Clinical performance and application of novel serum collection "Ser-Col" device in the practice of laboratory diagnosis of infection diseases and several other immunochemical tests.

BACKGROUND: Dried blood collection devices might be beneficial for diagnosing infectious diseases in areas far from the medical facilities and in lockdown situations. There are several reports on the efficacy of such applications for qualitative tests. Here we demonstrated the feasibility of a novel Ser-Col blood collection device as a standardized approach for qualitative and quantitative detection of infectious markers and several over immunochemical tests. METHODS: In the current study, we included 395 adult participants, 191 men and 204 women, with a median age of 41 years, as well as 75 children with a median age of 3 years. Serological status was determined by testing serum samples for three groups of infection diseases: hepatitis A and C, SARS-CoV-2, and herpes family viruses, as well as for thyroid peroxidase (TPO), prolactin, vitamin B12, and folate. Blood collected on the Ser-Col device (Labonovum) was eluted using an automated system (SCAUT Ser-Col automation, Blok System Supply) and manually. Ser-Col results were compared with serum sampled via standard venipuncture considered as the reference. RESULTS: High correlation coefficients (r = 0.95-0.99) were observed between serum samples collected with Ser-Col and via standard venipuncture for the following tests: anti-HCV, anti-SARS-CoV-2 IgG, anti-HSV-2 IgG, and anti-CMV IgM. Correlation coefficients between Ser-Col and standard venipuncture serum for anti-HSV-1 IgG, anti-CMV IgG, and anti-EBV tests were relatively low (r = 0.73-0.77). Correlation coefficients for anti-TPO, prolactin, vitamin B12, and folate were also characterized with high values (r = 0.97-0.99). CONCLUSIONS: High accuracy and quantitative correlation were demonstrated between Ser-Col and samples collected by standard venipuncture. Hence, the Ser-Col blood collection device should be considered as a promising alternative for blood collection, storage, and transportation in both adult and pediatric populations.

Tracking the evolution of anti-SARS-CoV-2 antibodies and long-term humoral immunity within 2 years after COVID-19 infection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that gave rise to COVID-19 infection produced a worldwide health crisis. The virus can cause a serious or even fatal disease. Comprehending the complex immunological responses triggered by SARS-CoV-2 infection is essential for identifying pivotal elements that shape the course of the disease and its enduring effects on immunity. The span and potency of antibody responses provide valuable perspicuity into the resilience of post-infection immunity. The analysis of existing literature reveals a diverse controversy, confining varying data about the persistence of particular antibodies as well as the multifaceted factors that impact their development and titer, Within this study we aimed to understand the dynamics of anti-SARS-CoV-2 antibodies against nucleocapsid (anti-SARS-CoV-2 (N)) and spike (anti-SARS-CoV-2 (N)) proteins in long-term immunity in convalescent patients, as well as the factors influencing the production and kinetics of those antibodies. We collected 6115 serum samples from 1611 convalescent patients at different post-infection intervals up to 21 months Study showed that in the fourth month, the anti-SARS-CoV-2 (N) exhibited their peak mean value, demonstrating a 79% increase compared to the initial month. Over the subsequent eight months, the peak value experienced a modest decline, maintaining a relatively elevated level by the end of study. Conversely, anti-SARS-CoV-2 (S) exhibited a consistent increase at each three-month interval over the 15-month period, culminating in a statistically significant peak mean value at the study's conclusion. Our findings demonstrate evidence of sustained seropositivity rates for both anti-SARS-CoV-2 (N) and (S), as well as distinct dynamics in the long-term antibody responses, with anti-SARS-CoV-2 (N) levels displaying remarkable persistence and anti-SARS-CoV-2 (S) antibodies exhibiting a progressive incline.

Kinetics of anti-nucleocapsid IgG response in COVID-19 immunocompetent convalescent patients.

The comprehension of a long-term humoral immune response against SARS-CoV-2 can shed light on the treatment and vaccination strategies of COVID-19 disease, improving the knowledge about this virus infection and/or re-infection. We assessed the IgG antibodies against SARS-CoV-2 nucleocapsid (N) protein (anti-SARS-CoV-2 (N) IgG) in 1441 COVID-19 convalescent patients within 15 months longitudinal study from middle-developed country. The main inclusion criteria was positive RT- PCR result on nasopharyngeal swab samples at least one month before antibody testing and absence of any induced or inherited immunodeficiency. 92.7% of convalescent patients' serum contained anti-SARS-CoV-2 (N) IgG and only 1.3% of patients had a delayed antibody response. In the majority of convalescent patients' the durability of antibodies lasted more than one year. The kinetics of anti-SARS-CoV-2 (N) IgG took a bell-shaped character-increased first 25-30 weeks, then started to decrease, but were still detectable for more than 15 months. We found that on the one hand anti-SARS-CoV-2 humoral response level correlates with disease severity, on the other, in particular, the level of peak antibodies correlates with age-older patients develop more robust humoral response regardless of sex, disease severity and BMI.