Vaccination and Timing Influence SIV Immune Escape Viral Dynamics In Vivo

CD8+ cytotoxic T lymphocytes (CTL) can be effective at controlling HIV-1 in humans and SIV in macaques, but their utility is partly offset by mutational escape. The kinetics of CTL escape and reversion of escape mutant viruses upon transmission to MHC-mismatched hosts can help us understand CTL-mediated viral control and the fitness cost extracted by immune escape mutation. Traditional methods for following CTL escape and reversion are, however, insensitive to minor viral quasispecies. We developed sensitive quantitative real-time PCR assays to track the viral load of SIV Gag164–172 KP9 wild-type (WT) and escape mutant (EM) variants in pigtail macaques. Rapid outgrowth of EM virus occurs during the first few weeks of infection. However, the rate of escape plateaued soon after, revealing a prolonged persistence of WT viremia not detectable by standard cloning and sequencing methods. The rate of escape of KP9 correlated with levels of vaccine-primed KP9-specific CD8+ T cells present at that time. Similarly, when non-KP9 responder (lacking the restricting Mane-A*10 allele) macaques were infected with SHIVmn229 stock containing a mixture of EM and WT virus, rapid reversion to WT was observed over the first 2 weeks following infection. However, the rate of reversion to WT slowed dramatically over the first month of infection. The serial quantitation of escape mutant viruses evolving during SIV infection shows that rapid dynamics of immune escape and reversion can be observed in early infection, particularly when CD8 T cells are primed by vaccination. However, these early rapid rates of escape and reversion are transient and followed by a significant slowing in these rates later during infection, highlighting that the rate of escape is significantly influenced by the timing of its occurrence

The testis and epididymis are productively infected by SIV and SHIV in juvenile macaques during the post-acute stage of infection

BACKGROUND: Little is known about the progression and pathogenesis of HIV-1 infection within the male genital tract (MGT), particularly during the early stages of infection. RESULTS: To study HIV pathogenesis in the testis and epididymis, 12 juvenile monkeys (Macacca nemestrina, 4–4.5 years old) were infected with Simian Immunodeficiency Virus mac 251 (SIV(mac251)) (n = 6) or Simian/Human Immunodeficiency Virus (SHIV(mn229)) (n = 6). Testes and epididymides were collected and examined by light microscopy and electron microscopy, at weeks 11–13 (SHIV) and 23 (SIV) following infection. Differences were found in the maturation status of the MGT of the monkeys, ranging from prepubertal (lacking post-meiotic germ cells) to post-pubertal (having mature sperm in the epididymal duct). Variable levels of viral RNA were identified in the lymph node, epididymis and testis following infection with both SHIV(mn229 )and SIV(mac251). Viral protein was detected via immunofluorescence histochemistry using specific antibodies to SIV (anti-gp41) and HIV-1 (capsid/p24) protein. SIV and SHIV infected macrophages, potentially dendritic cells and T cells in the testicular interstitial tissue were identified by co-localisation studies using antibodies to CD68, DC-SIGN, αβTCR. Infection of spermatogonia, but not more mature spermatogenic cells, was also observed. Leukocytic infiltrates were observed within the epididymal stroma of the infected animals. CONCLUSION: These data show that the testis and epididymis of juvenile macaques are a target for SIV and SHIV during the post-acute stage of infection and represent a potential model for studying HIV-1 pathogenesis and its effect on spermatogenesis and the MGT in general

A randomised comparison of CPX-351 and FLAG-Ida in adverse karyotype AML and high-risk MDS: the UK NCRI AML19 trial

Liposomal daunorubicin and cytarabine (CPX-351) improves overall survival (OS) compared to 7+3 chemotherapy in older patients with secondary acute myeloid leukaemia (AML); to date there have been no randomized studies in younger patients. The high-risk cohort of the UK NCRI AML19 trial (ISRCTN78449203) compared CPX-351 with FLAG-Ida in younger adults with newly-diagnosed adverse cytogenetic AML or high-risk myelodysplastic syndromes (MDS). 189 patients were randomized (median age 56y). By clinical criteria 49% had de novo AML, 20% secondary AML and 30% high risk MDS. MDS-related cytogenetics were present in 73% of patients, with complex karyotype in 49%. TP53 was the most commonly mutated gene, in 43%. Myelodysplasia-related gene mutations were present in 75 patients (44%). The overall response rate (CR + CRi) after course two was 64% and 76% for CPX-351 and FLAG-Ida (OR:0.54, 95%CI 0.28-1.04, p=0.06). There was no difference in OS (13.3 months vs 11.4 months, HR:0.78, 95%CI 0.55-1.12, p=0.17) or event-free survival (HR:0.90, 95%CI 0.64-1.27, p=0.55) in multivariable analyses. However, relapse-free survival was significantly longer with CPX-351 (median 22.1 vs 8.35 months, HR:0.58, 95% CI 0.36-0.95, p=0.03). There was no difference between the treatment arms in patients with clinically defined secondary AML (HR:1.1, 95%CI 0.52-2.30) or those with MDS-related cytogenetic abnormalities (HR:0.94, 95%CI 0.63-1.40), however an exploratory sub-group of patients with MDS-related gene mutations had significantly longer OS with CPX-351 (median 38.4 vs 16.3 months, HR:0.42, 95%CI 0.21-0.84, heterogeneity p=0.05). In conclusion, OS in younger patients with adverse risk AML/MDS was not significantly different between CPX-351 and FLAG-Ida

Fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin with gemtuzumab ozogamicin improves event-free survival in younger patients with newly diagnosed aml and overall survival in patients with npm1 and flt3 mutations

Purpose To determine the optimal induction chemotherapy regimen for younger adults with newly diagnosed AML without known adverse risk cytogenetics. Patients and Methods One thousand thirty-three patients were randomly assigned to intensified (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin [FLAG-Ida]) or standard (daunorubicin and Ara-C [DA]) induction chemotherapy, with one or two doses of gemtuzumab ozogamicin (GO). The primary end point was overall survival (OS). Results There was no difference in remission rate after two courses between FLAG-Ida + GO and DA + GO (complete remission [CR] + CR with incomplete hematologic recovery 93% v 91%) or in day 60 mortality (4.3% v 4.6%). There was no difference in OS (66% v 63%; P = .41); however, the risk of relapse was lower with FLAG-Ida + GO (24% v 41%; P < .001) and 3-year event-free survival was higher (57% v 45%; P < .001). In patients with an NPM1 mutation (30%), 3-year OS was significantly higher with FLAG-Ida + GO (82% v 64%; P = .005). NPM1 measurable residual disease (MRD) clearance was also greater, with 88% versus 77% becoming MRD-negative in peripheral blood after cycle 2 (P = .02). Three-year OS was also higher in patients with a FLT3 mutation (64% v 54%; P = .047). Fewer transplants were performed in patients receiving FLAG-Ida + GO (238 v 278; P = .02). There was no difference in outcome according to the number of GO doses, although NPM1 MRD clearance was higher with two doses in the DA arm. Patients with core binding factor AML treated with DA and one dose of GO had a 3-year OS of 96% with no survival benefit from FLAG-Ida + GO. Conclusion Overall, FLAG-Ida + GO significantly reduced relapse without improving OS. However, exploratory analyses show that patients with NPM1 and FLT3 mutations had substantial improvements in OS. By contrast, in patients with core binding factor AML, outcomes were excellent with DA + GO with no FLAG-Ida benefit

Assessing implementation fidelity of an on-site pharmacist intervention within Australian residential aged care facilities:A mixed methods study

Background: An on-site pharmacist (OSP) intervention was implemented which sought to improve medication management within residential aged care facilities (RACFs) in the Australian Capital Territory, Australia. The objectives of this mixed methods study were to evaluate the implementation fidelity of the OSP intervention and to determine the moderating factors which influenced delivery of this intervention. Methods: This convergent parallel mixed methods study was underpinned by Hasson’s conceptual framework for implementation fidelity. Implementation fidelity for seven intervention RACFs was quantitatively assessed using three quantitative data sets: (1) range of OSP intervention activities delivered; (2) random sample of 10% of medication reviews assessed for quality; (3) proportion of residents who received at least one medication review. Semi-structured interviews (n = 14) with managers and OSPs across the intervention RACFs were conducted to identify moderating factors which may have influenced OSP intervention delivery. Results: The OSP intervention was generally delivered as intended with overall medium levels of implementation fidelity. This delivery was supported by a range of facilitation strategies with most participants perceiving that the intervention was delivered to a high standard. RACF managers and OSPs were mostly well engaged and responsive. A number of potential barriers (including the part-time OSP role, COVID-19 pandemic, RACFs spread out over a large area with significant distance between resident dwellings) and facilitators (including the pharmacist support meetings, OSPs who took time to establish relationships, RACF managers who actively supported OSPs and worked with them) for OSP intervention delivery were identified which have potential implications for the roll out of OSPs within Australian RACFs. Conclusion: In this study, the implementation fidelity of OSP intervention delivery was assessed with overall medium levels of fidelity found across the intervention RACFs. This suggested that the OSP intervention can generally be delivered as intended in real world RACFs. OSP intervention delivery was influenced by a range of moderating factors, some of which posed barriers and others which facilitated the OSP intervention being delivered as intended.</p

In Vivo Fitness Costs of Different Gag CD8 T-Cell Escape Mutant Simian-Human Immunodeficiency Viruses for Macaques▿

The kinetics of immune escape and reversion depend upon the efficiency of CD8 cytotoxic T lymphocytes (CTL) and the fitness cost of escape mutations. Escape kinetics of three simian immunodeficiency virus Gag CTL epitopes in pigtail macaques were variable; those of KP9 and AF9 were faster than those of KW9. Kinetics of reversion of escape mutant virus to wild type upon passage to naïve major histocompatibility complex-mismatched macaques also varied. Rapid reversion occurred at KP9, gradual biphasic reversion occurred at AF9, and escape mutant KW9 virus failed to revert. The fitness impact of these mutations is KP9 > AF9 > KW9. These data provide insights into the differential utility of CTL in controlling viremia