Articular mastocytosis in rheumatoid arthritis

Abstract

The number and distribution of mast cells were assessed in 116 synovial membranes from patients with rheumatoid arthritis and in 30 control specimens. Rheumatoid synovial membranes contained a mean of 48.5 mast cells per 20 high-power fields (HPF) (range 0-252), and control synovial membranes had a mean of 3.9 mast cells per 20 HPF (range 0-13) (P < 0.001). In a comparison of high and low mast cell subgroups in rheumatoid arthritis, counts were directly related to the intensity of clinical synovitis in the affected joint, but not to hemoglobin concentration or erythrocyte sedimentation rate. Joints excised from 5 patients with rheumatoid arthritis were characterized by active bone remodeling with increased osteoid, active resorption by osteoclasts, and trabecular osteoporosis. Mast cells were prominent in both extraosseous pannus and intraosseous invasive tissue. The possible roles of mast cells in the pathogenesis of rheumatoid arthritis are discussed. (1-3). The accumulation of mast cells in the synovium is an early feature of adjuvant arthritis in the rat (4), although there are few reports of their prevalence in inflammatory synovitis in adult humans. Increased numbers of mast cells have been described in the synovial membrane of patients with juvenile rheumatoid arthritis (5-7), some of whom may also have circulating basophilia. The possibility that synovial mastocytosis could be a component of adult rheumatoid arthritis has received scant attention (8) and no controlled, quantitative studies have been reported. In 2 comprehensive reviews of the pathology of inflamed synovium, mast cells were not discussed (9,lO). In view of recent advances in the understanding of the possible role of mast cells in inflammation, bone resorption, and angiogenesis, it is reasonable to consider a function of these cells in the pathogenesis of the rheumatoid lesion. PATIENTS AND METHODSSynovial membranes from 116 patients with rheumatoid arthritis were obtained at surgical synovectomy of the knee and wrist, or at replacement arthroplasty of the knee and hip. Control specimens were obtained from 30 patients undergoing meniscectomy of the knee. Tissue was fixed in 10% neutral buffered formalin and embedded in paraffin blocks. Sections 4 pm thick were stained with 20% Giemsa solution. Mast cells were identified as cells of variable morphology, from oval to spindle-shaped or convoluted, possessing a single oval or round nucleus. The presence of red-violet metachromatic cytoplasmic granules was an absolute requirement for mast cell identification.In each case, 20 high-power fields (HPF) were counted by a single observer. A "high mast cell count" subgroup of patients with rheumatoid arthritis was arbitrarily defined

RETRACTED: Evidence for a functional role of IgE anticitrullinated protein antibodies in rheumatoid arthritis

“…Likewise, it was noted that mast cells numbers are increased in RA synovium (17). More recently, a role for mast cells has also been demonstrated in mouse models for arthritis.…”

Targeted mast cell silencing protects against joint destruction and angiogenesis in experimental arthritis in mice

“…relevance in human diseases, because large numbers of activated mast cells infiltrate tissue in the corresponding human diseases, such as allergic contact dermatitis, psoriasis, or RA (5)(6)(7)(8)(9)(10). However, the relative contribution of local mast cells to the initiation of these diseases is enigmatic.…”

Human Synovial Mast Cell Involvement in Rheumatoid Arthritis and Osteoarthritis. Relationship to Disease Type, Clinical Activity, and Antirheumatic Therapy

“…The mast cell contains in its granules a variety of proinflammatory substances, and thus is equipped to intensify acute and chronic synovitis (1 1). Histologic studies of human synovium have revealed an increased number of mast cells in rheumatoid and nonrheumatoid joint diseases (4,7). In addition, synovial mast cells are found in strategic locations: surrounding synovial blood vessels and lymphoid aggregates, and at the pannus-cartilage-bone erosion interface (2,(4)(5)(6)(7)9,10).…”