EC Microbiology

Lymphopenia, a marked reduction in circulating lymphocytes, is frequently observed in patients with severe COVID-19 and is strongly associated with increased disease severity and poor clinical outcomes. This paper explores a novel hypothesis that environmental exposure to heavy metals-specifically lead (Pb) and cadmium (Cd)-may contribute both to the mutation of Influenza A virus into SARS-CoV-2 and to the pathogenesis of lymphopenia in COVID-19 patients. Lead is known to impair T lymphocyte function and promote a shift from Th1- to Th2-dominant immune responses, reducing antiviral efficacy. Similarly, cadmium exposure leads to decreased lymphocyte viability, increased apoptosis, and disrupted immune function. Both metals are associated with systemic inflammation and elevated neutrophil-to-lymphocyte ratios, further implicating them in SARS COV-2 severity. The hypothesis posits that co-exposure to Pb and Cd may not only trigger viral evolution but also intensify immune dysregulation, ultimately contributing to lymphopenia. Further research is needed to investigate this potential etiological pathway and its broader implications for immune health and pandemic readiness.

 Keywords: Lymphopenia; SARS-CoV-2; Lead (Pb); Cadmium (Cd); Heavy Metals; Immune Dysregulation; T Helper Cells; Th1/Th2 Imbalance; Immunotoxicity; Viral Mutation; Influenza A

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