The risk factors for opportunistic infections are malnutrition, older age, congenital immunodeficiency, HIV infection, chronic diseases (such as emphysema), diabetes mellitus, and use of immunosuppressive medications such as corticosteroids, immunomodulators (methotrexate, thiopurines), and anti-TNF-a therapy [25, 26]. This evidence concerns the gene TNF and nutritional deficiency disease.