Desloratadine Efficacy in Relation to GSTM1 and GSTT1 Polymorphic Genes in Chronic Spontaneous Urticaria

BACKGROUND: The etiopathogeny of chronic spontaneous urticaria (CSU) is not well defined. Allelism in glutathione S-transferase GSTM1 and GSTT1 has been suggested as a risk factor. Desloratadine is the first-line treatment for this disease. OBJECTIVE: This study aimed to investigate the efficacy of a first-line treatment: desloratadine 5 mg/day on antioxidant status and clinical assessment in Tunisian patients with CSU and to identify possible associations between GSTT1 and GSTM1 genotypes and susceptibility to CSU. METHODS: Sixty patients with CSU and 60 age- and gender-matched healthy controls were included in the study. We calculated the urticaria activity score (UAS) and assessed the antioxidant parameters (total antioxidant status [TAS], glutathione S-transferase [GST], SOD, CAT, GPx]). Multiplex PCR was performed to find the relationship between GSTM1 and GSTT1 polymorphisms with CSU susceptibility. RESULTS: At baseline, GST, GPx, CAT, SOD activities, and TAS were significantly lower in CSU patients compared to healthy controls (P < 0.05). After treatment, GST, GPx, CAT, SOD activities and TAS were significantly increased in patients compared to those before treatment (P < 0.001). We observed a significant association in null alleles of GSTM1. Before treatment, GST activity was significantly lower in patients having GSTM1+ genotype than those having GSTM1- genotype (P = 0.001). After treatment, TAS and antioxidant enzymes GST, GPx, SOD, and CAT were significantly elevated in patients having GSTM1- genotype than those having GSTM1+ genotype (P < 0.05). CONCLUSION: These results suggest the impact of GSTM1 and GSTT1 on CSU susceptibility and desloratadine efficacy in Tunisian patients.