PDE4A and pulmonary tuberculosis: In this study, using a rabbit model of pulmonary TB, we show that immune modulation of Mtb infected animals with CC-3052, a phosphodiesterase-4 (PDE4) inhibitor that reduces tumor necrosis factor alpha (TNF-α) production by increasing intracellular cAMP levels, resulted in the down-regulation of host genes involved in the innate immune response.