Relationship between the ABO blood group and COVID-19 susceptibility, severity and mortality in two cohorts of patients.

BACKGROUND: Several articles reported the existence of an association between ABO blood groups and COVID-19 susceptibility. Group A and group O individuals showed a higher and lower risk, respectively, of becoming infected. No association was observed between ABO groups and mortality. To verify this association, we performed a retrospective study of two cohorts of patients with different demographic and clinical characteristics. MATERIAL AND METHODS: A total of 854 regular blood donors were recruited for convalescent plasma donation after recovering from a mild COVID-19 infection, and a group of 965 patients more severely affected who were transfused during hospitalisation were also included. We also investigated the potential role of the different risk factors on patient outcome and death. To eliminate the confounding effect of risk factors on mortality, a propensity score analysis was performed. RESULTS: Blood group A and blood group O COVID-19 blood donors showed a higher and lower risk, respectively, for acquiring COVID-19. In contrast, this association was not found in the group of patients transfused during hospitalisation, probably due to the great differences in demographic and clinical characteristics between the two groups. Regarding severity, age was one of the most significant risk factors. ABO blood groups were also seen to represent important risk factors for COVID-19 severity and mortality. Mortality risk in group A individuals was significantly higher than in group O individuals (OR: 1.75, 95% CI: 1.22-2.51). DISCUSSION: The association between the ABO blood groups and the susceptibility to acquire COVID-19 infection was confirmed in the group of blood donors. ABO blood groups were also associated to COVID-19 severity and mortality in the group of patients transfused during hospitalisation. Therefore, blood groups A and O are two important factors to be considered when evaluating the prognosis of patients with COVID-19.

T cell responses and viral variability in blood donation candidates with occult hepatitis B infection.

BACKGROUND & AIMS: Occult HBV infection (OBI) is defined by the presence of HBV DNA in the liver and/or serum and negative HBsAg testing. Since the implementation of highly sensitive HBV DNA screening, OBI is also detected in healthy blood donors. The aims of this study were to investigate HBV-specific immune responses and genetic variability in donors with OBI, established by HBV DNA in serum. METHODS: HBV-specific T-cell responses to HBV antigens were tested in 34 OBI donors by IFN-γ ELISpot, cytometric bead array, and intracellular cytokine staining. As comparison populations, 36 inactive HBV carriers, 22 donors with spontaneously resolved HBV infection, 24 vaccinated donors, and 25 seronegative donors were also included. Surface, pre-S, and pre-c/core genes from 44 genotype D isolates (24 OBI and 20 HBsAg-positive) were sequenced. RESULTS: The immune response of OBI donors to the 3 HBV antigens was 29-41%, similar to the response in subjects with resolved HBV infection and higher than that in HBsAg-positive subjects. On sequence analysis, OBI donors presented a higher HBsAg mutation rate than HBsAg-positive subjects. Mutations were clustered in the major hydrophilic region of HBsAg, and no stop codons or relevant mutations that could affect antigen formation or detection were observed. CONCLUSIONS: Our results suggest that immune response can suppress viral replication to low levels and HBsAg expression to undetectable levels in OBI blood donors. Relevant mutations were not found in the genomic HBsAg coding region. Hence, the fact that HBsAg was not detected in OBI is likely due to low HBsAg production, rather than to a failure of laboratory reagents.

Comparison of blood component preparation methods from whole blood bags based on buffy coat extraction.

We compared the data of our quality control laboratory of the blood components according to the blood component preparation method that we used. We prepared blood components from top and top whole blood (WB) bags and manual pooling of buffy coats (BCs) (method I) or from top and bottom WB bags and automated pooling of BCs with OrbiSac (method II). Pooled platelet concentrates (PC) obtained with method II had higher platelet content when compared with pooled PCs obtained with method I (3.5+/-0.7x10(11) vs. 2.6+/-0.8x10(11); p<0.001). The hemoglobin content in the RBCs obtained with method I was higher when compared with method II (55+/-7g vs. 52.5+/-6.6g; p<0.001).

Use of polyethylene glycol for performing autologous adsorptions.

BACKGROUND: Our reference adsorption procedure is to autoadsorb serum with ZZAP-pretreated patients' red cells (RBCs), although it is time-consuming. The aim of this study was to evaluate the use of polyethylene glycol (PEG) for performing autologous adsorption procedures without pretreatment of patients' RBCs. STUDY DESIGN AND METHODS: Equal volumes of patient's plasma, patient's RBCs, and PEG were mixed. This mixture was incubated for 15 minutes at 37 degrees C, and the adsorbed plasma-PEG mixture was immediately harvested to proceed to the antiglobulin test with anti-immunoglobulin G. The ZZAP-adsorption procedure was performed in our reference laboratory. RESULTS: Thirty-one samples were detected with warm autoantibodies in pretransfusion testing. A total number of 58 autologous adsorption procedures were performed with PEG in 870 minutes (mean, 28 min) and alloantibodies were detected in 4 (13%) cases (anti-E in 2 cases and anti-E + K in 2 cases). Our reference laboratory performed a total number of 61 adsorption procedures with ZZAP in 3660 minutes (mean, 118 min) and detected the same alloantibodies specificities. CONCLUSION: The PEG autologous adsorption procedure is an efficient method of enhancing autoantibody adsorption and alloantibody detection and decreasing the labor-intensive testing required by the presence of serum warm autoantibodies in pretransfusion samples.