From the FDA site:
The U.S. Food and Drug Administration (FDA) is informing the public that it continues to receive reports of a rare cancer of white blood cells (known as Hepatosplenic T-Cell Lymphoma or HSTCL), primarily in adolescents and young adults being treated for Crohn’s disease and ulcerative colitis with medicines known as tumor necrosis factor (TNF) blockers, as well as with azathioprine, and/or mercaptopurine.
Crohn's disease and ulcerative colitis cause inflammation of the digestive system. Common symptoms are pain in the abdomen, cramps, and diarrhea. Bleeding from the rectum, weight loss, joint pain, skin problems and fever also may occur. Children with the disease may have growth problems, develop intestinal blockage, and experience malnutrition.
FDA believes the risks and benefits of using TNF blockers, azathioprine, and/or mercaptopurine should be carefully weighed when prescribing these drugs to children and young adults, especially for the treatment of Crohn’s disease and ulcerative colitis. Patients should continue to talk to their Healthcare Professionals about the potential risk of HSTCL with use of these medications in order to make the best decision about their medical treatment.
The product labels for Remicade (infliximab) and Humira (adalimumab) have been updated and the product labels for azathioprine and mercaptopurine are being updated to include warnings about HSTCL that have been reported in patients treated with these products
http://www.fda.gov/Drugs/DrugSafety/ucm250913.htm
