Subject headings

Abstract

AIM To study the clinicalpeculiarities of patients infected with different genotypes of hepatitis C virus (HCV).
METHODS Genotypes of HCV in 90 HCV-RNA-positive patients in Xuzhou area were examined.Clinical data of the patients were compared.
RESULTS HCV Ⅱamountedto 78.9% (71/ 90), predominating over HCV Ⅲand HCV Ⅱ/ Ⅲwhich held 18.9% (17/ 90) and 2.2% (2/ 90) respectively inthe area. ALT level and ALT positivity rate were higher in HCV Ⅱthan in HCV Ⅲ(P<0.05) within a range of >200 U/ L. Anti-HCV OD value and anti-HCV positivity ratewhen its OD value was over 2, were lower in HCV Ⅱthan in HCV Ⅲ(P<0.05). Most jaundice patients (87%) were infected with HCVⅡ. No significantdifference was found in age, sex and transfusion experience between HCV Ⅱand HCV Ⅲpatients (P>0.05).
CONCLUSION Distribution of HCV genotypes in Xuzhou area is consistent with that in the wholeChina, reflecting its distribution in eastern coastal areas. The immunogenicity of HCV Ⅱis lower than that of HCV Ⅲ, but the damage of hepaticfunction is more serious in HCV Ⅱpatients than in HCV Ⅲpatients, which might be due to different pathogenicmechanisms. Infection with HCV Ⅱ/ Ⅲis related to repeated usage of blood products andrepeated hemodialysis. HCV Ⅱand HCV Ⅲ,we believe, might play coordinated roles in pathogenesis.

INTRODUCTION

In recent years, it has been foundthat HCV genotypes differ greatly in various regions and that the clinical manifestationsof patients infected with different genotypes of HCV vary in the severity^[1-5] . We examined the genotypes of HCV in Xuzhou area byrestriction enzyme analysis method and compared the clinical data of patients infectedwith different genotypes of HCV.

MATERIALS AND METHODS
Patients

A total of 90 hepatitis C (HC)patients (65 males and 25 females) who were positive for anti-HCV in the sera and HCV-RNAwere recruited for the study. They were out- and in-patients from our hospital during theperiod from January 1993 to October 1995. Their ages ranged from 3 to 67 years, with amean of 36.8±13.0 years. Among them, 63 underwent blood transfusion and 27 did not. Thediagnosis was based on the criteria established in the National Conference on VirusHepatitis in Shanghai in 1990.

Reagents

ELISA kit of the second generationfrom Shanghai Kehua Industrial and Commercial Limited Company was used for anti-HCVdetection. Anti-HCV OD value was determined with PG 3022 enzyme-marked instrument producedby East China Electron Instrument Plant. PCR detection for HCV-RNA was conducted with thekit from Institute of Hepatic Disease of Beijing Medical University. PCR primer wasdesigned at the end of 5＇-noncoding region (5＇-NCR). The PCR product was 145 base pairs (bp) in length. Hae Ⅲ for restriction enzyme analysisand PBR 322/ Hae Ⅲ (DNAmarker) were purchased from SABC. Liver function was determined through the detection ofALT and serum bilirubin (SB) with automatic biochemistry analyzer from our hospital.

Methods

Sera were detected for HCV-RNA by PCR. Genotypes of HCV in 90 HCV-RNA positive patients were examined^[4,5] with5＇-NCR restrictionenzyme analysis. The electrophoresis product was 145 bp (one band) for HCV Ⅱ, 89 bp, 56 bp (two bands) forHCV Ⅲ, 145 bp, 89 bp,56 bp (three bands) for HCV Ⅱ/ Ⅲrespectively.

Statistical analysis The sample mean wasexpressed as mean±SD and analyzed statistically using U test and χ² test.

RESULTS
Distribution of HCV genotypes in Xuzhou area

Of 90 cases, HCⅡ,Ⅲ and Ⅱ/ Ⅲheld 78.9%(71), 18.9%(17) and 2.2%(2)respectively.

