Mast cell numbers in rheumatoid synovial tissues

Authors

  • Daniel G. Malone MD,

    Corresponding author
    1. Mast Cell Physiology Section, Laboratory of Clinical Investigation, NIAID
    2. Mast Cell Physiology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, and the Arthritis and Rheumatism Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland
    • NIH, Building 10, Room 11N-228, Bethesda, MD 20892
    Search for more papers by this author
  • Ronald L. Wilder MD, PhD,

    1. Arthritis and Rheumatism Branch, NIAMSD
    2. Mast Cell Physiology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, and the Arthritis and Rheumatism Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author
  • Ana Maria Saavedra-Delgado MD,

    1. Mast Cell Physiology Section, Laboratory of Clinical Investigation, NIAID
    2. Mast Cell Physiology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, and the Arthritis and Rheumatism Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author
  • Dean D. Metcalfe MD

    1. Mast Cell Physiology Section, Laboratory of Clinical Investigation, NIAID
    2. Mast Cell Physiology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, and the Arthritis and Rheumatism Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author

Abstract

Synovial biopsy specimens from 20 patients with rheumatoid arthritis were subjected to quantitative analysis for several parameters of inflammation and for enumeration of synovial tissue mast cells. Strong positive correlations were found between numbers of mast cells per cubic millimeter of synovial tissue and the following synovial tissue parameters: inflammatory index (a quantification of lymphocytic infiltration), Leu-3a grade (T helper/inducer lymphocytes), Leu-1 grade (T lymphocyte), and plasma cell grade. A strong negative correlation was found between the synovial mast cell count and the extent of sublining layer fibrin deposition. Correlations between synovial mast cell count and Leu-2a grade, ratio of Leu-3a grade:Leu-2a grade, OKM1 grade, HLA–DR grade, and lining layer thickness grade did not reach statistical significance. In addition, we obtained synovial specimens from 6 of the patients both before and after long-term therapy with oral methotrexate and from 3 of the patients before, and 1 week after, an intraarticular injection of steroid. The 3 patients who had an intraarticular steroid injection showed a 67–96% decrease in the number of synovial tissue mast cells; there was no significant change in the number of synovial mast cells in the tissues of the 6 patients who received oral methotrexate. These observations are the first documentation of a quantitative relationship between the number of mast cells and the number and phenotypic profile of infiltrating lymphocytes in an inflamed tissue, which in this case, is human synovium. Our findings suggest that mast cells are involved in the pathologic interactions in rheumatoid arthritis and might play a role in the early phases of exacerbations of disease activity.

Ancillary