AD Differs Significantly Between African American and European American Patients

09/17/2018

eczema

A recent study found significant differences in the molecular profile of lesions from African American patients with atopic dermatitis (AD) compared with European American patients. The results from this study could help explain differences in severity and lack of response to current therapies among African American patients, as well as improve treatment options among this patient population.

While African Americans are disproportionately affected by AD, with a higher prevalence of this skin condition and unique therapeutic challenges, molecular profiling used to develop targeted therapies for AD are derived mainly from European American patients, the researchers noted. In the study, the researchers sought to characterize the global molecular profile of AD among African American patients compared with European American patients and healthy controls. RNA sequencing with real-time polymerase chain reaction (RT-PCT) validation and immunohistochemistry studies were used to assess lesional and non-lesional skin of African American and European American patients with AD and compared with healthy controls.  
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Compared with AD lesions from European American patients, AD lesions from African American patients were characterized by greater infiltration of dendritic cells (DCs) and marked by high affinity Immunoglobulin E (IgE) receptor (FcεR1+). Although both cohorts of patients with AD showed similarly robust upregulation of Th2-related and Th22-related markers (IL- 22, S100A8/9/12), African American patients with AD had decreased expression of innate immune (TNF, IL-1β), TH1-related (IFN-γ, MX1, IL-12RB1), and Th-17 related markers (IL-23p19, IL-36G, CXCL1) compared with European American patients.  

In addition, Th2 (IL-13) and Th22-related products (IL-22, S100A8/9/12) and serum IgE were significantly correlated with clinical severity, based on Scoring Atopic Dermatitis (SCORAD) scores, among African American patients. Among European American patients with AD, filaggrin was exclusively downregulated. Both AD cohorts had downregulated loricrin, which was negatively correlated with SCORAD scores among African American patients.  

“The molecular phenotype of African American AD skin is characterized by attenuated Th1 and Th17 but similar Th2/Th22-skewing to European American AD,” the researchers concluded. “Our data encourages a personalized medicine approach accounting for phenotype-specific characteristics in future development of targeted therapeutics and clinical trial design for AD.”

Reference 

Sanyal RD, Pavel AB, Glickman J, et al. Atopic dermatitis in African American patients is TH2/TH22-skewed with TH1/TH17 attenuation [published online September 14, 2018]. Ann Allergy Asthma Immunol. https://doi.org/10.1016/j.anai.2018.08.024