A Compartmentalized Bias for T-Cell Receptor Vβ Usage in Summer-Type Hypersensitivity Pneumonitis

Several monoclonal antibodies specific to the human T-cell receptor (TCR) variable (V) region were used to examine whether T-cell oligoclonality plays a key role in the development of the T-cell-mediated lung disease, summer-type hypersensitivity pneumonitis (SHP). The usage of TCR V-regions was examined using bronchoalveolar lavage (BAL) and matched peripheral blood lymphocytes (PBL) in patients with SHP. In 18 SHP patients, the majority of lymphocytes in both BAL and PBL was CD3+ cells (94.2 vs. 63.9%, respectively), which was similar to that in normals (n = 7). Of CD3+ lymphocytes in a SHP patient, the percentage of CD4+ cells in BAL was reduced compared to those in paired PBL, whereas the percentage of CD8+ cells was significantly elevated. In contrast, the percentage of CD4+ cells was much higher than that of CD8+ cells in both BAL and PBL of normal subjects. While a majority of CD3+ T cells expressed TCR alpha/beta+ in BAL and PBL from both SHP patients and normal controls, a marked increase of the expression of TCR gamma/delta+ was observed in PBL in 4 out of 18 SHP patients. A markedly increased prevalence (> 3 SD) of specific TCR alpha/beta+ V-region families in BAL was detected in 5 of 18 patients with SHP as compared to normal controls, whereas no specific increase was found in PBL. Increased V beta 8 was detected in 3 cases; V beta 6 was observed in 1 patient, and V beta 5 in another patient.(ABSTRACT TRUNCATED AT 250 WORDS)