The fact that biologics inhibits the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) raises a concern about their use without predisposing the patient to opportunistic infections (OIs) [5,6]. The use of infliximab and etanercept is associated with increased susceptibility to intracellular pathogens such as Mycobacterium tuberculosis, atypical mycobacteria, and endemic fungi such as Histoplasma capsulatum, Coccidioides immitis, yeasts such as Cryptococcus neoformans and Candida, Pneumocystis pneumonia, and Listeria monocytogenes [5,6]. This evidence concerns the gene TNF and pneumocystosis.