In this retrospective cohort study, we investigated the formation of individual classes of antibodies to SARS-CoV-2 in archived serial sera from hospitalized patients with the medium–severe (n = 17) and severe COVID-19 (n = 11). The serum/plasma samples were studied for the presence of IgG, IgM and IgA antibodies to the recombinant S- and N-proteins of SARS-CoV-2. By the 7th day of hospitalization, an IgG increase was observed in patients both with a positive PCR test and without PCR confirmation of SARS-CoV-2 infection. Significant increases in the anti-spike IgG levels were noted only in moderate COVID-19. The four-fold increase of IgM to N-protein was obtained more often in the groups with mild and moderate infections. The IgA levels decreased during the infection to both the S- and N-proteins, and the most pronounced decrease was in the severe COVID-19 patients. The serum IgG to S-protein one week after hospitalization demonstrated a high-power relationship (rs = 0.75) with the level of RBD antibodies. There was a medium strength relationship between the levels of CRP and IgG (rs = 0.43). Thus, in patients with acute COVID-19, an increase in antibodies can develop as early as 1 week of hospital stay. The SARS-CoV-2 antibody conversions may confirm SARS-CoV-2 infection in PCR-negative patients.

Введение. Пандемия COVID-19 стала глобальной проблемой мирового сообщества. Основным патогенетическим механизмом заболевания представляется развитие иммунного тромбоза, результатом которого являются нарушение микроциркуляции, артериальные и венозные тромбозы, респираторный дистресс-синдром, полиорганная недостаточность. Изучение механизмов развития гиперкоагуляционных изменений у пациентов с COVID-19 вызывает огромный интерес и позволит улучшить исходы заболевания. Цель исследования: оценка состояния плазменного звена гемостаза у пациентов с коронавирусной инфекцией в остром периоде заболевания. Материалы и методы. Обследованы 59 пациентов с тяжелым и среднетяжелым течением коронавирусной инфекции, получавшие антикоагулянтную профилактику. Определяли следующие параметры системы гемостаза: активированное парциальное тромбопластиновое время, протромбиновый тест, концентрацию фибриногена, активность фактора VIII, антитромбина, протеинов C и S, содержание D-димера, фактора Виллебранда и гомоцистеина, а также генерацию тромбина методом калиброванной автоматизированной тромбинографии. Результаты. У пациентов с COVID-19 по сравнению со здоровыми лицами было выявлено увеличение концентрации фибриногена, уровня фактора Виллебранда, гомоцистеина и D-димера, значительное снижение уровня свободного протеина S, усиление генерации тромбина, снижение чувствительности к тромбомодулину. Была выявлена прямая корреляция между тяжестью состояния пациентов и уровнями фактора Виллебранда и гомоцистеина. Заключение. Несмотря на проводимую антикоагулянтную терапию, у пациентов с коронавирусной инфекцией отмечены выраженные признаки активации системы гемостаза, которые характеризуются как повышением отдельных маркеров гиперкоагуляции, так и значимым усилением генерации тромбина на фоне угнетения работы системы протеина С. Повышенный уровень гомоцистеина плазмы крови является дополнительным фактором риска, ухудшающим течение заболевания. Значительное повышение уровня фактора Виллебранда может быть неблагоприятным прогностическим признаком течения заболевания. Background. The COVID-19 pandemic is a global health care challenge. The concept of immunothrombosis has established as a central pathogenic factor leading to thrombosis complications, respiratory insufficiency and multiple organ failure. The study of hypercoagulability mechanisms in patients with COVID-19 may be useful for improving disease’s outcomes. Objectives: to evaluate plasma hemostasis in patients with coronavirus infection at the acute period of the disease. Patients / Methods. We examined 59 patients with severe and moderate coronavirus infection who received anticoagulant treatment. The following hemostasis parameters were determined: activated partial thromboplastin time, prothrombin test, fibrinogen, factor VIII, von Willebrand factor, D-dimer, protein C and S, homocysteine, and thrombin generation. Results. Fibrinogen, von Willebrand factor, D-dimer, homocysteine, and thrombin generation were higher in patients with COVID-19 than in healthy people, protein S was reduced. The direct correlation between the severity of the patient’s condition and the levels of von Willebrand factor and homocysteine was found. Conclusions. Patients with COVID-19 had significant hypercoagulability despite of the anticoagulant treatment. Signs of hemostasis activation are characterized by both increasing of hypercoagulation individual markers and thrombin generation with inhibition of protein C system. High level of plasma homocysteine is an additional risk factor that worsens the disease course. High level of von Willebrand factor may be an unfavorable prognostic sign of the disease course.

BACKGROUND: Despite the continuing global spread of the coronavirus infection COVID-19 caused by the SARS-CoV-2 coronavirus, the mechanisms of the pathogenesis of severe infections remain poorly understood. The role of comorbidity with other seasonal viral infections, including influenza, in the pathogenesis of the severe course of COVID-19 remains unclear. MATERIALS AND METHODS: The present study used sera left over from ongoing laboratory studies of patients with varying degrees of severity of COVID-19. The study was approved by the Local Ethics Committee of the Federal State Budgetary Scientific Institution IEM (protocol 3/20 from 06/05/2020). We studied 28 paired samples obtained upon admission of patients to the hospital and after 57 days of hospital stay. Paired sera of patients with COVID-19 were tested for antibodies to influenza A and B viruses. The presence of IgG antibodies specific to the SARS-CoV-2 spike (S) protein was studied using an enzyme-linked immunosorbent assay (ELISA). The serum concentration of C-reactive protein and the neutrophil-lymphocyte ratio on the day of hospitalization were also assessed. RESULTS: At least a 4-fold increase in serum IgG antibodies to SARS-CoV-2 S protein was found both in patients with PCR-confirmed SARS-CoV-2 infection and without PCR confirmation. It was shown that out of 18 patients with moderate and severe forms of COVID-19 infection, six of them showed at least a 4-fold increase in antibodies to influenza A/H1N1, in one to influenza A/H3N2 and in two cases to the influenza B. Laboratory data in these two groups were characterized by significant increases in serum C-reactive protein and neutrophil-lymphocyte ratio concentrations compared with the moderate COVID-19 group. CONCLUSIONS: Serological diagnostics can additionally detect cases of coronavirus infection when the virus was not detected by PCR. In moderate and severe cases of COVID-19, coinfections with influenza A and B viruses have been identified. The results obtained confirm the need for anti-influenza immunization during the SARS-CoV-2 pandemic. Influenza virus screening can significantly improve patient management because recommended antiviral drugs (neuraminidase inhibitors) are available.

No abstract