Tenofovir for prevention of mother to child transmission of hepatitis B in migrant women in a resource-limited setting on the Thailand-Myanmar border: a commentary on challenges of implementation.

BACKGROUND: The aim of this manuscript is to highlight challenges in the implementation of maternal tenofovir disoproxil fumarate (tenofovir) for prevention of mother to child transmission (PMTCT) of hepatitis B virus (HBV) in resource limited setting. Current preventive strategies in resource-limited settings fail mainly due to prohibitive costs of hepatitis B immunoglobulin (HBIG) and a high proportion of homebirths, meaning both HBIG and hepatitis B birth dose vaccine are not given. A new strategy for PMTCT without the necessity of HBIG, could be daily tenofovir commenced early in gestation. Implementation challenges to early tenofovir for PMTCT can provide insight to elimination strategies of HBV as the burden of disease is high in resource-limited settings. METHODS: Challenges encountered during implementation of a study of tenofovir for PMTCT before 20 weeks gestation in rural and resource-limited areas on the Thailand-Myanmar border were identified informally from trial study logbooks and formally from comments from patients and staff at monthly visits. ClinicalTrials.gov Identifier: NCT02995005. MAIN BODY: During implementation 171 pregnant women were hepatitis B surface antigen (HBsAg) positive by point of-care test over 19 months (May-2018 until Dec-2019). In this resource-limited setting where historically no clinic has provided tenofovir for PMTCT of HBV, information provided by staff resulted in a high uptake of study screening (95.5% (84/88) when offered to pregnant women. False positive point-of-care rapid tests hinder a test and treat policy for HBV and development of improved rapid tests that include HBeAg and/or HBV DNA would increase efficiency. Integrated care of HBV to antenatal care, transport assistance and local agreements to facilitate access, could increase healthcare at this critical stage of the life course. As safe storage of medication in households in resource-limited setting may not be ideal, interactive counseling about this must be a routine part of care. CONCLUSION: Despite challenges, results from the study to date suggest tenofovir can be offered to HBV-infected women in resource-limited settings before 20 weeks gestation with a high uptake of screening, high drug accountability and follow-up, with provision of transportation support. This commentary has highlighted practical implementation issues with suggestions for strategies that support the objective of PMTCT and the World Health Organization goal of HBV elimination by 2030.

Knowledge regarding hepatitis B mother-to-child transmission among healthcare workers in South China.

To determine the knowledge regarding hepatitis B virus (HBV) mother-to-child transmission (MTCT) and its prevention and treatment among healthcare workers (HCWs) in Guangdong Province, China, an HBV endemic area. An HBV knowledge questionnaire was administered to 900 HCWs from the 3rd Affiliated Hospital of Sun Yat-Sen University and 2 rural hospitals in Guangdong Province. The 27 items in the questionnaire fell into 3 sections: HBV MTCT general knowledge, respondents' practices of preventing HBV MTCT and awareness of the resources of preventing HBV MTCT. The data collected were coded and analysed using SPSS software version 20. In total, 503 of 900 HCWs responded to the survey (response rate: 55.9%). Eighty-four individuals responded correctly to all of the knowledge questions: 58 were doctors, and 26 were nurses (P < .05). Doctors more often performed practices than nurses (t = 3.591, P < .01). Participants from the infectious disease department demonstrated a significantly higher proportion of correct answers and resource utilization than other specialties (χ2  = 14.052, 7.998, P < .01). In terms of the average knowledge score, t test or ANOVA showed that there were significant differences between the specialty groups (t = 3.110, P < .01), hospital level groups (t = 2.337, P < .05) and age groups (F = 3.020, P < .05). Respondents' initiative increased with hospital level and age (t = 2.993, 7.493, P < .01). A considerable percentage of HCWs has misconceptions about HBV MTCT. Healthcare workers, in particular nurses, those working in noninfectious disease departments or township hospitals and younger medical staff, lack systematic and comprehensive knowledge about HBV MTCT and are in urgent need of HBV-related training.

Differences in hepatitis C virus prevalence and clearance by mode of acquisition among men who have sex with men.

