Analysis of T cell receptor V_β gene expression and clonality in bronchoalveolar fluid lymphocytes from a patient with chronic eosinophilic pneumonitis

Chronic eosinophilic pneumonitis (CEP) is characterized by longstanding respiratory symptoms accompanied by a massive pulmonary eosinophil infiltration. T lymphocytes in bronchoalveolar lavage (BAL) from patients with chronic eosinophilic pneumonitis are considered to recognize unknown antigens. To analyze the pathogenesis of CEP, we examined the T cell receptor (TCR) repertoire and T cell clonotype of BAL lymphocytes and peripheral blood lymphocytes (PBLs) in a 66-year-old woman patient with CEP. The expression of TCR BV gene was analyzed by the family PCR method using specific primers for 20 TCR BV genes and BC gene. The clonotype of BAL and peripheral T cells was examined by the PCR-single-strand conformation polymorphism (SSCP) method. Functional sequences of some T cell clones were also carried out. A TCR repertoire of BAL T cells was heterogeneous as well as PBLs. However, SSCP analysis showed that distinct T cell clonotypes were detected in BAL T cells, TCR BV3, BV4, BV6, BV8, BV9, BV14, and BV18-positive T cell clones especially, expanded clonally in BAL from the patient. Sequencing analysis showed that GVD, LGG, RDXS, and SSG amino acid sequence motif were found in the CDR3 in lung-specific T cells. BAL-specific T cell clones accumulated in the patient with CEP. Thus, we can conclude that BAL T cells are induced by the antigen-driven stimulation and these cells might play a crucial role in the generation of CEP.