What is Hepatitis C?
1. Hepatitis C
Hepatitis C is a form of hepatitis caused by an RNA (Ribo Nucleic Acid) virus, and accounts for most of the hepatitis cases previously referred to as non-A, non-B hepatitis. The Hepatitis C Virus (HCV) was first identified in 1988 and a hepatitis C antibody test (anti-HCV) to identify individuals exposed to HCV became available in 1990. In 1995 the hepatitis C virus was seen for the first time by using an electron microscope.
The hepatitis C virus has a high mutation rate. These ongoing changes in the virus make it difficult for the body's own immune system to fight it off, as by the time the immune system figures out the virus, it has changed to look different.
Hepatitis C is considered a bloodborn disease, and it is thought that many people with hepatitis C contracted it either through a blood transfusion or by receiving blood products that were contaminated with hepatitis C, or by sharing needles with intravenous drug users that were infected with hepatitis C. Thanks to HCV testing after 1990 the risk of acquiring hepatitis C from blood transfusion has been reduced tremendously.
2. Chronic Hepatitis C
Hepatitis C Virus (HCV) infection becomes chronic in about 60-80% of cases, therefore HCV is known to cause the most cases of Chronic Active Hepatitis.
Chronic hepatitis C behaves differently from hepatitis B. The disease is generally milder and most people are asymptomatic or have vague or no symptoms. Nevertheless, 10-15 years from the infection, the complications of cirrhosis appear in about one third of patients, sometimes unexpectedly. The percentage of patients who develop cirrhosis is much greater than in chronic hepatitis B, while primary liver cancer appears to be much less common.
About 80% of patients have abnormal aminotrasferase values. A characteristic feature of chronic hepatitis C is the fluctuation in aminotrasferase values seen in half of cases. Fluctuations seem to represent effects of mutations in the virus or episodic immune reactions. Transaminase values don't correlate well with histological features of disease.
>About one fifth of patients with positive diagnostic tests for HCV have persistently normal liver enzymes. Some of them progress to more advanced disease, in others infection appears to remain quiescent.
HCV has the property to involve bile duct epithelial cells, causing a significant cholestatic component, with abnormalities of serum Alkaline Phosphatase and Gamma Glutamyl Transferase (GGT) levels.
|What is hepatitis C - symptoms and treatment|
3. Diagnosis of Hepatitis C
Hepatitis C can be detected with a simple blood test.
Hepatitis C has been called the silent epidemic. That is, people who have the disease often do not know it. In fact, chronic hepatitis C may be discovered during a routine blood test, when it was not suspected. Now effective tests for detecting HCV in the blood were developed during this past decade.
A commonly used test is called an enzyme immunoassay (ELISA) for hepatitis C virus antibody. These tests look for antibodies, or chemicals, in the blood that the body produces in response to the hepatitis C virus.
If the test finds these antibodies, it means you may have been exposed and infected with the virus. These test results can be confirmed with other more scientifically advanced blood tests.
Interferon alfa, alone (monotherapy) or in combination with the drug ribavirin (combination therapy), may offer a potential cure for some patients. Indeed, combination therapy is now recognized as the new standard of treatment for hepatitis C.
As discussed before, there is no vaccine against hepatitis C. However, unlike most other viral diseases, hepatitis C, once detected, can be cured in some patients. That's where interferons come in. Interferons are naturally occurring proteins released by cells in the human body. Interferons have been found to interfere with a virus's ability to replicate itself in the body. This is called an antiviral effect. These proteins can now be mass produced, purified, and made available to help boost the body's response to the hepatitis C virus. One of these proteins, interferon alfa, has been found to have a number of antiviral effects, making it a powerful tool in fighting the hepatitis C virus.
Today, studies have shown that the effectiveness of interferon alfa is greater when it is used in combination with the antivirus drug ribavirin (combination therapy).
5. Combination Therapy
In Western conutries, a combination therapy has recently been approved for treatment of chronic HCV infection. The first in this new drug class is the combination of interferon alfa (Interferon alfa-2b) and the antivirus drug ribavirin. This drug combination is from the pharmaceutical company Schering-Plough and is called Rebetron.
Clinical studies have shown that when interferon alfa was combined with ribavirin, the beneficial effects of therapy lasted longer than when interferon alfa was used alone. In fact, clinical studies have shown that up to 40% of patients achieved a durable or sustained benefit with the combination of interferon alfa and ribavirin. When interferon alfa alone was used, clinical studies found that up to 15% of patients achieved this type of response. These results seem to suggest that the combination of interferon alfa and ribavirin may offer a longer-lasting benefit to more patients. Patients who remain free of the virus after treatment usually have a long-term remission and may be considered cured.