We examined the characteristics associated with hepatitis C virus (HCV) antibody (anti-HCV) prevalence and HCV clearance between injection drug using (IDU) and non-IDU men who have sex with men (MSM). Stored serum and plasma samples were tested for anti-HCV and HCV RNA to determine the HCV status of 6925 MSM at enrolment into the Multicentre AIDS Cohort Study (MACS). Prevalence and clearance ratios were calculated to determine the characteristics associated with HCV prevalence and clearance. Multivariable analyses were performed using Poisson regression methods with robust variance estimation. Anti-HCV prevalence was significantly higher among IDU than among non-IDU MSM (42.9% vs 4.0%), while clearance was significantly lower among IDU MSM (11.5% vs 34.5% among non-IDU MSM). HIV infection, Black race, and older age were independently associated with higher prevalence in both groups, while smoking, transfusion history, and syphilis were significantly associated with prevalence only among non-IDU MSM. The rs12979860-C/C genotype was the only characteristic independently associated with HCV clearance in both groups, but the effects of both rs12979860-C/C genotype [clearance ratio (CR) = 4.16 IDUs vs 1.71 non-IDUs; P = 0.03] and HBsAg positivity (CR = 5.06 IDUs vs 1.62 non-IDUs; P = 0.03) were significantly larger among IDU MSM. HIV infection was independently associated with lower HCV clearance only among non-IDU MSM (CR = 0.59, 95% CI = 0.40-0.87). IDU MSM have higher anti-HCV prevalence and lower HCV clearance than non-IDU MSM. Differences in the factors associated with HCV clearance suggest that the mechanisms driving the response to HCV may differ according to the mode of acquisition.

Admixture analysis of spontaneous hepatitis C virus clearance in individuals of African descent.

Hepatitis C virus (HCV) infects an estimated 3% of the global population with the majority of individuals (75-85%) failing to clear the virus without treatment, leading to chronic liver disease. Individuals of African descent have lower rates of clearance compared with individuals of European descent and this is not fully explained by social and environmental factors. This suggests that differences in genetic background may contribute to this difference in clinical outcome following HCV infection. Using 473 individuals and 792,721 single-nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS), we estimated local African ancestry across the genome. Using admixture mapping and logistic regression, we identified two regions of interest associated with spontaneous clearance of HCV (15q24, 20p12). A genome-wide significant variant was identified on chromosome 15 at the imputed SNP, rs55817928 (P=6.18 × 10(-8)) between the genes SCAPER and RCN. Each additional copy of the African ancestral C allele is associated with 2.4 times the odds of spontaneous clearance. Conditional analysis using this SNP in the logistic regression model explained one-third of the local ancestry association. Additionally, signals of selection in this area suggest positive selection due to some ancestral pathogen or environmental pressure in African, but not in European populations.

Relation of HLA class I and II supertypes with spontaneous clearance of hepatitis C virus.

Human leukocyte antigen (HLA) genotype has been associated with the probability of spontaneous clearance of hepatitis C virus (HCV). However, no prior studies have examined whether this relationship may be further characterized by grouping HLA alleles according to their supertypes, defined by their binding capacities. There is debate regarding the most appropriate method to define supertypes. Therefore, previously reported HLA supertypes (46 class I and 25 class II) were assessed for their relation with HCV clearance in a population of 758 HCV-seropositive women. Two HLA class II supertypes were significant in multivariable models that included: (i) supertypes with significant or borderline associations with HCV clearance after adjustment for multiple tests, and (ii) individual HLA alleles not part of these supertypes, but associated with HCV clearance in our prior study in this population. Specifically, supertype DRB3 (prevalence ratio (PR)=0.4; P=0.004) was associated with HCV persistence, whereas DR8 (PR=1.8; P=0.01) was associated with HCV clearance. Two individual alleles (B*57:01 and C*01:02) associated with HCV clearance in our prior study became nonsignificant in analysis that included supertypes, whereas B*57:03 (PR=1.9; P=0.008) and DRB1*07:01 (PR=1.7; P=0.005) retained their significance. These data provide epidemiologic support for the significance of HLA supertypes in relation to HCV clearance.

Single nucleotide polymorphisms and haplotypes in the IL10 region associated with HCV clearance.

