Interrelations between viral load and cellular immunity in patients with COVID-19 of varying severity

Assessment of viral load levels in various biological samples taken from the respiratory tract can be an indicator of an ongoing process of active viral replication and may be used to monitor severe respiratory viral infections. The study of the relationship between SARS-CoV-2 viral load and immunological laboratory parameters is an important step in the search for clinical markers of COVID-19.The aim of this research was to quantify viral load in patients with COVID-19 and to identify the relation-ship between viral load and changes in the parameters of the cellular component of the immune system.A laboratory examination was carried out on 74 patients diagnosed with COVID-19, they were divided into 3 groups based on the severity of the disease: mild, moderate, severe. Total viral load in clinical samples was determined by the number of SARS-CoV-2 RNA copies per 100 copies of the reference RNaseP gene.     A comprehensive assessment of the cellular component of the immune system was performed using flow cytometry and direct monoclonal antibodies, and the IL-6, and C-reactive protein concentrations were determined.We revealed a relationship between the development of serious clinical conditions in the patients with COVID-19, and the levels of viral load. High levels of viral RNA in biological samples correlate with main indicators of the T cell component of the immune system associated with disease severity. In a subgroup of patients with an extremely high viral load, strong positive correlations were found between the relative numbers of cytotoxic lymphocytes (CD3+CD8+), activated T lymphocytes (CD3+HLA-DR+), as well as absolute and relative numbers of activated B lymphocytes and NK cells (CD3-CD25+).Laboratory monitoring of the cellular component of the immune system, along with the assessment of viral loads, should improve  early assessment of clinical condition in the patients with COVID-19. Changes   in expression levels of activation markers on immune cells can be potentially viewed as indicators of recovery during COVID-19

Клиническая эффективность и безопасность применения иммунной плазмы реконвалесцентов для лечения COVID-19

Aim: to evaluate the efficacy and safety of convalescent plasma therapy for patients with severe SARS-CoV-2 infection.Materials and methods: the study included 64 patients with laboratory-confirmed severe new coronavirus infection. The control group consisted of 58 patients who, in addition to standard therapy, received a transfusion of plasma from donors who had recovered from COVID-19. The effectiveness of immune plasma was assessed by the duration of fever, the level of oxygen (SpO2 %) in dynamics, the detection of SARSCoV-2 RNA in nasopharyngeal and oropharyngeal swabs using PCR method in dynamics, as well as by the dynamics of blood tests results. Adverse events (any medically adverse events that occurred after immune plasma transfusion) were recorded as safety criteria.Results: patients who received convalescent plasma, showed a significantly shorter period of SARS-CoV-2 replication compared with the control group. The use of immune plasma did not have a statistically significant effect on the duration of the fever, as well as the dynamics of blood oxygenation. Also, there were no significant differences compared with the control group when assessing blood tests parameters.Conclusion: The use of COVID-19 convalescent plasma to treat severe COVID-19 did not show significant clinical effect but reduced the period of viral replication. It also showed no unexpected or serious adverse events. Цель. Оценка эффективности и безопасности применения иммунной плазмы реконвалесцентов для лечения COVID-19 у пациентов с тяжелой степенью тяжести.Материалы и методы. В исследование были включены 64 пациента с подтвержденной новой коронавирусной инфекцией тяжёлой степени тяжести, которым, помимо стандартной терапии, проводили трансфузию иммунной плазмы реконвалесцентов новой коронавирусной инфекции. Контрольную группу составили 58 пациентов, получавших базисную терапию. Эффективность терапии иммунной плазмы оценивалась по длительности лихорадки, уровню сатурации (SpO2 %), выявлению РНК SARS-CoV-2 методом ПЦР в отделяемом со слизистой рото-/носоглотки в динамике, а также по изменениям общеклинических и биохимических показателей крови. В качестве критериев безопасности регистрировались нежелательные явления (любые неблагоприятные с медицинской точки зрения события, возникшие после трансфузии иммунной плазмы).Результаты. У пациентов, получавших иммунную плазму реконвалесцентов, отмечался достоверно более короткий период вирусной репликации SARS-CoV-2 по сравнению с контрольной группой. На продолжительность лихорадки, а также динамику насыщения кислородом крови применение иммунной плазмы статистически значимого влияния не оказывало. Также не отмечалось достоверных различий по сравнению с контрольной группой при оценке общеклинических, биохимических показателей крови.Заключение. Терапия пациентов с тяжёлым течением COVID-19 иммунной плазмой реконвалесцентов, перенёсших инфекцию, вызванную SARS-CoV-2, достоверно не оказывала значимого клинического эффекта, однако сокращала период репликации вируса. Трансфузия иммунной плазмы также не вызывала серьёзных нежелательных явлений