Validación de la técnica de dihidrorodamina 123 para el diagnóstico de la enfermedad granulomatosa crónica en Colombia

Introduction

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in the respiratory burst of phagocytes. Affected patients often suffer from granulomas and recurrent infections, mainly due to encapsulated bacteria.

Aim

To standardize the dihydrorhodamine test (DHR) in Colombia used for the diagnosis of CGD by evaluating the respiratory burst in human blood neutrophils and monocytes after in vitro activation.

Methods

Phagocyte respiratory burst in peripheral blood samples from 10 healthy controls was evaluated by flow cytometry after leukocyte activation with several concentrations of phorbol myristate acetate (PMA). The different oxidation patterns of DHR in X-linked or autosomal recessive CGD were also obtained.

Results

The most suitable concentrations of PMA for the evaluation of the respiratory burst in peripheral blood were 0.2 to 5 μg/ml. Reference values for this test in neutrophils from our population were established. It was shown that the oxidation patterns of DHR in monocytes were not always identical to those observed in neutrophils.

Conclusion

The evaluation of DHR oxidation by flow cytometry is a screening method that easily identifies the different phenotypes of CGD, with good sensitivity and at a lower cost. However, it is crucial that every laboratory establishes its own normal range for this test, in order to achieve the accurate characterization of this condition. DHR oxidation patterns may be also evaluated in different blood cells, since cell type-specific defects have also been reported.