To reveal whether the PF from the patients with endometriosis and the control subjects may affect the cytokine and chemokine production by CD4+ T cells, we evaluated cytokine and chemokine production following the 5-day culture of unstimulated and CD3/CD28/IL-2-stimulated CD4+ T cells, where stimulation with CD3/CD28 beads mimics antigen stimulation conditions [27,28]. The gene discussed is CD28; the disease is endometriosis.