Seroprevalence of hepatitis B virus infection in children in Taipei, 1989: five years after a mass hepatitis B vaccination program

A nationwide hepatitis B vaccination program was launched in Taiwan in 1984. To study the impact of this ongoing program on hepatitis B virus (HBV) infection, a follow-up seroepidemiologic study was carried out in 1989 in a Taipei district where pre-vaccination seroepidemiology had been studied. HBV markers were studied in 1134 apparently healthy children (619 boys and 515 girls) under 13 years of age between March and July 1989. The prevalence of hepatitis B surface antigen (HBsAg) in children under 5 years of age decreased from 9.3% in 1984 to approximately 2% in 1989. A significant decrease in HBsAg prevalence and hepatitis B core antibody in 5- to 8-year-old children who were not immunized against HBV showed that horizontal infection among the older children had also decreased. Thus, this program not only protected vaccinated subjects; the reduction in numbers of highly infectious young HBV carriers also contributed to a lower prevalence of hepatitis B infection and carrier rates in some older children. This study demonstrates that hepatitis B vaccination is effective in protecting the majority of children in hyperendemic areas from HBV infection and from becoming chronic carriers.     

Safety and immunogenicity of a recombinant hepatitis B vaccine

A hepatitis B vaccine produced in yeast by recombinant DNA technology was evaluated using 5-micrograms and 10-micrograms doses in a randomized trial lasting 7 months in 110 male armed forces recruits aged 17-19 years. Results were compared to those of an identical trial of a plasma-derived vaccine. No allergic reactions were observed, and the rate of mild side effects was similar to the plasma-derived vaccine. Seroconversion rates in the first month were 60% (33/55) and 67% (37/55) with the 5-micrograms and 10-micrograms doses of the recombinant vaccine, respectively. All participants seroconverted by 3 months, and none lost antibody. These results are very similar to those for plasma-derived vaccine. Comparison of titres of antibody to hepatitis B surface antigen (anti-HBs) showed a slightly higher level with the 10-micrograms than with the 5-micrograms dose of the recombinant vaccine. Geometric mean titres of anti-HBs after the booster dose were similar in the 5-micrograms and 10-micrograms dose recombinant vaccine groups (2,620 and 2,748 IU/l, respectively) and in the 5-micrograms plasma-derived vaccine group (3,591 IU/l) but significantly higher (9,227 IU/l) with the 10-micrograms dose of the plasma-derived vaccine. These results confirm the safety and immunogenicity of the recombinant vaccine, although further study is needed on the duration of immunity.     

Very low dose hepatitis B vaccination in the newborn: anamnestic response to booster at four years

Seventy-eight children who had received three very low doses (1 or 2 microg) of Merck, Sharp and Dohme (MSD) plasma-derived vaccine (PDV) in early infancy were followed to approximately four years of age. Of the 70 who had responded to the initial course of vaccine with measurable anti-HBs, levels had fallen to below 10 mlU/ml in 38% of subjects given 1 microg doses and in 17% of those who had been given 2 microg doses. None of the children were positive for anti-HBc. Two weeks after 2 microg dose of MSD recombinant DNA (rDNA) vaccine all subjects had more than 10 mlU/ml of anti-HBs, with 90% exceeding 1,000 mlU/ml. A response to hepatitis B vaccine in infancy is followed by an effective immunological memory for several years, even if anti-HBs falls to low levels. The rDNA hepatitis B vaccine (MSD) in 2 microg doses is an effective booster following a primary course of plasma derived vaccine.     

Maternal-infant transmission of hepatitis B in Egypt

In order to determine whether maternal-infant (vertical) transmission of hepatitis B is a common route of infection leading to chronic antigenemia in Egypt, 901 asymptomatic women in labor were evaluated. Forty-three women (4.8 percent) were positive for HBsAg, but only one woman was positive for HBeAg. From one year of observation of children born to 13 of the HBsAg-positive mothers, vertical transmission of hepatitis B was estimated to have occurred in approximately 1.7% of births, with chronic antigenemia resulting from 0.6% of births. It was also possible to observe 29 children born to women negative for HBsAg. Horizontal transmission of hepatitis B occurred in 17.2 percent of these children during the first year of life. Maternal-infant transmission of hepatitis B at birth does not appear to be the predominant mechanism of hepatitis B transmission or a common cause of chronic antigenemia in Egypt. The first year after birth appears to be a more important period of hepatitis B transmission. Therefore, vaccination of all children at birth with hepatitis B vaccine could be an effective vaccine strategy despite a low incidence of vertical hepatitis B transmission.     

