Although the innate immune response does not play a significant role in these processes, the adaptive immune response, in particular virus-specific cytotoxic T lymphocytes(CTLs), contributes to most of the liver injury associated with HBV infection. CTLs eliminate HBV infection by killing infected cells and producing antiviral cytokines, which are then used to purge HBV from viable hepatocytes. Although liver damage is initiated and mediated by the CTLs, antigen-nonspecific inflammatory cells can worsen CTL-induced immunopathology, and platelets activated at the site of infection may facilitate the accumulation of CTLs in the liver. Diagnosis
The tests, called assays, for detection of hepatitis B virus infection involve serum or blood tests that detect either viral antigens (proteins produced by the virus) or antibodies produced by the host. Interpretation of these assays is complex.The hepatitis B surface antigen (HBsAg) is most frequently used to screen for the presence of this infection. It is the first detectable viral antigen to appear during infection. However, early in an infection, this antigen may not be present and it may be undetectable later in the infection as it is being cleared by the host. The infectious virion contains an inner "core particle" enclosing viral genome. The icosahedral core particle is made of 180 or 240 copies of the core protein, alternatively known as hepatitis B core antigen, or HBcAg. During this window in which the host remains infected but is successfully clearing the virus, IgM antibodies specific to the hepatitis B core antigen (anti-HBc IgM) may be the only serological evidence of disease.
This is because in comparison to their previous lifestyle where they would engage in strenuous physical activity daily and have meals that are low in fat and high in fiber, the Westernized lifestyle has less physical activity and the diet includes high levels of carbohydrates and fats. Age related changes
Android fat distributions change across life course. The main changes in women are associated with menopause. Premenopausal women tend to show a more gynoid fat distribution than post-menopausal women - this is associated with a drop in oestrogen levels. An android fat distribution becomes more common post-menopause, where oestrogen is at its lowest levels. Older men show android fat distributions more often than younger men  which may be due to lifestyle changes, or hormonal changes related to age. Older adults have a greater waist-to-hip ratio than young adults which indicates high levels of android fat in older adults. Computed tomography studies show that older adults have a two-fold increase in visceral fat compared to young adults. These changes in android fat distribution in older adults occurs in the absence of any clinical diseases. == References ==