Recent studies have shown that lymphopenia with cytokine storm syndrome is frequently found in COVID-19 patients. These features may suggest that the modified immune system plays a key role in determining disease progression. Lymphopenia or lymphocytopenia is a condition in which the number of lymphocytes in the blood is low. Although T cells can be increased at the onset of COVID-19, these patients tend to have low lymphocyte counts, which is associated with increased COVID-19 severity. Thus, individuals who died of COVID-19 have been shown to have significantly lower lymphocyte levels than survivors. There is evidence that myeloid cells play a role in the pathophysiology of coronavirus infection, either directly as virus targets or indirectly as effectors of cytokine release syndrome. Monocytes are innate hematopoietic cells that maintain vascular homeostasis and provide early responses to pathogens during acute infections. The role of monocytes and macrophages in the resolution of inflammation has also been emphasized as an important component of the response to SARS-CoV-2. Accordingly, it was investigated whether the change observed in blood monocyte levels was an effective parameter in the prognosis process in Covid-19 cases with lymphopenia, considering that monocyte levels could be useful as a guide in the course of the disease.

Inclusion Criteria:

• Patients over the age of 18
• Male and female of both genders
• Admitted to the intensive care unit
• Diagnosed with Covid-19 with lymphopenia
• Patients with confirmed COVID-19 diagnosis in polymerase chain reaction (PCR) tests performed on nasopharyngeal swab samples

Exclusion Criteria:

• Those with a negative PCR test
• Aged 18 and under

The study was conducted among patients admitted to the intensive care unit of a tertiary hospital.