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Immune complexes in epidemic (type A) hepatitis. Detection by three methods using laser nephelometry
Insights
Circulating immune complexes are present in children with epidemic hepatitis (Type A). Their complement-fixing capacity decreases as the disease progresses, but remains high in asymptomatic contacts.
Area of Science:
- Immunology
- Hepatology
- Virology
Background:
- Hepatitis A is a significant public health concern, particularly in pediatric populations.
- The role of immune complexes in the pathogenesis and diagnosis of Hepatitis A requires further elucidation.
Purpose of the Study:
- To investigate the presence and characteristics of circulating immune complexes (CICs) in children with acute epidemic Hepatitis A.
- To assess the correlation between CICs and disease progression, including incubation and convalescent phases.
- To evaluate CICs in asymptomatic contacts of Hepatitis A patients.
Main Methods:
- Laser ray nephelometry was used to detect CICs in serum samples.
- Complement fixation capacity of CICs was assessed.
- Antivirus A antibody activity and C4 levels in precipitates were correlated to verify CIC specificity.
Main Results:
- Circulating immune complexes were detected in 79% of Hepatitis A patients during the acute phase.
- CICs were also found in 80% during the incubation period, with diminishing complement fixation capacity as the disease evolved.
- Asymptomatic contacts showed a higher prevalence (94%) and greater complement fixation capacity of CICs.
Conclusions:
- Circulating immune complexes are a significant finding in acute epidemic Hepatitis A.
- The dynamics of CICs, particularly their complement-fixing ability, may offer insights into disease progression and immune response.
- Elevated CICs with high complement fixation in asymptomatic contacts warrant further investigation regarding their predictive value.
Abstract:
Thirty-eight children with acute epidemic hepatitis (Type A) and 22 children in "contact" with the disease, 5 of whom subsequently developed hepatitis, were studied. Three technics based on laser ray nephelometry were employed to investigate the presence of circulating immune complexes. Our results indicated that circulating immune complexes are present in the serum during the course of epidemic hepatitis. These were demonstrated in 79% of the patients. The capacity to fix complement diminishes as the disease evolves toward the convalescent phase. We also detected a similar percentage of immune complexes (80%) in the patients during the incubation period. In the subjects in "contact" with the disease who subsequently did not develop hepatitis, the immune complexes were shown to have a greater capacity to fix complement, and the percentage of immune complexes present was higher (94%). The specificity of the immune complexes was verified by correlating the antivirus A antibody activity with the percentage of C4 in the precipitates obtained by polyethylene glycol (3.5%).