[The role of an immunologic survey prior to using collagen implants. Theoretical aspects and practical methods].

Collagen implants (Zyderm and Zyplast) are effective and well tolerated. However, certain inflammatory reactions may occur. The immunological mechanisms responsible for such reactions are analysed: cell-mediated reactions, humoral reactions (specific antibodies) and the role--certainly major--of the genetic predisposition which modulates the expression of these reactions. The practical consequences are logically derived from the histological and serological findings observed, i.e. strict respect of the systemic contraindications (auto-immune diseases, severe atopy); rigorous conduct of a preoperative skin test to detect the great majority of reactive subjects; lastly, consideration, in the evaluation of the potential risk, of individual dysimmune susceptibility (family history, personal clinical or laboratory elements) in a very small proportion of patients.