Establishment and clinical application of an assay for the activity of circulating immune complexes using human O-erythrocytes as an indicator system.
Clin Chim Acta 2022;
533:156-167. [PMID:
35787990 DOI:
10.1016/j.cca.2022.06.023]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/20/2022] [Accepted: 06/22/2022] [Indexed: 11/23/2022]
Abstract
OBJECTIVE
To develop a suitable clinical laboratory assay for detecting the activity of circulating immune complexes (CICs) that activate complement (ACIC).
METHODS
CICs measured in serum were initially used to activate complement, and the remaining complement was activated through sensitized human O-erythrocytes. ACIC was quantified by the degree of hemolysis. Each serum sample was tested for ten consecutive days to determine its stability. Reference ranges are suggested. ACIC was measured in both healthy individuals and patients with autoimmune diseases as well.
RESULTS
The OD values of the hemolysis degree index were inversely proportional to ACIC (r=0.986, P=0.002). A pooled serum was used to eliminate interference and optimize the experiment. The hemolysis degree (HD) was used to indicate the detection result. HD = (detection value OD/negative value OD)*100. The inter-batch results showed good stability with a CV of 6.5%. HD differences between males and females were significant (P=0.015) while the normal distribution for both genders was conformed. The HD recommended reference range for men is 56-88 while for women is 51-86. Serum HD of healthy subjects and autoimmune disease patients showed a significant difference (P=0.001). Autoimmune disease patients have higher HD which was a result of having stronger ACIC.
CONCLUSION
The ACIC assay while utilizing human O-erythrocytes as an indicator system is sensitive and accurate, and has potential in clinical applications.
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