The inhibition factor of the leukocytic migration was studied in 26 patients with Acne Vulgaris, stages III and IV, being positive in all the cases. The LIF positive shows the mobilisation of lymphocytic population, answering an active and constant immunologic conflict. As the PA is antigenic, because it produces a blastification (TTL positive), we can say that it acts as antigen provoking immunologic mechanisms with help to explain the inflammatory process at the pilosebaceous follicle in the AV.