Am. J. Respir. Crit. Care Med., Vol 154, No. 6, 12 1996, 1903-1907.
Cellular distribution of bronchus-associated lymphoid tissue in rheumatoid arthritis
A Sato, H Hayakawa, H Uchiyama and K Chida
Second Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
Bronchus-associated Lymphoid tissue (BALT) has been reported to be present
in the lungs of patients with rheumatoid arthritis (RA). However, little is
known about the structure and cellular distribution of BALT in this
disease, so we investigated these points using immunohistochemical methods.
The subjects were eight RA patients with BALT in biopsy specimens and a
histologic diagnosis of follicular bronchiolitis. Seven patients had cough
and purulent sputum, and four patients had positive sputum cultures. BALT
was histologically composed of four distinct regions, which were the
lymphoepithelium, the dome area, the follicular area, and the
parafollicular area. Surface IgM+ B cells were predominant in the
follicular area, whereas IgA+ cells were scattered in the dome and
parafollicular areas. T cells were mainly found in the parafollicular area
(CD4+ > CD8+), and most of them expressed the T Cell receptor alpha beta
(alpha beta TCR). These findings were similar to those described previously
for BALT in diffuse panbronchiolitis, which manifests as a chronic
respiratory infection. The present study indicated that extrinsic
stimulation as well as alterations of the immune response are involved in
the development of BALT in RA, although the exact mechanism requires
further clarification.
