Citrus limon Peel Essential Oil–Induced Type IV Hypersensitivity Reaction

Background Several studies have shown anti-inflammatory, anti-microbial, antifungal, and antioxidant effects from Citrus limon–peel essential oil (Cl-PEO). Cl-PEO can be developed as topical drugs for oral ulceration because of its potential active components. There have been no studies on the topical application of Cl-PEO inducing type IV hypersensitivity reaction. Purpose To investigate the potential of Cl-PEO from Batu City to induce type IV hypersensitivity reactions based on clinical changes, lymphocytes, macrophages, IFNγ, andIL10 expression. Methods This study was adapted from a guinea pig maximization-test method in Indonesia and the guidance of ISO 10,993-10:2010, and conducted on 20 guinea pigs (Cavia cobaya) divided into a control group and a treatment group. The treatment group was given Cl-PEO and the control group CMC-Na. Clinical changes were observed, then tissue specimens taken for hematoxylin–eosin and immunohistochemistry staining. Results There were no clinical changes after exposure. Lymphocyte and macrophage numbers and IFNγ and IL10 expression increased in the treatment group compared to the control group (p=0). Conclusion Cl-PEO can induce type IV hypersensitivity reactions in guinea pigs based on cellular and molecular cytokines, but there are no clinical changes after topical application.