AGE and CALLY Index in Familial Mediterranean Fever

February 23, 2026 updated by: Altuğ Güner, Bursa City Hospital

Association Between Skin Autofluorescence-Measured Advanced Glycation End Products and the CALLY Index in Patients With Familial Mediterranean Fever: A Cross-Sectional Controlled Study

Familial Mediterranean Fever (FMF) is an autoinflammatory disease characterized by recurrent inflammatory attacks and persistent low-grade inflammation. Even during attack-free periods, subclinical inflammation may continue and contribute to long-term complications.

Advanced glycation end products (AGEs) are molecules that accumulate under chronic inflammatory and oxidative stress conditions. AGEs can be measured non-invasively using skin autofluorescence (SAF). The C-reactive protein-albumin-lymphocyte (CALLY) index is a composite marker derived from routine laboratory parameters and reflects systemic inflammation and nutritional status.

This observational cross-sectional study aims to evaluate the association between skin autofluorescence-measured AGE levels and the CALLY index in patients with FMF. The study will also compare AGE levels between FMF patients and age- and sex-matched healthy controls.

The study does not involve any intervention, treatment assignment, or randomization. All laboratory parameters will be obtained from routine clinical evaluations, and AGE measurement will be performed using a non-invasive device.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disorder characterized by recurrent episodes of fever and serositis. Although clinical attacks are intermittent, persistent subclinical inflammation may continue between attacks and contribute to long-term complications such as amyloidosis and increased cardiovascular risk.

Advanced glycation end products (AGEs) are bioactive molecules formed through non-enzymatic glycation and oxidation of proteins and lipids. AGEs accumulate under chronic inflammatory and oxidative stress conditions and may perpetuate inflammation via activation of the AGE-RAGE signaling pathway. Increased AGE burden has been associated with chronic inflammatory and metabolic disorders.

Skin autofluorescence (SAF) is a validated, non-invasive method for assessing tissue AGE accumulation using the AGE Reader™ device (DiagnOptics Technologies B.V.). This method provides a rapid and painless measurement without requiring blood sampling.

The C-reactive protein-albumin-lymphocyte (CALLY) index is calculated using CRP, albumin, and lymphocyte count and reflects systemic inflammation and nutritional status. It has been investigated as a prognostic marker in several inflammatory conditions.

This single-center, observational, cross-sectional case-control study aims to:

Evaluate the association between SAF-measured AGE levels and the CALLY index in FMF patients.

Compare AGE levels between FMF patients and age- and sex-matched healthy controls.

Assess associations between AGE levels and inflammatory parameters (CRP, ESR, serum amyloid A).

Explore relationships between AGE levels and metabolic parameters (HbA1c, lipid profile) and renal involvement markers.

Eligible FMF patients aged 18-65 years who meet the Tel-Hashomer diagnostic criteria will be included. Healthy volunteers matched for age and sex will serve as controls. No treatment assignment, intervention, or randomization will be performed.

All laboratory parameters will be derived from routine clinical assessments. AGE measurements will be performed once at baseline using the skin autofluorescence method. The study poses minimal risk, as it is non-interventional and involves only non-invasive measurement procedures.

Study Type

Observational

Enrollment (Estimated)

150

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Adult patients diagnosed with Familial Mediterranean Fever and age- and sex-matched healthy volunteers recruited from a single tertiary care center.

Description

Inclusion Criteria:

For FMF Patients:

  • Age between 18 and 65 years
  • Diagnosis of Familial Mediterranean Fever according to Tel-Hashomer criteria
  • At least 6 months of clinical follow-up
  • Available routine laboratory data (CRP, albumin, lymphocyte count)
  • Not in an acute FMF attack at the time of assessment
  • Ability to provide written informed consent

For Healthy Controls:

  • Age between 18 and 65 years
  • No history of chronic inflammatory, autoimmune, metabolic, or renal disease
  • Ability to provide written informed consent

Exclusion Criteria :

  • Diagnosis of diabetes mellitus
  • Chronic kidney disease stage 3 or higher
  • Active infection
  • Malignancy within the past 5 years
  • Dermatologic condition affecting the forearm measurement site
  • Use of high-dose antioxidant or vitamin supplementation within the past 3 months
  • Any condition that, in the opinion of the investigators, may interfere with study participation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Familial Mediterranean Fever Patients
Patients aged 18-65 years diagnosed with Familial Mediterranean Fever according to Tel-Hashomer criteria. Participants will undergo a single non-invasive skin autofluorescence measurement for assessment of advanced glycation end products (AGE). Routine laboratory parameters will be used to calculate the CALLY index. No intervention or treatment assignment will be performed.
Device: Skin Autofluorescence Measurement
Non-invasive measurement of advanced glycation end products (AGE) using skin autofluorescence technology. The assessment is performed once at baseline using a validated optical device applied to the volar side of the forearm. The procedure is painless, requires no blood sampling, and does not involve any therapeutic intervention or treatment assignment.
Other Names:
  • AGE Reader
Healthy Controls
Age- and sex-matched healthy volunteers without chronic inflammatory or metabolic disease. Participants will undergo a single non-invasive skin autofluorescence measurement for assessment of advanced glycation end products (AGE). No intervention or treatment assignment will be performed.
Device: Skin Autofluorescence Measurement
Non-invasive measurement of advanced glycation end products (AGE) using skin autofluorescence technology. The assessment is performed once at baseline using a validated optical device applied to the volar side of the forearm. The procedure is painless, requires no blood sampling, and does not involve any therapeutic intervention or treatment assignment.
Other Names:
  • AGE Reader

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlation Between Skin Autofluorescence-Measured AGE Levels and CALLY Index
Time Frame: Baseline
Assessment of the association between advanced glycation end products (AGE) levels measured by skin autofluorescence and the C-reactive protein-albumin-lymphocyte (CALLY) index in patients with Familial Mediterranean Fever.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Comparison of AGE Levels Between FMF Patients and Healthy Controls
Time Frame: Baseline
Comparison of skin autofluorescence-measured advanced glycation end product (AGE) levels between Familial Mediterranean Fever patients and age- and sex-matched healthy controls.
Baseline
Association Between AGE Levels and Inflammatory Parameters
Time Frame: Baseline
Evaluation of the relationship between AGE levels and inflammatory markers including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and serum amyloid A (SAA).
Baseline
Association Between AGE Levels and Metabolic Parameters
Time Frame: Baseline
Assessment of the association between AGE levels and metabolic markers including HbA1c and lipid profile (total cholesterol, HDL, LDL).
Baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bursa City Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

February 1, 2026

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

February 23, 2026

First Submitted That Met QC Criteria

February 23, 2026

First Posted (Actual)

February 27, 2026

Study Record Updates

Last Update Posted (Actual)

February 27, 2026

Last Update Submitted That Met QC Criteria

February 23, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026rheumotology-3

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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