Immunologic aspect in diagnosis and treatment of SARS-COV-2 patients

Abstract

Recent worldwide outbreak of novel coronavirus disease (CoVID-19) has affected massive human population including Pakistan, and has caused a huge number of mortalities in few months. CoVID-19 is an infectious disease caused by a virus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which is single stranded RNA enveloped beta coronavirus and affects lower respiratory tract. It transmits from human to human through respiratory droplets. It uses its S-protein to recognize ACE2 (Angiotensin Converting Enzyme-2) receptors in lung epithelial cells where it attaches and causes infection. The incubation period is 2-14 days. In pre-symptomatic phase, body’s immune system starts antibodies production. Significant antibodies are IgM and IgG that produces within 03-06 days and 8-12 days respectively. This review provides the available information about immunological aspects in terms of diagnosis and screening of CoVID-19 and potential therapeutic targets for combating SARS-CoV-2 infection. Immunologic techniques to detect these antibodies are ELISA (Enzyme-linked Immunosorbent Assay), CMIA (Chemiluminescent Micro particle Immunoassay) and ICT (Immunochromatographic Test). Among these, ELISA and CMIA are found to be highly specific and sensitive in convalescent phase of infection. While the fundamental confirmatory test for SARS-CoV-2 infection is RT-PCR (Reverse Transcription Polymerase Chain Reaction) which detects the viral RNA in respiratory samples preferably nasopharyngeal swab. Serological assays are essential to find out rate of infection, and most importantly antibody titers in recovered patients to be used for therapeutic purpose. After some successful studies Convalescent Plasma is considered as a good therapeutic option in the absence of specific antiviral therapy.