Evaluation of Phagocytic Component of the Immune System in Patients with Organic Acidemia

Background: There are several reports of recurrent infections in patients with organic acidemia. Almost all studies on the immune system of these patients have investigated the immune system in the acidotic phase of the disease. In the present study, the phagocytic component of the immune system was evaluated in patients with organic acidemia. Methods: After exclusion of patients in the acidotic phase of the disease, 31 patients with organic acidemia were included in the study. All patients completed the written informed consents, and the study was approved by the ethics committee of Mofid Children’s hospital. Information including age, sex, type of organic acidemia, and history of hospitalization due to infection was recorded. Screening tests of phagocytic component of the immune system, including total and differential white blood cell (WBC) count and nitroblue tetrazolium (NBT) test, were performed for all the patients. Results: The prevalence of neutropenia was highamongpatients (22.6%); it was even more frequent in patients younger than 3 years (42.6%). On the other hand, in most patients (93.5%), neutrophils showed normal function on the NBT test. Conclusions: Neutropenia in the nonacidotic phase of organic acidemia can be the cause of recurrent infections in these patients. It can be independent of bone marrow suppression, caused by reduced production of these cells as a result of reduced pH in the acidotic phase of the disease.