Assessment of retinol-binding protein 4 in patients with alopecia areata and androgenetic alopecia

Background Several interactions between retinoids and immune system exist. Current evidences suggest a role of retinoic acid in controlling hair cycle. Retinol-binding protein 4 (RBP4) belongs to the lipocalin family and is the specific carrier for retinol (vitamin A) in the blood. It delivers retinol from the liver stores to the peripheral tissues. The pathogenesis of alopecia areata (AA) may be related to increased serum RBP4 level. Objective To assess the level of RBP4 in patients with AA. Patients and methods This comparative study was conducted on 60 participants who were divided into three groups: group A consisting of 20 patients with active AA; group B consisting of 20 patients with androgenetic alopecia, selected as an example of noninflammatory hair loss; and group C consisting of 20 normal healthy controls. Blood samples were collected from all participants and RBP4 level was measured using enzyme-linked immunosorbent assay. Results RBP4 mean value was found to be 38.37±2.83, 37.27±5.05, and 32.10±2.28 μg/ml for groups A, B, and C, respectively. Healthy control group had statistically significant lower value of RBP4 than did the other two groups, but there were no significant difference between AA patients and androgenetic alopecia patients. In AA group, there was no significant relation between number of lesions and the level of RBP4. Conclusion The level of RBP4 was found to be increased in serum of both AA and androgenetic alopecia patients. The role of RBP4 may be as a nonspecific molecule leading to hair loss or miniaturization through controlling hair cycle. However, the exact role of RBP4 in the hair cycle and its clinical significance in treatment of AA remains to be elucidated.