Screening for type II hereditary angioedema—the 'poor man’s c1-inhibitor function'

Autor: Ankur Kumar Jindal, MD, DM, Valerie Chiang, MBBS, Prabal Barman, MD, Archan Sil, MD, Sanchi Chawla, MSc, Elaine Y.L. Au, MBBS, FRCPA, Amit Rawat, MD, Philip H. Li, MD, FRCP
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Journal of Allergy and Clinical Immunology: Global, Vol 3, Iss 1, Pp 100179- (2024)
Druh dokumentu: article
ISSN: 2772-8293
DOI: 10.1016/j.jacig.2023.100179
Popis: Background: Hereditary angioedema (HAE) is a rare genetic disease. Patients with type II HAE have normal or elevated C1-inhibitor (C1-INH) levels but C1-INH protein is dysfunctional. C1-INH function requires careful sample handling and technical expertise and may account for the lack of diagnosed patients with type II HAE in resource-limited countries. Objective: We sought to assess the diagnostic performance of elevated C1-INH levels in diagnosing type II HAE. Methods: All patients with confirmed type II HAE in Hong Kong and India were analyzed. Diagnosis was confirmed by persistent low C1-INH function and/or pathogenic SERPING1 gene mutations. Their C1-INH levels were compared with those of matched controls. Results: A total of 31 (14 Chinese, 17 Indian) patients with type II HAE and 31 matched controls were analyzed. Overall, 77.4% (24/31) of patients with type II HAE had elevated C1-INH levels compared with 38.7% (12 of 31) of controls (odds ratio, 2.00; 95% CI, 1.34-2.98; P = .017). C1-INH levels in patients with type II HAE were significantly higher than in controls (52.2 ± 20.0 mg/dL vs 29.1 ±3.6 mg/dL; P < .001). Findings were consistent when C1-INH values in the Chinese and Indian subgroups were analyzed separately. Receiver-operating characteristic curve demonstrated excellent performance for elevated C1-INH levels to diagnose patients with type II HAE with an area under the curve of 0.953 (95% CI, 0.941-0.992; P < .001). Positive and negative predictive values of both a low C4 and an elevated C1-INH level for patients with type II HAE were 100% and 82.9%, respectively. Conclusions: Low C4 and elevated C1-INH levels may be considered as a screening tool for type II HAE, especially in countries where C1-INH function testing is not readily available.
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