In patients with periodontitis, when they receiving chemotherapy, this causes the levels of LL-37 and IL-29 to decrease. Chemotherapy may not affect clearly on HSV-1 levels in individuals with periodontitis . Due to the low levels of HSV-1 in patients getting chemotherapy and those who were not receiving chemotherapy, we expect that HSV-1 may not a causative agent of periodontitis in these 2 groups.