A serological and molecular survey of hepatitis B in children 15 years after inception of the national hepatitis B vaccination program in eastern China

The emergence of mutations in the hepatitis B virus (HBV) S gene has threatened the long‐term success of vaccination programs since the worldwide introduction of effective vaccines against hepatitis B. This study was conducted on 5,407 children (0–8 years old) in eastern China in 2007. We analyzed the prevalence of HBsAg, anti‐HBs, and “a”‐determinant mutations in the HBV S gene by microparticle enzyme immunoassays, PCR, and DNASTAR software. The total HBsAg prevalence was 1.52% (82/5,407) in the children and increased with age. In contrast, the positive rate (65.42%, 2,374/3,629) and the titers of anti‐HBs decreased with age. The predominant infection was HBV of genotype C and serotype adr (45/51; 88% of cases). Mutations of I126T, amino acid 137 (nt553T deletion mutation), G145A, G145R, and F158S were found in the children; the mutations of amino acid 137 and F158S have not been reported previously. The total prevalence of mutant strains was 14% (7/51). To investigate whether the infection resulted from maternal transmission, we compared the S gene sequences in 16 mother–child pairs. Fourteen mother–child pairs exhibited the same HBV genotype, with 99.5–100% sequence homology in the S gene, while two pairs exhibited different genotypes. This study suggested that the hepatitis B vaccination strategies in eastern China have been successful. Although the emergence of “a”‐determinant mutations in the HBV S gene have resulted in HBV infection in immunized children, this does not pose a threat to the vaccination strategies. The HBV‐infected children had contracted the infection via vertical transmission. J. Med. Virol. 81:1517–1524, 2009. © 2009 Wiley‐Liss, Inc.     

Long‐term immunogenicity of preservative‐free hepatitis B vaccine formulations in adults

Vaccination with recombinant hepatitis B vaccines is highly effective in preventing hepatitis B infection. Recently, a preservative‐free (PF) formulation of hepatitis B vaccine [GlaxoSmithKline (GSK) Biologicals, Rixensart, Belgium] has been licensed. The immunogenicity of the PF hepatitis B vaccine and antibody persistence 6 years later was assessed in this study. This formulation was compared with the preservative‐ containing (PC) formulation of the vaccine and a low‐preservative (LP) content formulation. Five hundred forty‐one healthy adult subjects were evaluated in the primary study. Over 94% of the subjects in the three study groups had seroprotective anti‐HBs antibody concentrations (≥10 mIU/ml) 1 month after completing primary vaccination. Antibody measurements in 242 healthy adults who returned for the follow‐up study and who had received primary vaccination 6 years earlier showed that over 81% of subjects in the three study groups still had anti‐HBs antibody concentrations ≥10 mIU/ml. No apparent differences in antibody decline or distribution between the study groups were observed. These results indicate that the removal of preservatives from the hepatitis B vaccine does not affect adversely its immunogenicity both in the short and in the longer term. J. Med. Virol. 81:1710–1715, 2009. © 2009 Wiley‐Liss, Inc.     

Flow cytometric and functional analysis of mononuclear cells infiltrating the liver in experimental autoimmune hepatitis.

Experimental autoimmune hepatitis was produced by immunizing Wistar rats with syngeneic liver proteins. Mononuclear cells infiltrating the liver tissue were identified by immunohistochemical techniques using monoclonal antibodies specific for subpopulations of rat lymphocytes. The strong infiltration of CD8+ cytotoxic T lymphocytes (CTL) were found in the portal areas. Subpopulations of mononuclear cells infiltrating the liver, spleen cells and peripheral blood lymphocytes were identified by flow cytometry. Flow cytometric analysis revealed the presence of CD5- and CD8+ lymphocytes in the liver tissues. Mononuclear cells infiltrating the liver were isolated from Wistar rats having autoimmune hepatitis to determine whether those exhibit cytotoxicity against syngeneic hepatocytes; they exhibited cytotoxicity against isolated syngeneic hepatocytes, but failed to lyse K562 cells, syngeneic concanavalin A-activated splenocytes and allogeneic hepatocytes. Depletion of CD8+ T cells significantly reduced the cytotoxic ability of mononuclear cells infiltrating into the liver against syngeneic hepatocytes. These findings support the idea that liver cell injury in experimental autoimmune hepatitis may at least in part be mediated by CTL.     

