An observational study in Giant Cell Arteritis and Polymyalgia Rheumatica, sponsored by University of Bonn. Recruiting at 1 site in Germany. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-04-10.
Sponsored by University of Bonn · Observational
The GCAIO study is an innovative, multimodal research initiative designed to enhance the understanding, diagnosis, and management of giant cell arteritis (GCA) and frequently associated polymyalgia rheumatica (PMR). This longitudinal study aims to dissect the complex immunological landscape and systemic manifestations of these conditions through a combination of diagnostic imaging and detailed immunological profiling.
The study focuses on three primary objectives: (1) Identifying and analyzing cytokine profiles and immune cell phenotypes, employing techniques like flow cytometry, enzyme-linked immunosorbent assays (ELISA), and next-generation sequencing to predict disease activity and therapeutic responses. (2) Advancing diagnostic and monitoring capabilities through the application of novel and established imaging technologies, including MRI, optical coherence tomography angiography (OCTA), and ultrasound. These modalities aim to improve the detection of neuro-ophthalmological, cardiac, and aortic complications in GCA, potentially offering more precise monitoring and earlier diagnosis. (3) Enhancing the understanding of PMR within the context of GCA by exploring specific biomarkers and advanced imaging to refine diagnostic accuracy and treatment strategies, thus improving patient outcomes.
GCA is an immune-mediated vasculitis that affects medium and large-sized vessels, leading to vascular changes and occlusion due to severe vascular inflammation, neoangiogenesis, and remodeling. GCA has the potential to impact almost any organ. Despite advancements in understanding the pathophysiology and clinical manifestations of GCA, many aspects of the disease remain unexplored. The GCAIO study aims to fill these gaps using an integrative research approach to enhance the diagnosis, understanding, and management of GCA.
The GCAIO study cohort includes patients at their first diagnosis, throughout the disease, and during recurrent activity, facilitating a thorough longitudinal analysis of GCA. The research focuses on the complex immunological processes of the disease. Techniques such as flow cytometry (FACS), enzyme-linked immunosorbent assays (ELISA), and 3'-mRNA transcriptome analysis are employed to identify biomarkers that can assess GCA activity, track disease progression, and predict therapeutic responses, particularly for those unresponsive to interleukin (IL)-6 receptor (R) inhibitors. Additionally, the project is pioneering personalized treatment protocols tailored to individual immune profiles by developing a cell-based ex-vivo assay designed to forecast how patients will respond to different disease-modifying anti-rheumatic drugs (DMARDs).
Alongside the immunological research, the project emphasizes improving diagnostic and monitoring techniques through imaging technologies. Recent advancements have demonstrated that optimized diagnostics significantly enhance treatment outcomes for GCA patients. The planned prospective multimodal imaging aims to investigate potential neuro-ophthalmological, cardiac, and aortic manifestations during the course of GCA, enabling a detailed assessment of the involvement of various structures. Established imaging methods such as magnetic resonance imaging (MRI), optical coherence tomography angiography (OCTA), and vascular ultrasound are being extended into new areas to evaluate their diagnostic and prognostic merits. Furthermore, the investigators are exploring innovative diagnostic tools like transorbital ultrasound (TOS) and contrast-enhanced ultrasound (CEUS) for their potential as predictive biomarkers, facilitating earlier diagnosis and more precise disease monitoring. By correlating imaging findings with immunological data, our goal is to alter the way GCA is detected and monitored.
The inclusion of patients with PMR enhances our understanding of its pathophysiology, clinical manifestations, and its connection to often-associated GCA. The investigators are dedicated to developing new diagnostic criteria and exploring alternative therapeutic approaches for PMR maintenance therapy. By identifying alternative clinical, laboratory, or instrumental diagnostic methods to predict PMR, the investigators aim to set new diagnostic standards and deepen our understanding of its pathophysiology and immunological processes.
