Cryoglobulins, cryofibrinogens, and cold agglutinins in cold urticaria : literature review, retrospective patient analysis, and observational study in 49 patientsKatharina Ginter
, Dalia Melina Ahsan
, Mojca Bizjak
, Karoline Krause
, Marcus Maurer
, Sabine Altrichter
, Dorothea Terhorst
, 2021, original scientific article
Abstract: Introduction: Cryoproteins, such as cryoglobulins, cryofibrinogens and cold agglutinins, precipitate at low temperatures or agglutinate erythrocytes and dissolve again when warmed. Their pathogenetic and diagnostic importance in cold urticaria (ColdU) is unclear. In this study, we aimed to characterize the prevalence of cryoproteins in patients with ColdU. Methods: We conducted 3 analyses: i) a systematic review and meta-analysis of published data using an adapted version of the Johanna Briggs Institute's critical appraisal tool for case series, ii) a retrospective analysis of 293 ColdU patients treated at our Urticaria Center of Reference and Excellence (UCARE) from 2014 to 2019, and iii) a prospective observational study, from July 2019 to July 2020, with 49 ColdU patients as defined by the EAACI/GA2LEN/EDF/UNEV consensus recommendations. Results: Our systematic review identified 14 relevant studies with a total of 1151 ColdU patients. The meta-analyses showed that 3.0% (19/628), 1.1% (4/357) and 0.7% (2/283) of patients had elevated levels of cryoglobulins, cryofibrinogens, and cold agglutinins, respectively. Our retrospective analyses showed that cryoproteins were assessed in 4.1% (12/293) of ColdU patients. None of nine ColdU patients had cryoglobulins, and one of 5 had cold agglutinins. In our prospective study, none of our patients had detectable cryoglobulins (0/48) or cryofibrinogens (0/48), but 4.3% (2/46) of patients had cold agglutinins (without any known underlying autoimmune or hematological disorder). Conclusion: Our investigation suggests that only very few ColdU patients exhibit cryoproteins and that the pathogenesis of ColdU is driven by other mechanisms, which remain to be identified and characterized in detail.
Keywords: urticaria, review, observational study, retrospective studies, cold urticaria, cryoglobulins, cryofibrinogens, cold agglutinins, retrospective analysis
Published in DiRROS: 28.05.2021; Views: 654; Downloads: 493
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