<prompt> Which of the following tests would be most beneficial in the diagnosis of a patient suspected of having chronic granulomatous disease of childhood?E rosette - forming assayCell-mediated cytolysisNitroblue tetrazolium NBT testDetermination of CD4: CD8 ratio  <response>: Patients with the chronic granulomatous disease, a sex-linked recessive disease, are deficient in phagocyte function. The neutrophils monocytes lack reduced nicotinamide adenine dinucleotide phosphate NADPH oxidase, a critical enzyme that is needed for the production of reactive oxygen intermediates ROIs responsible for the respiratory burst. Nitroblue tetrazolium NBT is a pale yellow dye that accepts H and is reduced as a result of NADPH oxidation to a blue intracellular precipitate. In the NBT test, peripheral blood neutrophils take up the dye after a stimulus latex beads or other paicles. Failure of the cells to reduce the NBT dye to a blue color is consistent with a diagnosis of chronic granulomatous disease.E rosette-formation is a historically impoant assay for identification of human lymphocytes. T cells have a receptor CO2 by which they are able to bind sheep erythrocytes E. A lymphocyte with several erythrocytes attached to it has the appearance of a rosette. 