IL-6 level but not MBL level is associated with disease severity in hospitalized patients with COVID-19

BACKGROUND AND AIM: The identification of reliable biomarkers for severe Coronavirus Disease 2019 (COVID-19) is still needed. Therefore, we analyzed mannose-binding lectin (MBL) in conjunction with interleukin-6 (IL-6) to elucidate their association with disease severity in COVID-19.METHODS: In this prospective, observational cohort study, 88 patients with COVID-19 [severe (n=28), non-severe (n=60)] were analyzed. Correlations of serum MBL and IL-6 levels with labo-ratory parameters were analyzed. Receiver operating characteristic (ROC) curves were used to analyze the impact of MBL and IL-6 levels on disease severity. Logistic regression analysis (LRA) was performed to assess the association between severity and risk factors.RESULTS: MBL level was similar in both groups (0.81 vs. 0.80 ng/mL, p=0.76) and showed no correlation between laboratory parameters nor hospitalization duration. The ROC curve showed that the area under the curve (AUC) of MBL was 0.520 (95% Cl: 0.390-0.650, p=0.76). IL-6 levels were higher in the severe group (36.6 vs. 14.5 pg/mL, p=0.03) and correlated with hospitalization duration. At 32.75 pg/mL, IL-6 could differentiate the severe group with an AUC of 0.642 (95% Cl: 0.512-0.771, p=0.03). In multivariate LRA, interleukin-6 level >32.75 pg/mL (Odds Ratio (OR): 3.991, 95% Cl: 1.475-10.799, p=0.006) remained a significant risk factor for severe disease.CONCLUSIONS: IL-6 has predictive value for both disease severity and hospitalization duration in COVID-19, while MBL is not a reliable biomarker for disease severity.