B lymphocytes infiltrating Wegener's granuloma: the immunoglobulin VH gene repertoire from granulomatous tissues displays an antigen-driven maturation and suggests a microbial trigger
© The Author(s) 2004
Received: 16 January 2004
Published: 24 February 2004
In Wegener's granulomatosis (WG) the development of a generalized vasculitis is based on strong expression of proteinase 3 (PR3) on the surface of neutrophil granulocytes and the appearance of circulating high-affinity anti-PR3 autoantibodies (PR3-ANCAs) suggesting an antigen-driven B lymphocyte maturation.
In order to analyze mechanisms relevant to the induction of ANCA, we compared the immunoglobulin heavy chain (VH) gene repertoire in biopsy specimen of granulomas from two cases of ANCA-negative localized WG and from two cases of ANCA-positive generalized WG with a healthy control.
Frozen tissue samples were stained for B lymphocytes by anti-CD20 APAAP. DNA was prepared, purified and subjected to a PCR with individual VH primers matching to the families VH1–VH6 and a JH consensus primer. After bacterial subcloning PCR products were sequenced and characterized for gene usage and mutational pattern.
In WG a subset of autoreactive PR3-producing B cells may be induced to produce PR3-ANCA within granulomatous lesions after Staphylococcus aureus B-cell superantigen stimulation. Selected B cells undergo affinity maturation and differentiate into plasma cells that produce high levels of circulating ANCAs, which are involved in the pathogenesis of the systemic vasculitis.
This work is supported by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 367, A11) and by the University of Luebeck (FUL N20-2001).