Serum IgG Profile in Convalescent COVID-19 Patients in Different ABO Blood Grouping System: A Retrospective Study

Introduction: The plasma collected from the recovered Coronavirus Disease 2019 (COVID-19) patients is used therapeutically in serious COVID-19 patients as a life saving procedure. Serum Immunoglobulin G (IgG) estimation is a routine procedure followed in these voluntary donors. In this routine procedure, authors have come across patients with particular blood group having more chances of seronegativity for COVID-19 IgG antibody. This is the reason why the present study was conducted. Aim: To find out the variable IgG response in recovered COVID19 patients with different types of clinical manifestations along with the possible relation with different types of blood groups of ABO system. Materials and Methods: This retrospective study was conducted in plasma bank of Veer Surendra Sai Institute of Medical Science and Research, Burla, Odisha, India, from 1st August to 15th December 2020. Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) specific IgG antibody level was estimated quantitatively using Chemiluminescence Immunoassay (CLIA) method. Patients with IgG level more than 1.4 were taken as positive. Results: This study had estimated IgG level during screening of 440 voluntary plasma donors. Out of these, seropositivity was found in 354 patients. Patients with blood group O and AB were having seropositivity rate more than that of other ABO blood groups, whereas seronegativity percentage was more in blood group A patients. Conclusion: There was a non specific relation between severity of symptoms and detectable development of IgG antibody in recovered corona patients. Also, blood group A patients develop less likely IgG antibody against COVID-19