11(S)-HETE, an (S) enantiomer of 11(R)-HETE and a type of oxylipin, is non-enzymatically synthesized from arachidonic acid. Compared to its counterpart, 11(S)-HETE levels are found to be elevated in both isolated human plasma and serum, as well as in LPS-stimulated isolated human plasma. Notably, patients with allergic rhinitis exhibit a decrease in 11(S)-HETE levels in their serum following one year of double-mite subcutaneous immunotherapy (DM-SCIT), correlating with an enhanced quality of life, particularly in aspects related to rhinoconjunctivitis.