Correspondence

Anti-CD20 (rituximab) treatment for atopic eczema

Although T cells are considered as the central component in immune-mediated diseases, supportive evidence has demonstrated that B cells also contribute to the progression of these diseases. B cells are divided into various subsets according to their secreted cytokines. Different B cell subsets play diverse roles in immune-mediated dermatoses. Regulatory B cells (Bregs) are defined functionally by their ability to secrete IL-10, which has been revealed to contribute to immunological tolerance. Drugs that deplete B cells, such as rituximab, are now used for the treatment of several immune-mediated dermatoses. In this review, we present and discuss the current knowledge on the roles of B cells in several immune-mediate dermatoses including psoriasis, pemphigus, bullous pemphigoid, and dermatomyositis, atopic dermatitis.

Atopic dermatitis (AD), a common chronic pruritic inflammatory skin disease, impacts the quality of life of patients and caregivers and has become a global health problem. It is increasingly recognized as a disease not only of children but also of adults who may have a persistent or relapsing course from childhood or who develop new-onset adult disease. Besides well-established atopic comorbidities, associations with a number of nonatopic comorbidities have been reported. AD is characterized by both immune dysregulation and epidermal barrier dysfunction. The findings that nonlesional skin in AD has both terminal keratinocyte differentiation defects and immune abnormalities as well as multiple markers of immune and inflammatory activation in the circulation point to the systemic nature of the disease and have important translational implications. Although AD is predominantly associated with type 2 immune responses, activation of other cytokine pathways including T_H1, T_H22, and T_H17/IL-23 has been reported, suggesting potential therapeutic targets and provide a rationale for treatment with novel biologics. Dupilumab, a fully human mAb targeting the IL-4 Rα subunit, blocks signaling of both IL-4 and IL-13 and is the first biologic to be approved for the treatment of moderate-to-severe AD in adult patients. Other biologics in current trials for AD are targeting the IL-31 receptor, IL-13, and the common p40 subunit of IL-12/IL-23.

Biologic agents are important therapeutic options for treating multiple moderate-to-severe cutaneous diseases. Monoclonal antibodies already in use or under investigation are targeted for psoriasis, atopic dermatitis, melanoma, hidradenitis suppurativa, and pemphigus vulgaris.

Atopic dermatitis (AD) is a complex skin disease frequently associated with other diseases of the atopic diathesis. Recent evidence supports the concept that AD can also recognize other comorbidities, such as chronic inflammatory bowel or cardiovascular diseases. These comorbidities might result from chronic cutaneous inflammation or from a common, yet-to-be-defined immunologic background leading to immune deviations. The activation of immune cells and their migration to the skin play an essential role in the pathogenesis of AD. In patients with AD, an underlying immune deviation might result in higher susceptibility of the skin to environmental factors. There is a high unmet medical need to define immunologic endotypes of AD because it has significant implications on upcoming stratification of the phenotype of AD and the resulting targeted therapies in the development of precision medicine. This review article emphasizes studies on environmental factors affecting AD development and novel biological agents used in the treatment of AD. Best evidence of the clinical efficacy of novel immunologic approaches using biological agents in patients with AD is available for the anti–IL-4 receptor α-chain antibody dupilumab, but a number of studies are currently ongoing with other specific antagonists to immune system players. These targeted molecules can be expressed on or drive the cellular players infiltrating the skin (eg, T lymphocytes, dendritic cells, or eosinophils). Such approaches can have immunomodulatory and thereby beneficial clinical effects on the overall skin condition, as well as on the underlying immune deviation that might play a role in comorbidities. An effect of these immunologic treatments on pruritus and the disturbed microbiome in patients with AD has other potential consequences for treatment.