Abstract
Purpose: :
To compare the number of mast cells found in orbital fat tissue samples of thyroid eye disease (TED) patients versus gender and age-matched controls. Mast cells have been implicated in playing an important role in the inflammatory process in TED1. Treatment with mast cell inhibitors has been shown to reduce the symptoms of TED2.
Methods: :
The study was approved by NYEEI ethics committee. Review of the NYEEI pathology database from January 1990 to July 2007 identified 33 orbital fat decompression specimens from patients with TED and 19 blepharoplasty specimens from gender and age-matched controls. Two pathologists counted the number of mast cells under 20x in 10 high-power-fields in a masked fashion. Data was analyzed using the Mann-Whitney test and the conventional t-test.
Results: :
o Number of mast cells in control samples: Mean=14.71, SD=10.61, and Median=11.0o Number of mast cells in the TED samples: Mean=11.71, SD= 7.89, and Median=10.0o Mann Whitney test (Non-parametric): p=0.3416o A greater number of degranulated mast cells were observed in TED samples vs. controls.
Conclusions: :
o There is no significant difference in the number of mast cells found in TED patients vs. controls.o However, mast cells have been observed in some animal models of TED. In vitro, mast cells have been shown to induce prostaglandin synthesis and GAG production in human orbital fibroblasts3. Furthermore, the expression of histamine and leukotrienes by degranulating mast cells may partially explain some of the characteristic clinical and histopathologic findings in TED including lid retraction, vascular congestion, fibrosis and GAG deposition2.o Treatment with monteleukast and cetirizine has been shown to alleviate the symptoms of TED2.o Further study with greater study power may be needed to show a significant difference and the role of degranulated versus intact mast cells needs to be clarified.References:1. Many M-C, Costagliola S, Detrait M, Denef J-F, Vassart G, Ludgate M. Development of an animal model of autoimmune thyroid eye disease. J Immunol 1999;162:4966-74.2. Lauer SA, Silkiss RZ, McCormick SA. Oral Montelukast and Cetirizine for Thyroid Eye Disease. Ophthal Plast and Reconstr Surg. Accepted for publication 11/07.3. Hufnagel TJ, Hickey WF, Cobbs WH et al. Immunohistochemical and ultrastructural studies on the exenterated orbital tissues of a patient wit Graves’ disease. Ophthalmology 1984;91:1411-9.
Keywords: pathology: human • orbit • inflammation