The natural killer-activating receptor, NKG2D, on CD3+CD8+ T cells plays a critical role in identifying and killing autologous myeloma cells.

BACKGROUND: The NKG2D receptor, one of the natural killer (NK) cell-activating receptors, is expressed on the surface of CD3+CD8+ T cells, γδ+ T cells, NK cells, NKT cells, and a few CD4+ T cells. We show, for the first time, a critical role for the NKG2D receptor on CD3+CD8+ T cells isolated from myeloma patients, in identifying and killing autologous myeloma cells isolated from the same patients' marrow. We also show that blocking NKG2D using anti-NKG2D reverses the cytotoxicity while blocking HLA-I using antibodies does not have the same effect, showing that the autologous cytotoxicity is NKG2D dependent and major histocompatibility complex (MHC)-I independent. We further confirmed the NKG2D specificity by small interfering RNA (siRNA) down regulation of NKG2D receptor. STUDY DESIGN AND METHODS: Using ex vivo expansion methods that enrich for NKG2D+CD3+CD8+ T cells, we investigated whether these ex vivo expanded NKG2D+CD3+CD8+ T cells would recognize and lyse autologous and allogeneic myeloma cells, independent of T-cell receptor or MHC-I expression. RESULTS: Myeloma cell lysis by the NKG2D+CD3+CD8+ T cells correlated with the amount of NKG2D ligand expression. With receptor-ligand interaction, interferon-γ and tumor necrosis factor-α were released. Blocking the NKG2D receptor by using either monoclonal antibodies or siRNAs inhibited the receptor's function and prevented myeloma cell lysis. CONCLUSION: Clinical trials are ongoing to determine a correlation with the number and function of NKG2D+CD3+CD8+ T cells and clinical outcomes in transplanted myeloma patients, including lymphocyte recovery following transplant and overall survival.

Covering the Distance: A Study of Parent and Teen Attitudes on COVID-19 Mitigation Measures During the COVID-19 Pandemic.

Background The Unity® Consortium surveyed teens and parents and guardians of teens across the country at three distinct time points or waves during the COVID-19 pandemic to assess participant attitudes and beliefs regarding COVID-19 mitigation guidelines, such as mask-wearing and physical distancing. Methodology A third-party market research company conducted 15-minute, online surveys from nationally representative panels. Surveys were conducted at three distinct time points or waves (August 2020, February 2021, and June 2021) with 300 teens aged 13-18 years in each wave and 593/531/500 parents and guardians of teens aged 13-18 years in each wave, respectively. Participants responded using a five-point Likert scale (strongly agree to strongly disagree) on their COVID-19 experiences, including the perceived importance of strictly following mask-wearing and/or social distancing guidelines and the perceived effectiveness of mask-wearing and social distancing in preventing the spread of COVID-19. Data were analyzed for differences across waves and demographic variables. Statistical analyses included frequencies, analysis of variance (ANOVA), and t-tests/z-tests. Results While significantly more parents and teens in Waves 2 and 3 knew someone who was hospitalized or died due to COVID-19 compared to Wave 1, significantly fewer in Wave 3 reported experiencing a lot or some stress and worry regarding the pandemic. By Wave 3, 58% of teens and 56% of parents had received at least one dose of a COVID-19 vaccine. Despite changes in experiences over time, a significant majority of parents and teens consistently agreed on the importance and effectiveness of social distancing and masking guidelines against the spread of COVID-19. In Wave 3, the demographic variables significantly associated with agreement on importance included race (Black (92%) > White (80%)), community type (urban (91%) > suburban (79%) and rural (73%)), and positive vaccination status of parents and teens (92%/89%) > not vaccinated (73%/73%), respectively). The demographic variables significantly associated with agreement on effectiveness included race (Black (91%) > White (81%)), community type (urban (89%) > suburban (83%) and rural (71%)), and positive vaccination status of parents and teens (94%/90% > not vaccinated (72%/70%), respectively). Conclusions This study into the perceived importance and perceived effectiveness of mitigation strategies during the COVID-19 pandemic revealed differences in attitudes among sociodemographic groups. Understanding these differences can help shape how adherence to public health guidelines in a pandemic is promoted.

Immune mobilization of autologous blood progenitor cells: direct influence on the cellular subsets collected.

