Shiraz Universityof Medical Sciences,

The Orgeneratingenzyme NADPH oxidase, plays a crucial role in host defense against microbial infectionthroughthe productionof reactiveoxygenspecies (ROS).' The multisubunitNADPH oxidase complex can be detected in vitro by the nitrobluetetrazolium test (NBT).2 The NBT test is used for the diagnosis of chronic granulomatousdisease.3 However, several factors,such as some cytotoxicdrugs and antibioticscan affectthe resultsof this test. The impairedcapabilityof neutrophilsto reduce NBT from a patienttreated for tuberculosisand non-Hodgkin's lymphoma, before the final diagnosis was made intrigued us to evaluate the NBT reduction test in that patient after completionof his treatment.Then, we observed a subsequent increase of the capability of Phorbol Myristic Acetate (PMA) stimulated NBT test. We therefore concluded that NBT test may not be useful for evaluationof ROS generation in neutrophilsafter chemotherapyand/or administrationof antibiotics.This observationmay be attributedeither to the effectof immunosuppressivedrugs which inhibitPMA-induced superoxidegenerationof neutrophils,4 or the anti-inflammatoryeffects of antibioticswhich can decrease the abilityof ROS productionfrom polymorphonuclearleukocytes.