Am. J. Respir. Crit. Care Med., Vol 154, No. 1, 07 1996, 50-56.
Shared amino acid motifs in T-cell receptor beta junctional regions of bronchoalveolar T cells in patients with pulmonary sarcoidosis
Y Usui, H Kohsaka, Y Eishi, I Saito, F Marumo and N Miyasaka
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
To clarify the nature of the accumulated lung T cells of pulmonary
sarcoidosis, we studied bronchoalveolar and peripheral blood (PB)
lymphocytes from Japanese patients for expressed T-cell receptor beta-
chain variable (TCR V beta) gene usage. Quantitative polymerase chain
reaction technique revealed that the V beta repertoires of bronchoalveolar
and PB T cells were heterogeneous. However, the bronchoalveolar lymphocytes
from five out of 10 patients showed overrepresentation of T cells, with a
few TCR V beta families, which varied among individuals, possibly
reflecting a difference in the human leukocyte antigen (HLA) backgrounds.
Nucleotide sequence analysis of third complementarity determining region
(CDR3) segments in overrepresented V beta families demonstrated limited
diversity of the transcripts. Two HLA-DR 12(5)+ individuals with
overrepresented V beta 6 gene transcripts in the lungs shared a common
amino acid motif within their CDR3. By contrast, non-overrepresented TCR V
beta transcripts did not show clonal expansion, and the oligoclonal clones
in the lung were not found in PB of the corresponding patient. These
results showed that, at least in subsets of Japanese patients with
pulmonary sarcoidosis, a limited number of T-cell clones are accumulated in
the lung in response to a specific antigen. They may mediate an immune
response to shape pathology of the disease.
