NFKB1 and pneumocystosis: Furthermore, upon analysis, we found a number of TFs either down- or upregulated that have been previously implicated in Pneumocystis AM interactions, including previously upregulated TFs Irf1, and Nfkb1, and in the murine Pneumocystis pneumonia (PCP) model, we observed the downregulation of Egr1 [9].