Study of serum interleukin (IL) 18 and IL-6 levels in relation with the clinical disease severity in chronic idiopathic urticaria patients of Kashmir (North India)

Background: Chronic urticaria is termed as idiopathic if there is an absence of any identifiable causes of mast cell and basophil degranulation. Various cytokines have been found to be involved in inflammatory processes associated with chronic idiopathic urticaria, including interleukin (IL) 18 and IL-6.

Objective: To evaluate any possible correlation of IL-18 and IL-6 cytokines with the clinical disease severity in chronic idiopathic urticaria (CIU).

Methods: IL-18 and IL-6 levels of CIU patients (n = 62) and healthy controls (n = 27) were assessed by commercially available enzyme linked immunosorbent assay kits following the manufacturer's protocols.

Results: Serum IL-18 concentration (mean ± standard deviation [SD], 62.95 ± 36.09 pg/mL) in CIU patients and in healthy controls (54.35 ± 18.45 pg/mL) showed no statistical significance (p > 0.05). No statistically significant difference (p > 0.05) was observed between autologous serum skin test (ASST) positive and ASST negative patients with regard to the serum IL-18 levels either. Similarly, serum IL-6 concentration (0.82 ± 4.6 pg/mL) in CIU patients and in healthy controls (0.12 ± 1.7 pg/mL), showed no statistical significance (p > 0.05). Also, comparison between positive and ASST negative patients with regard to the serum IL-6 levels was statistically nonsignificant (p > 0.05). However, statistical significance was found both in IL-18 and IL-6 concentrations in certain grades with regard to the clinical disease severity of urticaria.

Conclusion: There is no significant association as such found between IL-18 and IL-6 levels with CIU, however, these cytokines may help in predicting the clinical disease severity in CIU. Hence, these cytokines may indicate a potential role as a biomarker to assess the disease severity in CIU.