Recombinant-yeast-derived hepatitis B vaccine in healthy adults: safety and two-year immunogenicity of early investigative lots of vaccine

We tested the safety and long-term immunogenicity of two of the early investigative lots of a recombinant-yeast-derived hepatitis B vaccine in immunocompetent adults. Three 10-micrograms doses of recombinant hepatitis B vaccine (Merck Sharp & Dohme Research Laboratories, West Point, PA) were administered by deltoid intramuscular injection at time 0, 1, and 6 months to 65 seronegative adult health workers. Following a complete three-injection course, 98% of vaccinees acquired anti-HBs, 97% at levels greater than 10 mlU/ml, and 95% maintained such "protective" antibody levels at 1 year. At 2 years, 93% retained antibody, but only 68% had levels greater than 10 mlU/ml. In those who responded to vaccination by achieving any detectable level of antibody, the peak geometric mean titer of anti-HBs, measured at 9 months, was 741 +/- 6 mlU/ml; the geometric mean titer fell to 348 +/- 6 at 1 year and to 66 +/- 7 at 2 years. Side effects were trivial, and levels of yeast antibody, as measured by radioimmunoassay, were not changed from prevaccine levels. No serious adverse effects were encountered, and neither type B nor non-B hepatitis occurred in any vaccine. These findings demonstrate that the recombinant yeast hepatitis B vaccine is safe and immunogenic but that 10 micrograms of the early investigative lots of the recombinant vaccine is less immunogenic than 20 micrograms of the plasma-derived vaccine. Recipients of early investigative vaccine lots should be considered for booster vaccination with currently available, more immunogenic vaccine lots.     

Comparison of safety and immunogenicity of adw and ayw hepatitis b vaccines

The safety and immunogenicity of adw and ayw hepatitis B vaccines were compared in a double-blind randomized trial in Greek Air Force recruits. One hundred and ten out of 240 eligible nonimmune recruits were randomly selected and allocated to thc two vaccine treatment groups. Two 20-m?g doses 1 month apart and a third 20-m?g booster dose, at 6 months, were given intramuscularly. Severe local or general side effects were not observed. The frequency of mild side effects (local discomfort or pain, fever less than 37.5°C, and malaise) was slightly higher with the adw than with the ayw vaccine. Antibodies developed earlier and in higher titers in adw vaccinees. However, after the booster dose all ayw and all but one adw vaccinees developed anti-HBs in almost similar titers. It is concluded that both vaccines are equally safe and immunogenic after administration of two doses at a 1-month interval followed by a booster dose at 6 months.     

乙型肝炎疫苗长期免疫效果评价及免疫持久性研究

目的 评价我国新生儿乙型肝炎(乙肝)疫苗免疫后的长期保护效果,为乙肝防控和乙肝疫苗HepB免疫策略提供参考.方法 用横断面调查和分层整群抽样的方法,在乙肝疫苗免疫效果观察监测点收集1987-1996年出生(13～22岁)、全程接种乙肝血源疫苗的人群,以及1997-2008年出生(1 ～ 12岁)、全程接种乙肝重组酵母疫苗人群的血清样本和资料;用微粒子酶免疫法检测HBV感染指标,结合本底资料和乙肝疫苗免疫史进行分析.结果 在河北正定、广西隆安、上海黄浦、青海同德和湖南湘潭5个监测点共收集1～12岁重组酵母疫苗免疫人群样本8133例,13 ～22岁血源疫苗免疫人群样本4848例,5个监测点的HBsAg平均阳性率均显著低于本底值,疫苗总体保护效果分别为86.04％～96.14％;河北正定、青海同德和湖南湘潭的年龄分布差异无统计学意义,广西隆安和上海黄浦的结果显示19～22岁人群HBsAg阳性率偏高;Anti-HBs阳性率随免疫年龄增长而下降,重组疫苗免疫人群从1～2岁组的86.84％下降至11～12岁组的46.40％,17 ～18岁组的Anti-HBs阳性率处于较低水平,而19～22岁组出现升高;几何平均浓度(GMC) ＜10 mIU/ml(Anti-HBs阴性)的比例随着年龄增长逐渐升高,100～999.99 mIU/ml和≥1000 mIU/ml的比例随着年龄的增长呈现下降趋势.结论 血源疫苗免疫后13～ 22年、重组酵母疫苗免疫后1～12年的总体保护效果良好;不必开展加强免疫,建议加强监测18岁以上人群的Anti-HBs水平,对GMC＜10 mIU/ml者开展加强免疫.     

