Immunomodulatory and clinical responses to zinc gluconate supplementation in patients with Behçet's disease: A double-blind, randomized placebo-controlled clinical trial.

Background & Aims: Toll-like receptor (TLR) 2 and 4 are involved in the pathogenesis of Behçet's disease (BD). The current study aimed to investigate the effect of zinc supplementation on TLR-2/4 expression and the clinical manifestations of BD.

Methods: In this double-blind placebo-controlled randomized clinical trial, 50 BD patients were randomly allocated into either zinc gluconate (30 mg/day) or placebo groups for 12 weeks. Before and after the intervention, the surface and mRNA expression level of TLR-2 and TLR-4 in the leukocytes, serum level of zinc and tumor necrosis factor-α (TNF-α), quality of life, anthropometric measures, and blood pressure of patients were collected. BD activity was studied using the nonocular Iranian Behçet's disease dynamic activity measure (IBDDAM), Behçet's disease current activity form (BDCAF), and total inflammatory activity index (TIAI) at the pre-and post-intervention phases. The effect sizes were compared between two groups using analysis of covariance.

Results: There were significant decrease in TLR-2 mRNA (P = 0.038) and protein expression (P = 0.034) and nonocular IBDDAM score (P = 0.046) in the zinc group compared to placebo at the endpoint. The serum level of zinc was increased in the zinc group (P < 0.001). Zinc supplementation significantly decreased the TLR-4 surface (P = 0.012) and mRNA expression (P = 0.028) within the group. However, this decrease was not significant compared to the placebo group. There was no significant difference between the two groups regarding the serum level of TNF-α, BDCAF, TIAI, quality of life, anthropometric measures, and blood pressure (P > 0.05).

Conclusions: The present study revealed that zinc supplementation significantly improved nonocular IBDDAM score and TLR-2 expression in BD patients.

Gov Registration Number: NCT05098678.