T Cell Receptor Vβ Expression in Patients with Allergic Asthma before and after Repeated Low-Dose Allergen Inhalation

The objective of this study was to identify disease-associated T cell subsets by characterizing the lung and blood T cell receptor (TCR) repertoires in allergic asthmatics before and after repeated low-dose allergen challenge. Peripheral blood lymphocyte (PBL) and bronchoalveolar lavage (BAL) samples were obtained from eight patients with allergic asthma before and after a period of repeated low-dose allergen inhalations. RT–PCR followed by Southern blot allowed the quantification of relative Vβ gene segment usage. Thirteen healthy individuals served as controls at PBL level. PBL as well as BAL T cells of asthmatics displayed a higher usage of Vβ3, Vβ5.2, and Vβ6.1-3 and a lower usage of Vβ16, Vβ18, and Vβ19 compared to PBL of healthy controls. Interestingly, TCR Vβ7 and Vβ9 usage was significantly higher in BAL than in PBL in asthmatics before as well as after challenge. TCR repertoire alterations after allergen challenge differed between individuals, with relatively mild changes.