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[Modification of complement factors and their inhibitors during meningococcal sepsis (author's transl)]
Insights
Meningococcal sepsis significantly depletes complement components, particularly C3 and C5, especially in patients with disseminated intravascular coagulation (DIC). These levels remain low 24 hours later, indicating severe complement activation.
Area of Science:
- Immunology
- Pediatric Infectious Diseases
Context:
- Meningococcal sepsis is a severe infection with high mortality.
- Complement system activation plays a critical role in sepsis pathogenesis.
- Disseminated intravascular coagulation (DIC) is a common complication of meningococcal sepsis.
Purpose:
- To investigate the levels of various complement components and seric immunocomplexes in children with meningococcal sepsis.
- To compare complement profiles between patients with and without DIC.
- To assess changes in complement components over 24 hours.
Summary:
- Complement components (C'1s, C'3, C'4, C'5, C'8, C'9) and inhibitors were measured in 43 children with meningococcal sepsis, categorized into Group I (with DIC, n=28) and Group II (without DIC, n=15).
- Group I showed significantly decreased complement levels, especially C'3 and C'5, which further lowered at 24 hours. Group II had normal levels except for C'5. Catabolic products of C'3 and C'3 activation products were more frequent in Group I.
- Seric immunocomplexes (PEG precipitation) were detected in both groups, with IgG, IgM, C'3, and C'4 found more frequently in sepsis without DIC and at 24 hours. C'1 and C'3b inhibitors decreased in Group I, suggesting enhanced complement activation.
Impact:
- Findings highlight the profound complement consumption in severe meningococcal sepsis with DIC.
- Demonstrates the utility of monitoring complement components as biomarkers for sepsis severity and prognosis.
- Suggests a role for complement dysregulation in the progression of meningococcal sepsis and associated DIC.
Abstract:
Various complement components (C'1s, C'3, C'4, C'5, C'8, C'9, C'3 act., C'1 inh., C'3b inact.) and seric immunocomplexes (by polyethylene glycol, PEG) were evaluated in 43 children with meningococcal sepsis. 28 patients had disseminated intravascular coagulation (DIC), group I, and 15 did not show it, group II; 14 patients died in group I and none of group II. In 21 cases studies were repeated 24 hours later. In group I all complement components were decreased, specially C'3 (x: 67 mg./100 ml., p < 0.01) and C'5 (x: 8 mg./100 ml., p < 0.01) and they were lower 24 h. later. Results of group II were normal, except a decrease of C'5. Catabolic products of C'3 were founded in 11/14 cases of group I and two/nine of group II and products of C'3 act. in four/14 and one/10. PEG precipitation was positive in 10/14 cases of group I and 10/12 of group II and IgG, IgM, C'3 and C'4 were found in precipitations. This complement components were more frequently present in sepsis without DIC and after 24 h. of evolution. C'1 and C'3b inhibitors decreased after evolution in group I and by contrast increased in group II. This fall enhances complement activation.