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.     

Genetic Analysis of a Cohort of 275 Patients with Hyper-IgE Syndromes and/or Chronic Mucocutaneous Candidiasis

Hyper-IgE syndromes and chronic mucocutaneous candidiasis constitute rare primary immunodeficiency syndromes with an overlapping clinical phenotype. In recent years, a growing number of underlying genetic defects have been identified. To characterize the underlying genetic defects in a large international cohort of 275 patients, of whom 211 had been clinically diagnosed with hyper-IgE syndrome and 64 with chronic mucocutaneous candidiasis, targeted panel sequencing was performed, relying on Agilent HaloPlex and Illumina MiSeq technologies. The targeted panel sequencing approach allowed us to identify 87 (32 novel and 55 previously described) mutations in 78 patients, which generated a diagnostic success rate of 28.4%. Specifically, mutations in DOCK8 (26 patients), STAT3 (21), STAT1 (15), CARD9 (6), AIRE (3), IL17RA (2), SPINK5 (3), ZNF341 (2), CARMIL2/RLTPR (1), IL12RB1 (1), and WAS (1) have been detected. The most common clinical findings in this cohort were elevated IgE (81.5%), eczema (71.7%), and eosinophilia (62.9%). Regarding infections, 54.7% of patients had a history of radiologically proven pneumonia, and 28.3% have had other serious infections. History of fungal infection was noted in 53% of cases and skin abscesses in 52.9%. Skeletal or dental abnormalities were observed in 46.2% of patients with a characteristic face being the most commonly reported feature (23.1%), followed by retained primary teeth in 18.9% of patients. Targeted panel sequencing provides a cost-effective first-line genetic screening method which allows for the identification of mutations also in patients with atypical clinical presentations and should be routinely implemented in referral centers.

     

Pembrolizumab for treatment of progressive multifocal leukoencephalopathy in primary immunodeficiency and/or hematologic malignancy: a case series of five patients

Journal of Neurology - Progressive multifocal leukoencephalopathy is a rare opportunistic infection of the brain by John Cunningham polyomavirus in immune-compromised patients. In cases where no...