Ethnic disparities in progression to advanced liver disease and overall survival in patients with chronic hepatitis C: impact of a sustained virological response.

BACKGROUND: Chronic hepatitis C (CHC) can lead to cirrhosis and hepatocellular carcinoma (HCC). A sustained virological response (SVR) is associated with improved outcomes, however, its impact on different ethnic groups is unknown. AIM: To evaluate ethnic differences in the natural history of CHC and the impact of SVR. METHODS: We conducted a cohort study of 8039 consecutive adult CHC patients seen at two medical centres in California between January 1997 and June 2016. Individual chart review confirmed CHC diagnosis. RESULTS: Asian and Hispanic but not African American patients had significantly higher cirrhosis and HCC incidence than Caucasians. On multivariate analysis, Hispanic ethnicity was independently associated with increased cirrhosis (adjusted HR 1.37, CI, confidence interval 1.10-1.71, P=.006) and HCC risk (adjusted HR 1.47, CI 1.13-1.92, P=.004) compared to Caucasian. Asian ethnicity had a significant association with cirrhosis (adjusted HR 1.28, CI 1.02-1.61, P=.034) and HCC risk (adjusted HR 1.29, CI 0.94-1.77, P=.025). In patients who achieved SVR, Hispanic ethnicity was no longer independently associated with cirrhosis (adjusted HR 1.76, CI 0.66-4.71, P=.26) or HCC (adjusted HR 1.05, CI 0.27-4.08, P=.94); nor was Asian ethnicity (adjusted HR 0.62, CI 0.21-1.82, P=.38 for cirrhosis; 2.01, CI 0.63-6.36, P=.24 for HCC). Similar findings were observed with overall survival among the ethnicities by SVR status. CONCLUSION: Hispanic and Asian ethnicity was independently associated with increased cirrhosis and HCC risk. Achieving an SVR eliminates the ethnic disparity in liver disease progression and overall survival between Hispanic and Asian vs Caucasian CHC patients.

Immune responses to measles and mumps vaccination of infants at 6, 9, and 12 months.

Immunizing infants against measles at the youngest age possible has the potential to reduce morbidity and mortality. The ability of infants at 6, 9, or 12 months to respond to measles and mumps vaccines was evaluated by measuring T cell proliferation, interferon-gamma production, and neutralizing antibody titers before and after vaccination. Infants in all age groups had equivalent cellular immune responses to measles or mumps viruses, with or without passive antibodies when immunized. In contrast, 6-month-old infants without passive antibodies had low geometric mean titers of antibody to measles or mumps viruses and low seroconversion rates. Geometric mean titers of antibody to measles virus increased if infants were revaccinated at 12 months. Six-month-old infants had limited humoral responses to paramyxovirus vaccines, whereas cellular immunity was equivalent to that of older infants. T cell responses can be established by immunization with these live attenuated virus vaccines during the first year, despite the presence of passive antibodies.

IL-12, IFN-gamma, and T cell proliferation to measles in immunized infants.

Measles infection in infants is associated with severe complications, and secondary infections are attributed to generalized immunosuppression. Measles binding to its monocyte receptor down-regulates IL-12 which is expected to diminish Th1-like cytokine responses, including IFN-gamma. Whether young infants can be immunized effectively against measles is an important public health issue. We evaluated Ag-specific IL-12, IFN-gamma, and T cell responses of infants at 6 (n = 60), 9 (n = 46), or 12 mo (n = 56) of age and 29 vaccinated adults. IL-12 and IFN-gamma release by PBMC stimulated with measles Ag increased significantly after measles immunization in infants. IL-12 and IFN-gamma concentrations were equivalent in younger and older infants, but IL-12 concentrations were significantly lower in infants than in adults (p = 0.04). IL-12 production by monocytes was down-regulated by measles; the addition of recombinant human IL-12 enhanced IFN-gamma production by PBMC stimulated with measles Ag, but infant T cells released significantly less IFN-gamma than adult T cells under this condition. Of particular interest, the presence of passive Abs to measles had no effect on the specific T cell proliferation or IFN-gamma production after measles stimulation. Cellular immunity to measles infection and vaccination may be limited in infants compared with adults as a result of less effective IFN-gamma and IL-12 production in response to measles Ags. These effects were not exaggerated in younger infants compared with effects in infants who were immunized at 12 mo. In summary, infant T cells were primed with measles Ag despite the presence of passive Abs, but their adaptive immune responses were limited compared with those of adults.

