[513] Expression Analysis of Homing Molecules in Cutaneous and Systemic Mastocytosis

CD Jennings, U Sundram. Stanford University Medical Center, Stanford, CA

Background: Mastocytosis is a rare disorder characterized by accumulation of mast cells in one or more organs. Cutaneous mastocytosis can present as urticaria pigmentosa or mastocytoma. In children, this disease has a benign course, whereas in adults there is a chance of having associated systemic disease. In systemic mastocytosis, mast cells can be found accumulated in various tissues, most often skin and bone marrow, but also liver, spleen, and the gastrointestinal tract. Involvement of homing molecules/receptors, adhesion molecules, and chemokines in lymphocyte trafficking has been described in cutaneous inflammatory disorders and lymphomas. Currently, not much is known about the mechanisms involved in the recruitment and accumulation of neoplastic mast cells in specific organs as in mastocytosis.
Design: We used immunohistochemistry to investigate the potential role of homing molecules in mast cell recruitment to the skin and other sites in mastocytosis. Skin biopsies from thirty-two patients with cutaneous mastocytosis and two cases of systemic mastocytosis, liver and bone marrow, confirmed by CD117 or mast cell tryptase (MCT) were stained. Immunohistochemistry was performed with antibodies directed against various homing molecules, including CD29 (β1-integrin), CD54 (ICAM-1), CD62-L (L-selectin), CD183 (CXCR3), sialyl-Lewis x (SLX).
Results: CD183 was expressed in mast cells in 30 of 32 cutaneous cases, CD29 was expressed in 28 of 32 cutaneous cases, while CD54, CD62L, and SLX were consistently negative in cutaneous mast cells. CD54 was negative in mast cells; however, the dermal vessels consistently stained positive for CD54. In the systemic cases of mastocytosis, the liver mast cells expressed CD29 but not CD183 and bone marrow mast cells expressed CD183 and CD29. CD54 was negative in both systemic cases.
Conclusions: In summary, we have demonstrated in this study that accumulated mast cells in cutaneous mastocytosis express CD183 and CD29, and lack expression of CD54, CD62-L and sialyl Lewis x. Thus, unlike cutaneous lymphomas or leukemia cutis, cutaneous mastocytosis does not appear to involve selectins, but integrins and chemokines may be important for mast cell accumulation in skin. Additional studies are in progress, including testing ligands of molecules presented in this report, and comparison with additional bone marrow lesions in systemic mastocytosis.
Category: Dermatopathology

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 69, Monday Morning

 

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