Fig. 3: Serum biomarkers in relation to disease status and severity, and correlation between those markers and peripheral cell counts.

A–C C-Reactive protein (CRP), D-dimer and ferritin levels showed similar trends being significantly higher in COVID-19 patients than NC. There was no significant trend in relation to severity of COVID-19 disease. HIV-1 infected patients with both COVID-19 and tuberculosis had higher levels of all three markers than those with COVID-19 alone. Comparisons between the NC and COVID-19 groups were performed using a Mann Whitney test and other comparisons were performed using a Kruskal-Wallis test. D Lactate dehydrogenase was significantly higher in COVID-19 patients than NC, with levels tending to increase with increasing COVID-19 disease severity. There was however no relationship with HIV-1 and/or tuberculosis status. Comparisons between the NC and COVID-19 groups were performed using a Mann Whitney test and other comparisons were performed using a Kruskal-Wallis test (two sided). E, F Correlation matrix of serum biomarkers in COVID-19 patients (E) and NC participants (F). Amongst COVID-19 patients there was strong positive correlation between total white cell (WCC) and neutrophil counts, and moderate between ferritin and LDH, and between lymphocyte and monocyte counts. In NC participants, the relationship between total white cell (WCC) and neutrophil counts, and between ferritin and LDH was also observed. Positive correlations are indicated in blue and negative correlation in red. Spearman R-values are indicated in each square. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Line indicates the median value and shaded area the normal range.