ABSTRACT
Dendritic cells (DCs), monocytes, and macrophages are leukocytes with critical roles in immunity and tolerance. The DC network is evolutionarily conserved; the homologs of human tissue CD141(hi)XCR1⺠CLEC9A⺠DCs and CD1c⺠DCs are murine CD103⺠DCs and CD64⻠CD11b⺠DCs. In addition, human tissues also contain CD14⺠cells, currently designated as DCs, with an as-yet unknown murine counterpart. Here we have demonstrated that human dermal CD14⺠cells are a tissue-resident population of monocyte-derived macrophages with a short half-life of <6 days. The decline and reconstitution kinetics of human blood CD14⺠monocytes and dermal CD14⺠cells in vivo supported their precursor-progeny relationship. The murine homologs of human dermal CD14⺠cells are CD11b⺠CD64⺠monocyte-derived macrophages. Human and mouse monocytes and macrophages were defined by highly conserved gene transcripts, which were distinct from DCs. The demonstration of monocyte-derived macrophages in the steady state in human tissue supports a conserved organization of human and mouse mononuclear phagocyte system.
Subject(s)
Lipopolysaccharide Receptors/metabolism , Macrophages/immunology , Skin/immunology , Animals , CD11b Antigen/biosynthesis , Cell Differentiation/immunology , Cell Lineage/immunology , Cell Movement/immunology , Cells, Cultured , Dendritic Cells/immunology , Female , Humans , Immunologic Memory/immunology , Mice , Mice, Transgenic , Receptors, IgG/biosynthesis , Skin/cytology , T-Lymphocytes/immunologyABSTRACT
BACKGROUND: Alopecia areata (AA) is an autoimmune disease characterized by non-scarring hair loss in adults and children. Clinical manifestations range from hair loss in small, well-circumscribed patches to total hair loss on the scalp or any other hair-bearing areas. Although the exact pathogenesis of AA is not fully understood, it is thought that loss of immune privilege caused by immunological dysregulation of the hair follicle is key. Genetic susceptibility also plays a role. Response to currently available treatments is widely variable, causing patient dissatisfaction and creating an unmet need. AA is frequently associated with multiple comorbidities, further affecting patient quality of life. AIMS AND FINDINGS: AA causes a significant burden on dermatologists and healthcare systems in the Middle East and Africa. There is a lack of data registries, local consensus, and treatment guidelines in the region. Limited public awareness, availability of treatments, and patient support need to be addressed to improve disease management in the region. A literature review was conducted to identify relevant publications and highlight regional data on prevalence rates, diagnosis, quality of life, treatment modalities, and unmet needs for AA in the Middle East and Africa.
ABSTRACT
Prescribing for pregnant or lactating patients and male patients wishing to father children can be a difficult area for dermatologists. There is a lack of review articles of commonly used systemic medications in dermatology with respect to their effects on developing embryogenesis and their potential transfer across the placenta, in breast milk and in seminal fluid. This paper aims to provide an up to date summary of evidence to better equip dermatologists to inform patients about the effects of systemic medications commonly used in dermatology to treat conditions such as atopic dermatitis, psoriasis and acne, on current and future embryogenesis and fertility.