Despite acceptable sensitivity (IgG 93.3% and IgM 90.0%) and low specificity (IgG 88% and IgM 84%) as reported in internal institutional documentation (MET-CNSP-183 and MET-CNSP-184, National Institute of Health, Lima, Peru), the ELISA could produce a cross-reactivity with other infections produced by other Bartonella species and unrelated pathogens [12]. Here, CD40LG is linked to infection.