Serum substance P and calcitonin gene-related peptide levels in Behcet's disease and their association with disease activity

Abstract

Substance P (SP) and calcitonin gene-related peptide (CGRP) are neuropeptides that have a role in several cutaneous diseases and inflammations. Aim. To evaluate SP, CGRP and serum interleukin (IL)-8 levels in Behçet's disease (BD) and to explore the relationship of these peptides with BD activity. The study group comprised 30 patients with BD, and 30 healthy individuals acted as controls. Serum levels of SP, CGRP and IL-8 were determined by micro-ELISA test during the active and inactive disease periods of patients with BD. These data were compared with each other and controls. Active and inactive periods of BD were established. The mean +/- SD serum CGRP (ng/ml) and IL-8 levels (pg/ml) in inactive BD (5.87 +/- 2.49 and 0.62 +/- 0.24, respectively) were significantly higher than the control group (4.74 +/- 1.17 and 0.46 +/- 0.11) (P < 0.05 for both). The difference between serum CGRP and IL-8 levels in active BD were also significantly higher than in inactive BD (P < 0.05 for both). Serum SP values (ng/ml) in active BD (18.27 +/- 5.38) were significantly higher than in inactive BD (15.26 +/- 5.74) and controls (12.6 +/- 4.45) (P < 0.05 for all), whereas the difference between the serum SP values in inactive BD and the control group was not statistically significant (P > 0.05). Serum SP and CGRP may have a role in the pathogenesis of BD. In addition, serum IL-8, SP and CGRP levels can be used as laboratory parameters indicating activity in BD.