Q45. A Golden retriever (photo ‘A’) has cutaneous histiocyto…
Q45. A Golden retriever (photo ‘A’) has cutaneous histiocytosis, an inflammatory Lymphohistiocytic proliferative disorder that primarily involves skin and subcutis. Lesions may disappear spontaneously or regress and appear at new sites simultaneously. A biopsy of the skin (see photomicrograph ‘B’) reveals cells that are on IHC and express CD1, CD11c, MHC class II, CD4, and CD90. On transmission EM (see photomicrograph ‘C’), the tumor cells contain Birbeck granules comprised of antigen-bound Langerin (Langerin is a c-type lectin). Which of the following types of immune cells is most likely responsible for the inflammatory infiltrate in this dog?