This notion is actually supported with a seminal study published by Long (12), who showed the fact that anti-SARS-CoV-2 antibodies titer declined in 81% and 62% of asymptomatic and symptomatic COVID-19 patients, respectively, in the convalescent phase (i.e., eight weeks after medical center discharge). targeted at recognizing the current presence of humoral response against the trojan, for either epidemiological reasons (i.e., monitoring seroprevalence and/or herd immunity), or for sometimes complementing nucleic acidity amplification exams (NAATs) in particular circumstances, for instance when the test outcomes of molecular diagnostics are undefined or could be falsely harmful due to a huge selection of pre-analytical and analytical problems (3,4). Recent evidence is emerging, that serology testing in COVID-19 may have additional rather than less essential clinical implications. The existing armamentarium of immunoassays for calculating anti-SARS-CoV-2 antibodies encompass methods which measure an individual immunoglobulin course (i.e., IgM, IgG or IgA) or those calculating the full total immunoglobulins response, aswell simply because qualitative, semi-quantitative and quantitative strategies (5). Although we’d all concur that semi-quantitative and qualitative methods are certainly sufficient for epidemiologic reasons, clinical evidence is certainly rising that quantitative antibodies evaluation (i.e., titration) could be more appropriate through the entire clinical span of COVID-19. The to begin such reasons may be the solid and positive association that’s being increasingly discovered between antibodies titer and disease intensity, which distinguishes asymptomatic from symptomatic sufferers (6), but also predicts development towards serious/critical disease (7). Although no definitive explanations have already been provided up to now for this interesting biologic relationship, the introduction of antibody-dependent improvement (ADE) continues to be advocated among the feasible underlying systems, whereby the humoral response against SARS-CoV-2, seen as a appearance of particular antibodies, may donate to amplify disease severity paradoxically. More specifically, the viral contaminants destined with their particular antibodies might enhance viral entrance within FcR-bearing cells, bypassing receptor-mediated pathways, which may be accompanied by amplified viral replication after that, activation of immune system cells and discharge into the blood stream of a huge selection of pro-inflammatory cytokines (i.e., mirrored with the so-called cytokine surprise), which would donate to cause eventually, maintain and propagate the systemic inflammatory response characterizing the unfavorable development in COVID-19 (8). Within this circumstance, the identification of patients with higher antibodies titer would enable to establish more appropriate therapies, for example CX-5461 based on early administration of antiviral and anti-inflammatory drugs aimed at preventing lung or disseminated organ injury (9). Quantitative assays would also allow a better reflection of neutralizing activity, more strictly associated with protection against SARS-CoV-2 contamination than measuring total antibodies (10), whilst non-neutralizing antibodies may provide also anti-viral protection via recruitment of complement and/or Fc receptors, which are present on all immune cells (11). Monitoring natural immunity is usually a second important reason, which specifically requires precise quantification of antibodies titer. Although it is usually by far too early to make conclusions on nature and duration of the host immune response against SARS-CoV-2 and on the effectiveness of virus neutralization over time as protection against the risk of re-infection, clear evidence has emerged that not only the anti-SARS-CoV-2 antibodies titer seems to decline quite rapidly in certain patients, but also that many patients with SARS-CoV-2 contamination would become seronegative within 2C3 months after recovery. This notion is clearly supported by a seminal study published by Long (12), who showed that this anti-SARS-CoV-2 antibodies titer declined in 81% and 62% of asymptomatic CX-5461 CX-5461 and symptomatic COVID-19 patients, respectively, in the convalescent phase (i.e., 8 weeks after hospital discharge). Even more importantly, as many as 40% and 13% of asymptomatic and symptomatic COVID-19 patients become seronegative on follow-up. It is hence rather understandable that longitudinal quantification of anti-SARS-CoV-2 antibodies titer seems almost unavoidable for monitoring the evolution of humoral response of patients recovering from COVID-19, for especially identifying those who will be at theoretically higher risk of being re-infected and, perhaps, of developing ADE. The opportunity to adopt locally validated cut-offs for the different immunoassays is usually a third and more technical issue, which would justify specific anti-SARS-CoV-2 antibodies titration. A recent study by our group showed that local redefinition of diagnostic thresholds of different commercial methods may be necessary for optimizing test performance, but also for enhancing inter-assay agreement and Rabbit Polyclonal to TFEB improving harmonization of serological SARS-COV-2 testing worldwide.