There was an increased number of CD4+ iNKT cells expressing IL-17 in the peripheral blood of patients with endometriosis and severe dysmenorrhea compared to those with mild/absent dysmenorrhea (11.1 ± 4.7 vs. 4.3 ± 4.0; p = 0.038) (Table 4). This evidence concerns the gene CD4 and endometriosis.