IL6 and infection: Some studies have suggested that lymphopenia and cytokine release syndrome (CRS) are associated with the severity of the disease [2,3]; CRS is a systemic inflammatory response that can be triggered by a variety of factors, such as infections, toxins or an idiosyncratic response to medications, and is characterized by an increased level of pro-inflammatory cytokines, including interleukin-6 (IL-6).