Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 16, 2025 2 hours, 1 minute ago
Medical News: A closer look at immune system weakness in COVID patients
Researchers from the Cancer Hospital of Shantou University Medical College and the Second Affiliated Hospital of Shantou University Medical College in Guangdong, China, have uncovered serious disruptions in the body’s immune defense among people infected with COVID-19. Their study focused on T-lymphocytes—white blood cells that are central to fighting viruses. By comparing blood samples from 60 COVID-19 patients with those from 36 healthy individuals, they revealed clear evidence of immune cell loss and imbalance. This
Medical News report highlights how COVID-19 weakens the very cells that protect the body from infection.
COVID-19 Infection Causes Major Damage to T-Cells
What the study found about T cells
The researchers discovered that patients with COVID-19 had significantly fewer T-lymphocytes overall compared to healthy people. This included both CD4+ helper T cells and CD8+ killer T cells, which are normally responsible for coordinating immune defense and directly attacking infected cells. Not only were total numbers lower, but the balance between different types of T cells was disrupted.
For example, the “naïve” T cells, which are fresh cells that can respond to new infections, were particularly depleted. This means patients, especially older ones, had a harder time mounting a strong defense. In contrast, “memory” T cells, which carry records of past infections, were more common, suggesting the immune system was shifting to a less flexible state.
Severity and age made the problem worse
When looking at patients by illness severity, the team found that those in critical condition had the lowest numbers of T-lymphocytes. Even the specialized regulatory T cells, which normally help keep the immune system balanced, were much reduced in the sickest patients.
Age also played a major role. The study showed that older patients had sharply lower levels of CD8+ naïve T cells. This suggests that age-related weakening of the immune system combines with COVID-19 infection to leave elderly patients especially vulnerable to severe disease.
Why this matters for long-term health
The findings underline how SARS-CoV-2 infection doesn’t just cause lung problems but strikes at the very foundation of the immune system. The drop in key T cells makes it harder for the body to fight off not only COVID-19 itself but also other infections that may appear while the immune system is weakened. By identifying which immune cells are most affected, doctors may be able to better monitor patients and predict who is at higher risk of worsening illness.
Final thoughts
This study provides strong evidence that COVID-19 severely weakens cellular immunity, especially in older and critically ill patients. The loss of naïve T cells and the imbalance in immune subgroups explain why recovery can be difficult and why
complications are common. These results highlight the importance of monitoring immune health in patients and developing treatments that help restore immune balance. The damage to T cells may also explain why some people continue to face long-term health issues after infection.
The study findings were published in the peer reviewed journal: Biochemistry Research International.
https://onlinelibrary.wiley.com/doi/10.1155/bri/5791950
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Read Also:
https://www.thailandmedical.news/news/italian-study-alarmingly-finds-that-covid-19-vaccination-weakens-t-cell-defenses
https://www.thailandmedical.news/news/alarming-changes-in-transitional-b-cells-reveal-hidden-immune-dysregulation-in-long-covid-sufferers
https://www.thailandmedical.news/news/platelets-and-t-cells-in-covid-19-recovery
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