Most common cause of chronic granulomatous disease in children is:

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. staph/coliforms. 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