Ankylosing spondylitis in monozygotic twins: studies on immunological parameters

OBJECTIVE—To examine immunological parameters that might explain disease discordance in monozygotic twin pairs with ankylosing spondylitis (AS). METHODS—11 monozygotic twin pairs (nine with AS, two with undifferentiated spondyloarthropathy) were investigated. The peripheral T cell receptor Vβ repertoire was investigated using FACS analysis and 14 different Vβ antibodies. In addition serum samples were tested for antibodies to Klebsiella pneumoniae, Streptococcus pyogenes, Candida albicans, Proteus mirabilis, and Escherichia coli. Peripheral blood lymphocyte reactivity against a number of bacteria was investigated by interferon γ ELISPOT assays. RESULTS—Twins suffering from AS showed cellula…