It is known that IgA nephropathy (IgAN) often progresses to end-stage renal failure within a period of 20 years. There are many reports suggesting the relationship between the tonsillar autoimmune response and the pathogenesis of IgA nephropathy, however, definitive evidence has not been detected. Recently, studies of T-cell receptor variable (TCR V) region gene usage in human autoimmune disease showed that the TCR V beta repertoire of pathogenic T cells was highly restricted. In this study, we examined expression of TCR V beta families in tonsils from IgAN patients. The study group consisted of 7 IgAN patients and 7 obstructive sleep apnea syndrome (OSAS) patients. Total RNA was extracted from the tonsils of each patients, and expression of each TCR V beta subfamily gene were examined by reverse transcription-polymerase chain reaction (RT-PCR) method. V beta 6 is more frequently used in tonsils of IgAN patients than in those of OSAS patients (p=0.01), and V beta 20 is more frequently used in OSAS patients than IgAN patients (p=0.01). It was already reported that the frequency of V beta 6 subfamily usage is elevated in both peripheral blood lymphocytes (PBL) and renal tissues of IgAN patients. Therefore, our results suggested that the tonsils may be one of the sources of specific T cells related to the pathogenesis of IgAN.
