A study conducted in a highly heterogeneous cohort of COVID-19 patients identified a core peripheral blood immune signature with three distinct traits, according to an article published in Nature Medicine.
The analysis included 63 hospital-treated patients with COVID-19 and 55 healthy controls; including 23 previously exposed seropositive individuals and 10 patients hospitalised for non-COVID-19 lower respiratory tract infections.
Participants' peripheral blood was subject to immunophenotyping, for broad lymphocyte composition, effector/memory T cell status, γδ T cell status, B cells, cell cycling, leukocyte counts, lymphocyte activation and exhaustion, innate immune cells, and 22 cytokines and antibodies against SARS-CoV-2.
Based on the results, the researchers were able to identify a signature that includes discrete changes in B and myelomonocytic cell composition, profoundly altered T cell phenotypes, selective cytokine/chemokine upregulation, and SARS-CoV-2-specific antibodies.
Some signature traits identify links with other settings of immunoprotection and immunopathology. Others, including basophil and plasmacytoid dendritic cell depletion, correlated strongly with disease severity. A third set of traits, including a triad of chemokine IP-10, interleukin-10 and interleukin-6, anticipated subsequent clinical progression.
This multifaceted immune signature provides a basis for addressing many clinical and research questions, including COVID-19 clinical progression.