Measurement of Eosinophil Kinetics In Vivo.

Radiolabeled leukocyte scans are used in nuclear medicine to detect sites of infection and inflammation. We have previously demonstrated the use of clinical grade immunomagnetic beads to isolate autologous eosinophils and image their distribution in healthy volunteers. Here we describe the use of radiolabeled eosinophils coupled to single-photon emission computed tomography (SPECT) to quantify eosinophil uptake in the lungs of healthy volunteers, patients with asthma, and patients with focal eosinophilic inflammation.

Lesson of the month: novel method to quantify neutrophil uptake in early lung cancer using SPECT-CT.

Neutrophils play an important role in the lung tumour microenvironment. We hypothesised that radiolabelled neutrophils coupled to single-photon emission CT (SPECT) may non-invasively quantify neutrophil uptake in tumours from patients with non-small cell lung cancer. We demonstrated increased uptake of radiolabelled neutrophils from the blood into tumours compared with non-specific uptake using radiolabelled transferrin.

Radiolabelled leucocytes in human pulmonary disease.

Introduction: Radionuclides for leucocyte kinetic studies have progressed from non-gamma emitting cell-labelling radionuclides through gamma emitting nuclides that allow imaging of leucocyte kinetics, to the next goal of positron emission tomography (PET).

Sources Of Data: Mostly the authors' own studies, following on from studies of the early pioneers.

Areas Of Controversy: From early imaging studies, it appeared that the majority of the marginated granulocyte pool was located in the lungs.

Effects of tocilizumab on neutrophil function and kinetics.

Background: Decreases in circulating neutrophils (polymorphonuclear leucocytes, PMNs) have been reported in patients treated with the anti-interleukin-6 receptor (IL-6R) antibody tocilizumab (TCZ); the mechanism for this is unclear. We hypothesize that TCZ reduces circulating neutrophils by affecting margination and/or bone marrow trafficking without affecting neutrophil function or apoptosis.

Materials And Methods: Eighteen healthy subjects were randomized to single intravenous dose of TCZ 8 mg/kg (n = 12) or placebo (n = 6) on day 0.

Clinical application of autologous technetium-99m-labelled eosinophils to detect focal eosinophilic inflammation in the lung.

The detection of focal eosinophilic inflammation by non-invasive means may aid the diagnosis and follow-up of a variety of pulmonary pathologies. All current methods of detection involve invasive sampling, which may be contraindicated or too high-risk to be performed safely. The use of injected autologous technetium-99m (Tc-99m)-labelled eosinophils coupled to single-photon emission computed tomography (SPECT) has been demonstrated to localise eosinophilic inflammation in the lungs of a patient with antineutrophil cytoplasmic antibody-positive vasculitis.

Measurement of eosinophil kinetics in healthy volunteers.

Radiolabelled leukocyte scans are widely used in nuclear medicine to locate sites of infection and inflammation. Radiolabelling of leukocyte subpopulations can also yield valuable information on cell trafficking and kinetics in vivo, but care must be taken to minimize inadvertent cell activation ex vivo. Here, we describe the use of autologous indium(111)-labelled eosinophils to measure eosinophil intravascular life-span and monitor their distribution and fate using gamma camera imaging in healthy non-atopic individuals.

Biomarkers of eosinophilic inflammation in asthma.

Eosinophils are mediators of allergic inflammation and are implicated in the pathogenesis of numerous conditions including asthma, parasitic infections, neoplasms, hyper-eosinophilic syndromes, vasculitic disorders, and organ-specific conditions. Assessing eosinophilic inflammation is therefore important in establishing a diagnosis, in monitoring and assessing response to treatment, and in testing novel therapeutics. Clinical markers of atopy and eosinophilic inflammation include indirect tests such as lung function, exhaled breath condensate analysis, fractional exhaled nitric oxide, serum immunoglobulin E levels and serum periostin.

Use of 111-Indium-labeled autologous eosinophils to establish the in vivo kinetics of human eosinophils in healthy subjects.

Eosinophils are the major cellular effectors of allergic inflammation and represent an important therapeutic target. Although the genesis and activation of eosinophils have been extensively explored, little is known about their intravascular kinetics or physiological fate. This study was designed to determine the intravascular life span of eosinophils, their partitioning between circulating and marginated pools, and sites of disposal in healthy persons.