Increased Retinol-Binding Protein 4 and Anti-RBP4 Antibody in Alopecia Areata

The study compared serum protein profiles of 15 patients with biopsy-confirmed alopecia areata (AA) to those of 15 healthy controls and found that RBP4 expression was significantly upregulated in AA patients. Serum levels of RBP4 were higher in AA patients (mean ± SD: 49,233.47 ± 13,590.86 ng/mL) compared to healthy controls (mean ± SD: 32,408.80 ± 8,883.29 ng/mL) and male pattern hair loss patients (mean ± SD: 32,946.33 ± 9,041.21 ng/mL). Additionally, 67% of AA patients had IgG reactivity to recombinant human RBP4, compared to 13% of healthy controls and 7% of male pattern hair loss patients. The study concluded that the increased serum levels of RBP4 and positive IgG immunoreactivity against RBP4 in AA patients suggest an involvement of the retinoic acid biosynthesis pathway in the disease's pathogenesis, although further research is needed to understand the clinical significance and precise role of RBP4 in AA.