Comparison of primary sensitization of naive human T cells to varicella-zoster virus peptides by dendritic cells in vitro with responses elicited in vivo by varicella vaccination.

Dendritic cells (DC) are potent APC during primary and secondary immune responses. The first objective of this study was to determine whether human DC mediate in vitro sensitization of naive CD4+ T cells to epitopes of the immediate early 62 (IE62) protein of varicella zoster virus (VZV). The induction of CD4+ T cell proliferative responses to eight synthetic peptides representing amino acid sequences of the VZV IE62 protein was assessed using T cells and DC from VZV-susceptible donors. The second objective was to compare in vitro responses of naive T cells with responses to VZV peptides induced in vivo after immunization with varicella vaccine. T cell proliferation was induced by three peptides, P1, P4, and P7, in 71-100% of the donors tested before and after vaccination using DC as APC. Monocytes were effective APC for VZV peptides only after immunization. Two peptides, P2 and P8, induced naive T cell proliferation less effectively and were also less immunogenic for T cells from vaccinated or naturally immune donors. T cell recognition of specific peptides was concordant between naive, DC-mediated responses, and postvaccine responses using monocytes as APC in 69% of comparisons (p = 0.05; chi2); the predictive value of a positive response to an IE62 peptide before immunization for T cell sensitization in vivo was 82%. These observations indicate that primary T cell responses detected in vitro using DC as APC may be useful to characterize the potential immunogenicity of viral protein epitopes in vivo.

Isolation and utilization of human dendritic cells from peripheral blood to assay an in vitro primary immune response to varicella-zoster virus peptides.

A human dendritic cell-based assay used to monitor a T cell proliferation response to viral peptides in vitro is described. Dendritic cells and autologous CD4+ T cells were isolated from peripheral blood by a series of density-gradient centrifugations or magnetic bead separations (or both). Peptides corresponding to residues of the immediate early protein, IE62, of varicella-zoster virus (VZV) were used as stimulating antigens, and persons with no history of varicella and no humoral or cellular immunity to VZV served as naive donors for the assays. Three VZV-susceptible donors were tested, and all demonstrated an in vitro response to multiple VZV peptides. This assay has potential as a screen to establish the immunogenicity of viral antigens in vitro using T cells from naive donors.

Genital herpes during pregnancy: inability to distinguish primary and recurrent infections clinically.

OBJECTIVE: To determine if the signs and symptoms of genital herpes in pregnancy accurately identify primary genital herpes infections using serologic testing for final classification. METHODS: Twenty-three women with clinical signs and symptoms suggestive of primary genital herpes infections in the second and third trimesters of pregnancy were subsequently cultured and tested serologically (for herpes simplex virus type 1 and herpes simplex virus type 2 antibodies) and classified as having true primary (no herpes simplex virus type 1 or type 2 antibodies), nonprimary (heterologous herpes simplex virus antibodies present), or recurrent (homologous antibodies present) infections. RESULTS: Only one of 23 women with clinical illnesses consistent with primary genital herpes virus simplex infections had serologically-verified primary infection. This primary infection was caused by herpes simplex virus type 1. Three women had nonprimary type 2 infections, and 19 women had recurrent infections. Among culture-proven recurrent infections, 12 were caused by herpes simplex virus type 2 and three by herpes simplex virus type 1. Only one infant was born preterm, and no clinically significant perinatal morbidity was observed. CONCLUSION: Correct classification of gestational genital herpes infections can be accomplished only when clinical evaluation is correlated with viral isolation and serologic testing using a type-specific assay. Severe first episodes of genital herpes infections among women in the second and third trimesters of pregnancy are not usually primary infections and are not commonly associated with perinatal morbidity.

