During COVID-19 pandemic, it is essential to analyze an appropriate antibody response in the presence of hyperglycemia to get insights into the mechanisms related to the worse hospital outcomes of COVID-19 pneumonia in patients with diabetes. A recent study published in Diabetologia characterized the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with diabetes. The study was conducted in a cohort of 509 individuals with documented diagnosis of COVID-19. The investigators characterized antibodies IgG, IgM and IgA response against multiple antigens of SARS-CoV-2 using a highly specific and sensitive measurement of antibodies by fluid-phase luciferase immunoprecipitation assays. The clinical outcomes and anibody titres were analyzed based on the presence of hyperglycaemia, i.e., either diagnosed or undiagnosed diabetes, at the time of, or during, hospitalisation.The authors revealed that diabetes was associated with increased levels of inflammatory biomarkers and hypercoagulopathy, leucocytosis and neutrophilia. There is also observed a strong association between higher glucose levels and risk of death was documented irrespective of diabetes diagnosis (HR 1.14×1.1 mmol/l [95% CI 1.08, 1.21], p<0.001). The humoral response against SARS-CoV-2 in patients with diabetes was present and superimposable, as for timing and antibody titres, to that of non-diabetic patients, with marginal differences, and was not influenced by glucose levels. Among the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike receptor-binding domain (RBD) was predictive of survival rate, both in the presence or absence of diabetes.

      The study arrived at the concluding remark that increased severity and mortality risk of COVID-19 pneumonia in patients with hyperglycemia was not the result of an impaired humoral response against SARS-CoV-2. In addition, the positive response for IgG can be considered as associated with a protective effect, thus giving space to optimistic thoughts about the efficacy of future vaccines against SARs-COV-2 in people with diabetes.