The most complete R. typhi longitudinal humoral immunity data before our study was that of a New Zealand murine typhus patient with IgM and IgG reciprocal titres of 80 and 1280 on admission, titres of 2560 and 1280 at day 26, and titres of 40 and negative at 13 months, respectively [10]. The gene discussed is CD40LG; the disease is typhus.