CD1a-positive dendritic cell-enriched pigmented purpuric dermatosis in association with dyslipidemia

Indeterminate cells (ICs) are dendritic cells (DCs) that share the histologic features of Langerhans cells and macrophages but lack Birbeck granules. It remains unclear whether IC histiocytosis is a separate disease entity or a reactive process. We report the case of a male with an 8-year history of dyslipidemia who developed extensive pigmented purpuric papules. Laboratory studies revealed peripheral monocytosis (8.2%), and two skin biopsies showed a dermal lichenoid lymphohistiocytic infiltrate composed of CD4+ T cells and CD8+ T cells and CD68+CD163+CD1a+Langerin histiocytes. PD-1/PD-L1+T cells were present in the dermis. Our case may help in understanding the pathogenesis of IC histiocytosis, and we hypothesize that expression of CD1a+ dermal DCs and T-cell dysfunction is a reactive process to dyslipidemia.

[1]  Lisa Mask-Bull,et al.  S100-Negative, CD1a-Positive Cutaneous Histiocytosis in a Patient with S100-Positive, CD1a-Positive Pulmonary Histiocytosis. , 2015, The American Journal of dermatopathology.

[2]  S. Shalin,et al.  Granulomatous pigmented purpuric dermatosis , 2015, Clinical and experimental dermatology.

[3]  A. Tall,et al.  Cholesterol Efflux Pathways Regulate Myelopoiesis: A Potential Link to Altered Macrophage Function in Atherosclerosis , 2014, Front. Immunol..

[4]  Florent Ginhoux,et al.  Dendritic cells, monocytes and macrophages: a unified nomenclature based on ontogeny , 2014, Nature Reviews Immunology.

[5]  T. D. de Gruijl,et al.  IL-10 Conditioning of Human Skin Affects the Distribution of Migratory Dendritic Cell Subsets and Functional T Cell Differentiation , 2013, PloS one.

[6]  U. Adamson,et al.  Impaired endothelium-dependent skin microvascular function during high-dose atorvastatin treatment in patients with type 1 diabetes , 2013, Diabetes & vascular disease research.

[7]  Rachel A. Botting,et al.  Identification of Lineage Relationships and Novel Markers of Blood and Skin Human Dendritic Cells , 2013, The Journal of Immunology.

[8]  C. Cockerell,et al.  Treatment of indeterminate cell histiocytosis with pravastatin. , 2011, Journal of the American Academy of Dermatology.

[9]  Michael J. Zilliox,et al.  Phenotype, Function, and Gene Expression Profiles of Programmed Death-1hi CD8 T Cells in Healthy Human Adults , 2011, The Journal of Immunology.

[10]  M. Cline.  Histiocytes and histiocytosis. , 1994, Blood.