NOD2 and pneumonia: Upregulation of genes for pattern recognition receptors that signal upstream of NF-κB activation (for example, Nod1, Nod2, Tlr2, Tlr4, Tlr6, Tlr7, Tlr9, Nlrp3), cytoplasmic signaling molecules that signal downstream of these receptors (Pycard, Casp1), and mRNAs coding for proteins that interact with NF-κB subunits to regulate activation (Nfkbia, Nfkbib, Nfkbie) indicate complex regulation of and by NF-κB in neutrophils during S. pneumoniae-induced pneumonia.