Interferon-γ and interleukin-4 detected in serum and saliva from patients with oral lichen planus

Our previous salivary study had demonstrated an apparent T helper 2 (Th2)-predominance in saliva of oral lichen planus (OLP) patients and suggested a potential of salivary interleukin-4 (IL-4) as a biomarker for monitoring disease severity. To further determine the consistency of Thl/Th2 bias of OLP, this study investigated the expression profile of interferon-gamma (IFN-gamma) and IL-4 in serum and the relationship of the serum levels of these cytokines with their saliva partners. Sixty ethnic Chinese patients with OLP (40 of the erythematous/ulcerative form and 20 of the reticular form) were recruited for this study, with 40 age-sex-matched healthy volunteers as control group. IFN-gamma and IL-4 levels in serum and paired saliva samples were screened by enzyme-linked immunosorbent assay. OLP patient showed a low-level IFN-gamma but high-level IL-4 expression profile in both serum and saliva, with a lower IFN-gamma/IL-4 ratio. Serum IL-4 level in the erythematous/ulcerative group was significantly higher than that in the reticular group. Serum levels of IFN-gamma and IL-4 were significantly and positively correlated with their saliva partners. These results provided more evidence for Th2 cytokine-predominant immune imbalance in OLP, as well as the potential of IL-4 as the biomarker for monitoring severity of OLP.