Hypocomplementemia in Reye Syndrome: Relationship to Disease Stage, Circulating Immune Complexes, and C3b Amplification Loop Protein Synthesis

摘要

Summary: Measurement of C1q, C2, C4, C5, C6, factor B, properdin, β1H, and C3bINA were made in acute sera from 31 patients with Reye syndrome. Abnormalities were found in 18 patients. The magnitude of the complement component depression correlated with disease severity. Sera from patients with stage IV illness had significantly lower complement levels than did sera from patients with stage 1 (P P P < 0.05) disease. Circulating immune complex measurements were performed on all 31 acute sera and were present in six (19%). However, from the results of the present study, it would appear that in the majority of the patients circulating immune complexes are not the cause of the lowered levels of, at least, C3 and factor B. Rather, these low levels could be explained as secondary to reductions in the levels of the C3b amplification loop control proteins β1H and C3bINA.Speculation: In Reye syndrome, the exact mechanism responsible for reduction of many complement proteins including β1H and C3bINA remains obscure. Although circulating immune complexes are present transiently, the observed low levels of at least C3 and factor B are best explained by hyposynthesis of their control proteins, β1H and C3bINA. Although the mechanism of this hyposynthesis is unknown, the absence of a pattern of complement depression typical of severe liver disease suggests a generalized cellular disturbance resulting in impaired complement protein synthesis.