In summary, the goal of the GCAIO study is to make substantial contributions to the fields of GCA and PMR by developing innovative diagnostic and therapeutic strategies that improve treatment and quality of life for affected patients. The identification of specific biomarkers and the establishment of new diagnostic standards could lead to more precise diagnoses and optimized management of therapy, thereby enhancing patient care and reducing the risk of complications and therapy failures.
147 studies on the registry are indexed under Giant Cell Arteritis; 49 are open to participants now.
This study's planned enrollment of 100 is below the median of 128 across 78 observational studies indexed under Giant Cell Arteritis.
Browse Giant Cell Arteritis studies →University of Bonn is the lead sponsor of 39 studies on the registry; 20 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The GCAIO study focuses on patients with newly diagnosed GCA and PMR or those experiencing a flare-up. The primary sites for patient recruitment include the ophthalmological and rheumatological departments of the University Hospital of Bonn, Germany. Additional participants can be referred by local rheumatologists and primary care physicians. Healthy controls are recruited through the ophthalmological and rheumatological department of the University Hospital Bonn.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients diagnosed with GCA and/or PMR will be enrolled in this cohort. They will undergo a series of interventions including immunological profiling (cytokine profiling and immune cell phenotyping using flow cytometry, ELISA, 3'mRNA sequencing, high content analysis via a cell-based ex-vivo assay), and diagnostic imaging (MRI, OCTA including further ophthalmological assessment, vascular and transorbital ultrasound. Samples will be collected from patients at various stages of the disease (t=0, t=6, t=12, t=18 months, during flare-ups). Furthermore, TAB will be stained with a VAP-1 antibody to assess the expression and localization of VAP-1 in the arterial tissue.
Diagnostic Test: Aortic/ cardiac magnetic resonance imaging · Diagnostic Test: Vascular ultrasound · Diagnostic Test: Transorbital Ultrasound · Diagnostic Test: Contrast-Enhanced Ultrasound · Diagnostic Test: Optical coherence tomography angiography · Diagnostic Test: Fluorescein angiography · Diagnostic Test: Fundus autofluorescence · Diagnostic Test: Color Fundus Photography · Diagnostic Test: Cell-based ex-vivo assay with high-content analysis · Diagnostic Test: 3'mRNA sequencing · Diagnostic Test: Enzyme-linked immunosorbent assay · Diagnostic Test: Flow cytometry · Diagnostic Test: Laboratory assessment: · Diagnostic Test: Immunohistochemistry of Temporal Artery Biopsies · Diagnostic Test: Functional assessment questionnaires
Age- and gender-matched healthy subjects will serve as the control group to provide baseline data for comparative purposes. This group will not receive any treatment related to GCA or PMR but undergoes similar diagnostic procedures for baseline measurements, including imaging and immunological assessments.
Diagnostic Test: Aortic/ cardiac magnetic resonance imaging · Diagnostic Test: Vascular ultrasound · Diagnostic Test: Transorbital Ultrasound · Diagnostic Test: Contrast-Enhanced Ultrasound · Diagnostic Test: Optical coherence tomography angiography · Diagnostic Test: Fluorescein angiography · Diagnostic Test: Fundus autofluorescence · Diagnostic Test: Color Fundus Photography · Diagnostic Test: Cell-based ex-vivo assay with high-content analysis · Diagnostic Test: 3'mRNA sequencing · Diagnostic Test: Enzyme-linked immunosorbent assay · Diagnostic Test: Flow cytometry · Diagnostic Test: Laboratory assessment: · Diagnostic Test: Functional assessment questionnaires
MRI scans will be performed to detect systemic vascular involvement in GCA patients, aiming to provide detailed images of affected tissues.
Also known as: Aortic/ cardiac MRI
Vascular ultrasound will be employed to examine the temporal and axillary arteries in GCA patients, searching for signs indicative of active inflammation.
Transorbital ultrasound will be employed to assess the ophthalmic artery and its branches in GCA patients to detect intracranial inflammatory processes that could lead to severe neuro-ophthalmological complications.
