Single-cell sequencing revealed thymosin alpha-1 increased NKT killer cell populations and T cell receptor diversity in both COVID-19 patients and healthy controls, supporting its use as an immune-modulating peptide therapy.
NKT cells significantly increased (p=0.010–0.031)Thymosin alpha-1 increased CD3+ KLRD1+ and TBX21+ CD8+ NKT cell populations in both COVID-19 patients and healthy controls, with enhanced cytotoxicity pathways
What the researchers found
In 33 COVID-19 patients and 11 healthy controls analyzed by scRNA-seq and TCR-seq:
- CD3+ KLRD1+ NKT cells increased with Tα1 in COVID-19 (p = 0.024) and healthy controls (p = 0.016)
- TBX21+ CD8+ NKT cells increased with Tα1 in COVID-19 (p = 0.010) and healthy controls (p = 0.031)
- Tα1-treated NKT cells showed higher expression of KLRB1, PRF1 (perforin) and enrichment of NK cell cytotoxicity, chemokine signaling, and JAK-STAT pathways
- Increased TRBV9-TRBJ1-1 T cell receptor pair in both groups after Tα1 treatment
- 1,389 common CDR3 sequences between untreated COVID-19 and healthy, but 0 common sequences between treated groups — indicating Tα1 diversifies T cell clones
- Tα1 promotes NKT cell activation and cytotoxicity through gene expression regulation
Why it matters
This is one of the most detailed studies of how thymosin alpha-1 modifies the immune system, using advanced single-cell technology to reveal changes at individual cell level. The finding that Tα1 enhances NKT killer cells and diversifies T cell receptors provides a molecular rationale for its use as an immunomodulator — not just in COVID-19 but potentially in other infections and in immunocompromised patients.
How the study worked
Peripheral blood mononuclear cells from 33 symptomatic COVID-19 patients (with and without Tα1 treatment) and 11 healthy controls (with and without Tα1) were analyzed using single-cell RNA sequencing (scRNA-seq) and T cell receptor sequencing (TCR-seq). Differential expression analysis and functional enrichment analysis were performed to identify immune changes mediated by Tα1.
What this study cannot tell us
The sample size is small (44 total participants), limiting statistical power. The study is observational without randomization — patients who received Tα1 may have differed from those who didn't. The scRNA-seq analysis captures a snapshot at one time point, not the dynamic immune response over time. Clinical outcomes (symptom improvement, hospital stay, mortality) were not correlated with the immunological findings. The COVID-19 variants involved were not specified.
How to read the evidence
This is an observational study using advanced single-cell sequencing in a relatively small cohort. While the technology provides unprecedented detail about immune changes, the lack of randomization and small sample size limit causal conclusions.
When this study was published
Published in 2023, this study used state-of-the-art single-cell sequencing to analyze Tα1's immunomodulatory effects during the COVID-19 pandemic era.
The bigger picture
Thymosin alpha-1 has been used clinically in over 30 countries, primarily for hepatitis B and as an immune adjuvant. Its use during the COVID-19 pandemic brought renewed attention to peptide-based immunomodulation. This single-cell study provides the deepest mechanistic evidence yet for how Tα1 reshapes the immune landscape, potentially informing its use in future pandemics and in immunodeficiency states.
Questions still open
- Do the NKT cell increases and TCR diversification with Tα1 translate to measurably better COVID-19 clinical outcomes?
- Could Tα1 be used as an adjuvant to COVID-19 vaccination to enhance immune responses, particularly in immunocompromised individuals?
- Are Tα1's immune-modulating effects sustained after treatment is stopped?
Common questions
What is thymosin alpha-1?
Did thymosin alpha-1 help COVID-19 patients?
Read the original research
Thymosin α1 modulated the immune landscape of COVID-19 patients revealed by single-cell RNA and TCR sequencing.
International immunopharmacology, 124(Pt B), 110983
Citation
Bai, Han; Liang, Liyuan; Qi, Xin; Xu, Yao; Liu, Yijia; Ren, Doudou; Cai, Zeqiong; Mao, Weikang; Wang, Xiaorui; Qin, Hongyu; Hu, Fang; Shi, Bingyin. (2023). Thymosin α1 modulated the immune landscape of COVID-19 patients revealed by single-cell RNA and TCR sequencing.. International immunopharmacology, 124(Pt B), 110983. https://doi.org/10.1016/j.intimp.2023.110983