T cell recognition and cytokine production elicited by common and type-specific glycoproteins of herpes simplex virus type 1 and type 2.

T cell recognition of common and type-specific herpes simplex virus (HSV) glycoproteins was measured in 72 subjects. T cells were stimulated with whole HSV-2 antigen and glycoproteins gB2, gD2, and gG2. T cell proliferation in response to HSV-2 antigen and gG2 was significantly higher in subjects with HSV-2 infection than in those with HSV-1 infection only; responses to gB2 and gD2 were the same. T helper (Th) type 1 and Th2 cytokine production in response to whole HSV-2 antigen, gB2, and gD2 was evaluated in 33 subjects. Interleukin (IL)-2 and interferon-gamma responses to most antigens were significantly higher among HSV-2-seropositive subjects than among seronegative subjects. IL-4 synthesis was negligible; IL-10 was produced in seronegative and seropositive persons, but HSV-2 antigen responses were significantly higher in HSV-2-seropositive persons. Naturally acquired immunity to HSV involves T cell recognition of common and type-specific glycoproteins, prominent Th1 responses, and discordant Th2 responses with little IL-4 but substantial IL-10 production.

Detection of antibodies to herpes simplex virus type 2 with a mammalian cell line expressing glycoprotein gG-2.

The gene (US4) coding for herpes simplex virus type 2 (HSV-2) glycoprotein G (gG-2) was cloned and constitutively expressed in Chinese hamster ovary (CHO) cells. The expression vector containing the dihydrofolate reductase (dhfr) gene, and the HSV-2 US4 gene under the control of the Simian virus 40 early promoter (SV40 EP), was transfected into dhfr-deficient CHO cells. The transfected cells were selected and amplified using methotrexate (MTX). To demonstrate that the gG-2 produced in these transformed cells had antigenic determinants in common with the native glycoprotein, CHO cells expressing gG-2 were used in an immunofluorescent assay (IFA) for the detection of HSV-2 type-specific antibodies in human serum samples. Seven of eight serum samples from adults with prior episodes of culture proven HSV-2 infections were found to be positive by the IFA method whereas none of seven serum samples from young children with culture documented HSV-1 infections were positive by IFA. Thus the recombinant CHO : gG-2 cells have diagnostic utility in an HSV-2 specific serologic assay.

Identification of women at unsuspected risk of primary infection with herpes simplex virus type 2 during pregnancy.

BACKGROUND: Primary infections with herpes simplex virus type 2 (HSV-2) acquired by women during pregnancy account for about half of the morbidity and mortality from HSV-2 among neonates. The other half results from reactivation of old infections. Better methods are needed to identify which women are at risk for primary HSV-2 infection. METHODS: We prospectively studied HSV-2 infections among pregnant women who were patients in private obstetrical practices. Using an enzyme-linked immunosorbent assay that detects type-specific antibodies to HSV-2 glycoprotein G, we determined the prevalence at base line of HSV-2 infections among pregnant women and their husbands, the frequency of discordance for infection between partners, and the risk of seroconversion during pregnancy among the seronegative women whose husbands were seropositive. RESULTS: The seroprevalence of HSV-2 was 32 percent among the 277 women followed throughout their pregnancies and 25 percent among the 190 husbands studied. Two thirds of the HSV-2-seropositive women had no history of genital herpes. Of the 190 couples, 139 (73 percent) were serologically concordant for HSV-2 antibodies (57 percent being seronegative and 16 percent being seropositive), whereas 51 couples (27 percent) were discordant, despite having been sexually intimate for a mean of 6.1 years. Eighteen women who were seronegative for HSV-2 (9.5 percent) had seropositive partners, of whom 10 (56 percent) had no history of genital herpes. Thus, approximately 5 percent of these pregnant women had an unsuspected risk of contracting a primary HSV-2 infection. One of the 18 seronegative women with a seropositive husband seroconverted to HSV-2 during pregnancy; none of the other women seroconverted. CONCLUSIONS: In this study about 10 percent of pregnant women were at risk of contracting a primary HSV-2 infection from their HSV-2-seropositive husbands. In addition, about a third of these women were seropositive for HSV-2 and thus at risk for asymptomatic, reactivated infections. Serologic testing of couples can identify women who are at risk for primary or reactivated HSV-2 infections during pregnancy.

