What if it becomes possible to screen patients who are at risk of developing a severe form of Covid-19? This is what the results of a study published in the scientific journal Cell reveal. This would pave the way for a new therapeutic approach.

Covid-19: a new test to detect severe forms?Covid-19: a new test to detect severe forms?

Anticipate the serious forms to better treat them. This is the hope brought by a new study on Covid-19, published in the scientific journal Cell.

This study was conducted by researchers and doctors from Gustave Roussy, Assistance Publique – Hôpitaux de Paris AP-HP, Inserm, Université Paris-Saclay and Université de Paris, in collaboration with several foreign teams (Singapore, China and Israel).

They found that patients who develop

a severe form of Covid-19, present “a deficit in the functions of the innate immunity of myeloid cells (fraction of white blood cells) such as polynuclear neutrophils, monocytes), associated with a very high level of calprotectin, a pro-inflammatory protein of the alarmins family, in the blood“, as can be read in the AP-HP press release.

To arrive at these results, the researchers studied the case of 158 patients admitted to the emergency room on suspicion of Covid-19. Among them, 86 tested positive with varying degrees of severity: mild, moderate, severe.

The cells of these patients were then analyzed. In those who have developed a severe form, studies “revealed changes in the production and distribution of certain myeloid cells of the immune system in patients with severe Covid-19“In particular, the level of calprotectin, a protein generated in inflammation, was very high, between 100 and 1000 times higher than normal.

Our results suggest that calprotectin may be responsible for the worsening of Covid-19, since its amount correlates with oxygen requirements as well as the factors involved in thrombosis“, underlines in the press release from the AP-HP Aymeric Silvin, researcher in immunology, specialist in myeloid cells, in Unit 1015 Gustave Roussy / Inserm / Université Paris-Saclay and director of the study.”The large increase in calprotectin in the blood could occur before the cytokine storm associated with the inflammatory runaway in patients developing a severe form. We believe that an amplification loop is created between calprotectin and interleukin-6, inducing chronic inflammation resulting in immunosuppression“.

This discovery allows us to consider

a diagnostic test that could detect a serious form in order to bring it under control as quickly as possible. “The early diagnosis of a severe form of Covid-19 can be made on a blood tube by combining a calprotectin assay and a flow cytometry test easily implantable in routine hematology laboratories“, said Professor Michaela Fontenay, head of the biological hematology service at Cochin Hospital, AP-HP, quoted in the press release.”An equivalent test has been deployed in recent years in France with the aim of facilitating the diagnosis of a haematological disease“.

A novel therapeutic approach is therefore considered: “blockade of the calprotectin receptor, a pro-inflammatory protein of the alarmin family“as well as”emergency myelopoiesis“. Clinical trials are still needed to evaluate this lead.

Covid-19: hygiene rules when you go to work

Created Aug 10, 2020

Sources:

  • Silvin, A., Chapuis, N., Dunsmore, G., Goubet, A.-G., Dubuisson, A., Derosa, L., Almire, C., Hénon, C., Kosmider, O., Droin, N., Rameau, P., Catelain, C., Alfaro, A., Dussiau, C., Friedrich, C., Sourdeau, E., Marin, N., Szwebel, T.-A., Cantin, D. , Mouthon, L., Borderie, D., Deloger, M., Bredel, D., Mouraud, S., Drubay, D., Andrieu, M., Lhonneur, A.-S., Saada, V., Stoclin , A., Willekens, C., Pommeret, F., Griscelli, F., Ng, LG, Zhang, Z., Bost, P., Amit, I., Barlesi, F., Marabelle, A., Pène, F., Gachot, B., André, F., Zitvogel, L., Ginhoux, F., Fontenay, M., Solary, E., Elevated calprotectin and abnormal myeloid cell subsets discriminate severe from mild COVID-19, Cell ( 2020), doi:

    https://doi.org/10.1016/j.cell.2020.08.002.

  • “Identification of a new potential therapeutic target against Covid-19”, Press release from the Assistance Publique des Hôpitaux de Paris (AP-HP) – (

    accessible online).