Immunoprophylaxis of perinatal transmission of the hepatitis B virus: efficacy of hepatitis B immune globulin and hepatitis B vaccine in a low-prevalence area

One hundred eleven newborn infants born of Spanish hepatitis B surface antigen (HBsAg) carrier mothers were consecutively assigned to one of three treatment groups. Group A was treated with three or four doses of hepatitis B immune globulin (HBIG) in one of three different schedules. Group B received one dose of hepatitis B vaccine (Hevac-B, Pasteur) at birth and at 1, 2 and 12 months. Group C was treated with the same vaccination schedule as group B and in addition received a single dose of HBIG at birth. Comparisons were made in the 85 babies who had strictly completed the immunization schedule and had been followed for at least 12 months. The three immunization protocols were equally effective, since none of the children became a chronic HBsAg carrier or developed acute symptomatic infection. There were five transient and subclinical infections among children who received only HBIG (group A), one transient infection in group B, and one in group C. There seems to be some correlation between anti-HBs levels and degree of protection, since all transient infections in group A occurred in the subgroups who did not maintain protective antibodies during the first 6 months. Although the percentage of responders in the two vaccinated groups did not differ significantly, children who received only vaccine reached higher antibody levels than those who also received HBIG. Our results suggest that any immunization schedule able to maintain anti-HBs levels during the first 6 months of life would be useful to prevent mother-to-infant transmission of the hepatitis B virus in areas where most of the carrier women are expected to be anti-HBe positive and hence relatively less infectious.     

慢性乙型肝炎患者细胞毒T细胞内穿孔素的表达与病毒载量的关系

目的 研究慢性乙型肝炎患者细胞毒T细胞内穿孔素(Perforin)、干扰素(IFN-γ)和白细胞介素10(IL-10)表达与病毒消除的关系.方法 对50例慢性乙型肝炎患者外周血进行短期培养后,利用流式细胞术测定CD8~+细胞内Perforin、IFN-γ和IL-10表达,并与30例正常对照进行比较;利用荧光定量PCR检测慢性乙型肝炎患者HBV DNA的载量,分析其与CD8~+细胞内Perforin、IFN-γ和IL-10表达的关系.结果 慢性乙型肝炎组CD8~+T细胞Perforin、IFN-γ和IL-10的表达分别为(5.30 ±2.62)%、(4.05±2.25)%和(0.77 ±0.50)%,明显低于正常对照组(t分别为4.50、4.56、4.20,P均<0.01);26例HBeAg阳性的慢性乙型肝炎患者CD8~+T细胞Pefforin和IFN-γ的表达分别为(4.54 ±1.93)%和(3.32 ±1.59)%,明显低于24例HBeAg阴性的慢性乙型肝炎患者(t分别为2.22、2.54,P均<0.05);慢性乙型肝炎患者CD8~+T细胞内Perforin和IFN-γ表达率与乙肝病毒DNA载量成负相关(r分别为-0.539、-0.340,P<0.01、P<0.05).结论 慢性乙型肝炎患者细胞毒T细胞内Perforin、IFN-γ和IL-10表达减少,可能与慢性乙型肝炎患者病毒长期存在,病程迁延不愈有关.     

The prevalence and long term outcome of occult hepatitis B virus infections in community based populations

Features of occult hepatitis B infection in community‐based populations have yet to be described. In this study we documented: (1) the prevalence and demographics, (2) associated serology and viral loads, and (3) clinical outcomes of occult hepatitis B infection in community‐based populations. Hepatitis B surface antigen (HBsAg)‐negative sera collected from three Northern Canadian communities (HBsAg prevalences: 11–12%) in 1983–1985 were tested for HBV‐DNA by nested stage polymerase chain reaction. Of 706 HBsAg negative sera, 9 (1.3%) were HBV‐DNA positive. The median age of occult hepatitis B infected patients at the time of sampling was 9.8 years (range 3.1–50.4 years) and six (67%) were female. Two (22%) individuals were anti‐HBs positive (in the absence of prior vaccination). Viral loads were undetectable in all but two samples (2.40 and 2.86 log₁₀ IU/ml). Only one of the five (20%) patients who were assessed clinically, remained HBV‐DNA positive at 25–30 year follow‐up. There was no clinical, biochemical or radiologic evidence of chronic hepatitis, cirrhosis or hepatocellular carcinoma in these individuals or on review of the charts from the remaining four infected patients. The results of this study suggest that in community‐based populations: (1) occult hepatitis B infection is not as common as HBsAg positive infection, (2) the majority of infected subjects are young females, (3) a minority are anti‐HBs positive, (4) viral loads are either undetectable or low, and (5) in the absence of concurrent liver disease, occult hepatitis B infection does not appear to be associated with long term adverse clinical outcomes. J. Med. Virol. 84:1369–1375, 2012. © 2012 Wiley Periodicals, Inc.     

