A study from Krakow followed hospitalized COVID-19 patients for five years to see if their initial immune profiles - T, B, and NK cells - could predict who would
die in the following years, or develop long COVID.🧵
die in the following years, or develop long COVID.🧵
https://twitter.com/harryspoelstra/status/1980947085957697927
Out of 103 patients from 2020, researchers followed 80 over 54 months.
23 had died, 57 were alive - and about half of those survivors (29 people) still lived with long COVID symptoms.
That’s one of the longest immune follow-ups after COVID-19 so far.
23 had died, 57 were alive - and about half of those survivors (29 people) still lived with long COVID symptoms.
That’s one of the longest immune follow-ups after COVID-19 so far.
During the acute infection, those with severe disease showed a collapse of T and NK cells.
Their total T cells dropped to a median of 340 per µl (vs 705 in milder cases).
CD4+ helper T cells fell to 183 vs 452, and CD8+ cytotoxic T cells to 109 vs 227.
Even NK cells were lower (107 vs 157).
Meanwhile, the proportion of B cells was paradoxically higher - 18.5% vs 12.5%.
Their total T cells dropped to a median of 340 per µl (vs 705 in milder cases).
CD4+ helper T cells fell to 183 vs 452, and CD8+ cytotoxic T cells to 109 vs 227.
Even NK cells were lower (107 vs 157).
Meanwhile, the proportion of B cells was paradoxically higher - 18.5% vs 12.5%.
This imbalance wasn’t just a marker of severity - it predicted who would live or die.
Those who eventually died already had about 40–50% lower T and NK cell counts during the infection.
At the same time, they had more B cells (19% vs 13%).
In short - the weaker the T/NK response at the start, the higher the chance of dying later.
Those who eventually died already had about 40–50% lower T and NK cell counts during the infection.
At the same time, they had more B cells (19% vs 13%).
In short - the weaker the T/NK response at the start, the higher the chance of dying later.
And what about long COVID?
Half of the survivors reported symptoms like fatigue, brain fog, breathlessness, or joint pain -
but their initial immune profiles looked the same as those who recovered fully.
No differences in T, B, or NK cell levels at the time of infection.
Half of the survivors reported symptoms like fatigue, brain fog, breathlessness, or joint pain -
but their initial immune profiles looked the same as those who recovered fully.
No differences in T, B, or NK cell levels at the time of infection.
So
Low T/NK cells predicted death,
but not long COVID.
Low T/NK cells predicted death,
but not long COVID.
That’s the key message.
COVID-19 left behind two distinct immune legacies:
Immune collapse - when the body’s defenses never fully recover, leaving long-term vulnerability and higher mortality.
Immune persistence - when the immune system keeps reacting to lingering viral antigens, driving long COVID.
Two very different post-viral paths.
One loses strength, the other balance.
COVID-19 left behind two distinct immune legacies:
Immune collapse - when the body’s defenses never fully recover, leaving long-term vulnerability and higher mortality.
Immune persistence - when the immune system keeps reacting to lingering viral antigens, driving long COVID.
Two very different post-viral paths.
One loses strength, the other balance.
The study didn’t specify what the patients died from or how old they were at death.
At baseline, severe cases were older (63 y vs 59.5 y), but causes of late mortality weren’t analyzed.
Still - the signal is unmistakable.
Immune collapse predicted death long before medicine knew why.
Sometimes the immune system tells the story before medicine does.
At baseline, severe cases were older (63 y vs 59.5 y), but causes of late mortality weren’t analyzed.
Still - the signal is unmistakable.
Immune collapse predicted death long before medicine knew why.
Sometimes the immune system tells the story before medicine does.
Matyja-Bednarczyk at al., Baseline Dysregulation in B, T, and NK Cells in COVID-19 Predicts Increased Late Mortality but Not Long-COVID Symptoms: Results from a Single-Center Observational Study. mdpi.com/1999-4915/17/1…
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