Urinary tract infections affect more than 130 million people worldwide each year. Almost 50% of women will have at least one urinary tract infection during their lifetime, usually cystitis. Half of them will have recurrent cystitis. Antibiotics are the first-line treatment for cystitis, but their effectiveness is decreasing due to the rapid spread of multi-resistant uro-pathogenic bacteria. The objective of this study is to identify blood biomarkers associated with a high risk of recurrent cystitis. Immune system cells, and more specifically innate immunity cells, play a key role in controlling urinary tract infections. In addition, clinical studies have shown that there is a high inter-individual variability in the ability of innate immune cells to respond to different stimuli. We therefore hypothesized that there was an association between the risk of recurrent cystitis and a deficiency of certain immune cell types in producing certain pro-inflammatory cytokines, including TNF-α, in response to one or more bacterial stimuli, particularly flagellin.

Inclusion Criteria:

• Female aged 18 to 28 years;
• Subject accepting to be serologically tested for HIV and HCV;
• Subject considered healthy by the physician on the basis of medical history and clinical examination;
• Subject with a body mass index between 18.5 and 30 kg/m2;
• Subject understands and speaks French and is able to give written consent;
• Subject affiliated to Social Security or a similar regime;
• Having reported a single cystitis since the age of 14 (Group 1), or 3 or more cystitis over a 12-month period since the age of 14 (Group 2).

Exclusion Criteria:

• Subject protected by law under guardianship or curatorship, or unable to participate in a clinical study under Article L. 1121-16 of the French Public Health Code;

• Subject who has participated in a clinical research study in the last 3 months in which he/she was exposed to a pharmaceutical product or medical device;

• Subject who has stayed in a tropical or subtropical country in the last 3 months;

• Pregnant or breastfeeding subject for women of childbearing age;

• Subject with special diet for medical reasons and prescribed by a doctor or dietician (e.g. a low-calorie diet or a diet intended to lower cholesterol levels);

• Subject who regularly consumes large quantities of alcohol, i. e. more than 50 g of pure alcohol per day (e. g. more than 4 glasses of 150 ml wine, more than 4 pints of 250 ml beer, or more than 4 glasses of 40 ml containing strong alcohol);

• Subject who has used an illegal recreational drug in the past 3 months;

• Subject who has taken an immunosuppressive or immunomodulatory drug (excluding intranasally or topically administered corticosteroids) in the past 2 weeks, or for more than 14 consecutive days in the past 6 months;

• Subject who has been vaccinated within the last 3 months;

• Subject who received a blood transfusion or immunoglobulins in the last 3 months;

• Subject stating that he has not been fasting for at least 10 hours;

• Subject reporting HIV or HCV status;

• Subject who had an infectious episode or was treated with antibiotics during the 4 weeks prior to the visit;

• Subject with a positive urinary pregnancy test;

• Subject with a severe and/or chronic and/or recurrent pathology, in particular:

  • A chronic inflammatory and/or autoimmune or allergic disease and in particular a chronic inflammatory disease of the intestine (Crohn's disease, ulcerative colitis), epidermis (psoriasis, atopic dermatitis), joints (rheumatoid arthritis), nervous system (multiple sclerosis), type I diabetes;
  • High blood pressure or type II diabetes;
  • A neurodegenerative disease.

• Subject who has been diagnosed with cancer and has not been in remission for more than 5 years.