BACKGROUND AIMS: A phase I trial examined the ability of immunotherapy to mobilize progenitor and activated T cells. METHODS: Interleukin (IL)-2 was administered subcutaneously for 11 days, with granulocyte (G)-colony-stimulating factor (CSF) (5 mcg/kg/day) and granulocyte-macrophage (GM)-CSF (7.5 mcg/kg/day) added for the last 5 days. Leukapheresis was initiated on day 11. Thirteen patients were treated (myeloma n = 11, non-Hodgkin's lymphoma n = 2). RESULTS: Toxicities were minimal. IL-2 was stopped in two patients because of capillary leak (n = 1) and diarrhea (n = 1). Each patient required 2.5 leukaphereses (median; range 1-3) to collect 3.2 x 106 CD34+ cells/kg (median; range 1.9-6.6 x 106/kg). Immune mobilization increased the number of CD3+ CD8+ T cells (P = 0.002), CD56+ natural killer (NK) cells (P = 0.0001), CD8+ CD56+ T cells (P = 0.002) and CD4+ CD25+ cells (P = 0.0001) compared with cancer patients mobilized with G-CSF alone. There was increased lysis of myeloma cells after 7 days (P = 0.03) or 11 days (P = 0.02). The maximum tolerated dose of IL-2 was 1 x 106 IU/m²/day. CONCLUSIONS: Immune mobilization is well tolerated with normal subsequent marrow engraftment. As cells within the graft influence lymphocyte recovery, an increased number of functional lymphocytes may result in more rapid immune reconstitution.

Chimeric NKG2D receptor-expressing T cells as an immunotherapy for multiple myeloma.

OBJECTIVE: Most myeloma tumor cells from patients express NKG2D ligands. We have reported the development of a chimeric NKG2D receptor (chNKG2D), which consists of the NKG2D receptor fused to the CD3zeta chain. T cells expressing this receptor kill and produce cytokines in response to NKG2D-ligand+ tumor cells. Therefore, we investigated whether human chNKG2D T cells respond against human myeloma cells. MATERIALS AND METHODS: ChNKG2D T cells were generated from healthy donors and myeloma patients. The effector phase of chNKG2D T cells was analyzed by cell-surface marker expression and human myeloma cell lines were tested for expression of NKG2D ligands. Lysis of myeloma cell lines and cytokine secretion by chNKG2D T cells was determined. ChNKG2D T cells grown in serum-free media, or cyropreserved, were assessed for effector cell functions. RESULTS: Myeloma cell lines expressed NKG2D ligands. ChNKG2D T cells from healthy donors and myeloma patients lysed myeloma cells, and secreted proinflammatory cytokines when cultured with myeloma cells or patient bone marrow, but not with peripheral blood mononuclear cells or normal bone marrow. Lysis of myeloma cells was dependent on chNKG2D T-cell expression of NKG2D and perforin. Additionally, chNKG2D T cells upregulated CD45RO, did not express CD57, and maintained expression of CD27, CD62L, and CCR7, indicating that the T cells were at an early effector stage. Finally, we showed that chNKG2D T cells generated with serum-free media, or when cryopreserved, maintained effector functions. CONCLUSION: ChNKG2D T cells respond to human myeloma cells and can be generated using clinically applicable cell culture techniques.

Implementation of peripheral blood CD34 analyses to initiate leukapheresis: marked reduction in resource utilization.

BACKGROUND: Analysis of the peripheral blood (PB) C34 value may determine the optimal time to initiate leukapheresis. STUDY DESIGN AND METHODS: After selecting a threshold PB CD34 value of five CD34 + cells per microL to initiate leukapheresis procedure, a prospective analysis of 50 consecutive patients was initiated to identify the optimal time to initiate leukapheresis and its impact on costs and resource utilization. Clinical decisions were made to commence or to postpone leukapheresis with this PB CD34 threshold number. Based on PB CD34 values for each patient, the number of leukapheresis procedures, postponed or canceled, the number of CD34+ cells per kg, and the total number of cells collected were identified. Costs of mobilization were obtained from the hospital cost accounting system. RESULTS: In 13 months, 50 patients with a hematologic disorder underwent mobilization. There were 34 cancellations or postponements of collections due to a low PB CD34 value in 13 patients. By use of our identified costs per initial collection, this resulted in a savings of 67,660 US dollars. CONCLUSIONS: This prospective study defines how the implementation of the PB CD34 value results in costs savings. A low PB CD34 value canceled or postponed a significant number of leukapheresis procedures, resulting in a substantial cost savings. Use of the PB CD34 value should be the standard of care during mobilization and peripheral blood progenitor cell collection.