Table 1 Summary of tryptase and cytokine immunolocalization data

MC tryptase

Approximately 50% of specimens showed local

All specimens contained MCs, but with variable distributions and

accumulations of MCs, most with extracellular enzyme

states of activation both between and within individual specimens

indicative of activation/degranulation

TNF-α

Approximately 80% of specimens stained; occasional

Most specimens showed only intracellular staining; usually

extracellular staining of cartilage matrix and intracellular

macrophages of the synovial lining layer

staining of chondrocytes

IL-1β

Approximately 80% of specimens positive; extracellular

Commonly observed for a proportion of macrophages, especially

distribution often reflecting that for TNF-α

those in the lining layer

IL-1α

Staining limited to about 30% of specimens and

Mainly restricted to a minor proportion of macrophages of the

usually associated with macrophages

synovial lining layer

IL-15*

Microfocal staining observed for about 30% of

Restricted to approximately 40% of specimens; usually

specimens, usually associated with macrophages,

macrophages of the synovial lining and a few fibroblastic cells;

and especially chondrocytes; no association with TNF

seldom associated with TNF⁺, IL-1⁺ or tryptase⁺ cells

or IL-1