<prompt> Most common cause of chronic granulomatous disease in children is:Myeloperoxidase deficiencyDefective phagocytosisDefective H2O2 productionJobs disease  <response>: Answer is C Defective H2O2 production Chronic granulomatous disease is a disorder of microbial killing characterized by decreased ability of neutrophils to produce H4-Q Chronic granulomatous disease is a disorder of microbial killing characterized by decreased ability of neutrophils to produce H,O2.Q Patients, here become susceptible to disease caused by organisms that produce catalase, which destroys the small amount of H2O, present in these cells and leads to failure of bacterial killing. The disease is called so, because granulomas, are formed in various tissues, as a second line defence against organisms, that normally would be removed by the acute inflammatory response. Manifestations: Recurrent infections with which catalase ve Pyogenic bacteria e.g. staphcoliforms. Q - catalase negative bacteria e.g. streptococcus, Pneumococcus are often handled normally.Q Normal humoral immune response? but Defective killing process: Leucocytes are unable to kill bacteria after phagocytosis the major reason being decreased production of H-O2.Q Screening method: NBT test: Nitroblue retrazolium dye is not reduced by neutrophils in vitro. Q 