Frequency of gamma delta T cells in peripheral blood, synovial fluid, synovial membrane and lungs from patients with rheumatoid arthritis.

The percentages and absolute numbers of gamma delta T cells per CD3 positive cells (T cells) in four different compartments, namely peripheral blood, synovial fluid, synovial membrane and lungs from patients with rheumatoid arthritis (RA) and in peripheral blood from healthy controls were studied by two color flow-cytometric analysis. The percentages (mean +/- SEM = 6.3 +/- 0.8%, n = 22) and absolute numbers (70 +/- 11/microliters, n = 22) of gamma delta T cells in peripheral blood from RA patients were not different from those of 22 age-matched healthy controls (7.5 +/- 0.9%, 81 +/- 17/microliters, respectively). The gamma delta T cells in peripheral blood from 50 RA patients were, however, significantly decreased in negative correlation with the value of CRP as a marker for inflammation, although they had no correlation with the titer of rheumatoid factor as an autoantibody. The percentages of gamma delta T cells in synovial fluid from 10 patients (3.3 +/- 0.5%, n = 10) or in synovial membrane from 5 patients (4.2 +/- 1.9%, n = 5) and in bronchoalveolar lavage fluid from 6 patients (3.6 +/- 0.8%, n = 6) were not different from those in peripheral blood from the same patients. Thus, gamma delta T cells are not the dominant infiltrating T cell subset in the inflammatory sites of RA patients.