A new potentially fatal COVID-related syndrome has emerged

A rare but deadly autoimmune disease appears to be on the rise in the north of England, and new research indicates the outbreak may be linked to COVID-19. Known as anti-MDA5-positive dermatomyositis, the disease was mainly seen in Asian populations before the pandemic, but is now seeing a resurgence among Caucasian residents of Yorkshire.

Triggered by antibodies that attack an enzyme called MDA5 (melanoma differentiation-associated protein 5), the disease is associated with progressive interstitial lung disease, characterized by scarring of the lung tissue. Between 2020 and 2022, doctors in Yorkshire reported an unprecedented 60 cases of MDA5 autoimmunity, resulting in eight deaths.

Analyzing this increase in a new study, researchers point out that the sudden increase in cases coincides with major waves of COVID-19 infections during the peak years of the pandemic. This immediately caught their attention because MDA5 is an RNA receptor that plays a key role in recognizing the SARS-CoV-2 virus.

“Here we report an increase in the rate of anti-MDA5 positivity tests in our region (Yorkshire) during the second year of the COVID-19 pandemic, which was notable as this entity is relatively rare in the UK” , write the authors of the study. . This phenomenon, they say, is likely indicative of a “distinct form of MDA5+ disease in the COVID-19 era,” which they termed “MDA5 autoimmunity and contemporary interstitial lung disease of COVID-19.” (MIP-C).

To understand the mechanisms underlying this newly identified symptom, researchers used data analysis tools that look for common traits among members of medical cohorts. In doing so, they discovered that patients with MDA5 autoimmunity also tended to have elevated levels of an inflammatory cytokine called interleukin-15 (IL-15).

Commenting on this finding in a statement, study author Pradipta Ghosh explained that IL-15 “can push cells to the brink of exhaustion and create an immunological phenotype that is very, very often considered a characteristic progressive interstitial lung disease, or fibrosis of the lung. »

Overall, only eight of the 60 patients had previously tested positive for COVID-19, suggesting that many of them may have had asymptomatic infections that they were unaware of. This implies that even mild infections producing no initial symptoms may be sufficient to trigger MDA5 autoimmunity.

“Given that the peak of MDA5 positivity testing 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.

According to Ghosh, the phenomenon is unlikely to be limited to Yorkshire, and reports of MIP-C are now coming in from all over the world.

The study was published in the journal eBioMedicine.