By comparing the frequency of anti-AAM antibodies in acute phase pneumonia sera and control sera, our results revealed that antibodies (IgG or IgM, or both) to A. felis, A. felis genospecies A, Afipia genospecies 1, Afipia genospecies 3, B. eneae, B. massiliensis, B. vestrisii, B. thiooxidans, M. amorphae, N. oligomobilis, Rasbo bacterium, C. pneumoniae, P. acanthamoeba BN9 were found more frequent in sera from the acute-phase of pneumonia than in control sera (Table 1). Here, CD40LG is linked to pneumonia.