Opioid use may affect the HIV-1 reservoir and its reversal from latency. We studied 47 virally suppressed people with HIV (PWH) and observed that lower concentration of HIV-1 latency reversal agents (LRAs), used with small molecules that did not reverse latency, synergistically increased the magnitude of HIV-1 reactivation ex vivo, regardless of opioid use. This LRA boosting, which combined a second mitochondria-derived activator of caspases mimetic or low-dose PKC agonist with histone deacetylase inhibitors, generated more unspliced HIV-1 transcription than PMA with ionomycin (PMAi), the maximal known HIV-1 reactivator. LRA boosting associated with greater histone acetylation, modulated surface activation-induced markers, and altered T cell production of TNF-α, IL-2, and IFN-γ. HIV-1 reservoirs in PWH contained unspliced and polyadenylated virus mRNA, the ratios of which were greater in resting than total CD4+ T cells and corrected to 1:1 with PMAi exposure. We characterized treated suppressed HIV-1 infection as a period of inefficient, not absent, virus transcription. Multiply spliced HIV-1 transcripts and virion production did not consistently increase with LRA boosting, suggesting the presence of a persistent posttranscriptional block. LRA boosting can be leveraged to probe mechanisms of an effective cellular HIV-1 latency reversal program.

The role of adaptive immunity in long-term outcomes in early breast cancer is increasingly recognised. Standard (neo)adjuvant chemotherapy can have adverse effects on immune cells. We conducted a retrospective longitudinal study of full blood counts (FBC) of 200 patients receiving (neo)adjuvant chemotherapy for early breast cancer at a single institution. FBC results at four time points from pre-treatment to 12 months post-chemotherapy were analysed. Flow cytometry was performed for patients with matched pre- and post-chemotherapy peripheral blood mononuclear cell samples. A significant decrease in absolute lymphocyte count at 12 months post-chemotherapy was observed (p < 0.01), most pronounced in pre-menopausal patients (n = 73; p < 0.01), patients receiving dose-dense chemotherapy regimens (n = 60; p < 0.01) and patients receiving adjuvant radiotherapy (n = 147, p < 0.01). In pre-menopausal patients, significant changes in CD4+ T cells subsets post-chemotherapy were observed. Further investigation, including long-term clinical outcomes, is needed to meaningfully improve long-term anti-tumour immunity.
© 2024. The Author(s).

Outcomes for children with relapsed and refractory neuroblastoma are dismal. ENCIT-01 is our first-in-human experience in patients with relapsed and refractory neuroblastoma using chimeric antigen receptor (CAR) T cells targeting L1-CAM, an adhesion molecule that is overexpressed in neuroblastoma with limited normal tissue expression. This trial evaluated three different CAR constructs: a short spacer second-generation 4-1BB CAR (Arm A), a short spacer third-generation 4-1BB+CD28 CAR (Arm B) and a long spacer second-generation 4-1BB CAR (Arm C). Thirty-six patients were enrolled and 22 were treated (Arm A n=11, Arm B n=8 and Arm C n=3). Cytokine-release syndrome, skin rash and dose-limiting hyponatremia were recurrently encountered toxicities. Patterns of toxicity appeared at lower dose levels on Arm B and Arm C compared to Arm A, suggesting enhanced potency of the third generation and long spacer products. No objective responses were seen. Correlative analyses demonstrated CAR T cells infiltration into tumor and skin, with evidence of macrophage tumor infiltration. In addition, enhanced CD107a production in the third-generation products when compared to patient matched second generation product, potentially explaining the observation of toxicities at lower dose levels. While feasible to manufacture in a heavily pretreated population, additional engineering safety of L1CAM CAR T cells and/or strategies to target the immunosuppressive tumor microenvironment may be needed to prevent toxicity and provide durable anti-tumor effects.

The combined effects of the HIV-1 and opioid epidemics on virus reservoir dynamics are less well characterized. To assess the impact of opioid use on HIV-1 latency reversal, we studied forty-seven suppressed participants with HIV-1 and observed that lower concentrations of combination latency reversal agents (LRA) led to synergistic virus reactivation ex vivo , regardless of opioid use. The use of a Smac mimetic or low-dose protein kinase C agonist, compounds that did not reverse latency alone, in combination with low-dose histone deacetylase inhibitors generated significantly more HIV-1 transcription than phorbol 12-myristate 13-acetate (PMA) with ionomycin, the maximal known HIV-1 reactivator. This LRA boosting did not differ by sex or race and associated with greater histone acetylation in CD4 + T cells and modulation of T cell phenotype. Virion production and the frequency of multiply spliced HIV-1 transcripts did not increase, suggesting a post-transcriptional block still limits potent HIV-1 LRA boosting.

Graft-versus-host disease (GVHD) remains a serious limitation of allogeneic hematopoietic cell transplantation (allo-HCT). While post-transplant administration of cyclophosphamide (PTCy) is increasingly used as GVHD prophylaxis, its precise mechanisms of action and its impact on graft-versus-leukemia effects have remained debated. Here, we studied the mechanisms of xenogeneic GVHD (xGVHD) prevention by PTCy in different humanized mouse models. We observed that PTCy attenuated xGVHD. Using flow cytometry and single-cell RNA-sequencing, we demonstrated that PTCy depleted proliferative CD8+ and conventional CD4+ T cells but also proliferative regulatory T cells (Treg). Further, T-cell receptor β variable region sequencing (TCRVB) analyses demonstrated that highly xenoreactive T-cell clones were depleted by PTCy. Although Treg frequencies were significantly higher in PTCy-treated than in control mice on day 21, xGVHD attenuation by PTCy was not abrogated by Treg depletion. Finally, we observed that PTCy did not abrogate graft-versus-leukemia effects.
© 2023 The Authors.