MISC Autoimmune Flashcards
What is the cell of origin of canine cutaneous histiocytoma?
Langerhans cells
What are the cell markers for Langerhans cells/
CD1a, CD11c/CD18, E-cadherin
T/F: Langerhans cell disorders have not been reported in feline skin.
TRUE - however they do get pulmonary Langerhans cell histiocytosis
What is the cell of origin of histiocytic sarcomas?
interstitial dendritic cells
_____ is an indolent form of localized histiocytic sarcoma that originates in the skin of cats
progressive histiocytosis
In what tissues are Langerhans cells found?
Epithelia of skin, alimentory, respiratory, and reproductive tracts
What is the only histiocytic disease of dogs and cats that originates in macrophages?
hemophagocytic histiocytic sarcoma
Blood monocytes can differentiate into Langerhans cells under the influence of what cytokines or growth factors?
granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4
What do keratinocytes secrete that promote differentiation of Langerhans cells from CD14+ precursor cells?
TGF-beta1
What are the two major locations of dendritic cells?
epidermis (Langerhans cells) and dermis (adjacent to postcapillary venules – dermal interstitial dendritic cells)
What are CD11/CD18 and what is their function?
beta-2 integrins, critically important adhesion molecules expressed by all leukocytes
What is the function of E-cadherin with respect to Langerhans cells?
LCs localize within epithelia via E-cadherin homotypic adhesion w/ E-cadherin expressed by epithelial cells
What is a marker for dermal interstitial dendritic cells?
Thy-1 (CD90), CD11c (a subset also express CD11b)
What are key morphological features of histiocytomas?
1) Lesions have an epidermal focus (top-heavy) and intraepidermal foci are common; 2) Histiocytes have diverse nuclear morphology (round, ovoid, indented, or compelx nuclear contours); 3) Multinucleated cells and cytologic atypia are rare.
Key morphologic features of cutaneous Langerhans cell histiocytosis?
1) Multiple cutaneous lesions are observed. Metastasis to lymph nodes and internal sites is possible. 2) Lesions are otherwise identical to histocytoma but may have a higher frequency of multinucleated cells and cellular atypia.
Cell markers for feline pulmonary Langerhans cell histiocytosis?
CD1a, CD18, E-cadherin
Morphological features of feline pulmonary Langerhans cell histiocytosis
Multinodular to diffuse involvement of all lung lobes. Lesions consist of cohseive histiocytic infiltrates, which obliterate terminal airways and extend to pleural surfaces. Birbecks granules observed by TEM.
What is the cell of origin of cutaneous histiocytosis?
interstitial dendritic cells
What are the cell markers for cutaneous histiocytosis?
CD1a, CD4, CD11c/CD18, CD90
Morphological features of cutaneous histiocytosis
Vasocentric lesions are focused on mid-dermis to subcutis (bottom heavy). Lesions are pleocellular but are dominated by histiocytes and lymphocytes. Lymphohistiocytic vasculitis is commonly osberved. Histiocytes lack cytologic atypia, multinucleated giant cells are rare. Skin draining lymph nodes may be infiltrated
What is the cell of origin of systemic histiocytosis?
interstitial dendritic cells
What are the cell markers for systemic histiocytosis?
CD1a, CD4, CD11c/CD18, CD90
Morphological features of systemic histiocytosis
Identical lesions to cutaneous histiocytosis in skin - lesions extend to lymph nodes, ocular and nasal mucosa and internal organs
What is the cell of origin of feline progressive histiocytosis?
interstitial dendritic cells
What are the cell markers for feline progressive histiocytosis?
CD1a, CD11b/CD18, CD5 (50%)
Morphological features of feline progressive histiocytosis
skin nodules and plaques. Lesions occupy the dermis with an epidermal focus - intraepidermal foci (40%) occur. In early lesions, histiocytes have minimal cytologic atypia. In later lesions, histiocytes manifest cytological atypia as described for histiocytic sarcoma
What is the most common histiocytic disease of cats?
feline progressive histiocytosis
What breeds are predisposed to histiocytomas?
Boxers, Dachshunds
Cutaneous Langerhans cell histiocytosis has been reported in what breed?
Shar Peis
Histiocytomas are progressively infiltrated by what cell type?
CD8+ T cells
What IHC markers are necessary to differentiate histiocytomas from epitheliotropic T-cell lymphoma?
CD3 (T-cells) and CD18 (dendritic cells)
What cell markers are useful to differentiate interstitial dendritic cells and Langerhans cells?
interstitial dendritic cells (CD90+), Langerhans cells (E-cadherin+)