#auto-immunité

Covid long : l’infection, même légère, peut entrainer la production d’auto-anticorps

▻https://www.sciencesetavenir.fr/sante/covid-long-l-infection-meme-legere-peut-entrainer-la-production-d-a

https://www.sciencesetavenir.fr/assets/img/2023/05/05/cover-r4x3w1200-6455286c109e0-075-nikoubazl-iranirgc230127-npufv.jpg

Presque la totalité d’entre eux (15 sur 17) présentait une production anormalement élevée d’au moins deux de ces auto-anticorps. La sévérité de la phase aiguë du Covid ne semble pas être déterminante, car la majorité des patients Covid #long dans cette étude (16 sur 17) avaient eu des formes légères du #Covid, ne nécessitant pas d’hospitalisation. C’est donc l’infection qui est importante pour la production de cette auto-immunité, plus que la gravité du Covid. Cette production élevée d’auto-anticorps chez les patients Covid long était indépendante de l’âge et du sexe de la personne ainsi que du temps écoulé depuis l’infection.
Les #réinfections pourraient augmenter le risque de Covid long

La majorité des patients Covid, mais sans Covid long avait aussi une production d’auto-anticorps supérieure que les personnes n’ayant pas été infectées, mais à des niveaux plus faibles que les patients avec Covid long. Et le niveau de ces anticorps était directement corrélé avec une baisse des performances cognitives et une hausse de symptômes neurologiques, expliquant peut-être la différence entre les patients Covid long et les patients Covid sans Covid long (avec des niveaux élevés, mais moins élevés que ceux avec Covid long). Les auteurs alertent que ces niveaux d’auto-anticorps pourraient augmenter à chaque infection, augmentant ainsi la probabilité d’un Covid long.
Le vaccin ne protège pas entièrement contre cette #auto-immunité

Il y a environ une année, il avait été montré que les personnes vaccinées pouvaient développer un Covid long (même si cette possibilité est moindre que chez les non vaccinés). Cette étude confirme ces résultats, car l’infection est survenue après la vaccination chez presque la moitié des patients avec Covid long de cette étude (41%). La vaccination ne protège donc pas entièrement contre le Covid long.

Et elle ne serait pas non plus un traitement efficace pour les personnes ayant déjà cette maladie. Il avait été proposé que la vaccination pourrait être un traitement contre le Covid long, diminuant la sévérité des symptômes. Mais cette étude met en évidence que la dose de rappel n’avait aucun effet sur le niveau de ces auto-anticorps. Cependant, il est possible que la vaccination post-infection puisse avoir un effet sur d’autres causes du Covid long, maladie très diverse qui pourrait aussi avoir différentes causes en plus de ces autoanticorps. Toutefois, les auteurs soulignent que ces résultats mettent en lumière la nécessité de trouver d’autres stratégies pour restreindre la propagation du coronavirus, tels que des vaccins mieux adaptés aux souches actuelles qui parviennent à éviter effectivement l’infection.

Bon tout le monde s’en fout hein, en plus l’OMS a sifflé la fin de partie donc ça sert à rien d’en rajouter avec ça :

▻https://www.sciencesetavenir.fr/sante/covid-long-le-risque-et-les-symptomes-dependraient-des-origines-eth

ou meme ça :

▻https://www.courrierinternational.com/article/le-chiffre-du-jour-le-covid-long-menacerait-une-personne-infe

parce qu’on a dit dès le début que ça serait une maladie psychosomatique donc ce serait con de revenir dessus non ?

The four most urgent questions about long COVID
▻https://www.nature.com/articles/d41586-021-01511-z

It seems unlikely that the virus itself is still at work, says Evans. “Most of the studies have shown that after a few weeks you’ve pretty much cleared it, so I very much doubt it’s an infective consequence.”

However, there is evidence that fragments of the virus, such as protein molecules, can persist for months7, in which case they might disrupt the body in some way even if they cannot infect cells.

A further possibility is that long COVID is caused by the immune system going haywire and attacking the rest of the body. In other words, long COVID could be an autoimmune disease. “#SARS-CoV-2 is like a nuclear bomb in terms of the immune system,” says Steven Deeks, a physician and infectious-disease researcher at the University of California, San Francisco. “It just blows everything up.” Some of those changes might linger — as has been seen in the aftermath of other viral infections (see ‘What is the relationship between long COVID and other #post-infection syndromes?’).

