Objective: To explore the detection of pre-S2 antigen (pre-S2Ag) of hepatitis B virus and its clinical significance. Methods: HBV markers fHBV M 1 and pre-S2Ag were detected in 88 samples of1,and HBV DNA was detected in 62 samples of1. Results: HBV DNA and pre-S2Ag were detected simultaneously in 162 serum samples, and there was no statistical difference between them (X2=2.78, P > 0.05). There was significant difference in the positive rate of pre-S2Ag between HBeAg(+) group and HBeAb(+) group (X2=28.03, P < 0.005). The positive rate of pre-S2Ag in HBeAg(+) group and HBclgM(+) group was 100%, while that in HBSAg(+) group was 95.0%, which was significantly higher than that in HBV-DNA(-) group (18.4%, P < 0.005). Conclusion: Pre-S2Ag is an indicator of virus infection and replication, which is related to clinical activities. It can be used as an observation index of curative effect and prognosis, and can improve and supplement the detection of serum markers of hepatitis B virus.
China is an epidemic area of HBV infection. Hepatitis B virus is the most common hemolytic virus causing viral hepatitis, which not only has a high infection rate. Moreover, some HBV infections may be caused by peripheral tolerance, low T cell reaction, inhibition of antigen presentation, selective immunosuppression, down-regulation of virus gene expression or gene variation, which leads to T cell recognition disorder and is easy to turn into chronic infection. Some patients may develop cirrhosis or even primary liver cancer. Different HBV serum immune marker patterns suggest different clinical significance. At present, HBV-DNA is the main index to judge whether the virus infected by HBV is replicated and infectious. Understanding the relationship between immunology and molecular biological markers is very valuable for clinical diagnosis and treatment. It is estimated that there are 65.438+0.2 billion asymptomatic hepatitis B virus carriers and more than 30 million hepatitis B patients in the world, of which 65.438+0.5% ~ 25% will die of chronic liver diseases (liver cancer and cirrhosis), which will bring great harm to human health. In order to diagnose, guide treatment and judge prognosis in time and accurately, the detection indexes of hepatitis B virus are increasing day by day. Literature shows that the positive detection rate of pre-S2Ag is the highest in HBSAg(+), HBeAg(+) and anti-HBc(+) modes, followed by anti-HBSAg(+), anti-HBe(+) and anti-HBe+ modes, and other modes are lower. In this paper, the positive rate of pre-S2Ag was compared with the detection results of HBV DNA and HBV M to explore the clinical significance of pre-S2Ag detection. The report is summarized and analyzed as follows:
1. Data and methods
1. 1 sample source
We collected 188 outpatients and inpatients in our hospital from March to June 2006. Among them, HBVM and HBV-DNA*** 162 patients were simultaneously detected, including 6 cases of acute hepatitis B, 20 cases of hepatitis B surface antigen positive and clinically diagnosed as liver cancer.
1.2g ~+reagent
HBVM and HBcIgM reagents are provided by a limited company; Pre-S2Ag reagent was provided by the Liver Disease Reagent Research Center of a city, and all the above were detected by ELISA. HBV-DNA reagent was purchased from a limited company, and the result was ≥500 copies/ml. The above operations are carried out in strict accordance with the kit instructions.
1.3 detection instrument
Sijak's fully active immunoassay analyzer-Alice and HBV-DNA were determined by the People's Hospital of our city using the automatic fluorescence PCR amplification instrument of Roche company abroad.
1.4 statistical method
T-test and x2-test were used to analyze the measurement data and compare the counting data, and all the data were processed by SPSS 10.0forWindowS statistical software package.
