Impaired T cell functions along with elevated activated Tregs at the early stage of asymptomatic SARS-CoV-2 infection
Authors: Yang et al.
Journal/ Pre-Print: MedRxiv
Tags: Clinical, Immunology/Immunity
1. In an asymptomatic individual, T lymphocyte exhibited peak proliferation (Ki-67) by day 7 after testing SARS-CoV-2 positive. T lymphocyte and Treg activation peaked by day 13, whilst frequencies of Th1 and Treg increased over the first 28 days.
2. The patient produced virus-specific IgM by day 7, but did not begin to produce IgG.
In an asymptomatic individual, T lymphocyte exhibited peak proliferation (Ki-67) by day 7 after testing SARS-CoV-2 positive. T lymphocyte and Treg activation peaked by day 13, whilst frequencies of Th1 and Treg increased over the first 28 days. The patient produced virus-specific IgM by day 7 but did not begin to produce IgG.
Impact for SARS-CoV2/COVID19 research efforts
Understand the immune response to SARS-CoV2/COVID19
Clinical symptoms and pathogenesis of SARS-Cov2/COVID19
· Single patient Case study
Strengths and limitations of the paper
Novelty: Longitudinal changes to T lymphocytes in an asymptomatic patient
Standing in the field: There are over 6 million confirmed cases of COVID-19 globally. Therefore, even though asymptomatic, it should be possible to conduct studies with more than one patient by now.
Appropriate statistics: None. Observational study of a single patient.
Viral model used: SARS-CoV-2 infection in single patient in March 2020
· Very limited longitudinal study of a single patient compared to 11 healthy age-matched controls who were sampled at a single timepoint
· Unclear what normalisation or standardisation of the gating strategy was used to compare cell subsets over time; no cell counts over time which may have been significantly impacted by the recognised changes in T cell numbers in SARS-CoV
· Unclear which test was used to confirm SARS-CoV-2 specific antibodies (specificity, sensitivity, etc)
· Debatable gating strategies (e.g. CD4+CD25+Foxp3neg cells may not actually be Tregs during active infection); unclear if FMO or isotype controls used
· Some FACS plot appear to have been artificially cut off (e.g. Fig 2B IL-17)