Mycobacteria-Specific T Cells May Be Expanded From Healthy Donors and Are Near Absent in Primary Immunodeficiency Disorders

Pathogen-specific T Cells: Targeting Old Enemies and New Invaders in Transplantation and Beyond

Adoptive immunotherapy with virus-specific cytotoxic T cells (VSTs) has evolved over the last three decades as a strategy to rapidly restore virus-specific immunity to prevent or treat viral diseases after solid organ or allogeneic hematopoietic cell-transplantation (allo-HCT). Since the early proof-of-principle studies demonstrating that seropositive donor-derived T cells, specific for the commonest pathogens post transplantation, namely cytomegalovirus or Epstein-Barr virus (EBV) and generated by time- and labor-intensive protocols, could effectively control viral infections, major breakthroughs have then streamlined the manufacturing process of pathogen-specific T cells (pSTs), broadened the breadth of target recognition to even include novel emerging pathogens and enabled off-the-shelf administration or pathogen-naive donor pST production. We herein review the journey of evolution of adoptive immunotherapy with nonengineered, natural pSTs against infections and virus-associated malignancies in the transplant setting and briefly touch upon recent achievements using pSTs outside this context.

Emerging trends in COVID-19 treatment: learning from inflammatory conditions associated with cellular therapies

Coronavirus disease 2019 (SARS-CoV2) is an active global health threat for which treatments are desperately being sought. Even though most people infected experience mild to moderate respiratory symptoms and recover with supportive care, certain vulnerable hosts develop severe clinical deterioration. While several drugs are currently being investigated in clinical trials, there are currently no approved treatments or vaccines for COVID-19 and hence there is an unmet need to explore additional therapeutic options. At least three inflammatory disorders or syndromes associated with immune dysfunction have been described in the context of cellular therapy. Specifically, Cytokine Release Syndrome (CRS), Immune Reconstitution Inflammatory Syndrome (IRIS), and Secondary Hemophagocytic Lymphohistiocytosis (sHLH) all have clinical and laboratory characteristics in common with COVID19 and associated therapies that could be worth testing in the context of clinical trials. Here we discuss these diseases, their management, and potential applications of these treatment in the context of COVID-19. We also discuss current cellular therapies that are being evaluated for the treatment of COVID-19 and/or its associated symptoms.

Virus-specific T-cell therapies for patients with primary immune deficiency

Viral infections are common and are potentially life-threatening in patients with moderate to severe primary immunodeficiency disorders. Because T-cell immunity contributes to the control of many viral pathogens, adoptive immunotherapy with virus-specific T cells (VSTs) has been a logical and effective way of combating severe viral disease in immunocompromised patients in multiple phase 1 and 2 clinical trials. Common viral targets include cytomegalovirus, Epstein-Barr virus, and adenovirus, though recent published studies have successfully targeted additional pathogens, including HHV6, BK virus, and JC virus. Though most studies have used VSTs derived from allogenic stem cell donors, the use of banked VSTs derived from partially HLA-matched donors has shown efficacy in multicenter settings. Hence, this approach could shorten the time for patients to receive VST therapy thus improving accessibility. In this review, we discuss the usage of VSTs for patients with primary immunodeficiency disorders in clinical trials, as well as future potential targets and methods to broaden the applicability of virus-directed T-cell immunotherapy for this vulnerable patient population.

The pipeline of antiviral T-cell therapy: what's in the clinic and undergoing development

Virus-specific T cells allow targeting of multiple pathogens in patients after hematopoietic stem cell transplantation and have demonstrated potential efficacy for cytomegalovirus, Epstein-Barr Virus, and adenovirus. Novel targets may include BK virus, JC virus, varicella zoster virus, human herpesvirus 6, Aspergillus, human parainfluenza virus-3, herpes simplex virus Type I, Zika virus, and mycobacteria. Generation of patient-specific products and third-party products may expand feasibility of therapy.