In IBD, drug-induced pneumonias are mainly related to purine analogues (Azathioprine, 6-mercaptopurine), 5-ASA derivates (mesalazine, sulfasalazine), Methotrexate, and anti-tumor necrosis factor (TNF) alpha [53, 57, 58]. The gene discussed is TNF; the disease is susceptibility to pneumonia measurement.