For the first time, a team of biologists, led by Samuel Alizon, research director at the CNRS, studied the evolution of human papillomavirus infection. HPV is known to be involved in cervical cancer, which affects 3,000 women in France each year.
Research on papillomaviruses, these HPVs known to the general public as part of adolescent vaccination campaigns against the risk of cervical cancer, has just taken a giant step forward thanks to a study carried out in Montpellier.
Unpublished internationally, it was published this Tuesday, January 21 in the leading American scientific journal Plos Biology.
PATRICK_IMBERT/COLLEGE DE FRANCE
Led by Samuel Alizon, CNRS research director who left Montpellier two years ago to join the interdisciplinary research center in biology (CIRB) of the Collège de France, in Paris, it is based on the unprecedented monitoring of 189 women aged 18 to 25 years old, recruited at Montpellier University Hospital, for four years.
None have cancer, that is not the objective of the study.
Women seen every two months
“We know about papillomaviruses because they cause cancer in a minority of infected women,” nevertheless recalls Samuel Alizon.
His team, however, collected an impressive sum of“biological samples obtained with cutting-edge techniques in molecular biology and immunology” among the participants, seen every two months, over the course of 900 visits scheduled between 2016 and 2020, to “understand the processes that occur during an infection, from start to finish. We realized that we didn’t know much”.
The infectious episode is generally asymptomatic and the disease is benign, it recovers “in 9 out of 10 cases in less than two years”. In one case in 100, it persists.
What do the samples say? “In this age group, one in four women is infected with HPV”, “including vaccinated women”. But the vaccine worked well: in the latter, “we do not find the most dangerous viruses, involved in cancer, HPV16 and HPV18”underlines Samuel Alizon.
Avoid worrying unnecessarily
In infected women: “The quantity of virus increases exponentially in a few weeks, then reaches a plateau which lasts 18 months on average, before gradually decreasing. We are in an intermediate situation between acute infection and chronic infection. This is unusual The first lesson from our research is that there is no point in repeating a test too quickly in the event of infection, and in worrying unnecessarily.reports the scientist.
-The study also shows that there are two immune response scenarios: one is “innate”the other “adaptive”. Each has its own specific biological markers. The first were present in the women who controlled the infection the fastest. The two types of markers are present when the infection persists over time, suggesting that the body reacted in two stages, explains Samuel Alizon.
For what ? “We are opening up quite a few avenues. Our study can help research into therapies, which are very active, particularly in immunotherapy, and optimize vaccine protection”explains the scientist.
A virus in latency?
By understanding the mechanisms of infection, the team wants to pave the way for new therapies, and, perhaps later, for cancer treatment: “By understanding the phenomenon of spontaneous healing, we have the keys to curing chronic infections.”
To go further, Samuel Alizon is ready to relaunch the search for European credits, which kicked off this study ten years ago.
“It’s a long time, but we ourselves are working for a long time, recalls Samuel Alizon, who hopes to solve another mystery: “Will women who develop cancer have been reinfected, or will they experience the consequences of a past infection, which we thought was cured, with a virus remaining in a latency state in the body?”
Health Insurance, which is organizing a cervical cancer prevention week from January 23, recalls that“It takes between 10 to 20 years between HPV infection and the appearance of precancerous or cancerous lesions.”
The 19th European Cervical Cancer Prevention Week
“Every year, more than 3,000 women in France are diagnosed with cervical cancer, and nearly 1,100 die from it. However, 90% of these cancers could be avoided thanks to two effective and efficient prevention measures. complementary: regular screening and vaccination against human papillomavirus”alert the Occitanie regional health agency, Health Insurance and the Regional Cancer Screening Coordination Center (CRCDC) Occitanie, on the occasion of the 19th European Cervical Cancer Prevention Week, January 23 to 29.
Health authorities are calling on women aged 25 to 65 to be screened by their general practitioner, a gynecologist, a midwife or at a Health Insurance health examination center.
In 2024, 60,000 letters were sent to the region as part of organized screening. The analysis of the sample is then covered 100%, without advance costs, by Health Insurance. In Occitanie, participation in screening is 61.8% (59.5% in France), very far from the objectives of an effective campaign defined at the European level: 70% participation.
Vaccination of adolescents, the only effective means of cancer prevention, is also insufficient: in 2023, 43.8% of 16-year-old girls and 15.2% of boys.
