Further, irinotecan stimulates the production of thromboxane A2, a potent physiological stimulant of chloride and water secretion in the colon (Sakai et al., 1997; Suzuki et al., 2000) as well as tumor necrosis factor- α (TNF-α) a pro-inflammatory cytokine and a primary mediator of immune regulation associated with CID (Yang et al., 2005). This evidence concerns the gene TNF and combined immunodeficiency.