Hepatitis C virus (HCV) is an infectious blood-borne pathogen that usually persists as a chronic infection. However, approximately 15% of the time, patients can clear the virus, indicating that host differences could be critical in determining the course of HCV infection. The inflammatory response is crucial to resolving or failing to resolve an acute HCV infection. Some previous reports have implicated interleukin 10 (IL10) polymorphisms with successful anti-HCV therapy and natural viral clearance. We tested 54 single nucleotide polymorphisms (SNPs) in the IL10 region (+/-300 kb and 24 within the IL10 gene itself), which contains 13 genes including the IL10 immunomodulatory paralogs IL19, IL20, and IL24, for association with HCV clearance vs persistence. SNPs from two haplotype block regions, one at IL10 and the other from IL19/IL20, were associated with HCV clearance in African Americans (91 clearance cases and 183 chronically infected matched controls; P=0.05-0.002) while with expectation-maximization algorithm-reconstructed haplotypes, these associations remained (P=0.05-0.002). However, no significant associations were detected in European Americans (108 clearance and 245 chronic). Our results indicate that variants of the immunomodulatory IL10 and IL19/IL20 genes may be involved in natural clearance of HCV in the African-American population.

An analysis of tumor necrosis factor alpha gene polymorphisms and haplotypes with natural clearance of hepatitis C virus infection.

The cytokine tumor necrosis factor alpha (TNF-alpha) is important in generating an immune response against a hepatitis C virus (HCV) infection. The functions of TNF-alpha may be altered by single-nucleotide polymorphisms (SNPs) in its gene, TNF. We hypothesized that SNPs in TNF may be important in determining the outcome of an HCV infection. To test this hypothesis, we typed nine TNF SNPs in a cohort of individuals with well-defined HCV outcomes. Three of these SNPs were typed in a second cohort. Data were analyzed using logistic regression stratifying by ethnicity, since rates of HCV clearance differ in black subjects versus white subjects. The SNP -863A was associated with viral clearance in black subjects (odds ratios (OR) 0.52, 95% confidence interval (CI) 0.29-0.93). Furthermore, the common wild-type haplotype -863C/-308G was associated with viral persistence in black subjects (OR 1.91, 95% CI 1.24-2.95). These findings were independent of linkage with human leukocyte antigen (HLA) alleles. Further study of this polymorphism and haplotype is needed to understand these associations and the role of TNF-alpha in determining outcomes of HCV infection.

MICA and recovery from hepatitis C virus and hepatitis B virus infections.

The polymorphic MHC class I chain-related A (MICA) gene encodes a ligand that has different binding affinities for the NKG2D activating receptor of CD8+ T cells and natural killer (NK) cells. We hypothesized that MICA heterogeneity would affect recovery from hepatitis C virus (HCV) and hepatitis B virus (HBV) infections. To test the hypothesis, we initially typed known MICA polymorphisms for 228 persons who cleared HCV infection and 442 persons with persistent hepatitis C matched on other factors affecting viral persistence. Although MICA(*)015 was detected more than two-fold more often in persons with viral clearance (odds ratio 0.36, 95% confidence interval=0.19, 0.80), it occurred in fewer than 5% of the study population. In a similar analysis of 442 persons with chronic hepatitis B and 768 matched controls who recovered, MICA(*)015 was detected in 2.0% of persons with chronic hepatitis B and only 0.9% of controls. No significant associations were detected with other MICA polymorphisms. While further investigation may reveal a structural basis of the MICA(*)015 associations, these data provide little support for the hypothesis that differential distribution of MICA alleles substantially affects recovery from HCV and HBV infections.

Racial differences in HLA class II associations with hepatitis C virus outcomes.

A broad, vigorous CD4 T cell response, mediated by class II human leukocyte antigens (HLAs), favors hepatitis C virus (HCV) clearance. HLA-DQB1*0301 has been associated with viral clearance in an ethnically homogeneous cohort. To validate this association and to identify other class II associations in an ethnically varied cohort, molecular class II HLA typing was performed on 200 HCV clearance and 374 matched persistently infected subjects. HLA-DQB1*0301 was weakly associated with viral clearance in combined ethnic groups (odds ratio [OR], 0.72; 95% confidence interval [CI], 0.53-0.97) but was stronger in black subjects. In white subjects, viral clearance was associated with DRB1*0101 (OR, 0.32; 95% CI, 0.17-0.60) and its DQB1*0501 haplotype, whereas viral persistence was associated with DRB1*0301 (OR, 2.36; 95% CI, 1.23-4.52) and its DQB1*0201 haplotype. These results support a role for class II alleles in the immune response to HCV and underscore the importance of studying genetic associations in an ethnically diverse cohort.

Screening for hepatitis C virus in human immunodeficiency virus-infected individuals.