慢性乙型肝炎患者外周血T细胞KIR表达研究

目的：检测慢性乙型肝炎患者外周血T细胞表面KIR的表达情况。方法：采用三色流式细胞术检测慢性乙型肝炎患者外周血CD4^＋T细胞和CD8^high T细胞表面KIR分子表达，并与正常外周血比较。结果：慢性乙型肝炎患者外周血中CD8^high T细胞KIR表达明显高于对照组CD8^high T细胞。正常外周血CD4^＋T细胞几乎不表达KIR，慢性乙型肝炎患者外周血中CD4^＋T细胞表达KIR。结论：慢性乙型肝炎患者T细胞表面KIR表达明显增加。     

Response to hepatitis B vaccination in patients with liver cirrhosis

Hepatitis B vaccination is strongly recommended for all infants and children but also for adults who are at risk of HBV infection. Attempts to immunize patients with liver cirrhosis have been proven relatively ineffective, and several strategies have already been used to improve the immune response in this group. The primary aim of this review is to examine, discuss, and summarize the immunogenicity of hepatitis B vaccination in patients with liver cirrhosis. MEDLINE search identified 11 studies (n = 961). The dose of the vaccine and the schedule of the vaccination varied. The response rates to the HBV vaccination ranged from 16% to 87% among patients with cirrhosis regardless of the number and vaccine dose. In particular, patients who received the standard dose of vaccination achieved seroprotection rates ranged from 16% to 79% (mean response rate 38%) and those who received a double dose achieved relatively better seroprotection rates (range: 26%‐87%; mean response rate 53%). The overall mean response rate to the HBV vaccination was 47%. In conclusion, cirrhotic patients achieve lower seroprotection rates after the completion of HBV vaccination series. Several strategies have tried to improve the immunogenicity; however, there is a great need for additional studies to further explore (1) the immune response in relation to poor vaccination responsiveness confounding factors, (2) novel strategies to improve immunogenicity, and (3) the immune mechanism underlying the differences in response rates to HBV vaccination.     

Flow cytometry CD4+/CD8+ ratio of liver-derived lymphocytes correlates with viral replication in chronic hepatitis B.

T lymphocytes have been assumed to play an essential role in tissue injury in patients with chronic hepatitis B. As hepatitis B virus (HBV) is considered as a major factor controlling liver inflammation, we assessed whether a particular T lymphocyte subset could be preferentially detected in the liver in accordance with viral replication. Liver-derived lymphocytes and peripheral blood lymphocytes were analysed by flow cytometry in 21 patients with histologically confirmed chronic hepatitis B without cirrhosis. Viral replication was quantified by hybridization of serum HBV DNA. Eleven patients exhibited an active viral replication with serum HBV DNA ranging from 10 to 388 pg/ml at the time of the liver biopsy, whereas 10 patients had no detectable serum HBV DNA. In patients exhibiting viral replication, CD4+/CD8+ ratios of liver-derived lymphocytes were significantly higher (P < 0.05) than those obtained in patients without viral replication. In contrast, the percentage of T cells expressing the gamma/delta receptor and that of CD2+/CD57+ cells were similar in both groups of patients. Furthermore, in patients exhibiting viral replication, CD4+CD8+ ratios of liver-derived lymphocytes correlated with serum HBV DNA levels (P < 0.001). No relationship between CD4+/CD8+ ratio of liver-derived and peripheral blood lymphocytes was observed. Our data indicate that, in patients with chronic hepatitis B, the CD4+/CD8+ ratio of liver-derived lymphocytes correlates with viral replication. This suggests that in situ helper/inducer CD4+ T lymphocytes may positively regulate the cytotoxic T cell activity in patients with HBV-related chronic hepatitis.     