2. Results
2. 1 pre-s2ag, HBV-DNA and hepatitis B virus marker 4h(HBVM).
discuss
Chronic HBV infection often causes long-term and persistent damage to some liver cells, but the degree of damage is not positively correlated with HBV-DNA level. Immune response to HBV is the main mechanism of liver tissue injury and abnormal liver function. Pre-S2Ag is a part of hepatitis B virus coat protein. It is a 55 amino acid sequence added before the N-terminal of HBSAg peptide chain. It is exposed to the outer layer of HBV envelope and is also the surface antigen of the virus. HBV-DNA is the most sensitive and accurate evidence to measure the replication of hepatitis B virus, and it is also the most direct indicator to judge whether a patient is infectious. In Table 2, the detection results of HBV-DNA and pre-S2 Ag have no statistical significance (x2=2.78, P > 0.05) by paired data x2 test, which is the same as that reported in the literature. Pre-S2Ag has a polymerized human serum albumin receptor (PHSA-R), which can bind to pH-SA. Because of the existence of PHSA-R on the surface of hepatocytes, HBV can be adsorbed to the surface of hepatocytes through the mediation of PHSA in blood circulation, and finally enter hepatocytes through pinocytosis. Therefore, the detection of pre-S2Ag in patients' serum indicates that HBV replicates in hepatocytes. The existence of HBeAg in the serum of patients with hepatitis B is a classic sign of HBV replication and evaluation of its infectivity. The positive rate of pre-S2Ag in HBeAg(+) samples was 100%, while that in acute hepatitis B patients with HBclgM(+) was 100%, which also indicated that the existence of pre-S2Ag was related to virus replication and clinical activities. In Table 3, the detection rates of HBeAg(+ 1 group and HBeAbf+ 1 group) were compared with pre-S2Ag (x2=28.03, P < 0.005), which showed that the difference in detection rates of pre-S2Ag between the two groups was statistically significant. The positive rate of pre-S2Ag in HBeAb(+) group was lower than that in HBeAg(+) group. The transition from HBeAg to HBeAb shows that the virus replication is reduced and the infectivity is weakened, indicating that the negative conversion of pre-S2Ag is an indicator of the improvement of the disease and the weakening of infectivity. With the transformation from HBV-DNA(+) to HBV-DNA (-) and HBeAg to HBeAb, the absorbance of pre-S2Ag positive samples (the average value of A1.535→1.087→ 0.734) gradually decreased (P < 0.05), and at the same time, in the liver cancer group. The average value of pre-S2AS positive samples in HBcIgM(+) group was 1.305, and the average value of proS2Ag positive samples in two disease groups was also very high, indicating that the high titer of pre-S2Ag was related to the disease activity, while the low titer of pre-S2Ag indicated that HBeAg disappeared or improved.
Some data show that among asymptomatic HBV carriers. If pre-S2Ag is positive at the same time, it means that the virus is still active in the body and has not been eliminated, which has potential pathological damage to the liver. Such patients are more likely to develop cirrhosis or liver cancer. In this experiment, the positive rate of pre-S2Ag in patients with hepatitis B surface antigen (+) liver cancer reached 95%, which was consistent with the literature reports. In the sample of HBV-DNA(-), the positive rate of pre-S2Ag is 18.4%, mainly because pre-S2Ag exists not only on the surface of virus particles, but also on the surface of non-infectious spherical particles, which has the functions of regulating the immune response to S protein and controlling virus assembly. It is also possible that there is a low titer of pre-S2Ag and the level of HBV-DNA is too low to be detected when the disease improves and the infectivity is weakened. At the same time, it was found that the positive rate of HBSAg(-) in pre-S2Ag was 5.9%, which was rarely reported. It may be that although S gene and pre-S gene are located in the same open reading frame (ORF), their startup signals are different, and they can be expressed independently, resulting in different rates and contents of S protein and pre-S protein.
To sum up, this data shows that the expression of pre-S2Ag is an indicator of virus infection and replication, and pre-S2Ag is superior to HBSAg in reflecting disease activity and prognosis. The change of serum pre-S2 antigen titer often precedes the change of clinical course and ALT, and its detection rate and serum level increase with the increase of disease activity, and its negative conversion rate is higher than HBSAg at different follow-up times. The earlier the pre-S2 antigen turns negative in patients with acute hepatitis B, the better the prognosis, which is the earliest sign of virus clearance. On the contrary, if S2 continues to be positive, it will develop into chronic hepatitis. Some people think that it is not appropriate to directly carry out pre-S2Ag test instead of HBV-DNA in hospitals where PCR cannot be carried out at the grass-roots level due to experimental conditions. The contents of these two tests are different, and they are complementary. Pre-S2Ag can be used as a supplement to HBV markers and improve the detection of HBV serum markers. Posted in China Paper Download Center.