CD40LG and rheumatoid arthritis: Interestingly, in the context of a unique population in which anti-LtxA IgG is not useful to distinguish RA from controls, our data suggest that anti-LtxA IgM antibodies may identify a subset of patients who have been recently colonized or infected with Aa either during the transition from pre-symptomatic phase to early stages of RA or to established disease.