The aim of the study is to assess the expression of TLR 3, 7, and 9 in the population of peripheral blood mononuclear cells (PBMC) and in B lymphocytes (CD19+), T lymphocytes (CD4+ and CD8+) using flow cytometry in relation to the clinical parameters and outcome of COVID 19 patients .

Abnormal stimulation of innate immunity may have a great influence on the immunopathogenesis of COVID 19 disease .The involvement of innate immunity receptors-toll-like receptors (TLR)-in the pathogenesis of COVID 19 is not adequately studied. The activation of these receptors by specific ligands is thought to initiate autoimmune processes[1]. TLR stimulation leads to increased expression of proinflammatory cytokines (IL-6, IFN

Inclusion Criteria:

• Patients ≥18 years old of both genders.
• Patients diagnosed as confirmed COVID-19 when they have a positive result of RT-PCR for SARS-CoV-2 RNA or confirmed diagnosis by typical clinical picture and radiological methods , according to the WHO and Egyptian Ministry of Health and Population (MOH) definitions, at Assiut University Hospital.

Exclusion Criteria:

• Children less than 18 years.
• Patients refusal to participate in the study

Patients diagnosed as confirmed COVID-19 when they have a positive result of RT-PCR for SARS-CoV-2 RNA or confirmed diagnosis by typical clinical picture and radiological methods , according to the WHO and Egyptian Ministry of Health and Population (MOH) definitions, at Assiut University Hospital