Mast cells in pterygium: number and phenotype.
OBJECTIVE
To investigate the pathogenesis of pterygium.


METHODS
The number and phenotype of mast cells were examined in excised tissue from 35 pterygia patients and compared with those in normal conjunctival specimens obtained during cataract or other intraocular surgery.


RESULTS
Toluidine blue staining showed that the mean number of mast cells in the pterygia specimens was twice as high as that in the normal conjunctival tissues. Immunohistochemistry with a primary antibody to tryptase, specific for mast cells, also revealed a twofold increase in the mast cell number in the pterygia specimens compared with the normal conjunctival tissues. In the pterygia, more than 94% of the tryptase-positive mast cells were found to express chymase and c-kit. Almost all mast cells in the pterygia were tryptase-positive, chymase-positive mast cells (MC(TC)S). There was no phenotypic difference between the mast cells in the pterygia and those in the normal conjunctival tissues.


CONCLUSIONS
The MC(TC)S appear not to be immune system-related and to have functions in angiogenesis and tissue remodeling. The increase in the number of mast cells caused by nonallergic stimulation may contribute to the pathogenesis of pterygium.
Nakagami
T
T
Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan.
Murakami
A
A
Okisaka
S
S
Ebihara
N
N
D000911:Antibodies, Monoclonal; D002452:Cell Count; D053818:Chymases; D004396:Coloring Agents; D003228:Conjunctiva / Q000201:enzymology / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D008407:Mast Cells / Q000201:enzymology / Q000473:pathology*; D008875:Middle Aged; D010641:Phenotype; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011625:Pterygium / Q000201:enzymology / Q000473:pathology*; D012697:Serine Endopeptidases / Q000378:metabolism; D014048:Tolonium Chloride; D053802:Tryptases
D000911:Antibodies, Monoclonal; D004396:Coloring Agents; D014048:Tolonium Chloride; D019009:Proto-Oncogene Proteins c-kit; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; D053802:Tryptases