Also known as: TOS
Contrast-Enhanced Ultrasound (CEUS) is utilized to evaluate aortic involvement in GCA patients as an alternative, bed-side, realtime, radiation-free diagnostic tool.
Also known as: CEUS
OCTA will be used to assess vascular changes in the retina of GCA patients, providing detailed imaging that can help detect early signs of ocular involvement and identify risk factors of anterior ischemic optic neuropathy.
Also known as: OCTA
Fluorescein angiography will be performed to evaluate blood circulation and highlight any blockages in the blood vessels of the retina in patients with GCA to detect vascular abnormalities that may lead to severe vision complications.
This imaging technique will be used to observe the health of the retina and detect any changes in GCA patients that could suggest disease activity, particularly useful for assessing the integrity of the retinal pigment epithelium.
Color fundus photography will be used to document the appearance of the optic disc and retinal vasculature in GCA patients, aiding in the long-term monitoring of ocular changes and the effects of therapeutic interventions.
This assay predicts individual patient responses to different DMARDs by analyzing patient-derived PBMCs for specific immune responses to therapeutic agents.
Also known as: GCAIO-essay
3'mRNA sequencing analyzes gene expression profiles related to the immune response in PMR/GCA patients, aiding in understanding the genetic underpinnings of inflammation and vascular remodeling.
Used to measure cytokine levels in the serum and plasma of PMR/GCA patients, ELISA aids in profiling inflammatory markers that are indicative of disease activity and response to treatment.
Also known as: ELISA
Employed to analyze immune cell phenotypes in patients with PMR and/or GCA, this test helps identify various immune cell subsets and their activation states, which are critical for understanding disease mechanisms and guiding therapy.
Also known as: FACS
Serum Chemistry (nt-proBNP, troponin T, CRP, ESR, blood count)
Immunohistochemistry staining of TAB to assess local expression of endothelial adhesion molecules in acute inflammation.
Also known as: IHC TAB
The following questionnaires will be applied: FACIT-Fatigue, SF-36, BAS, Birmingham Vasculitis Activity Score, Montreal Cognitive Assessment, Mini-Mental Status Examination. These questionnaires collectively provide a comprehensive evaluation of the functional status, quality of life, and mental health of patients with GCA and PMR.
Number of Participants with Detected Neuro-Ophthalmological Manifestations
Use of OCTA, TOS, and additional ocular imaging to assess and monitor ocular and cranial vascular abnormalities indicative of GCA. Unit of Measure: Number of participants.
Time frame: At baseline, 3 months, 6 months, 9 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Number of Participants with Detected Cardiac and Aortic Involvement
Detection and monitoring of inflammatory changes and structural anomalies in the cardiac and aortic regions using MRI and CEUS. Unit of Measure: Number of participants.
Time frame: At baseline, 6 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Changes in Immune Cell Phenotype
Identification and quantification of immune cell types including changes over time using FACS. Unit of Measure: Changes in levels (percentages).
Time frame: At baseline, 6 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Changes in Cytokine Profiles
Identification and quantification of cytokines including changes over time using 3'-mRNA transcriptome analysis. Unit of Measure: Changes in levels (pg/mL).
Time frame: At baseline, 6 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Levels of Siglec-9 in Blood
Measurement of Siglec-9 levels on immune cells including changes over time using FACS. Correlation with clinical assessments of disease activity and imaging findings. Unit of Measure: Changes in levels (percentages).
Time frame: At baseline, 6 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Levels of sVAP-1 in Blood
Measurement of sVAP-1 levels in blood via ELISA including changes over time. Correlation with clinical assessments of disease activity and imaging findings. Unit of Measure: Changes in levels (ng/mL).
Time frame: At baseline, 6 months, 12 months, 18 months, and during flare-ups (assessed up to 18 months after diagnosis).
Plan to share: Undecided — Data are available upon reasonable request from the corresponding investigator.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Bonn