Azathioprine in ulcerative colitis: Why, when, how and how long to use it

Thiopurines induce oxidative stress in T-lymphocytes: a proteomic approach

Thiopurines are extensively used immunosuppressants for the treatment of inflammatory bowel disease (IBD). The polymorphism of thiopurine S-methyltransferase (TPMT) influences thiopurine metabolism and therapy outcome. We used a TPMT knockdown (kd) model of human Jurkat T-lymphocytes cells to study the effects of treatment with 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) on proteome and phosphoproteome. We identified thirteen proteins with altered expression and nine proteins with altered phosphorylation signals. Three proteins (THIO, TXD17, and GSTM3) with putative functions in cellular oxidative stress responses were altered by 6-TG treatment and another protein PRDX3 was differentially phosphorylated in TPMT kd cells. Furthermore, reactive oxygen species (ROS) assay results were consistent with a significant induction of oxidative stress by both TPMT knockdown and thiopurine treatments. Immunoblot analyses showed treatment altered expression of key antioxidant enzymes (i.e., SOD2 and catalase) in both wt and kd groups, while SOD1 was downregulated by 6-TG treatment and TPMT knockdown. Collectively, increased oxidative stress might be a mechanism involved in thiopurine induced cytotoxicity and adverse effects (i.e., hepatotoxicity) and an antioxidant cotherapy might help to combat this. Results highlight the significance of oxidative stress in thiopurines' actions and could have important implications for the treatment of IBD patients.

HEPATITIS AND PNEUMONITIS DURIN ADALIMUMAB THERAPY IN CROHN’ DISEASE: mind the histoplasmosis!

Context Tumor necrosis factor-alpha (TNF-α) inhibitor therapy plays a pivotal role in the management of moderate to severe inflammatory bowel disease. Because of the role of TNF-α in the host defenses, anti-TNF therapy has been associated with an increase the risks of granulomatous infections. Objective To report the first case of adalimumab-associated invasive histoplasmosis presenting as an acute hepatitis-like syndrome and febrile pneumonitis in a patient with Crohn’s disease. Method Case report of a patient with progressive histoplasmosis confirmed by percutaneous fine needle aspiration biopsy lung and urine Histoplasma antigen. Results We present the case of a young man with CD who developed pneumonia and acute hepatitis-like features caused by Histoplasma capsulatum infection during adalimumab therapy. To the best of our knowledge, this acute hepatitis-like manifestation has never been reported as a presentation of the histoplasmosis in patients with Crohn’s disease. Conclusions This case underscores the potential risk for serious infection that may arise in this setting and should alert clinicians to the need to consider the histoplasmosis diagnosis in patients presenting with acute hepatitis-like syndrome associated with prolonged febrile illness or pneumonitis during therapy with anti-TNF-α antibodies.