TRBV9 and Alzheimer disease: V genes, including TRBV5-1, TRBV7-3, TRBV9, TRBV16, TRBV20-1, TRBV7-8, TRBV5-4, and J genes, including TRBV5-1, TRBV7-3, TRBV9, TRBV16, TRBV20-1, TRBV7-8, and TRBV5-4, showed a higher frequency in the AD group than in NC (P <0.05).The results indicating that the change of V and J genes usage spectrum in AD might be stimulated by some similar antigens.