Serologic Investigations In Viral Hepatitis

SEROLOGIC INVESTIGATIONS IN VIRAL HEPATITIS DR EJEMAI EBOREIME

INTRODUCTION • Viral Hepatitis is a systemic disease primarily affecting the liver. • Hepatotropicviruses are the culprits in about 99% of cases

HEPATOTROPIC VIRUSES • Hepatitis A virus (HAV): ▫ Picornavirus ▫ Transmitted feco-orally ▫ Causes acute but no chronic infection

• Hepatitis B virus (HBV): ▫ ▫ ▫ ▫

Hepadna virus Aka Dane particle Transmitted via body fluids Causes both acute and chronic infections

STRUCTURE OF HBV HBsAg

HBVDNA

HBV-DNA Polymeras e

HBcAg HBeAg (blood)

• Hepatitis C virus (HCV): ▫ RNA-containing flavivirus ▫ Causes chronic hepatitis ▫ Commonest mode of transmission is blood and blood products ▫ Sexual and vertical transmissions are not very common

• Hepatitis D virus (HDV): ▫ RNA-defective virus ▫ Incapable of independent replication ▫ Requires HBV

• Hepatitis E virus (HEV): ▫ RNA virus ▫ Feco-oral transmission ▫ Chronic infection does not occur

NON HEPATOTROPIC VIRUSES (aka non A-E viral hepatitis) • • • •

CMV EBV HSV Yellow fever virus

Role of serology in hepatitis management • Serology involves the study of seroactive substances for the purpose of diagnosis and management of diseases • Such substances may include antigens and antibodies. • The presence and time of detection of these substances are essential in hepatological infectology

Hepatitis A • Anti HAV: ▫ Detectable at onset of symptoms (IgM) ▫ Persists for lifetime hence not very useful clinically (IgG)

• IgManti HAV indicates recent infection. Could remain +ve 4-6months post infection

Hepatitis B • Serologic markers include: ▫ Hep B surface antigen (HBsAg) Detectable in large quantities in serum Indicates acute infection and high infectivity Appears in blood late incubation period and disappears within 3-4 wks but may persist up to 6mths

▫ Anti HBs Indicates past infection with and immunity to HBV (if assoc. with anti HBc), presence of passive antibody from HBIG,or immune response from HBV vaccine

• Hep B core antigen (HBcAg) • Anti HBc: of 2 types ▫ IgM

Appears after about 2 mths and may persist till 7th mth. Indicates acute infection

▫ IgG

Indicates chronic infection

• HBe Ag ▫ ▫ ▫ ▫

Circulating form of HBcAg A marker of viral replication and infectivity Appears transiently at onset of infection and lasts 1-3mths Associated with HBV replication and indicates high titre and infectivity of serum

• Anti-HBe

▫ Appears from 10th wek ▫ Presence in serum of HBsAgcarrier suggests lower titre of HBV

• Most sensitive test is detection of HBV DNA in serum though not generally required for routine diagnosis

• HCV: ▫ Anti-HCV, for chronic infections ▫ Serum PCR

• HDV: ▫ Anti HDV (IgG & IgM)

• HEV: ▫ Anti HEV

CONCLUSION • Viral hepatitis is a common cause of CLD in this environment. • Healthworkers are particularly at risk of infection • Understanding the basis for serological investigations of viral hepatitis improves diagnosis, management, prognostication as well as prevention of the disease and its complications.

THANK YOU

High risk stage for Chronic Hepatitis B progression Symptom flares may occur if immunocompromised Conversion to Stage 3 Occurs in most adults rapidly Others convert 5-15% per year Early Acute HBsAg Positive HBeAg Positive Acute (2-12 weeks) HBsAg Positive HBeAg Positive xHBc IgM Antibody Positive xHBc IgG Antibody Positive Acute and Seroconversion (transitions into Stage 3) HBsAg Positive xHBc IgM Antibody Positive xHBc IgG Antibody Positive xHBe IgG Antibody Positive Stage 3: Inactive carrier state (3-6