significant associations between nAbs of patients or CCP units transfused were observed in the number of ICU or mechanical ventilation-free days. Administration of CCP units after 10 days of symptom onset resulted in a decrease in ICU-free days (p < 0.001) and mechanical ventilation-free days (p < 0.001). CONCLUSION: Transfusion of high titer nAbs CCP units may be a determinant in clinical strategies against COVID-19. We consider these data as useful parameters to guide future CCP transfusion practices.

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.

Red-blood-cell alloimmunization and prophylactic antigen matching for transfusion in patients with warm autoantibodies.

BACKGROUND: Warm autoantibodies (WAA) are antibodies that react with an antigen on a patient's own red-blood-cells and can complicate compatibility testing whether or not they cause clinical haemolysis. The goal of this study was to understand the overall prevalence of WAA, the risk of RBC alloimmunization and determine whether RBC selection practices have an impact on alloimmunization. MATERIALS AND METHODS: Records of patients (>1 year of age) with an indirect antibody detection test (IAT) and serologic evidence of WAA over a 10-year-period were included. Eight centres from 5 countries collectively reviewed 1 122 245 patients who had an IAT. RESULTS: Of patients having IAT, 1214 had WAA (0·17%). Transfusion information for 1002 of the patients was available; 631 were transfused after identification of the WAA (63%); of the transfused patients, 390 received prophylactic antigen-matched (PAM) RBCs and 241 did not. Of the 372 patients with WAA who were transfused and had serologic testing 30+ days following transfusion (30-2765 days), 56 developed new RBC alloimmunization (15·1%). Patients who were transfused using a PAM strategy were not protected from new RBC alloimmunization [14·6% (31 of 212 patients) having PAM transfusion approach compared with those not receiving PAM approach (15·6%, 25 of 160 patients, P = 0·8837)]. CONCLUSIONS: The prevalence of WAA in patients having an IAT is low (<1%). A significant portion of patients with WAA form new RBC alloimmunization (15·1%); however, the use of PAM approach for RBC selection was not found to be protective against new alloimmunization.

ID CORE XT as a tool for molecular red blood cell typing.

Introduction: Classic methods to determine human red blood cell (RBC) antigens are based on serologic testing, however there are some limitations. Based on these, several molecular techniques have been developed to bypass these restrictions and to detect the most important allelic variants, the last of great value for the approach in the personalized medicine, especially for patients in chronic transfusion regime. Areas covered: In this article, we provide an updated review of the ID CORE XT (Progenika Biopharma-Grifols, Bizkaia, Spain) that is one of the commercial DNA-based techniques available to genotyping of RBC antigens. Expert opinion: It is a platform based on Luminex technology with an automated workflow after DNA extraction and its robustness has been shown through validation studies. This technology provides a useful tool to increase the inventory of antigen-negative RBC units, through a mass-scale donor genotyping for RBC antigens and prevent immunization of patients who require chronic transfusion by providing compatible RBC units based on matching by DNA testing.