OKÜLT HEPATİT B VİRUS ENFEKSİYONU: MOLEKÜLER MEKANİZMALAR VE KLİNİK ÖNEMİ

Yıl 2017, Cilt: 80 Sayı: 2, 71 - 81, 30.06.2017

Bülent Çakal

https://doi.org/10.18017/iuitfd.330044

Öz

Okült Hepatitis B Virüs (HBV) infeksiyonu
(OBİ) serum HBV DNA statüsü dikkate alınmaksızın mevcut serolojik testler ile
HBV yüzey antijeni (HBsAg) negatif tespit edilen bireylerin karaciğerin de HBV
genomunun uzun süreli persistan varlığı olarak tanımlanır. OBİ virüse ve infekte
bireye ait faktörler ile çevresel faktörlerin zemininde gelişen genetik,
epigenetik ve immünolojik mekanizmaların karşılıklı etkileşimi ile şekillenen,
HBV infeksiyonunun doğal seyri içerisinde yer alan muhtemel safhalarından biri
olarak kabul edilir. OBİ klinik açıdan; okült virüsün kan transfüzyonu, doğum,
hemodiyaliz ve ortotopik karaciğer gibi organ nakli yolu ile bulaşını takiben
alıcıda tipik yeni HBV infeksiyonuna neden olabilmesi, immünsüpresyon
koşullarında OBİ reaktivasyonu ve takiben HBV ilişkili (akut ve fulminan
hepatit) karaciğer hastalıkları, kronik karaciğer hastalıklarının (KKH)
progresyonu üzerine etkisi ile özellikle hepatoselüler karsinoma (HSK) için artan bir risk faktörü olduğu yönünde hipotez
uyarınca yoğun bir tartışma ve araştırma konusudur. Buna karşın gerek HBV infeksiyonunun
bu özgün formuna neden olan gerekse ilişkili olduğu karaciğer hastalıklarının
patogenezinde rol alan moleküler mekanizmalar henüz tam olarak
aydınlatılamamıştır. Bu derlemede OBİ’nin klinik önemi, epidemiyolojik
özellikleri ve laboratuar tanısına yönelik bilimsel literatürün gözden
geçirilmesi amaçlanmıştır.

Anahtar
Kelimeler: Hepatit B virüs; okült hepatit B virüs infeksiyonu; bulaş;
reaktivasyon; kronik karaciğer hastalığı; hepatoselüler karsinoma.

Anahtar Kelimeler

Hepatit B virüs, okült hepatit B virüs infeksiyonu, bulaş, reaktivasyon, kronik karaciğer hastalığı, hepatoselüler karsinoma

OCCULT HEPATITIS B VIRUS INFECTION: MOLECULAR MECHANISMS AND CLINICAL SIGNIFICANCE

Öz

Occult Hepatitis B Virus (HBV) infection
(OBI) is defined as the long-lasting persistence of HBV genomes in the
hepatocytes of individuals testing negative for HBV surface antigen (HBsAg) by
currently available assays and usually for serum HBV DNA. OBI is considered as
the possible phase in the natural history of chronic HBV infection that the
host’s immune surveillance and epigenetic mechanisms are likely involved.
Clinical impact of OB is that it can be transmitted (i.e., through blood
transfusion, by liver organ
transplantation, hemodialysis and parturition) causing classic forms of
hepatitis B in newly infected individuals. The development of an
immunosuppressive status may induce OBI reactivation and development of acute
and often severe hepatitis. OBI can favor the progression of liver fibrosis.
Also OBİ infection has been hypothesized to be a significant risk factor
contributing to the progression of chronic liver diseases (CLD) with increased
risk for hepatocellular carcinoma (HCC) which may lead to an increased
progression of liver diseases. Although OBI is considered a phase in the natural
history of HBV, the molecular mechanisms leading to its occurrence and its contribution
to HCC development are yet poorly understood. In this review, it is aimed to examine
clinical importance, epidemiological aspects and laboratory diagnosis of OBI in
recent literature.

Keywords: Hepatitis B virüs;
occult hepatitis B virus infection; transmission; reactivation; chronic liver
disease; hepatocellular carcinoma.

Anahtar Kelimeler

Hepatitis B virüs, occult hepatitis B virus infection, transmission, reactivation, chronic liver disease, hepatocellular carcinoma

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