T-cell receptor gene usage in patients with fibrosing alveolitis and control subjects

Background Fibrosing alveolitis is characterized by inflammation, fibrosis and increased numbers of activated CD4(+) T-cells in the lower respiratory tract. The aims of this study were to compare the T-cell antigen receptor r epertoire in the lungs of subjects with fibrosing alveolitis systemic scler osis (FASSc) with cryptogenic fibrosing alveolitis (CFA) and normal control subjects, to determine whether FASSc is driven by a specific T-cell trigge r and is determined by a T-cell driven immune response, and to assess the c lonality of CD4+ and CD8(+) TcR usage in subjects with FASSc. Materials and methods We used reverse transcription polymerase chain reacti on with specific V alpha- and V beta-chain primers to identify the TcR gene usage in biopsy material, bronchoalveolar lavage fluid or peripheral blood from our subjects. Results We found individual-specific restriction of V alpha- and V beta-cha in usage in lung biopsies from patients and control subjects. To establish whether this was due to expression bias in the CD4(+) or CD8(+) T-cells and was restricted to the lung, the alpha beta-T-cell receptor chain usage was assessed in T-cell subsets separated from the lungs of patients with fibro sing alveolitis and was compared with that of the peripheral blood. There w as no consistent difference in the expression of any variable family chain among the population studied, although there was a significant difference b etween lung and peripheral blood lymphocyte V beta-families in CD8(+) T-cel ls (P = 0.0007). Conclusion We conclude that there is individual TcR V alpha- and V beta-exp ression bias in subjects with fibrosing alveolitis.