This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunomodulator, Subject name: Pharmacology
A 45 years old male patient a known case of Crohn's disease presents with recent flare-ups suggestive of fistulas. He was admitted and treated with immune-suppressive. Unfortunately, he got reactivation of his tuberculosis as a result of the side effects of the treatment. Which of the following immunosuppressive medication is the most likely cause of his TB reactivation? 
Select and explain. 
A. Methotrexate, B. Infliximab, C. Azathioprine, D. Mizorbine
B: Infliximab
Answer: B: Infliximab 
Explanation: Answer: b) InfliximabTREATMENT OF INFLAMMATORY BOWEL DISEASEAminosalicylates* 5-aminosalicylic acid (formulations known as mesalamine): acts topically in the colon.* Sulfasalazine (5-ASA + sulphapyridine), olsalazine (5-ASA+5-ASA) and balsalazide (5-ASA+ amino benzoyl Alanine) are effective for the treatment of ulcerative colitis.* 5-ASA is the first line treatment for mild ulcerative colitis.Glucocorticoids* Prednisone, hydrocortisone, prednisolone and budesonide: in moderate to severe ulcerative colitis and Crohn's disease.Purine analogs* Azathioprine and 6-MP: maintenance for remission of ulcerative colitis and Crohn's disease.Methotrexate: induction and maintenance of remission of Crohn's disease but not ulcerative colitis.Anti TNFa therapy: Infliximab, adalimumab and certolizumab are useful in Crohn's disease.Natalizumab: targeted against a-4 subunit of integrins. Should not be used with other immunosuppressants due to the risk of progressive multifocal leukoencephalopathy.* Infliximab therapy is associated with | incidence of respiratory infections; potential reactivation of tuberculosis or other granulomatous infections with subsequent dissemination.* Candidates for infliximab therapy should be tested for latent tuberculosis with purified protein derivative and chest radiographs, and patients who test positive should be treated prophylactically with isoniozid.* Infliximab also is contraindicated in patients with severe congestive heart failure.