Clinical data of patientswith genotypes Ⅱand ⅢHCV (Tables 1-3)

No obvious difference was shown inage, sex and transfusion experience between HC Ⅱand HC Ⅲpatients (P>0.05). Sera ALT level and positivity rate, when ALT was >200 U/ L, were significantlyhigher in HC Ⅱpatientsthan in HC Ⅲpatients(P<0.05). Anti-HCV ODvalue and positivity rate when anti-HCV OD was >2, were significantly lower in HC Ⅱpatients than in HC Ⅲpatients (P<0.05). Difference in abnormality rate of ALT and B and SBlevel between HC ⅡandHC Ⅲpatients did notreach the statistical significance (P>0.05). There were 2 patients infected with HCV Ⅱ/ Ⅲ. Onepatient (male, 28 years old) received repeated blood transfusion due to gastric ulcer. Thetransfused plasma amounted to 11 000 mL, the maximum among the 90 patients. The other one(female, 66 years old) underwent repeated hemodialysis for chronic renal dysfunction, upto 150 times. ALT level was over 200 U/ L in both cases. Jaundice occurred in neithercase.

Table 1 Comparison of clinical data ofgenotype Ⅱ withgenotype Ⅲ

	Ⅱ (n=71)	Ⅲ (n=17)
Age (yr)	37.3±12.9	37.8±13.5
Sex (m/ f)	50/ 21	13/ 4
Transfusion history (y/ n)	48/ 23	14/ 3
ALT(U/ L)	308.8±234.9	165.4±103.0a
Rate of ALT abnormality	53/ 71	14/ 17
SB(μmol/ L)	32.7±45.6	16.4±8.2
Rate of SB abnormality	20/ 71	3/ 17

^a P<0.05， compared with genotype Ⅲ.

Table 2 Comparison ofpositive rates between genotype Ⅱand genotype Ⅲat different ALT levels

	n	ALT≥200 U/ L		ALT<200 U/ L
		n	%	n	%
Ⅱ	71	38	( 53.5)	33	(46.5)
Ⅲ	17	4	( 23.5)	13	(76.5)a
Ⅱ/ Ⅲ	2	2	(100.0)	0	( 0.0)
Total	90	44	( 48.9)	46	(51.1)

^a P<0.05， compared with genotype Ⅱ.

Table 3 Comparison of anti-HCV OD between genotype Ⅱ and genotype Ⅲ

	anti-HCV OD
	n	±s	≥2		<2
			n	(%)	n	(%)
Ⅱ	71	1.49±0.95	33	(46.5)	38	(53.5)
Ⅲ	17	2.10±0.36a	13	(76.5)	4	(23.5)b

^a P<0.05，^b P<0.01， compared with genotype Ⅱ.

