Detection of Viral RNA and DNA and Immune Response Following Administration of Live Attenuated Measles and Varicella Vaccines in Children with Chronic Liver Disease.

Infections preventable by live virus vaccines are surging in the setting of decreased herd immunity. Many children with chronic liver diseases (CLD) are unimmunized and at increased risk for infection due to guidelines recommending against live vaccines within 4 weeks pre-transplant. This prospective study of 21 children with CLD and 13 healthy controls defined the timing of measles and varicella RNA- and DNA-emia following vaccination and compared immune responses to measles and varicella vaccines in both groups. Measles RNA and varicella DNA real-time PCR were measured weekly following vaccination; measles RNA was undetectable in all by 14 days post-vaccination, but varicella DNA, which can be managed with antivirals, was detected in one child in the CLD group at 21 days and one control at 28 days post-vaccination. Humoral or cell-mediated vaccine response was 100% to measles and 94% to varicella in the CLD group post-vaccination, while it was 100% to both vaccines in controls. Our pilot study suggests that both live vaccines can be safely and effectively administered up to 14-days prior to transplantation in children with CLD. We anticipate this will improve vaccination rates and thus decrease rates of vaccine preventable infections in vulnerable children with CLD.

Modern antiretroviral regimens in pregnant women: virologic outcomes and durability.

OBJECTIVES: Data are lacking on the virologic efficacy and durability of modern antiretroviral treatment (ART) regimens during pregnancy. We compared virologic outcomes at delivery among women receiving dolutegravir versus other ART and the rate of change of the initial pregnancy regimen. DESIGN: Single-site retrospective cohort between 2009 and 2019. METHODS: We used univariable and multivariable generalized estimating equations to model the relationship between the maternal ART anchor and the proportion of women with a detectable viral load (greater than or equal to 20 HIV RNA copies/mL of plasma) closest to delivery (suboptimal virologic control) and with a detectable viral load at any time in the third trimester. We also compared changes in ART during pregnancy. RESULTS: We evaluated 230 pregnancies in 173 mothers. Rates of optimal virologic control at delivery did not significantly differ in mothers who received dolutegravir (93.1%), rilpivirine (92.1%), boosted darunavir (82.6%), or efavirenz (76.9%) but were significantly lower among mothers receiving atazanavir (49.0%) or lopinavir (40.9%). The odds of having a detectable viral load at any time in the third trimester was also higher for atazanavir and lopinavir. Raltegravir, elvitegravir, or bictegravir were used in less than 10 mothers at delivery, which precluded statistical analyses. The frequency of change in ART was significantly higher in mothers who initially received elvitegravir (68%) or efavirenz (47%) than dolutegravir (18%). CONCLUSION: Dolutegravir-containing, rilpivirine-containing, and boosted darunavir-containing regimens conferred excellent virologic control in pregnancy. Atazanavir and lopinavir, elvitegravir, and efavirenz were associated with either high rates of virologic failure or regimen change during pregnancy.

Innate and Adaptive Cell-Mediated Immune Responses to a COVID-19 mRNA Vaccine in Young Children.

Background: There is little information on cell-mediated immunity (CMI) to COVID-19 mRNA vaccines in children. We studied adaptive and innate CMI in vaccinated children aged 6 to 60 months. Methods: Blood obtained from participants in a randomized placebo-controlled trial of an mRNA vaccine before and 1 month after the first dose was used for antibody measurements and CMI (flow cytometry). Results: We enrolled 29 children with a mean age of 28.5 months (SD, 15.7). Antibody studies revealed that 10 participants were infected with SARS-CoV-2 prevaccination. Ex vivo stimulation of peripheral blood mononuclear cells with SARS-CoV-2 spike peptides showed significant increases pre- to postimmunization of activated conventional CD4+ and γδ T cells, natural killer cells, monocytes, and conventional dendritic cells but not mucosa-associated innate T cells. Conventional T-cell, monocyte, and conventional dendritic cell responses in children were higher immediately after vaccination than after SARS-CoV-2 infection. The fold increase in CMI pre- to postvaccination did not differ between children previously infected with SARS-CoV-2 and those uninfected. Conclusions: Children aged 6 to 60 months who were vaccinated with a COVID-19 mRNA vaccine developed robust CMI responses, including adaptive and innate immunity.

Cytomegalovirus in biliary atresia is associated with increased pretransplant death, but not decreased native liver survival.

BACKGROUND: Biliary atresia (BA) is likely caused by a common phenotypic response to various triggers; one proposed trigger, cytomegalovirus (CMV), may lead to worse outcomes. The aim of this study was to determine the severity of disease and pretransplant outcomes of infants with BA, who have evidence of CMV (CMV+) at diagnosis compared with CMV-negative (CMV-) infants. METHODS: The study used data and biospecimens from the Childhood Liver Disease Research Network PROBE study of cholestatic infants. Plasma obtained at the time of hepatic portoenterostomy (HPE) of 249 infants with BA was tested for CMV by DNA-PCR and CMV-IgM. Comparisons between CMV+ and CMV- infants were made using Wilcoxon rank sum, Student t test, chi-square, or Fisher exact test. Native liver survival (NLS) outcomes were analyzed using Kaplan-Meier and Cox regression adjusting for age at HPE; pretransplant patient survival outcomes were analyzed using a competing risk model and adjusting for age at HPE. RESULTS: CMV+ infants (n = 29, 12%) underwent HPE later (67.8±13.6 d vs. 55.1±18.5 d, p = 0.0005) and had higher baseline alkaline phosphatase and aminotransferases. There was no difference between groups in jaundice clearance or NLS. The subdistribution HR of pretransplant death for CMV+ infants adjusted for age at HPE was 3.8 (p = 0.034). CONCLUSIONS: CMV infection at the time of HPE in infants with BA is not associated with worse NLS despite the association with worse liver injury, older age at HPE, and increased risk of pretransplant death adjusted for age at HPE. Continued evaluation of the consequences of CMV infection and the effects of antiviral treatment should be explored.

