Hepatitis C Test: Serum HCV Antibodies

Antibodies to HCV in serum are normal.

Viral hepatitis C ( Hepatitis C ) is a viral disease that most often occurs in the form of posttransfusion hepatitis with a predominance of jaundice and light forms and is prone to chronizing the process. The causative agent is the hepatitis C virus (HCV), contains RNA. Based on the phylogenetic analysis, 6 HCV genotypes and more than 80 subtypes have been isolated. Genotype 1 is the most common genotype in the whole world (40-80% of isolates). Genotype 1a is a predominant subtype for the United States, and 1b predominates in Western Europe and South Asia. Genotype 2 is common throughout the world, but occurs at a lower frequency than genotype 1 (10-40%). Genotype 3 is typical for India, Pakistan, Australia and Scotland. Genotype 4 is prevalent mainly in Central Asia and Egypt, genotype 5 in South Africa, and genotype 6 in Hong Kong and Macau.

40-75% of patients register an asymptomatic form of the disease, in 50-75% of patients with acute viral hepatitis C chronic hepatitis is formed, in 20% of them cirrhosis develops. An important role of viral hepatitis C is attributed to the etiology of hepatocellular carcinoma.

HCV genome contains the positively charged single-stranded RNA, which encodes 3 structural (nucleocapsid protein core and shell nucleoproteins E ₁ -E ₂ ) and 5 structural (NS ₁, NS ₂, NS ₃, NS ₄, NS ₅ ) proteins. To each of these proteins are synthesized AT, found in the blood of patients with viral hepatitis C.

A distinctive feature of viral hepatitis C is the undulating course of the disease, in which three phases are distinguished: acute, latent and reactive phase.

• The acute phase is characterized by an increase in the activity of hepatic enzymes in the blood serum, the content of antibodies of classes IgM and IgG (to nucleocapsid core) to HCV with the growth of titers, as well as HCV RNA.
• The latent phase is characterized by the absence of clinical manifestations, the presence in the blood of IgG antibodies (to nucleocapsid core and nonstructural NS ₃ -NS ₅ proteins ) to HCV in high titers, the absence of antibodies of IgM class and HCV RNA or their presence in low concentrations against the background of a slight increase activity of liver enzymes during periods of exacerbation.
• The reactivation phase is characterized by the appearance of clinical signs, an increase in the activity of liver enzymes, the presence of IgG antibodies (to nucleocapsid core and unstructured NS proteins) in high titers, the presence of HCV RNA and the growth of ATM class titers to HCV in dynamics.

Diagnosis of viral hepatitis C is based on the detection of total antibodies to HCV by ELISA, which appear in the first 2 weeks of the disease and indicate a possible infection with the virus or a transmitted infection. Anti-HCV antibodies can persist in the blood of convalescents for 8-10 years with a gradual decrease in their concentration. Perhaps later detection of antibodies a year or more after infection. In chronic viral hepatitis C, antibodies are determined continuously and in higher titers. Most of the currently used test systems for the diagnosis of viral hepatitis C are based on the definition of IgG antibodies. Test systems capable of detecting antibodies of IgM class will make it possible to verify an active infection. IgM antibodies can be detected not only in acute viral hepatitis C, but also in chronic viral hepatitis C. Decrease in their number during treatment of patients with chronic viral hepatitis C may indicate the effectiveness of drug therapy. In the acute phase of infection the coefficient of Ig IgM / IgG is within 3-4 (the predominance of antibodies IgM indicates a high activity of the process). As you recover, this coefficient decreases 1.5-2 times, indicating a minimal replicative activity.

Detection of total IgG antibodies to HCV by ELISA is not enough to diagnose hepatitis C virus, it is necessary to confirm their presence (by immunoblotting method) in order to exclude the false-positive result of the study. The patient should be examined for IgG-class antibodies to different HCV proteins (to the core protein and NS proteins) and antibodies of IgM class to HCV in dynamics. The results of serological studies in conjunction with clinical and epidemiological data allow to establish the diagnosis and stage of the disease (it is important for the correct choice of treatment method).

[1], [2], [3], [4], [5]