Still, it is too early to say which hypothesis is correct, and it might be that each is true in different people: preliminary data suggest that #long_COVID could be several disorders lumped into one

#post_covid #auto-immunité

Study reveals seven in ten patients hospitalised with #COVID-19 not fully recovered five months post-discharge
▻https://le.ac.uk/news/2021/march/covid-19-patients-not-fully-recovered

Étude (en cours) #PHOSP-COVID, britannique sur 1077 patients,

[...] “While the profile of patients being admitted to hospital with COVID-19 is disproportionately male and from an ethnic minority background, our study finds that those who have the most severe prolonged symptoms tend to be white women aged approximately 40 to 60 who have at least two long term health conditions, such as asthma or diabetes.”

The researchers were able to the classify types of recovery into four different groups or ‘clusters’ based on the participants’ mental and physical health impairments.

One cluster group in particular showed impaired cognitive function, or what has colloquially been called ‘#brain_fog’. Patients in this group tended to be older and male. Cognitive impairment was striking even when taking education levels into account, suggesting a different underlying mechanism compared to other symptoms.

[...] much of the wide variety of persistent problems was not explained by the severity of the acute illness - the latter largely driven by acute lung injury - indicating other, possibly more systemic, underlying mechanisms.”

The research has also uncovered a potential biological factor behind some post-COVID symptoms.

Professor Louise Wain, GSK/British Lung Foundation Chair in Respiratory Research at the University of Leicester and co-investigator for the PHOSP-COVID study, said: “When we looked at the symptom severity of patients five months after they were discharged from hospital, we found that in all but the mildest cases of persistent post-COVID symptoms, levels of a chemical called C-reactive protein [CRP], which is associated with inflammation, were elevated.

“From previous studies, it is known that systemic inflammation is associated with poor recovery from illnesses across the disease spectrum. We also know that autoimmunity, where the body has an immune response to its own healthy cells and organs, is more common in middle-aged women. This may explain why post-COVID syndrome seems to be more prevalent in this group, but further investigation is needed to fully understand the processes. The evidence for different recovery ‘clusters’, and ongoing inflammation, really is important in guiding how we conduct further research into the underlying biological mechanisms that drive ‘Long-COVID’.”

One of the purposes of the PHOSP-COVID study is to measure the impact of medicines given during hospitalisation to see if they affect patients’ recovery. Early indicators from the study show that while giving corticosteroids is a factor in reducing mortality in hospital, it does not appear to have an impact on longer term recovery.

[..,]

#long_covid #covid_long #auto-immunité

Coronavirus Deranges the Immune System in Complex and Deadly Ways | Kaiser Health News
▻https://khn.org/news/article/covid-autoimmune-virus-rogue-antibodies-cytokine-storm-severe-disease

https://khn.org/wp-content/uploads/sites/2/2021/03/GettyImages-1222115554.jpg

In some people with severe covid, however, helper T cells don’t stand down when the infection is over, said James Heath, a professor and president of Seattle’s Institute for Systems Biology.

About 10% to 15% of hospitalized covid patients Heath studied had high levels of these cells even after clearing the infection. By comparison, Heath found lingering helper T cells in fewer than 5% of covid patients with less serious infections.

In affected patients, helper T cells were still looking for the enemy long after it had been eliminated. Heath is now studying whether these overzealous T cells might inflict damage that leads to chronic illness or symptoms of autoimmune disease.

“These T cells are still there months later and they’re aggressive,” Heath said. “They’re on the hunt.”

[...]

New research shows that the coronavirus may activate preexisting autoantibodies, as well as prompt the body to make new ones.

In the January study**, half of the hospitalized covid patients had autoantibodies, compared with fewer than 15% of healthy people. While some of the autoantibodies were present before patients were infected with SARS-CoV-2, others developed over the course of the illness.

**▻https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852238

[...]

Dr. Shiv Pillai, a Harvard Medical School professor, notes that autoantibodies aren’t uncommon. Many healthy people walk around with dormant autoantibodies that never cause harm.

For reasons scientists don’t completely understand, viral infections appear able to tip the scales, triggering autoantibodies to attack, said Dr. Judith James, vice president of clinical affairs at the Oklahoma Medical Research Foundation and a co-author of Luning Prak’s study.

#auto-anticorps #auto-immunité #covid-19