Nikhil Prasad Fact checked by:Thailand Medical News Team Jul 10, 2025 13 hours, 17 minutes ago
Medical News: Rare and Dangerous Immune Condition Linked to COVID-19
A group of international researchers has uncovered worrying evidence that SARS-CoV-2, the virus behind COVID-19, can trigger a rare and life-threatening immune condition called Hemophagocytic Lymphohistiocytosis, or HLH. The research was conducted by scientists from North Carolina State University (USA), Wroclaw Medical University (Poland), Poznan University of Medical Sciences (Poland), Nicolaus Copernicus University (Poland), and Masaryk University (Czech Republic). This
Medical News report highlights how HLH, already known to be deadly if left untreated, can occur after COVID-19 infection—even weeks later.
Deadly Immune Disorder Triggered by COVID-19 Infection Uncovered
HLH causes the immune system to go into overdrive, attacking the body’s own organs and tissues. It can be inherited or acquired, often triggered by infections, including viruses. Researchers describe how COVID-19 can act as a spark, causing massive immune dysfunction, leading to severe inflammation and even organ failure in affected patients.
What Is HLH and Why Is It So Serious
Hemophagocytic Lymphohistiocytosis is a rare disorder where the body’s immune cells—particularly T-cells and natural killer (NK) cells—become overactive. These cells release a flood of inflammatory substances known as cytokines. This "cytokine storm" can lead to high fevers, enlarged spleen, liver problems, dangerously low blood counts, and multi-organ failure.
The disease is hard to diagnose. Doctors rely on a checklist that includes fever, low blood cell counts, abnormal liver function, and markers like high ferritin and triglyceride levels. If left untreated, HLH has a very high mortality rate—more than 40% of patients do not survive.
Case Studies Reveal Post COVID-19 Danger
The study presented real-world examples of patients who developed HLH after COVID-19. One case involved a 72-year-old woman with well-controlled rheumatoid arthritis who recovered from COVID-19, only to be struck down by HLH weeks later. Despite initial improvement after treatment with steroids and chemotherapy, her condition deteriorated, and she passed away due to severe complications.
Another case featured a 65-year-old man who experienced worsening respiratory symptoms after COVID-19, followed by rapid organ failure. His lab results showed dangerously high inflammation markers, including ferritin levels over 98,000 ng/mL—far above the normal range. Though he was given aggressive treatment, including immunosuppressants and supportive care, his outcome was grim.
How COVID-19 Triggers HLH
The researchers believe that severe COVID-19 infections may set off HLH by unleashing a wave of inflammatory molecules. The virus binds to the body’s ACE2 receptors and disrupts key immune signaling pathways. This leads to the overproduction of immune cells and inflammatory substances, mimicking or directly triggering HLH
. This type of response may explain why some COVID-19 patients deteriorate rapidly and suffer organ failure even after the virus is no longer detectable.
Doctors Urged to Be Alert to HLH in COVID-19 Cases
Doctors are often challenged when trying to tell the difference between severe COVID-19, sepsis, and HLH. All three conditions share similar symptoms, including fever, low blood pressure, and multi-organ problems. But missing an HLH diagnosis can be fatal if specific treatments like etoposide, dexamethasone, or advanced immune therapies are not given in time.
HLH is difficult to spot, but when caught early and treated properly, survival is possible. With more awareness and research, doctors may soon have better tools to recognize and manage this dangerous condition in patients recovering from COVID-19.
The study findings were published in the peer reviewed journal: Genes & Diseases
https://www.sciencedirect.com/science/article/pii/S2352304225002533
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