COVID-19 infection affecting every one of us from last one year and continue to affecting so far through various new strains. Recently, new variant i.e.Omicron of COVID-19 is emerged and start spreading across the globe.The major objective today is to save the patients as we can from lethal effect of this virus. Reports have shown the massive increase in various inflammatory mediators of COVID-19 patients resulting in cytokine storm and death. Steroids are well known powerful anti-inflammatory agents available in the market for the management of various diseases. Thus, use of steroids in COVID-19 patients could have the potential to reduce mortality. However, there is lot of confusion regarding use of steroids in COVID-19 patients as unnecessary use of these agents could results in various adverse drug reactions (ADRs). This article briefly present role of immune system and the importance of steroids in COVID-19 patients. Further, the main findings of recent meta-analysis done by our team is also summarized.
COVID-19 is already declared a pandemic by the World Health Organization, and various new strains are also emerging across the globe and creating havoc. Vaccines are being developed and showing promising results in the prevention of this infection. The role of vaccines against new strains is completely unclear so far. Further, till now, no specific drug is available for its treatment. Various classes of drugs such as specific antibiotics like doxycycline, azithromycin, etc.; anthelmintics like ivermectin; anti-gout agents like cholchicine; anti-viral agents like remdesivir, favipiravir, etc.; monoclonal antibodies like trastuzumab; antimalarials like hydroxychloroquine; anti-inflammatory agents like indomethacin; analgesics and antipyretics like paracetamol are being used in the management of COVID-19 patients depending upon the condition of the individual. Researchers across the globe are working hard to come up with a specific molecule against this infection.
The SARS-CoV-2 enters the body, and the spike protein specifically attaches to the angiotensin-converting enzyme (ACE-2) of the host, followed by the entry of the virus inside the cell. The SARS-CoV-2 is a single-stranded RNA virus that uses the machinery of the host cell to make millions of copies. As we know, the immune system plays a significant role in the protection of the body against exogenous agents. The immune system is broadly divided into two parts, i.e., the innate immune system and the adaptive immune system. The skin, mucous membranes, and white blood cells (WBCs) are part of the innate immune system, whereas T and B cells are parts of the adaptive immune system. Normally, skin protects us against harmful agents through keratin protein, but if exogenous agents enter through the mouth, nose, etc., the mucous membrane contains specific enzymes that do degradation of these agents. Further, if exogenous agents enter into blood circulation, WBCs will do the degradation and removal through the process of phagocytosis.
The most important feature of the immune system is to distinguish between self and non-self. The specific type of receptors called pattern recognition receptors (PRRs) act as a sensor for pathogen-associated molecular patterns (PAMPs) of exogenous agents. The toll-like receptors (TLRs) are a well-known example of PRRs. If the innate immune system is unable to handle it, as in the case of SARS-CoV-2 infection, the adaptive immune system is activated. The activation of the adaptive immune system usually takes 5-7 days for activation and is activated through the innate immune system. The antigen-presenting cells (APCs), like dendritic cells, WBCs, etc., present the processed viral protein to T cells (adaptive immune system). The presentation of antigen is done through specific proteins, i.e., major histocompatibility complex (MHCs) and co-stimulatory signals.
The activation of T cells releases various cytokines, which result in the clonal expansion. The released cytokines kill the antigen as well as activate cytotoxic T cells. The released cytokines also activate the B cells to produce antibodies. Unfortunately, in the case of SARS-CoV-2 infection, in some cases, the immune system is unable to handle it and results in overactivation, which results in the release of excessive cytokines. The excess release of cytokines could result in the death of patients also.
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