Association of Serum Complement C3 Levels with Severity and Mortality in COVID 19.

The severe acute respiratory distress syndrome-associated coronavirus-2 infection can activate innate and adaptive immune responses which may lead to harmful tissue damage, both locally and systemically. C3, a member of complement system of serum proteins, is a major component of innate immune and inflammatory responses. This study is aimed to assess serum C3 as a marker of COVID-19 severity and a predictor of disease progression. A total of 150 COVID-19 patients, confirmed by RT-PCR, and 50 healthy controls were recruited. Serum C3 levels were determined by using direct colorimetric method. Median levels of serum C3 in total cases and controls were 157.8 and 165.7 mg/dL respectively. Serum C3 although not significantly decreased, they were lower in cases when compared to controls. Similarly, significant differences were found between the groups, with severe group (140.6 mg/dL) having low levels of serum C3 protein when compared to mild (161.0 mg/dL) and moderate group (167.1 mg/dL). Interestingly, during hospitalization, significant difference between baseline (admission) and follow-up (discharge) was observed only in patients with moderate disease. Based on our results, lower levels of C3, with an increase in IL-6 and d-dimer levels, are associated with higher odds of mortality. Therefore, we would like to emphasize that measuring serum C3 levels along with other inflammatory markers might give an added advantage in early identification of patients who are prone to having a severe disease course and can help in a more effective follow-up of disease progression. Supplementary Information: The online version contains supplementary material available at 10.1007/s12291-023-01148-x.

Comparative Analysis of Serum Zinc, Copper and Magnesium Level and Their Relations in Association with Severity and Mortality in SARS-CoV-2 Patients.

The deficiencies of trace elements and infectious diseases often coexist and exhibit complex interactions. Several trace elements such as zinc (Zn), copper (Cu) and magnesium (Mg) have immunomodulatory functions and thus influence the susceptibility to the course and outcome of a variety of viral infections. So, this present study was aimed to study relations of trace metals in association with severity and mortality in SARS-CoV-2 patients. A total of 150 individuals infected with COVID-19 and 50 healthy individuals were recruited. Cases were divided based on severity (mild, moderate and severe) and outcome (discharged or deceased). Serum Zn, Mg and Cu levels were analysed by direct colourimetric method. Both serum Cu and Zn levels were significantly decreased in cases when compared to those in controls (p < 0.005 and p < 0.0001). Serum magnesium levels although not significant were found to be slightly decreased in controls. On comparing the trace elements between the deceased and discharged cases, a significant difference was found between serum copper and zinc levels, but for magnesium, both groups have similar levels. The receiver operating characteristic (ROC) curve results indicate that a serum Cu/Zn ratio along with the age of patient provides some reliable information on COVID-19 course and survival odds by yielding an AUC of 95.1% with a sensitivity of 93.8% and specificity of 89.8%. Therefore, we would like to emphasize that measuring the serum copper and zinc along with their ratio can be used as routine investigations for COVID-19 patients in proper identification and management of severe cases in upcoming new waves of COVID-19.

Association of iron-related biomarkers with severity and mortality in COVID-19 patients.

BACKGROUND: Nutritional deficiency is associated with weaken immune system and increased susceptibility to infection. Among other nutrients, several trace elements have been shown to regulate immune responses. Iron is one of the most abundant trace elements present in our body, which is required in various biological processes. Iron has an immunomodulatory function and thus influence the susceptibility to the course and outcome of a variety of viral infections. So, this present study was aimed to study relations of different iron-related biomarkers in association to severity and mortality in SARS-CoV-2 patients. MATERIALS AND METHODS: A total of 150 individuals infected with COVID-19 and 50 healthy individuals were recruited. Cases were divided based on severity (mild, moderate, and severe) and outcome (discharged or deceased). Serum iron, TIBC, ferritin, transferrin, transferrin saturation levels were analyzed by the direct colourimetric method. RESULTS: In cases the median levels of serum iron, TIBC, transferrin, transferrin saturation and ferritin are 29 µg/dL, 132.53 µg/dL, 106.3 mg/dL, 17.74 % and 702.9 ng/dL respectively. Similarly, in controls the median levels of serum iron, TIBC, transferrin, transferrin saturation and ferritin are 53 µg/dL, 391.88 µg/dL, 313.51 mg/dL, 12.81 % and 13.52 ng/dL respectively. On comparing the cases with the controls, a significant lower level of iron, TIBC, and transferrin were found in the cases along with the significant higher levels of ferritin and transferrin saturation. On comparing the Receiver operating characteristic (ROC) curves of Iron, Ferritin, Transferrin, Transferrin sat % and TIBC in relation to survival in COVID-19 patients it was found that iron, followed by transferrin and ferritin has the highest area under the curve (AUC) with 74 %, 63 % and 61 % respectively. Further, in pairwise analysis of ROC curve, a significant difference was found between the Iron-transferrin (p < 0.01), iron-TIBC (p < 0.001) and transferrin-ferritin (P < 0.01). The multiple regression model based on Iron and transferrin outperformed any other combination of variables via stepwise AIC selection with an AUC of 98.2 %. The cutoff point according to Youden's J index is characterized with a sensitivity of 98 % and a specificity of 96.8 %, indicating that iron along with transferrin can be a useful marker that may contribute to a better assessment of survival chances in COVID-19. CONCLUSION: Our study demonstrated a significantly decreased levels of iron, TIBC, & transferrin and a significantly increased levels of ferritin and transferrin saturation in COVID-19 patients when compared with controls. Further, Iron and transferrin were observed to be a good predictor of mortality in patients with COVID-19. From the above analysis we confirm that iron-related biomarkers play an important role in the development of oxidative stress and further lead to activation of the cytokine storm. So, continuous monitoring of these parameters could be helpful in the early detection of individuals developing the severe disease and can be used to decrease mortality in upcoming new waves of COVID-19.