Analysis of the Whole CDR3 T Cell Receptor Repertoire after Hematopoietic Stem Cell Transplantation in 2 Clinical Cohorts.

A major cause of morbidity and mortality for patients who undergo hematologic stem cell transplantation (HSCT) is acute graft-versus-host disease (aGVHD), a mostly T cell-mediated disease. Examination of the T cell receptor (TCR) repertoire of HSCT recipients and the use of next-generation nucleotide sequencing have raised the question of whether features of TCR repertoire reconstitution might reproducibly associate with aGVHD. We hypothesized that the peripheral blood TCR repertoire of patients with steroid-nonresponsive aGVHD would be less diverse. We also hypothesized that patients with GVHD who shared HLA might also share common clones at the time of GVHD diagnosis, thereby potentially providing potential clinical indicators for treatment stratification. We further hypothesized that HSCT recipients with the same HLA mismatch might share a more similar TCR repertoire based on a potentially shared focus of alloreactive responses. We studied 2 separate patient cohorts and 2 separate platforms for measuring TCR repertoire. The first cohort of patients was from a multicenter Phase III randomized double-blinded clinical trial of patients who developed aGVHD (NCT01002742). The second cohort comprised samples from biobanks from 2 transplantation centers and the Center for International Blood and Marrow Transplant Research of patients who underwent mismatched HSCT. There were no statistically significant differences in the TCR diversity of steroid responders and nonresponders among patients with aGVHD on the day of diagnosis. Most clones in the repertoire were unique to each patient, but a small number of clones were found to be both exclusive to and shared among aGVHD nonresponders. We were also able to show a strong correlation between the presence of Vß20 and Vß29 and steroid responsiveness. Using the Bhattacharya coefficient, those patients who shared the same HLA mismatch were shown to be no more similar to one another than to those who had a completely different mismatch. Using 2 separate clinical cohorts and 2 separate platforms for analyzing the TCR repertoire, we have shown that the sampled human TCR repertoire is largely unique to each patient but contains glimmers of common clones of subsets of clones based on responsiveness to steroids in aGVHD on the day of diagnosis. These studies are informative for future strategies to assess for reproducible TCR responses in human alloreactivity and possible markers of GVHD responsiveness to therapy.

Clonal Evolution and Changes in Two AML Patients Detected with A Novel Single-Cell DNA Sequencing Platform.

Next-generation sequencing (NGS) is used to detect gene variants in genetically complex cell populations of cancer patient samples. Traditional bulk analysis can only provide average variant allele frequencies of the targeted genes across all sampled cells. It fails to resolve mutational co-occurrences and may miss rare cancer cells. Genome analysis at the single cell level offers the opportunity to more fully resolve clonal architecture. Peripheral blood mononuclear cells were sampled from acute myeloid leukemia patients longitudinally and single-cell DNA sequencing libraries were generated with a novel droplet-based microfluidics approach. Molecular profiling of single nucleotide variants across thousands of cells revealed genetic chimerism in patients after bone marrow transplantation (BMT). Importantly, hierarchical clustering analysis of single nucleotide variants (SNVs) uncovered a distinct oncogenic clone of cells carrying mutated tumor-suppressor and/or oncogene(s). This novel single-cell DNA sequencing approach enabled precise monitoring of engraftment and revealed clonal evolution of oncogenic cells during the progression and treatment of the disease.

Efficacy of Pembrolizumab and Nivolumab in Crossing the Blood Brain Barrier.

Metastatic brain tumors are the leading cause of central nervous system malignancies in adults, surpassing primary central nervous system with non-small cell lung cancer, accounting for more than 50% of all cases. The emergence of immunotherapies such as antibodies targeting the immune check points has led to significant advancement in the field of cancer treatment since these approaches have overwhelmingly impacted outcomes in patients with metastatic non-small cell lung cancer. Here we report two cases of metastatic non-small cell lung cancer treated with immunotherapy. While one patient achieved an excellent systemic response but developed new metastatic brain lesions, the other showed remarkable systemic as well as central response. These cases highlight variable central nervous system penetration of programmed death 1 (PD-1) antibodies, and we also review the available literature on blood brain barrier permeability of PD-1 antibodies.

Donor-Derived Cytokine-Induced Killer Cell Infusion as Consolidation after Nonmyeloablative Allogeneic Transplantation for Myeloid Neoplasms.