DISCUSSION

Wang et al^[2] and Du et al^[4,5] determined the HCV genotypes in different regions of China.The existence of HCV Ⅱand Ⅲhas been confirmed. Their distributions differ regionally.Positivity rate of HCV Ⅲwas relatively high innorthen cities (30%-50%). In southern cities, HCV Ⅱinfectionwas preponderant (91%-100%). In eastern and western regions, the distribution showed nosignificant difference. It is shown in this paper that there exist 3 genotypes, HCV Ⅱ, HCV Ⅲ, HCVⅡ/ Ⅲin Xuzhou area with HCV Ⅱpreponderance, which is consistent with the distribution in wholeChina. The distribution in Xuzhou area might reflect the distribution in eastern coastalareas of China. Severity of HC is associated with the genotype of HCV infection. HCV Ⅱis closely related to hepatic carcinoma. Its positivity rate/constituent ratio presents an increasing trend in chronic persisting hepatitis (CPH),chronic active hepatitis (CAH), hepatocirrhosis, and hepatic carcinoma. HCV Ⅲ turns out contrary to HCV Ⅱ.Damage of liver function is more serious in HC Ⅱpatientsthan in HC Ⅲpatients (Table 1), which might be dueto greater toxicity of HCV Ⅱthan HCV Ⅲ, or due to their different pathogenic mechanisms. Furtherinvestigations are necessary to determine the correlation between the genotype of HCVinfection and the development or outcome of the disease. Sera anti-HCV OD value vary withdifferent genotypes. Anti-HCV positivity rate of the same genotype differed in variousranges of anti-HCV OD level. From this fact, we infer that a. Immunogenicity of HCV islower than that of HBV^[6,7] ,and much lower in HCV Ⅲthanin HCV Ⅱ. Less antibody is thus produced in HC Ⅱpatients than HCV Ⅲpatientseven if the amount of the virus is equal. b. Toxicity of HCV Ⅱ is stronger than that of HCV Ⅲ,so a few HCV Ⅱcan result in HC. If HCV Ⅱand Ⅲare provided with equalimmunogenicity, and the patients are infected with relatively more HCV Ⅲ, more antibody can be produced, thereby obtaining a high anti-HCVOD value. c. Anti-HCV OD value increases in some patients receiving interferon treatment,suggesting infection with HCV suppresses the patient＇simmunity, especially humoral immunity. Anti-HCV OD value is lower in HC Ⅱ patients than in HC Ⅲpatients,which might be explained by the stronger suppressive activity of HCV Ⅱthan HCV Ⅲ. d. HCV Ⅱmutates more frequently than HCV Ⅲ, and antibody against one particular strain of HCV Ⅱis thereby produced very little. e. Anti-HCV may function asneutralizing antibody. Its neutralization is enhanced with the increase of OD value. These5 points are, in a certain sense, related to the poor therapeutic effect of interferon onHCV Ⅱinfection.
Hino et al^[8] reported thattransmission of HCV Ⅱ/ Ⅲinfection through non-transfusion route was up to 73%. Du et al.^[4] believed that thiskind of infection was mainly related to usage of blood products. In our study, it wasobserved that, of 2 patients infected with HCV Ⅱ/ Ⅲ, one resulted from repeated usage of blood products, the otherfrom repeated hemodialysis. Both were categorized into iatrogenic infection, to whichgreat attention should be paid. Existence of HCV Ⅱ/ Ⅲinfection suggests that HCV can infect a patient repeatedly orsecondarily. Until now, no specific protective antibody, namely, neutralizing antibody,has been obtained. Secondary or mixed infection with HCV is due to poor immunogenicity andlack of cross immunoprotection between different genotypes. No interference suppression ispresent between different genotypes. HCV Ⅱ/ Ⅲinfection is not entirely due to secondary infection orsuccessive infection with different genotypes, but also due to the mutual transformationbetween different genotypes. HCV varies greatly. The gene sequences of HCV duringdifferent periods for the same patient are different to a certain degree. For example, HCVⅡ or HCV Ⅲ infectionoccurred initially. Soon, as a tolerating and escaping response to host＇s immunity, mutual transformation happens between HCV Ⅱand HCV Ⅲ, thus leading toHCV Ⅱ/ Ⅲinfection.No typical symptoms are shown in 2 HCV Ⅱ/ Ⅲpatients, agreeing with the general features of HC. ALT are over200 U/ L in both cases, suggesting different genotypes of HCV function cooperatively.

Department of Infectious Diseases, The Affiliated Hospitalof Xuzhou Medical College, Xuzhou 221002, Jiangsu Province, China
Dr. YAN Xue-Bing, male, born on November 19, 1967, in Jianhu County, Jiangsu Province,graduated from Xuzhou Medical College, Physician-in-Chief, engaged in the study ofhepatitis C virus genotyping, having 10 papers published.
Correspondence to: Dr. YAN Xue-Bing, Department of Infectious Diseases,Affiliated Hospital of Xuzhou Medical College, Xuzhou 221002, Jiangsu Province, China
Tel. +86·516·569850-2180
Received 1997-10-10 Revised 1998-02-19

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