Laboratory Diagnosis of Activated Protein C Resistance and Factor V Leiden.

The factor V Leiden (FVL) polymorphism is known as the most common inherited risk factor for venous thrombosis. In turn, FVL is the leading cause of an activated protein C resistance (APCR) phenotype, in which the addition of exogenous activated protein C to plasma does not result in the expected anticoagulant effect. In the routine laboratory approach to the formal diagnosis of FVL, an initial positive screening plasma-based method for APCR is often performed, and only if needed, this is followed by a confirmatory DNA-based assay for FVL. Multiple methods with accepted sensitivity and specificity for determining an APCR/FVL phenotype are commonly categorized into two separate groups: (1) screening plasma-based assays, including qualitative functional clot-based assays, for APCR, and (2) confirmatory DNA-based molecular assays, entailing several tests and platforms, including polymerase chain reaction-based and non-PCR-based techniques, for FVL. This review will describe the methodological aspects of each laboratory test and prepare suggestions on the indication of APCR and FVL testing and method selection.

The demographic and serological characteristics of COVID-19 convalescent plasma donors: Identification of basic criteria for optimal donor selection.

BACKGROUND AND OBJECTIVES: Convalescent plasma has attracted significant attention as a therapeutic option against infectious agents for more than a century. In March 2020, the use of Convalescent COVID-19 plasma (CCP) as a new research drug for COVID-19 treatment was approved by the FDA. The development of SARS-CoV-2 IgG antibodies following infection or vaccination is likely to be essential to provide adequate immunity for the population to halt the COVID19 pandemic. This study aimed to identify the criteria that would be used to determine the most appropriate CCP donors with the highest effective antiviral antibody titers. MATERIALS AND METHODS: In this prospective cohort, univariate analyses and multivariate regression analyses were performed to evaluate the relationship between characteristics of 11949 CCP donors and COVID-19 disease severity prior to donation with antibody titers estimated using ELISA technique and rapid tests. RESULTS: The antibody titer was measured among 8206 (68.7 %) donors. Elderly male and nulliparous female CCP donors who resided in the areas with high load of virus had positive ELISA and rapid test results as well as high levels of SARS-CoV-2 IgG antibodies titer. Moreover, the long hospital stay and elderly donors were the variables associated with high levels of SARS-CoV-2 IgG antibodies. CONCLUSION: This study suggests that nulliparous female and male donors with positive rapid tests who resided in areas with a higher prevalence of SARS-CoV-2, with more than 40 years of age and long hospitalization time can be the preferred donors for CCP donation.

Early high-titer convalescent plasma therapy in patients with moderate and severe COVID-19.

BACKGROUND AND OBJECTIVES: The use of COVID-19 convalescent plasma (CCP) has been approved by the FDA. We assessed the outcome of patients with moderate and severe COVID-19 following convalescent plasma therapy and the association with variables such as antibody titer in CCP units and transfusion time. MATERIALS AND METHODS: In this prospective cohort study, 3097 patients with moderate and severe COVID-19 (according to WHO Progression Scale) had heterogeneous demographic and clinical characteristics received plasma with an unknown titer at the transfusion time. Firstly, information about age, sex, blood group, the time interval from hospitalization to CCP transfusion, underlying disease, and antibody titer with the outcome were investigated. Then, multivariate logistic regression and area under the curve (AUC) were performed for the association between disease severity and intubation variables with transfusion time and outcome. RESULTS: Patients with younger age receiving CCP in the first five days of hospitalization had lower mortality (P < 0.0001). Moreover, patients without the underlying disease had lower mortality (P < 0.001). The mortality rate also decreased in severe patients who were intubated receiving CCP for less than five days (P < 0.001). In patients with moderate severity (score less than 5) who received IgG antibody levels above 1:320 in less than five days had lower mortality (P < 0.0001). CONCLUSION: Our findings suggested that COVID-19 patients with the moderate type of disease receiving CCP units with high antibody titers in the early stages of the disease experienced greater effectiveness of CCP therapy.

Molecular basis of rare congenital bleeding disorders.

Rare bleeding disorders (RBDs), including factor (F) I, FII, FV, FVII, combined FV and FVIII (CF5F8), FXI, FXIII and vitamin-K dependent coagulation factors (VKCF) deficiencies, are a heterogeneous group of hemorrhagic disorder with a variable bleeding tendency. RBDs are due to mutation in underlying coagulation factors genes, except for CF5F8 and VKCF deficiencies. FVII deficiency is the most common RBD with >330 variants in the F7 gene, while only 63 variants have been identified in the F2 gene. Most detected variants in the affected genes are missense (>50% of all RBDs), while large deletions are the rarest, having been reported in FVII, FX, FXI and FXIII deficiencies. Most were located in the catalytic and activated domains of FXI, FX, FXIII and prothrombin deficiencies. Understanding the proper molecular basis of RBDs not only can help achieve a timely and cost-effective diagnosis, but also can help to phenotype properties of the disorders.

Challenges and concerns of patients with congenital bleeding disorders affected by coronavirus disease 2019.

Coronavirus disease 2019 (COVID-19) is a new medical challenge for all individuals, especially for those with underlying disorders, such as congenital bleeding disorders (CBDs). Therefore, the pandemic might significantly change the behaviour of patients with CBDs and results in some challenges. In the present study, we assessed the main challenges of COVID-19 infection to patients with CBDs. Data were collected from medical files and interviews of patients with CBDs who had COVID-19 infection. Follow-ups were performed on patients who had active severe acute respiratory syndrome coronavirus 2 infection between April and October 2020. All patients were interviewed by an expert in order to collect the pertinent data. Some questions were about patients' preventive behaviors and feelings prior to infection, and some were about the consequences of infection on patients' replacement therapy and bleeding management. Among 25 patients, infection and death of loved ones (n: 7, 28%), and their own (n: 5, 20%) or family members' (n: 1, 4%) infection, and the resulting economic burden (n: 2, 8%) were main concerns. Six patients experienced depression during the pandemic. The pandemic caused all severely affected patients but one (n: 11, 92%) to abandon replacement therapy. However, two received on-demand therapy after exacerbation of their bleeding. Only one (25%) of four patients on prophylaxis received in-home therapy, whereas the others (75%) abandoned prophylaxis. It seems that COVID-19 infection has great consequences on the lives of patients with CBDs, causing some to take dangerous actions, such as abandonment of their treatment. Healthcare systems, and healthcare providers, should have an appropriate strategy for management of patients with CBDs that prevents infection and provides timely replacement therapy.