Use of polymerase chain reaction for successful identification of asymptomatic genital infection with herpes simplex virus in pregnant women at delivery.

The polymerase chain reaction was adapted to the amplification of a herpes simplex virus (HSV) DNA sequence, common to HSV types 1 and 2 (HSV-1, HSV-2). The amplified product was detectable by ethidium-bromide staining or Southern hybridization of gels and by dot hybridization. The HSV polymerase chain reaction detected HSV DNA in samples obtained from eight patients with genital lesions from which HSV-2 was isolated in tissue culture and from four patients with labial lesions from which HSV-1 was isolated. The HSV polymerase chain reaction identified HSV in clinical specimens obtained from 11 women who had asymptomatic genital HSV infections at delivery. None of 11 samples obtained at delivery from women who had antibodies to HSV-2, but whose delivery cultures were negative, were positive by polymerase chain reaction and no false-positive reactions were obtained when the reaction mixture contained human cell DNA or varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, or human papillomavirus DNA.

A prospective evaluation of primary genital herpes simplex virus type 2 infections acquired during pregnancy.

In order to study the epidemiology of herpes simplex type 2 (HSV-2) infections during pregnancy, we used an enzyme immunoassay to detect type-specific antibodies to HSV-2 glycoprotein G in serial blood samples obtained from a cohort of 1891 pregnant women. Blood samples obtained at about 17 and 32 weeks of gestation and at the time of delivery were assessed for antibody to HSV-2 glycoprotein G in order to evaluate the prevalence of past infections with HSV-2 and the rate of acquisition of HSV-2 infection during pregnancy. Three hundred eleven pregnant women (16.5%) were found to have had past infections with HSV-2. Four of the 1580 women who were initially seronegative developed antibodies to HSV-2 during pregnancy. The annualized rate of acquisition of HSV-2 infection in pregnant women was 0.58%. Three of four women had asymptomatic primary infections; all of the women had preexisting HSV-1 immunity. None of the women or their infants experienced any adverse consequences of gestational herpes. Based upon our very limited number of observations to date, asymptomatic primary episodes occurring in women with previous HSV-1 immunity may be of less consequence to the fetus and neonate than symptomatic true primary HSV-2 infections.

Use of routine viral cultures at delivery to identify neonates exposed to herpes simplex virus.

We obtained specimens for viral culture from mothers, infants, or both at the time of 6904 deliveries, without regard to the mothers' history of genital herpes. Herpes simplex virus (HSV) was recovered in cultured specimens from 14 of the 6904 deliveries (0.20 percent); all 14 mothers were asymptomatic. All viral isolates were herpes simplex virus type 2 (HSV-2). Only 1 of the 14 women (7 percent) had a history of genital herpes, whereas 12 (86 percent) had serologic evidence of a previous infection with HSV-2. None of the infants born to these 12 women contracted neonatal herpes. However, one of the two infants born to women with serologic evidence of a primary HSV infection at the time of delivery contracted neonatal herpes. Our findings show that most infants at risk of exposure to HSV at delivery will not be identified if concern about asymptomatic shedding of virus is limited to women with a history of genital herpes infection. Most neonatal exposure to an asymptomatic maternal HSV infection at delivery is not predictable or preventable. Therefore, physicians caring for newborns need to consider neonatal herpes in the differential diagnosis when infants become ill during the first weeks of life, regardless of the presence or absence of identifiable risk factors for HSV infection.

Type-specific antibodies to herpes simplex virus type 2 (HSV-2) glycoprotein G in pregnant women, infants exposed to maternal HSV-2 infection at delivery, and infants with neonatal herpes.

