Insights into the immunological description of cryoglobulins with regard to detection and characterization in Slovenian rheumatological patients

Ogrič, Manca (author), Švec, Tinka (author), Mrak Poljšak, Katjuša (author), Lakota, Katja (author), Podovšovnik, Eva (author), Kolopp-Sarda, Marie Nathalie (author), Hočevar, Alojzija (author), Čučnik, Saša (author)

The detection of cryoglobulins (CG) used to diagnose cryoglobulemic vasculitis requires strict adherence to protocol, with emphasis on the preanalytical part. Our main objectives were to introduce a more sensitive and specific protocol for the detection of CG and to characterize CG in Slovenian patients diagnosed with cryoglobulinemic vasculitis, other vasculitides, connective tissue diseases or non-rheumatic diseases examined at the Department of Rheumatology (University Medical Centre Ljubljana). Samples were routinely analyzed for the presence of CG with the protocol using the Folin-Ciocalteu reagent. In the newly introduced protocol, the type of CG was determined by immunofixation on visually observed positive samples, and the concentration of CG in the cryoprecipitate and rheumatoid factor (RF) activity were measured by nephelometry. RF, C3c and C4 were measured in the patients` serum, and decision tree analysis was performed using all results. The agreement between negative and positive results between the two protocols was 86%. Of the 258 patient samples tested, we found 56 patients (21.7%) with positive CG (37.5% - type II, 62.5% - type III). The RF activity was observed in 21.4% of CG positive subjects. The median concentration of type II CG was significantly higher than that of type III CG (67.4 mg/L vs. 45.0 mg/L, p = 0.037). Patients with type II had lower C4 concentrations and higher RF activity compared to patients with type III CG. In the decision tree, C4 was the strongest predictor of cryoglobulinemia in patients. With the newly implemented protocol, we were able to improve the detection and quantification of CG in the samples of our rheumatology patients and report the results to adequately support clinicians.

• Language: English
• Keywords: cryoglobulins, cryoglobulinemic vasculitis, rheumatoid factor activity, complement components, cryoglobulin detection, pre-analytical phase
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine; FFA - Faculty of Pharmacy
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: Str. 185–196
• Numbering: Vol. 72, iss. 2
• PID: 20.500.12556/RUL-155807
• UDC: 616-097
• ISSN on article: 0257-277X
• DOI: 10.1007/s12026-023-09434-9
• COBISS.SI-ID: 171557379
• Publication date in RUL: 19.04.2024

Record is a part of a journal

• Title: Immunologic research
• Shortened title: Immunol. res.
• Publisher: Springer Nature
• ISSN: 0257-277X
• COBISS.SI-ID: 514874649

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: krioglobulini, krioglobulinemični vaskulitis, aktivnost revmatoidnega faktorja, komponente komplementa, detekcija krioglobulina, predanalitična faza

Projects

• Funder: Other - Other funder or multiple funders
• Funding programme: University Medical Centre Ljubljana, Tertiary project

• Funder: ARRS - Slovenian Research Agency
• Project number: P3-0314
• Name: Sistemske avtoimunske bolezni