We conclude that the risk of primary CMV infection is a continuous lifelong event and correlates with age and female gender.

The causative role of maternal, anti-human leukocyte antigen (anti-HLA) class I antibodies in foetal and neonatal alloimmune thrombocytopenia (FNAIT) remains controversial. Furthermore, in FNAIT cases caused by anti-human platelet antigen-1a (anti-HPA-1a) antibodies, the possible additive effect of maternal anti-HLA class I antibodies on outcomes is unclear. Among 817 mother-father-neonate trios of suspected FNAIT, we assessed the possible association of maternal anti-HLA class I antibodies with neonatal platelet count, and the incidence of FNAIT caused by anti-HPA-1a antibodies. In 144 FNAIT cases caused by anti-HPA-1a antibodies, we investigated the possible association of maternal anti-HLA class I antibodies with neonatal platelet count, birth weight, and the incidence of intracranial haemorrhage (n = 16). Maternal anti-HLA class I antibodies were not associated with neonatal platelet count in suspected cases of FNAIT. There was no significant interaction between the presence of anti-HLA class I antibodies and anti-HPA-1a antibodies. In FNAIT cases caused by anti-HPA-1a antibodies, there was no association between the presence of anti-HLA class I antibodies and neonatal platelet count, birth weight, or occurrence of intracranial haemorrhage. This study's findings do not support the concept that maternal anti-HLA class I antibodies represent a risk factor of FNAIT or disease severity.

BACKGROUND An alloimmune response to red blood cell (RBC) transfusion in neonates is a rare event. Several guidelines recommend limited pretransfusion testing in neonates. The evidence for these recommendations is based on small studies with sample sizes of between 30 and 90 infants. STUDY DESIGN AND METHODS We conducted a retrospective cohort study among consecutive patients who received transfusions at a single university medical center. All non‐alloimmunized patients who had received their first RBC transfusion between 1994 and 2013 and who underwent at least one antibody screening follow‐up visit between 7 and 365 days after transfusion were included. RESULTS The incidence of alloimmunization in the control group of 17,084 adult patients age 45 years or older who had received a median of 5 RBC units (interquartile range, 2‐12 RBC units) was 3.55% (n = 607 alloimmunized patients). After transfusion of 40 RBC units, the cumulative incidence of alloimmunization in adult controls was 10.24% (95% confidence interval, 7.71%‐13.17%). In total, 1641 neonates and children up to age 3 years received a median of 4 RBC units (interquartile range, 2‐7 RBC units) in a median of two RBC transfusion episodes (interquartile range, one to five RBC transfusion episodes). Two children developed anti‐M and anti‐E antibodies post‐transfusion at the ages of 181 and 611 days, respectively. CONCLUSION To our knowledge, this study presents the largest longitudinal cohort study of RBC alloimmunization in neonates. Antibodies against RBC antigens were not detected within the first 6 months of life. Repeat antibody screening and cross‐matching during the first months of life can be safely omitted.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first affected humans in China on December 31, 2019 (Shi et al., 2020 ). Coronaviruses generally cause mild, self-limiting upper respiratory tract infections in humans, such as the common cold, pneumonia, and gastroenteritis (To et al., 2013 ; Berry et al., 2015 ; Chan et al., 2015 ). According to the Report of the World Health Organization (WHO)-China Joint Mission on COVID-19 (WHO, 2020 ), the case fatality rate of COVID-19 increases with age, while the rate among males is higher than that among females (4.7% and 2.8%, respectively). Since an effective vaccine and specific anti-viral drugs are still under development, passive immunization using the convalescent plasma (CP) of recovered COVID-19 donors may offer a suitable therapeutic strategy for severely ill patients in the meantime. So far, several studies have shown therapeutic efficacy of CP transfusion in treating COVID-19 cases. A pilot study first reported that transfusion of CP with neutralizing antibody titers above 1:640 was well tolerated and could potentially improve clinical outcomes through neutralizing viremia in severe COVID-19 cases (Chen et al., 2020 ). Immunoglobulin G (IgG) and IgM are the most abundant and important antibodies in protecting the human body from viral attack (Arabi et al., 2015 ; Marano et al., 2016 ). Our study aimed to understand the aspects of plasma antibody titer levels in convalescent patients, as well as assessing the clinical characteristics of normal, severely ill, and critically ill patients, and thus provide a basis for guiding CP therapy. We also hoped to find indicators which could serve as a reference in predicting the progression of the disease.