Increased Serum Thromboxane A2 and Prostacyclin but Lower Complement C3 and C4 Levels in COVID-19: Associations with Chest CT Scan Anomalies and Lowered Peripheral Oxygen Saturation

COVID-19 patients suffer from hypercoagulation and activated immune-inflammatory pathways. The current study examined the relationship between specific complements and coagulation abnormalities associated with chest CT scan anomalies (CCTAs) and peripheral oxygen saturation (SpO2) in COVID-19 patients. Serum levels of complement C3 and C4, and thromboxane A2 (TxA2) and prostacyclin (PGI2) were measured using an ELISA and albumin, calcium, and magnesium by using the spectrophotometric method in 60 COVID-19 patients and 30 controls. C3 and C4 were significantly decreased (p < 0.001), and TxA2 and PGI2 significantly increased (p < 0.001) in the COVID-19 patients compared with the controls with the highest levels in the CCTA patients’ group. Neural networks showed that a combination of C3, albumin, and TxA2 yielded a predictive accuracy of 100% in detecting COVID-19 patients. SpO2 was significantly decreased in the COVID-19 patients and was inversely associated with TxA2 and PGI2, and positively with C3, C4, albumin, and calcium. Patients with positive IgG results show significantly higher SpO2, TxA2, PGI2, and C4 levels than IgG-negative patients. CCTAs were accompanied by lower SpO2 and albumin and increased PGI2 and TxA2 levels, suggesting that interactions between immune-inflammatory pathways and platelet hyperactivity participate in the pathophysiology of COVID-19 and, consequently, may play a role in an enhanced risk of hypercoagulability and venous thromboembolism. These mechanisms are aggravated by lowered calcium and magnesium levels.