Interleukin-62/lymphocyte as a proposed predictive index for COVID-19 patients treated with monoclonal antibodies

Abstract

In a convenience sample of 93 patients treated with monoclonal antibodies (moAbs) against SARS-CoV-2, the interleukin-6²/lymphocyte count ratio (IL-6²/LC) was able to predict clinical worsening both in early stages of COVID-19 and in oxygen-requiring patients. Moreover, we analysed 18 most at-risk patients with asymptomatic or mild disease treated with both moAbs and antiviral treatment and found that only 2 had clinical progression, while patients with a similar risk were reported to have an unfavourable outcome in most cases from recent data. In only one of our 18 patients, clinical progression was attributable to COVID-19, and in the other cases, clinical progression was observed despite IL-6²/LC being above the risk cut-off. In conclusion, IL-6²/LC may be a valuable method to identify patients requiring more aggressive treatments both in earlier and later stages of the disease; however, most at-risk patients can be protected from clinical worsening by combining moAbs and antivirals, even if levels of the IL-6²/LC biomarker are lower than the risk cut-off.

Keywords: COVID-19; Interleukin; Lymphocytes; Monoclonal antibodies; SARS-CoV-2.

Fig. 1

Receiver operating characteristic curves for LC⁻¹ (left panel), IL-6 (middle panel) and IL-6²/LC (right panel). The reciprocal value of the lymphocyte count (LC⁻¹) was analysed instead of LC to preserve graph convexity. IL-6²/LC, as distinguished in ppi between ASY/MID and MOD/SEV disease, exhibits superior accuracy and area under the curve value