Non-myeloablative conditioning, such as with total lymphoid irradiation and antithymocyte globulin (TLI-ATG), has allowed allogeneic hematopoietic cell transplantation (allo-HCT) with curative potential for older patients and those with comorbid medical conditions with myeloid neoplasms. However, early achievement of full donor chimerism (FDC) and relapse remain challenging. Cytokine-induced killer (CIK) cells have been shown to have antitumor cytotoxicity. Infusion of donor-derived CIK cells has been studied for hematologic malignancies relapsed after allo-HCT but has not been evaluated as post-transplant consolidation. In this phase II study, we prospectively studied whether a one-time infusion of 1 × 108/kg CD3+ donor-derived CIK cells administered between day +21 and day +35 after TLI-ATG conditioning could improve achievement of FDC by day +90 and 2-year clinical outcomes in patients with myeloid neoplasms. CIK cells, containing predominantly CD3+CD8+NKG2D+ cells along with significantly expanded CD3+CD56+ cells, were infused in 31 of 44 patients. Study outcomes were compared to outcomes of a retrospective historical cohort of 100 patients. We found that this one-time CIK infusion did not increase the rate of FDC by day +90. On an intention-to-treat analysis, 2-year non-relapse mortality (6.8%; 95% confidence interval [CI], 0-14.5%), event-free survival (27.3%; 95% CI, 16.8-44.2%), and overall survival (50.6%; 95% CI, 37.5-68.2%) were similar to the values seen in the historical cohort. The cumulative incidence of grade II-IV acute graft-versus-host disease at 1-year was 25.1% (95% CI, 12-38.2%). On univariate analysis, the presence of monosomal or complex karyotype was adversely associated with relapse-free survival and overall survival. Given the favorable safety profile of CIK cell infusion, strategies such as repeat dosing or genetic modification merit exploration. This trial was registered at ClinicalTrials.gov (NCT01392989).

Stimulating Innate Immunity to Enhance Radiation Therapy-Induced Tumor Control.

Novel ligands that target Toll-like receptors and other innate recognition pathways represent a potent strategy for modulating innate immunity to generate antitumor immunity. Although many of the current clinically successful immunotherapies target adaptive T-cell responses, both preclinical and clinical studies suggest that adjuvants have the potential to enhance the scope and efficacy of cancer immunotherapy. Radiation may be a particularly good partner to combine with innate immune therapies, because it is a highly efficient means to kill cancer cells but may fail to send the appropriate inflammatory signals needed to act as an efficient endogenous vaccine. This may explain why although radiation therapy is a highly used cancer treatment, true abscopal effects-regression of disease outside the field without additional systemic therapy-are extremely rare. This review focuses on efforts to combine innate immune stimuli as adjuvants with radiation, creating a distinct and complementary approach from T cell-targeted therapies to enhance antitumor immunity.

Surgery for Acute Subdural Hematoma: Replace or Remove the Bone Flap?

OBJECTIVE: In surgery for acute subdural hematoma (ASDH), the bone flap can be fixed onto the skull, left riding to provide partial skull decompression, or removed. This study assessed whether removing the bone flap improved outcome. METHODS: We conducted an observational study on consecutive patients who were operated for ASDH in our hospital from July 2011 to June 2014. We retrospectively collected data on demographics, injury severity, and predicted and observed outcomes at 6 months. The cohort was divided into 2 groups based on whether the bone flap was replaced (fixed and riding flap craniotomy) or removed (decompressive craniectomy). The differences in functional status, postoperative control of intracranial hypertension, and number of cranial reoperations were analyzed. A subgroup analysis compared decompressive craniectomy with riding flap craniotomy alone. RESULTS: Data were obtained for 99 patients; 69 had decompressive craniectomy, 17 had riding flap craniotomy, and 13 had fixed flap craniotomy. The decompressive craniectomy group had statistically worse injuries, more predicted poor outcomes (69% vs. 57%, P = 0.013), more observed poor outcomes (59% vs. 37%, P = 0.037), equivalent control of intracranial hypertension, and a similar number of reoperations compared with the craniotomy groups. Subgroup analysis between decompressive craniectomy and riding flap craniotomy showed no significant difference in baseline characteristics and outcomes. CONCLUSIONS: Our study concluded that removing the bone flap after ASDH evacuation was not associated with a better outcome. We recommend replacing the bone flap if brain conditions allow. Further research is required to evaluate the role of skull decompression in surgery for ASDH.