Multicenter trial on the efficacy of HBIG and vaccine in preventing perinatal hepatitis B. Final report

In an attempt to interrupt perinatal transmission of hepatitis B, 92 infants born to HBsAg carrier mothers (49 to HBeAg-positive mothers, 30 to anti-HBe-positive with abnormally elevated ALT levels, and 13 to HBeAg/anti-HBe-negative mothers) received 0.5 ml/kg BW of HBIG at birth and at 1 month of age. Three IM injections of hepatitis B vaccine were given at 3, 4, and 9 months of life. All babies who were given the three doses of vaccine developed an active anti-HBs response: of these, 53 (62.3%) had antibody titers higher than 1,000 mIU/ml, 29 (34.2%) had levels between 100 and 1,000 mIU/ml, and the other three (3.5%) were below 100 mIU/ml. At the end of the 2-year follow-up, these three poor responders became anti-HBs negative, whereas the others still had antibody. All but three babies were protected by HBIG plus vaccine treatment. Two chronic HBV infections occurred within 6 months of life presumably because the babies were already infected when prophylaxis started. The third baby became an HBsAg carrier at 9 months of age in spite of a previous response to the vaccine. Simultaneous presence of HBsAg of y specificity and anti-HBs (anti-a) was still detectable at 24 months of age. The vaccine was well tolerated. Passive plus active immunization is an effective procedure for preventing perinatally transmitted HBV infection.     

Clinical and immunological efficacy of intradermal vaccine plus lamivudine with or without interleukin-2 in patients with chronic hepatitis B

To evaluate therapeutic immunostimulation nine chronic hepatitis B patients received six monthly intradermal vaccinations with HBsAg in combination with daily lamivudine. Another five patients received six doses of the vaccine and daily lamivudine together with daily Interleukin-2 (IL-2) s.c. within 3 months in an open-labeled trial. Clinical efficacy was assessed by alanine transaminase levels and HBV serology. The induction of specific T and B cell responses was analyzed serially by 3H-thymidine uptake, ELISA and ELISPOT assays. After the therapy was stopped, seven of nine vaccine/lamivudine and two of five vaccine/lamivudine/IL-2 recipients did not have detectable HBV DNA. Four complete responders cleared the virus and had normalized ALT levels, however, one of these patients showed transient disease reactivation followed by spontaneous viral clearance and normal ALT five months later. Low frequencies of anti-HBs producing B cells and HBV specific T helper cells secreting predominantly interferon-gamma were induced by i.d. vaccine therapy. The ELISPOT technique demonstrated transient induction of HBV peptide specific cytotoxic T cells in seven HLA-A2 positive chronic HBV carriers. The preliminary data from this study demonstrate that the HBV surface antigen vaccine in combination with antiviral or immunomodulating drugs induced antiviral immune responses and consequently viral elimination may be achieved in patients with unfavorable prognosis.     

Induction of peripheral blood T follicular helper cells expressing ICOS correlates with antibody response to hepatitis B vaccination

T follicular helper (TFH) cells, a critical subset of CD4⁺ T cells, provide help to B cells during the procession of the humoral immune response in the germinal center (GC) and extrafollicular sites. CXCR5⁺CD4⁺ T cells in human circulating blood, referred to herein as peripheral TFH (pTFH) cells, share phenotypes and functional properties with TFH cells in GC. Hepatitis B vaccine protects about 60% of the chronic hepatitis C patients from hepatitis B. The immunological bases that lead to the induction of protective antibody response is not well understood. In the present study, the pTFH cells subsets were determined in 18 healthy controls (anti-HBs ≥ 100 mIU/mL; HC), 21 nonresponders (anti-HBs < 10 mIU/mL; NR), and 23 weak responders (10 mIU/mL ≤ anti-HBs < 100 mIU/mL; WR) of chronic hepatitis patients upon routine hepatitis B vaccination. Though the frequency of the pTFH cell was equivalent in HC, WR, and NR, ICOS⁺pTFH cells in HC underwent expansion with increased IL-21 secretion and production of serum anti-HBs response at 4 weeks after a full course of hepatitis B vaccination. These changes were not shown in both NR and WR. Analysis of ICOS⁺pTFH cells represents a novel cellular determinant of the hepatitis B vaccine–induced humoral immune response, which may have relevance for design of hepatitis B vaccine.