Cytomegalovirus Immune reconstitution in cord blood transplant recipients on letermovir prophylaxis.

INTRODUCTION: Cytomegalovirus (CMV) can cause significant morbidity and mortality in cord blood transplant (CBT) recipients. Development of CMV-specific cell-mediated immunity (CMV-CMI) has been associated with protection against CMV clinically significant reactivation (CsCMV). In this study, we evaluated CMV-CMI reconstitution during letermovir prophylactic therapy, which prevents CsCMV without complete suppression of CMV reactivation. METHODS: We measured CMV-CMI in CMV-seropositive CBT recipients pre-transplant after Day+90 of letermovir prophylaxis and at Days +180, and +360- post-transplant using a dual color CMV-specific IFNγ/IL2 FLUOROSpot. CsCMV and nonCsCMV reactivations were abstracted from medical records. CsCMV was defined as CMV viral load ≥5,000 IU/ml using a whole blood assay. RESULTS: Among 70 CBT recipients, 31 developed CMV-CMI by Day+90 and an additional eight and five participants by Days +180 and +360, respectively. Thirty-eight participants developed CMV reactivation, including nine with CsCMV. Most reactivations (33 of 38) occurred before Day+180. Early CMV-CMI was present in six out of nine participants with CsCMV, indicating a lack of protection against CsCMV. Moreover, the magnitude of CMV-CMI at Day+90 did not differ between participants with CsCMV and nonCsCMV. CONCLUSION: Approximately 50% of CBT recipients reconstituted CMV-CMI during letermovir prophylactic therapy. However, CMV-CMI did not reach levels protective against CsCMV. Extension of CMV prophylaxis beyond Day+90 may be considered in CMV-seropositive CBT recipients.

Congenital Co-infections Among HIV-Exposed Infants Born to Mothers on Antiretroviral Treatment in the United States.

Background: Many women living with HIV (WLHIV) are co-infected with cytomegalovirus (CMV), Toxoplasma gondii (T gondii), and/or hepatitis C virus (HCV). The rates of congenital or perinatal transmission of these co-infections are not well defined in the current era, when most WLHIV receive antiretroviral therapy (ART) during pregnancy. Methods: Retrospective review of infants of WLHIV born between 2009-2019. Mothers were screened for antibodies to CMV, T. gondii, and HCV; chronic HCV infection was confirmed using plasma RNA PCR. Infants whose mothers had positive/unknown serostatus were screened for CMV using urine or saliva DNA PCR or culture at ≤3 weeks of life; T. gondii using serology at ≤1 month; and HCV using plasma RNA PCR at ≤6 months and serology at ≥12 months. Results: The study included 264 infants from 255 pregnancies in 191 mothers. At delivery, the median (IQR) CD4 count was 569 (406-748) cells/mm3 and plasma HIV load was 0 (0-24) RNA copies/mL. Among 243 infants born to CMV-seropositive (209) or CMV-missed serostatus (25) mothers, 163 (67.1%) were tested for CMV. Four infants had CMV detected, resulting in a rate of congenital infection of 2.5%. Among 65 infants from 54 (21.2%) pregnancies in T. gondii-seropositive women and 8 in women with unknown T. gondii-serostatus, one acquired congenital toxoplasmosis in the setting of acute maternal T. gondii infection. There were no episodes of vertical transmission from mothers with latent toxoplasmosis. Among 18 infants from 13 (5.1%) pregnancies in HCV RNA PCR-positive women and 4 in women with unknown HCV serostatus, there were no congenital or perinatal HCV transmissions. Conclusions: In a US cohort of pregnant WLHIV on ART, we identified high maternal CMV seroprevalence and a high rate of congenital CMV infection. We did not identify any congenital or perinatal transmissions of T. gondii or HCV among mothers who had latent or chronic infections. Our data support screening pregnant WLHIV and their infants for CMV and suggest that the rates of congenital and perinatal T. gondii and HCV infections among infants born to WLHIV on ART may be lower in the era of effective ART.

Upregulation of CD80 on glomerular podocytes plays an important role in development of proteinuria following pig-to-baboon xeno-renal transplantation - an experimental study.

We have previously reported that co-transplantation of the kidney with vascularized donor thymus from α-1,3-galactosyltransferase gene knockout pigs with an anti-CD154 with rituximab-based regimen led to improved xenograft survival in baboons with donor-specific unresponsiveness. However, nephrotic syndrome emerged as a complication in which the glomeruli showed mild mesangial expansion with similarities to minimal change disease (MCD) in humans. Since MCD is associated with CD80 expression in glomeruli and elevated urinary excretion, we evaluated a potential role for CD80 in xenograft nephropathy. Study 1 confirmed high urinary CD80 excretion in nephrotic animals with renal xenografts showing CD80 expression in glomeruli. In Study 2, baboons receiving xenografts received CTLA4-Ig once a week from the second postoperative week or no CTLA4-Ig. The non-CTLA4-Ig group developed severe proteinuria with modest mesangial expansion with high urinary excretion of CD80 and documented CD80 expression in glomerular podocytes. All of the recipients in non-CTLA4-Ig groups had to be euthanized before POD 60. In contrast, CTLA4-Ig group showed a marked reduction in proteinuria and survived significantly longer, up to 193 days. These results demonstrate that anti-CD80 targeted therapy represents a promising strategy for reduction of proteinuria following renal xeno-transplantation with improved survival.