CD4 and COVID-19: Thus, we speculated that, in COVID-19, uncontrolled IL-6 elevation and decreased eGFR may just reflect a state of immunity complication that could be somehow explained by vitamin D depletion [26,27,28,29] Our conclusion confirmed by the analysis performed on Covid-19-infected adults revealed an anomalous immunity picture composed of abnormal levels of both innate and adaptive immune components, such as monocyte, macrophages, and neutrophil, as well as CD4 and CD4-naïve T cells and B cells (data not shown).