Background: Deficiency of adenosine deaminase 2 (DADA2) is an autoinflammatory disease caused by mutations in the adenosine deaminase 2 (ADA2) gene. Loss of functional ADA2 activity results in vasculitis syndrome, immunodeficiency, and hematopoietic disorders. Early diagnosis is required for effective treatment.
Methods: We developed a dried blood spot (DBS)-based ADA2 activity colorimetric assay. Heparin-affinity purification was used during sample preparation to improve the assay more efficiently. The stability of ADA2 during DBS storage and ADA2 activity of DADA2 patients and healthy controls were examined.
Results: Active ADA2 was extracted from the DBS of healthy controls. ADA2 activity in DBS, stored either frozen or refrigerated, remained stable for at least 90 days. A significant difference in ADA2 activity was observed between healthy controls and patients. No ADA2 activity was detected in DBS from patients.
Conclusions: Our new DBS ADA2 activity assay is experimentally simple, highly adaptable, and requires no special equipment except for a microplate reader. A low background was achieved with heparin-affinity purification. The method differentiates clearly between healthy controls and patients. ADA2 activity can be reliably measured in DBS, providing an opportunity to diagnose DADA2 at an early stage.
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http://dx.doi.org/10.1016/j.ab.2021.114292 | DOI Listing |
Front Med
January 2025
International Center for Aging and Cancer (ICAC), Hainan Medical University, Haikou, 571199, China.
Adenosine, a critical molecule regulating cellular function both inside and outside cells, is controlled by two human adenosine deaminases: ADA1 and ADA2. While ADA1 primarily resides in the cytoplasm, ADA2 can be transported to lysosomes within cells or secreted outside the cell. Patients with ADA2 deficiency (DADA2) often suffer from systemic vasculitis due to elevated levels of TNF-α in their blood.
View Article and Find Full Text PDFmedRxiv
December 2024
Laboratory Inborn errors of Immunity, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium.
Human ADA2 deficiency (DADA2) is an inborn error of immunity with a broad clinical phenotype which encompasses vasculopathy including livedo racemosa and lacunar strokes, as well as hemato-immunological features. Diagnosis is based on the combination of decreased serum ADA2 activity and the identification of biallelic deleterious alleles in the gene. DADA2 carriers harbor a single pathogenic variant in and are mostly considered healthy and asymptomatic.
View Article and Find Full Text PDFBiology (Basel)
October 2024
Interdisciplinary Laboratory of Clinical Analysis (Interlab-UMU), Veterinary School, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, Campus de Espinardo s/n, Espinardo, 30100 Murcia, Spain.
Colostrum is a mammary secretion released from the time of farrowing to 36 h post-farrowing. After this time and during all the rest of lactation, the mammary secretion is considered milk. The objectives of this study were: (1) to perform an analytical validation in the colostrum and milk of sows of assays for four analytes related to immunity: total ADA (tADA) and its isoenzymes (ADA1 and ADA2), myeloperoxidase (Mpx), calprotectin, and calgranulin, and two analytes related to welfare: cortisol and alpha-amylase.
View Article and Find Full Text PDFCell Rep
November 2024
Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany; Department of Rheumatology and Clinical Immunology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany; RESIST - Cluster of Excellence 2155, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. Electronic address:
Although adenosine deaminase 2 (ADA2) is considered an extracellular ADA, evidence questions the physiological relevance of this activity. Our study reveals that ADA2 localizes within the lysosomes, where it is targeted through modifications of its glycan structures. We show that ADA2 interacts with DNA molecules, altering their sequences by converting deoxyadenosine (dA) to deoxyinosine (dI).
View Article and Find Full Text PDFFront Immunol
October 2024
Precision Vaccines Program, Department of Pediatrics, Boston Children's Hospital, Boston, MA, United States.
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