patients, including CD86 (2.8-fold increase in classic monocytes, p¼0.06) and CCR2 (2.9-fold in intermediate monocytes, p¼0.17; 11-fold in non-classic monocytes, p¼0.03). Conclusions:In cancer patients presenting with severe SARS-CoV-2 positive pneumonia, the infection may cause a hypercoagulable state, as suggested by higher levels of D-dimer, and unleash a pro-inflammatory response. Marked CD4 + T lymphocytopenia and NK expansion may reflect lymphocyte exhaustion and dysregulated cytotoxicity. Monocyte activation and recruitment also seem to be strongly upregulated.Legal entity responsible for the study: Hospital Clínico San Carlos.