Despite the benefit of anti-TNF therapy in a broad panel of inflammatory diseases, it has been well documented that the TNF inhibitors may present controversial effects in non-responder patients; this means patients who previously responded to the treatment but posteriorly, they are treatment-refractory and susceptible to infection from some bacteria such as Legionella pneumonia and Listeria monocytogenes [15,85]. This evidence concerns the gene TNF and Legionnaires' disease.