We used a murine monoclonal antibody to herpes simplex virus (HSV) type 2 (HSV-2) glycoprotein G (gG) to develop an enzyme immunoassay that detected HSV-2 type-specific antibodies in human sera. Antibodies to HSV-2 gG were detected in 98 (96%) of 102 sera from pregnant women with culture-proved HSV-2 infection. Sixty-five percent of the women had serological evidence of past HSV-2 infection by the Rawls index, based on titers of neutralizing antibody to HSV type 1 and HSV-2. Thirty (88%) of 34 infants exposed to maternal HSV infection at delivery had antibodies to HSV-2 gG and remained well. One infant exposed to primary maternal HSV-2 infection lacked antibodies to HSV-2 gG and developed neonatal HSV-2 infection. The mean +/- SD optical density by HSV-2 gG enzyme-linked immunosorbent assay for sera obtained from 17 infants within one week after onset of neonatal HSV-2 infection was 0.25 +/- 0.12, compared with 1.15 +/- 0.34 in cord blood sera from exposed infants who did not develop symptoms (P less than .0001 by t test).

Humoral and cell-mediated immunity in neonates with herpes simplex virus infection.

Fifty-nine neonates with herpes simplex virus (HSV) infection were evaluated with use of assays for neutralizing antibody (NAb), lymphocyte transformation (LT), alpha interferon production, and virus-specific antibody (immunoblots). Infants with disseminated disease or onset in the first week of life were more likely to lack NAb. Patients treated with vidarabine were more likely than those treated with acyclovir to develop a fourfold rise in NAb titer. Infants with encephalitis showed a broader spectrum of IgG and IgM antibody reactivity against HSV proteins by immunoblotting than did those who had earlier onset of mucocutaneous illness. Only 10 of 33 infants had HSV-specific LT, compared with eight of eight adults with primary HSV. Neonates with positive LT were more likely to show a fourfold rise in NAb titer. In vitro alpha interferon production was diminished in infants, compared with values in adults.

Low risk of herpes simplex virus infections in neonates exposed to the virus at the time of vaginal delivery to mothers with recurrent genital herpes simplex virus infections.

We studied the risk of herpes simplex virus (HSV) infections in neonates exposed to HSV at the time of vaginal delivery to mothers with a history of recurrent genital HSV infections. None of 34 infants exposed to HSV type 2 acquired an HSV infection. On the basis of this sample, the 95 percent confidence limit for the theoretical maximum infection rate is 8 percent. Cord blood or blood obtained during the first two weeks of life was available from 33 of the 34 exposed, uninfected neonates. All 33 of the samples possessed demonstrable neutralizing antibody to HSV type 2, and 79 percent had titers above 1:20. These results were compared with those in a previously studied group of neonates with HSV infections; the latter infants were significantly less likely at the onset of symptoms to have demonstrable neutralizing antibody to HSV type 2 (P = 0.000148) or to have titers above 1:20 (P less than 0.00001). We conclude that given the low attack rate, empirical antiviral therapy is not warranted in all infants of mothers with recurrent genital HSV infection who are exposed to the virus in the birth canal. Our findings suggest that the presence and titer of neutralizing antibody to HSV contribute to the low attack rate.

Failure of antepartum maternal cultures to predict the infant's risk of exposure to herpes simplex virus at delivery.

In 414 pregnant women with a history of recurrent genital herpes simplex infection, we studied the correlation between asymptomatic viral shedding in late pregnancy and at the time of delivery. Antepartum cultures for asymptomatic reactivation of herpes simplex virus were positive in 17 of the 414 women (4.1 percent). None of these women had positive cultures at the time of delivery. Cultures of specimens obtained at delivery from 5 of 354 asymptomatic mother-infant pairs (1.4 percent) were positive for asymptomatic excretion of herpes simplex virus. None of these women had had antepartum cultures that documented asymptomatic excretion of herpes simplex virus, despite the fact that culturing was repeatedly performed during the four weeks before delivery. Asymptomatic shedding of herpes simplex virus occurred with the same frequency at delivery, whether or not any episodes of symptomatic recurrence were noted during the pregnancy (1.4 vs. 1.3 percent). We conclude that antepartum maternal cultures do not predict the infant's risk of exposure to herpes simplex virus at delivery.