Cases of this potentially fatal autoimmune disease are increasing.
- Cases of dermatomyositis are increasing in the north of England.
- There have been more than 60 cases which have resulted in 8 deaths.
- Researchers believe this phenomenon is due to the Covid-19 epidemic.
A rare but deadly autoimmune disease is on the rise in the north of England, and new research indicates it may be linked to Covid-19.
What is dermatomyositis?
Known as “dermatomyositis”, the pathology in question was until now mainly observed in Asian populations.
Triggered by antibodies that attack an enzyme called “MDA5 (melanoma differentiation-associated protein 5)”, Dermatomyositis is associated with progressive interstitial lung disease. Between 2020 and 2022, doctors in Yorkshire reported 60 cases resulting in eight deaths.
Analyzing this wave, researchers noticed that the sudden increase in cases coincides with large waves of infections due to Covid-19. This immediately caught their attention, because MDA5 is an RNA receptor that plays a key role in recognizing the SARS-CoV-2 virus.
Dermatomyositis: what is the impact of Covid-19?
“Here we report an increase in the positivity rate of anti-MDA5 tests in our region (Yorkshire) during the second year of the Covid-19 epidemic, which is notable as this entity is relatively rare in the UK” , write the authors of the study in their report. According to them, this phenomenon is probably indicative of the development “a new form of dermatomyositis circulating at the time of Covid-19”, that they called “MIP-C”.
To understand the mechanisms underlying this phenomenon, researchers used data analysis tools that look for characteristics common to members of the same cohort. They found that patients with PID-C also tended to have high levels of an inflammatory cytokine called interleukin-15 (IL-15).
In a press release, Pradipta Ghosh, director of the study, explains that IL-15 “can push cells to the brink of exhaustion and create an immunological phenotype that is very, very often considered a hallmark of progressive interstitial lung disease or fibrosis of the lung.”
Dermatomyositis: few patients positive for Covid-19
Overall, only eight of the 60 patients had previously tested positive for Covid-19, indicating that many of them may have had asymptomatic infections that they were unaware of. This implies that even mild infections that do not produce initial symptoms may be enough to trigger PID-C.
“Given that the peak of MDA5 test positivity followed the peak of Covid-19 cases in 2021 and coincided with the peak of vaccination, these results suggest an immune reaction or autoimmunity against MDA5 during the exposure to SARS-CoV-2 and/or vaccine”, conclude the researchers.
They say this phenomenon is unlikely to be limited to Yorkshire.
The study was published in the journal eBioMedicine.
