Evaluation of Complement Level, Serum Electrophoretic Panel, and Anti-glomerular Basement Membrane in Coronavirus Disease 2019: Focus on Likelihood of Hypersensitivity Type III

Background: As an inflammatory process, the emergence of autoimmunity in COVID-19 is likely through molecular mimicry. In autoimmune hypersensitivity-III, immune complex (IC) formation leads to complement activation, inflammation amplification, and tissue damage. Having accumulated IC, lesions in organs such as the lung with tiny vessels are formed, and the complement is depleted. As a systemic disease, COVID-19 has similar therapies and laboratory findings with hypersensitivity-III. Objectives: This study was designed to evaluate complement level, serum electrophoretic pattern, and anti-glomerular basement membrane (GBM) in COVID-19 patients. Materials and Methods: Blood was collected, and complement component 3 (C3), C4, 50% hemolytic complement (CH50), anti-GBM level, as well as serum electrophoresis were evaluated. Results: C3/C4 levels were normal in 70% and increased in 30% of the subjects. Albumin was normal in 76.67% and decreased in 23.33% of the patients. Furthermore, alpha-1 and alpha-2 were normal in 33.33% and 53.33% of the patients, but their levels increased in 66.67% and 46.67% of patients, respectively. Moreover, gamma-band was normal in 70% and increased in 30% of the participants. Additionally, all of the subjects had normal beta-band, CH50, and anti-GBM. Conclusion: The possibility of autoimmune hypersensitivity-III in the lung and kidneys is not understood. Furthermore, alpha band may be a candidate red flag showing changes from moderate to severe forms of the disease.