Class II beta-tubulin is a novel marker for human tonsillar M cells and follicular dendritic cells.

OBJECTIVE

Membranous (M) cell of the human palatine tonsil is an antigen entry site for mucosal infection, but its location is obscure in histological sections. Recently, a microarray analysis has demonstrated that clusterin, annexin A5, CD44, MMP14, and beta-tubulin are candidate genes of M cell marker in mice. Among these genes, we here describe class II beta-tubulin as a new marker for human tonsillar M cells and follicular dendritic cells (FDCs), and present its usefulness for diagnosis of angioimmunoblastic T-cell lymphomas (AILTs).

MATERIALS AND METHODS

Immunohistochemistry and Western blotting for class II beta-tubulin were performed using 81 cases of lymphoid, gastrointestinal and thyroid tissues, and an FDC cell line, respectively. Double immunostaining with clusterin and class II beta-tubulin were carried out.

RESULTS

Class II beta-tubulin localized the M cells and FDCs in the palatine tonsils (10/10, 100%) and adenoids (10/10, 100%). It was colocalized with clusterin in the palatine tonsils. However, class II beta-tubulin staining did not identify intestinal M cells in the intestines. Immunoblot analysis revealed that class II beta-tubulin expression was upregulated in HK cells, a normal FDC cell line. Class II beta-tubulin immunostaining highlighted hyperplastic FDC meshworks in all AILTs (14/14, 100%).

CONCLUSION

Class II beta-tubulin is a specific histochemical marker for human tonsillar M cells and FDCs. Thus, class II beta-tubulin immunostaining may be useful to identify tonsillar M cells and to diagnose FDC proliferative lesions such as AILT.