A primary immune deficiency disorder is often suspected in children with recurrent deep seated and fungal infections and those admitted to pediatric intensive care units. Chronic granulomatous disease (CGD) is inherited disorder leading to infections caused due to defective superoxide production. Cases referred for testing for a primary immunodeficiency disorder were tested for Dihydrorhodamine 123 (DHR) assay by flow cytometry and nitroblue tetrazolium dye (NBT) slide test. The unstimulated and stimulated samples were tested for oxidative burst activity which gives bright fluorescence due to formation of Rhodamine 123 on flow cytometry and blue formazan pigment in NBT slide test. The test results were reported in real time. From a total of 330 patients screened for chronic granulomatous disease using DHR and NBT slide test, 17 patients (5.1%) were found to have CGD. These included 12 boys and 5 girls. They presented with deep seated infections, recurrent and multiple abscess, recurrent pneumonia and granulomatous lymphadenitis. The causative organisms were Mycobacteriae, Staphylococcus, Burkholderia cepacia, Pseudomonas, Aspergillus and Cytomegalovirus. In 6 out of 17 positive cases family studies were carried out. On follow up five children succumbed to disease, two patients underwent allogeneic bone marrow transplant, the chimerism status was demonstrated by repeat DHR assay at day 50 post-transplant. Rest are in follow up under prophylactic antibiotics and supportive care. As facilities for molecular testing are not easily available for primary immuno deficiency disorders, flow cytometry based clinical laboratories can help to screen for some of the frequently suspected disorders like chronic granulomatous disease. This has aided in paediatric care in our centre.
Keywords: Chronic granulomatous disease; DHR assay; Primary immunodeficiency diseases.
© Indian Society of Hematology and Blood Transfusion 2020.