Immunosuppression from human immunodeficiency virus (HIV) may impair antibody formation, and false-negative hepatitis C virus antibody (anti-HCV) tests have been reported in individuals coinfected with HIV and HCV. It is unknown if the frequency of false-negative tests is sufficiently high to change screening recommendations in this setting. Thus, the prevalence of false-negative results for anti-HCV by third-generation tests was determined with samples from HIV-infected individuals. Sera from 559 HIV-infected and 944 HIV-negative prospectively followed injection drug users were tested for anti-HCV by a third-generation enzyme immunoassay and for HCV RNA by using a branched DNA assay and the HCV COBAS AMPLICOR system. Of 559 HIV-infected participants, 547 (97.8%) were anti-HCV positive. One of the remaining 12 anti-HCV-negative participants was HCV RNA positive, and she later developed detectable anti-HCV. Of the 944 HIV-negative participants, 825 (87.4%) were anti-HCV positive. One of the remaining 119 anti-HCV-negative participants was HCV RNA positive, and she also developed detectable anti-HCV at a later visit. These data indicate that HIV infection does not alter the approach to hepatitis C virus screening, which should be performed with third-generation assays for anti-HCV unless acute infection is suspected.

Refinements of environmental assessment during an outbreak investigation of invasive aspergillosis in a leukemia and bone marrow transplant unit.

OBJECTIVES: To investigate an outbreak of aspergillosis in a leukemia and bone marrow transplant (BMT) unit and to improve environmental assessment strategies to detect Aspergillus. DESIGN: Epidemiological investigation and detailed environmental assessment. SETTING: A tertiary-care university hospital with a 37-bed leukemia and BMT unit PARTICIPANTS: Leukemic or BMT patients with invasive aspergillosis identified through prospective surveillance and confirmed by chart review. INTERVENTIONS: We verified the diagnosis of invasive fungal infection by reviewing medical charts of at-risk patients, performing a case-control study to determine risk factors for infection, instituting wet mopping to clean all floors, providing N95 masks to protect patients outside high-efficiency particulate air (HEPA)-filtered areas, altering traffic patterns into the unit, and performing molecular typing of selected Aspergillus flavus isolates. To assess the environment, we verified pressure relationships between the rooms and hallway and between buildings, and we compared the ability of large-volume (1,200 L) and small-volume (160 L) air samplers to detect Aspergillus spores. RESULTS: Of 29 potential invasive aspergillosis cases, 21 were confirmed by medical chart review. Risk factors for developing invasive aspergillosis included the length of time since malignancy was diagnosed (odds ratio [OR], 1.0; P=.05) and hospitalization in a patient room located near a stairwell door (OR, 3.7; P=.05). Two of five A. flavus patient isolates were identical to one of the environmental isolates. The pressure in most of the rooms was higher than in the corridors, but the pressure in the oncology unit was negative with respect to the physically adjacent hospital; consequently, the unit acted essentially as a vacuum that siphoned non-HEPA-filtered air from the main hospital. Of the 78 samples obtained with a small-volume air sampler, none grew an Aspergillus species, whereas 10 of 40 cultures obtained with a large-volume air sampler did. CONCLUSIONS: During active construction, Aspergillus spores may have entered the oncology unit from the physically adjacent hospital because the air pressure differed. Guidelines that establish the minimum acceptable pressures and specify which pressure relationships to test in healthcare settings are needed. Our data show that large-volume air samples are superior to small-volume samples to assess for Aspergillus in the healthcare environment.

Paecilomyces lilacinus fungemia in an adult bone marrow transplant recipient.

Paecilomyces lilacinus is a rare fungal pathogen in humans. We report a case of fungemia caused by P. lilacinus in a non-neutropenic adult, 120 days after bone marrow transplant. The patient's primary risk factor was the presence of an indwelling vascular catheter. Her initial clinical course was characterized by fever, chills, and rigors. Blood cultures from the central line and peripheral veins were positive, as was a peripheral specimen drawn after removal of the catheter. Two initial peripheral specimens were positive for P. lilacinus only by blind subculture and/or sustained incubation. She developed peripheral pulmonary nodules following the fungemia, thus raising the possibility of disseminated disease, but definitive diagnosis was confounded by Pseudomonas bacteremia. The nodules cleared and she recovered following removal of the central line and treatment with amphotericin B and 5-fluorocytosine, despite in vitro resistance to these antifungal drugs. This case underscores the increasing importance of P. lilacinus as a human pathogen capable of producing disease in immunocompetent, as well as in immunocompromised hosts. Also of note is that blood culture systems may require extended incubation or subcultures in order to detect fungi.

Class II HLA alleles and hepatitis B virus persistence in African Americans.

