ORIGINAL ARTICLE Langerhans, plasmacytoid dendritic and myeloid-derived suppressor cell levels in mycosis fungoides vary according to the stage of the disease Alessandro Pileri 1,2 & Claudio Agostinelli 3 & Maurizio Sessa 4 & Pietro Quaglino 5 & Marco Santucci 6 & Carlo Tomasini 7 & Vieri Grandi 2 & Paolo Fava 5 & Chiara Astrua 5 & Simona Righi 3 & Annalisa Patrizi 1 & Stefano A. Pileri 8,9 & Nicola Pimpinelli 2 Received: 20 November 2016 /Revised: 14 January 2017 /Accepted: 9 March 2017 /Published online: 20 March 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract Mycosis fungoides (MF) is characterized by a switch from indolent behaviour in the early stages to a worse clinical outcome in the advanced ones. Recently, various stud- ies have investigated the role the microenvironment might play in such a switch. We have analysed the distribution of Langerhans cells, plasmacytoid dendritic cells and myeloid- derived suppressor cells in 46 MF cases in various stages, aiming to assess whether changes occur from early to ad- vanced stage. We have investigated the number of langerin, CD303 and arginase-1 positive cells and their distribution at high power. Data were analysed using t test for continuous variables, χ 2 tests or Fisher’ s exact test for categorical vari- ables, as well as analysis of covariance. In comparing stages IA/B to IIB, we observed a significant decrease in Langerhans cells (p value 0.03) and a significant increase in CD303 and arginase-1 positive cells (p value <0.01 for both markers). Furthermore, a significant increase in Langerhans cells only was observed in stage IIB in comparison to stage III (p = 0.02), while in stage IV, a significant decrease in Langerhans cells was noted in comparison to stage III (p = 0.02). Our data suggest that changes in the microenviron- ment might influence disease progression, especially from stages IA/B to IIB, opening new scenarios in MF therapy. Keywords Mycosis fungoides . Dendritic cell . Myeloid-derived suppressor cell . Immunohistochemistry Introduction Mycosis fungoides (MF) is characterized by indolent be- haviour in the early stages while it becomes aggressive in advanced stages [1–3] (Fig. 1a–c). Clinical outcome cor- responds to histological progression: while early stages are characterized by scattered neoplastic cells in an in- flammatory background, later (tumour) lesions mostly Electronic supplementary material The online version of this article (doi:10.1007/s00428-017-2107-1) contains supplementary material, which is available to authorized users. * Alessandro Pileri alessandropileri@hotmail.it 1 Dermatology Unit, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Via Massarenti 1, 40138 Bologna, Italy 2 Dermatology Unit, Department of Surgery and Translational Medicine, University of Florence Medical School, Florence, Italy 3 Haematopathology Unit, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy 4 Department of Experimental Medicine, Section of Pharmacology L. Donatelli, Second University of Naples, Naples, Italy 5 Dermatology Unit, Department of Medical Sciences, University of Turin, Turin, Italy 6 Division of Anatomic Pathology, Department of Surgery and Translational Medicine, University of Florence Medical School, Florence, Italy 7 Dermatopathology Section, Azienda Ospedaliera Città della Salute e della Scienza, University of Turin, Turin, Italy 8 Unit of Diagnostic Haematopathology, European Institute of Oncology, Milan, Italy 9 Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy Virchows Arch (2017) 470:575–582 DOI 10.1007/s00428-017-2107-1