Biomedical subjects

Aman Sharma

Publications and source records attributed to Aman Sharma.

2 recordsLinked to original sources

PubMed2026

The utility of 18F-fluorodeoxyglucose PET/computed tomography in relapsing polychondritis: a systematic review and meta-analysis.

Relapsing polychondritis is a rare chronic autoimmune inflammation of the cartilage associated with life-threatening respiratory complications. Currently, no clear role of imaging modalities such as 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) is defined in the literature. This systematic review and meta-analysis provide current evidence on the PET-positivity rate and utility in relapsing polychondritis. Prospective or retrospective studies with more than five patients of suspected relapsing polychondritis who underwent 18F-FDG PET/CT during their management and reported a PET-positivity rate were included. Low-sample-size studies describing chondritis due to other aetiologies or utilizing PET-based radiopharmaceuticals other than FDG were excluded. A systematic search using relevant keywords was conducted across four databases (PubMed, Embase, Scopus and Web of Science) to include studies up to 25 April 2025. The Joanna Briggs Institute critical appraisal tools were used for risk-of-bias analysis. Data were analysed using the R software package (v4.3.1; 2023). Out of 962 articles, three with a total of 97 patients were included. With a pooled PET-positivity rate of 94% [95% confidence interval (CI): 73-99%, I2 = 0%, P = 0.76] and a pooled baseline SUVmax of 4.0 (95% CI: 3.5-4.6, I2 = 32%, P = 0.23), 18F-FDG PET identified asymptomatic cartilage involvement in more than 25% patients and PET parameters correlated well with inflammatory markers. It had a higher positivity rate for inaccessible sites, such as peripheral airways, and was crucial in treatment monitoring. The pooled PET-positivity rate of 18F-FDG PET in relapsing polychondritis is high but requires prospective large-sample-size studies to explore the diagnostic accuracy and prognostic implications of 18F-FDG PET in relapsing polychondritis.

Polychondritis, Relapsing↗

PubMed2025

Diagnostic Implications and Correlates of Plasma Adenosine Deaminase 2 Activity and ADA2 Variants.

OBJECTIVE: Deficiency of adenosine deaminase 2 (DADA2) is a monogenic autoinflammatory disease manifested as polyarteritis nodosa, stroke, and bone marrow failure. Leveraging an international cohort of 200 DADA2 cases, we aimed to characterize the diagnostic utility of a plasma ADA2 enzyme activity assay and understand the implications of residual ADA2 activity. METHODS: Data were collected from individuals who underwent ADA2 testing from 2018 to 2025. Plasma ADA2 activity was determined using an established spectrophotometric assay. ADA2 variants were analyzed in transfected cells by enzyme assay and western blotting. RESULTS: We determined that plasma ADA2 activity is 99.0% and 96.0% sensitive and 99.7% and 98.8% specific in distinguishing genetically confirmed DADA2 cases from controls and carriers, respectively. Eighteen individuals with DADA2 (9%) possessed detectable ADA2 activity, including several cases with levels seen in carriers. Residual ADA2 activity was associated with the vasculitis/inflammatory phenotype but not with disease severity. Genotype analysis revealed that 14 of 18 cases with residual plasma activity possessed at least one hypomorphic missense variant with greater than 20% residual ADA2 function when overexpressed in 293T cells, often occurring in trans with a more deleterious variant. In vitro analysis revealed that missense ADA2 variants exert variable dominant-negative effects by forming large intracellular protein aggregates via disulfide bond formation at a cysteine residue (Cys408). CONCLUSION: We confirmed the utility of plasma ADA2 activity as a diagnostic assay and showed that the inflammatory phenotype of DADA2 occurred in cases with residual activity. In vitro findings illustrate potential interactions of ADA2 variants to synergistically disrupt protein function.

Humans↗