Persistent dysregulation of cellular immunity following COVID-19 recovery despite minimal post-COVID-19 sequelae manifestation

Dear Sir,
Most individuals affected by COVID-19 recovered uneventfully. However, mounting evidence reported patients with persisting symptoms (post-COVID sequelae),1 and identifying the predisposing factors is beneficial for facilitating diagnosis and advising public health strategy. We read with great interest the recent multicenter study by Rombauts et al. reporting the association of SARS-CoV-2 RNAemia with more post-COVID symptoms 6 months following recovery.2 An orchestrated series of immune responses drive the innate and adaptive immunity to eliminate replicating viruses during the disease course. Ongoing systemic inflammation marked by activated cellular immunity and cytokine production has been associated with organ damage and increased mortality.3 Therefore, coordinated immune resolution is indispensable during the recovery phase. This study aims to observe the immunological alteration following COVID-19 illness. In addition to the antibody titer measurement, peripheral blood mononuclear cells (PBMCs) were also collected from patients recovering from COVID-19 infection to map the cellular and humoral immune response comprehensively.