输血后丙型肝炎抗C_(22)、C_(33)C和NS_5IgG及其亚群的检测和意义

Measurement and evaluation of anti HCV (C 22 , C 33C and NS 5) antibodies and their IgG subclasses in children with post transfusion hepatitis C infection

为探讨抗丙型肝炎病毒（ＨＣＶ）ＩｇＧ型抗体及其亚群在ＨＣＶ感染过程中的作用，采用酶联免疫吸附法对６６例输血后ＨＣＶ感染患儿的９２份急、慢性期血清和３２份α干扰素（αＩＦＮ）治疗后血清进行抗Ｃ２２、抗Ｃ３３Ｃ和抗ＮＳ５及其亚群的检测。结果表明，急性期抗Ｃ２２和抗Ｃ３３Ｃ检出率高，分别为９８．４３％和１００．００％；而抗ＮＳ５在急性期检出率仅为５３．１２％，明显低于慢性期（９１．６７％）和同期抗Ｃ２２和抗Ｃ３３Ｃ检出率（分别为９６．８８％和１００．００％）。三种抗体ＩｇＧ亚群在急性期的检出率和抗体水平均显著低于慢性期。抗Ｃ２２ＩｇＧ１为该抗体的优势亚群；而抗Ｃ３３Ｃ无明显优势亚群；抗ＮＳ５ＩｇＧ１及ＩｇＧ３至慢性期才显示其优势。６６例患儿中，１３例接受αＩＦＮ治疗，其中５例复发患儿在ＨＣＶＲＮＡ再次出现时，抗Ｃ２２ＩｇＧ１呈现有意义的下降，而抗Ｃ２２总水平并无明显变化，而接受αＩＦＮ治疗４例有效和另４例无效患儿无类似变化。提示抗Ｃ２２和抗Ｃ３３Ｃ是诊断急性ＨＣＶ感染的敏感指标；抗Ｃ２２ＩｇＧ１可能有助于评价αＩＦＮ治疗ＨＣＶ感染的疗效。

To investigate the significance of the IgG antibodies and their subclasses against the core antigen (C 22 ) and non structural antigens (C 33C and NS 5) of hepatitis C virus (HCV) in HCV infection,the authors measured anti HCV (C 22 , C 33c and NS 5) antibodies and their IgG subclasses in 92 samples of serum from 66 children with post transfusion HCV infection and 32 samples from 13 patients receiving the α interferon (αINF) therapy. The positive rates of the anti C 22 and anti C 33C were 98.43% and 100.00% in 92 samples, respectively. But only 53.12% of the sera from acute patients were anti NS 5 positive, which was significantly lower than the rate in chronic patients (91.67%), and was also much lower than the detection rates of anti C 22 (96.88%) and anti C 33C (100.00%) in acute phase. The levels and positive rates of IgG subclasses of the above three antibodies in acute phase were all significantly lower than those in chronic phase. Anti C 22 IgG 1 was found to be the main subclass during both acute and chronic phases and anti NS 5IgG 1 and IgG 3 subclasses were dominant in chronic phase, while anti C 33C showed no dominant subclasses. Five cases who had a transient response to αINF showed a significantly decreased level of anti C 22 IgG 1 when HCV RNA relapsed, with the total level of anti C 22 remained unchanged. Four cases of sustained response and another 4 non responders to αINF showed no similar changes. The present study showed some specific humoral immune responses to HCV infection in children with HCV infection and suggests that the anti C 22 and anti C 33C can be sensitive indicators in the diagnosis of acute HCV infection, and anti C 22 IgG 1 level may be useful in the assessment of the effectiveness of α INF therapy.