Persistence of hepatitis B virus (HBV) infection is likely due to the interplay of the virus and host immune response. Given its critical role in antigen presentation, allelic differences in the HLA complex may affect HBV persistence. In a prospectively followed African American cohort, molecular class I and class II HLA typing was done on 31 subjects with persistent HBV infection and 60 controls who cleared the infection. HBV persistence was significantly associated with two class II alleles, DQA1 *0501 (odds ratio [OR], 2.6; P=.05) and DQB1 *0301 (OR, 3.9; P=.01), the two-locus haplotype consisting of these same two alleles (OR, 3; P=. 005) and the three-locus haplotype, DQA1 *0501, DQB1 *0301, and DRB1 *1102 (OR, 10.7; P=.01). In addition, HBV persistence was associated with class II allelic homozygosity. Several class I associations with persistence were also noted but were not statistically significant after correction for multiple comparisons. These results underscore the importance of the class II-mediated immune response in recovery from HBV infection.

Differential modulation of TTX-sensitive and TTX-resistant Na+ channels in spinal cord astrocytes following activation of protein kinase C.

TTX-sensitive (TTX-S) and TTX-resistant (TTX-R) Na+ currents are expressed in high densities (2-8 channels/microns2) in astrocytes cultured from neonatal rat spinal cord. The two Na+ current types differ up to 1000-fold in their TTX sensitivity and additionally have different steady-state activation (g-V) and inactivation (h infinity) curves. Expression of TTX-S and TTX-R Na+ currents is confined to morphologically distinguishable subtypes of astrocytes, allowing characterization of the two types of Na+ currents in isolation: stellate cells express TTX-S Na+ currents and flat pancake cells express TTX-R Na+ currents. Activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) exhibited different effects on TTX-S and TTX-R Na+ currents. PMA reduced peak TTX-S Na+ currents by 25-60%; in contrast, PMA potentiated peak TTX-R Na+ currents by 60-150%. These effects developed within minutes, and were typically not reversible. PMA effects were voltage dependent, and shifted steady-state Na+ current activation of TTX-R and TTX-S currents by 6 and 18 mV, respectively, but without affecting their steady-state current inactivation (h infinity). PMA treatment also changed Na+ current kinetics. TTX-R current activation (tau m) was faster and current inactivation (tau h) changed from a single- to a bi-exponential after PMA exposure, suggesting that PKC phosphorylation may have activated formerly quiescent Na+ channels. In contrast, TTX-S current activation (tau m) was unchanged, and current inactivation (tau h), on average, decreased by 50% following PMA exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Ion channels in spinal cord astrocytes in vitro. III. Modulation of channel expression by coculture with neurons and neuron-conditioned medium.

1. Astrocytes cultured from rat spinal cord express voltage-activated Na+ channels in high densities (up to 8 channels per microns2). Stellate astrocytes express Na+ currents at all times in vitro. In pancake astrocytes, Na+ channel expression shows a distinct temporal pattern, an absence of channel expression at 1-3 days in vitro (DIV), and peak Na+ channel density at 7-8 DIV. 2. Coculture of spinal cord astrocytes with dorsal root ganglion (DRG) neurons substantially reduces the expression of voltage-activated Na+ channels in both spinal cord astrocyte types. In pancake spinal cord astrocytes, both the percentage of cells expressing Na+ channels and the channel density in Na+ channel-expressing cells are markedly reduced. In stellate spinal cord astrocytes, the percentage of Na+ channel-expressing cells is unchanged, but the Na+ channel density per cell is markedly reduced in coculture. 3. Culturing spinal cord astrocytes in neuron-conditioned media reduces Na+ channel expression in both spinal cord astrocyte types to levels intermediate between coculture and control, suggesting that, at least in part, neuronal effects on Na+ channel expression are mediated by a soluble factor secreted into the media by neurons. 4. As with the expression of voltage-activated Na+ channels, the expression of voltage-activated K+ channels is reduced in both spinal cord astrocyte types cocultured with DRG neurons. The effect is not mimicked by culturing cells in neuron-conditioned media, suggesting that effects on K+ channel expression are mediated by a less stable and more readily degradable factor. 5. Coculture with DRG neurons or culture in neuron-conditioned media do not alter the biophysical properties of voltage-activated Na+ currents in pancake spinal cord astrocytes. Thus steady-state activation, steady-state inactivation, and the time constants of activation and inactivation are virtually unchanged under the various culture conditions.