Mast cell changes in scleroderma. Presence of MCT cells in the skin and evidence of mast cell activation.
OBJECTIVE
To analyze the concentration and distribution of the MCT (tryptase-positive, chymase-negative) and MCTC (tryptase-positive, chymase-positive) types of mast cell in cutaneous lesions of scleroderma.


METHODS
Biopsy specimens were obtained from skin lesions in 24 patients with scleroderma, and subjected to double immunohistochemical analysis using mouse monoclonal anti-tryptase and anti-chymase antibodies.


RESULTS
Dermal mast cell concentrations were below the normal range in 12 of the specimens, most of which were obtained between 1 and 4 years after disease onset. All other specimens contained normal concentrations of mast cells. MCT cells were present in 12 specimens and comprised between 8% and 100% of the total mast cells. Extracellular tissue deposits of tryptase-positive and/or chymase-positive granular material were observed in 8 specimens, suggesting possible mast cell degranulation.


CONCLUSIONS
These findings are in contrast to those in normal skin, where MCTC cells are essentially the only type of mast cell present in the dermis. The results suggest that mast cells are involved in the pathogenesis of cutaneous lesions in scleroderma.
Irani
A M
AM
Department of Pediatrics, Medical College of Virginia, Richmond 23298.
Gruber
B L
BL
Kaufman
L D
LD
Kahaleh
M B
MB
Schwartz
L B
LB
D000328:Adult; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000276:immunology; D001706:Biopsy; D002452:Cell Count; D053818:Chymases; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008407:Mast Cells / Q000201:enzymology* / Q000473:pathology*; D008875:Middle Aged; D010447:Peptide Hydrolases / Q000032:analysis / Q000276:immunology; D010641:Phenotype; D012595:Scleroderma, Systemic / Q000201:enzymology / Q000473:pathology*; D012697:Serine Endopeptidases / Q000032:analysis / Q000276:immunology; D012867:Skin / Q000201:enzymology / Q000473:pathology*
D000911:Antibodies, Monoclonal; D010447:Peptide Hydrolases; C023073:tosylarginine methyl ester hydrolase; D012697:Serine Endopeptidases; D053818:Chymases