Pathophysiological Study of Characteristics of the Changes in the Cutaneous Immune System After Intradermal Antigen Injections

Inclusion Criteria: * Both genders eligible for study. * Female participants must use a contraceptive method. * Tuberculin skin test between 1 and 15mm * Participants must be able to understand and sign the Informed Consent, and comply with all aspects of the protocol. * Subjects registered in a social security system or with health insurance cover * First group: Healthy subjects aged from 18 to 75 years with 2 subgroups: 18-40 and 60-75 year old subjects * Second group: Patients with kidney transplants of longer than 6 months on immunosuppressive treatment Exclusion Criteria: * Pregnant or lactating women. * Previous allergic reaction to tuberculin skin test * Active skin disease on testing zone * Patients with a clinically significant disease (chronic, recurrent or active) * Local or systemic medication which interacts with the outcome measures. * Patients deprived of their civic rights, in custody, or under the care of a tutorial, judiciary or administrative body. * Patients relevant of a protection measure * Patients in a critical medical situation * Patients with a personal situation evaluated by the investigator as unable to give an optimal participation in the study, or where it could constitute a risk for the patient * Linguistic barrier or psychological profile disabling the patient from signing the consent form * Patient still in an exclusion period following participation in another clinical trial * Patients having earned more than 4500€ in indemnities following participation in clinical trials during the last 12 months, including this study For group 1 only: * Systemic corticotherapy or immunosuppressive treatment within the 2 weeks before first visit or within 2 weeks before the third visit or the biopsies. * Systemic non anti-inflammatory drugs the week before the first visit or within 1 week before the third visit or the biopsies