ABCB1 in dermatology: roles in skin diseases and their treatment

Adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1), also known as permeability glycoprotein, multidrug-resistant protein 1, or cluster of differentiation 243 (CD243), is a crucial protein for purging foreign substances from cells. The functions of ABCB1 have been investigated extensively for their roles in cancer, stem cells, and drug resistance. Abundant pharmacogenetic studies have been conducted on ABCB1 and its association with treatment responsiveness to various agents, particularly chemotherapeutic and immunomodulatory agents. However, its functions in the skin and implications on dermatotherapeutics are far less reported. In this article, we reviewed the roles of ABCB1 in dermatology. ABCB1 is expressed in the skin and its appendages during drug delivery and transport. It is associated with treatment responsiveness to various agents, including topical steroids, methotrexate, cyclosporine, azathioprine, antihistamines, antifungal agents, colchicine, tacrolimus, ivermectin, tetracycline, retinoid acids, and biologic agents. Moreover, genetic variation in ABCB1 is associated with the pathogenesis of several dermatoses, including psoriasis, atopic dermatitis, melanoma, bullous pemphigoid, Behçet disease, and lichen planus. Further investigation is warranted to elucidate the roles of ABCB1 in dermatology and the possibility of enhancing therapeutic efficacy through ABCB1 manipulation.

Environmental risk factors for early infantile atopic dermatitis

Previous studies of predictors of atopic dermatitis (AD) in Asia have had limited sample size and small numbers of variables focused primarily on family history or dietary exposures. The purpose of this study was to evaluate the influence of various environmental risk factors for early infantile AD. We used multistage, stratified systematic sampling to recruit 2048 mother-child pairs from the Taiwan national birth registration in 2003. Information on environmental risk factors for infant AD gathered by questionnaire were available from 1760 infants at 6 months of age. Multiple logistic regression was used to estimate adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) for risk factors for AD after adjusting for potential confounders. AD was noted in 118 of 1760 (6.7%) of the infants. After adjusting for maternal age and education, family history of atopy, infant gender, and gestational age, fungi on walls of the house [aOR 2.14 (95% CI 1.41-3.22)] and frequent use of microwave oven at home [aOR 1.71 (95% CI 1.13-2.58)] increased the risk of early infantile AD. This study suggests that environmental factors do play a role in early infantile AD. Fungi, a kind of aeroallergen, are especially important in humid climate as in Taiwan and their impacts might be felt at the early infant stage. The hazards of microwave use should be paid more attention.