Interest of the Dosage of Adalimumab Serum Levels in Crohn's Disease Patients for Prevention of Postoperative Recurrence

Study comparing 2 modalities of Crohn's disease patients postoperative follow-up treated with adalimumab (Humira® or biosimilar) : immunomonitoring of adalimumab serum levels versus standard follow-up, which is based on the clinical and biological activity of the disease.

Patients in the experimental arm will have a post-operative follow-up based on the immunomonitoring of serum levels of adalimumab. After ileocolic resection surgery, patients will have a therapeutic optimization of their adalimumab (Humira® or biosimilar) treatment, based on their serum residual rate of adalimumab.

Patients in the control group will receive a standard post-operative follow-up, which is based on clinical and biological recurrence.

Eligibility Criteria:
Inclusion Criteria:

* Patient between the ages of 18 and 75
* Use of an effective method of contraception during treatment with adalimumab for women of childbearing age
* Crohn's disease diagnosed according to the criteria defined by the national and international recommendations for at least 3 months
* IIeocolic resection with ileocolic anastomosis and absence of residual macroscopic lesion, or ileocolic resection with transient ostomy and restoration of continuity
* For anti-TNF-naive patients: negative pre-anti TNF balance
* Indication of postoperative treatment for the prevention of recurrence of Crohn's disease (with at least 1 risk factor for recidivism):

  * active smoking (≥ 1 cigarette / day at the time of surgery)
  * hail resection\> 50 cm
  * second intestinal resection
  * presence of anoperineal lesions
  * Penetrating impairment (B3 of the Montreal Classification)
  * Biotherapy treatment for more than 6 months before the surgery
* Written and signed consent by the participant and the investigator
* Affiliated person or beneficiary of the social security system.

Exclusion Criteria:

* Intolerance or allergy to adalimumab (Humira® or biosimilar)
* Patients to whom adalimumab (Humira® or biosimilar) is contraindicated
* Intestinal stoma without restoration of continuity
* Pregnant woman (dosage of positive βHCG) or breastfeeding according to article L1121-5 of the french public health law.
* Contraindication or refusal of ileocolonoscopy at 6 months
* Patient who could not be followed regularly for psychological, social or geographical reasons
* Vulnerable people according to article L1121-6 of the french public health law
* Persons subject to legal protection (guardianship, trusteeship) or unable to express their consent according to Article L1121-8 of the french public health law or under the protection of justice according to article L1122.2 of the CSP
* Concomitant participation of the patient in another research involving the human person.
* Patient not affiliated to the social security system (Article L.1121-11).
* Patient unable to sign the consent form
* Immunized patients (with anti-adalimumab antibodies \> 10ng / mL and undetectable adalimumab levels, Elisa drug sensitive technique used) for patients already treated with adalimumab (Humira® or biosimilar) before surgery
* Patients in combination therapy with azathioprine, 6-mercaptopurine or methotrexate Post-operative, or treated by another biotherapy (infliximab, vedolizumab, ustekinumab ...)