大嶺 謙

Adoptive transfer of T cells expressing a chimeric antigen receptor (CAR) is a promising cell-based anticancer therapy. Although clinical studies of this approach show therapeutic efficacy, additional genetic modification is necessary to enhance the efficacy and safety of CAR-T cells. For example, production of an antitumor cytokine from CAR-T cells can potentially enhance their tumor-killing activity, but there are concerns that constitutive expression of anticancer molecules will cause systemic side effects. Therefore, it is important that exogenous gene expression is confined to the tumor locality. Here, we aimed to develop an inducible promoter driven by activation signals from a CAR. Transgene expression in T cells transduced with the CD19-targeted CAR and an inducible promoter, including inducible reporter genes (CAR-T/iReporter), was only induced strongly by co-culture with CD19-positive target cells. CAR-T/iReporter cells also showed redirected cytolysis toward CD19-positive, but not CD19-negative, tumor cells. Overall, our study indicated that the inducible promoter was selectively driven by activation signals from the CAR, and transduction with the inducible promoter did not affect original effector activities including interleukin-2 and interferon-γ production and the antitumor activity of CAR-redirected cytotoxic T lymphocytes. Moreover, this inducible promoter permits visualization and quantification of the activation status in CAR-T cells.

GALLIUM is a global phase III study that demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) with obinutuzumab plus chemotherapy (G-chemo) versus rituximab plus chemotherapy (R-chemo) in previously untreated patients with follicular lymphoma (FL). In this single-country subgroup analysis, we explored patterns of efficacy and safety in patients enrolled in the GALLIUM study in Japan (Japanese subgroup). Patients were randomized to open-label induction treatment with G-chemo or R-chemo. Responders received maintenance monotherapy with their randomized antibody for up to 2 years. The primary endpoint was investigator-assessed PFS. Overall, 123 patients with FL were randomized in the Japanese subgroup (G-chemo, n = 65; R-chemo, n = 58). The majority of patients received cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy (82.9 vs 33.1% in the global GALLIUM FL population). PFS at 3 years was 89.9% (G-chemo) vs. 74.7% (R-chemo); hazard ratio 0.42; 95% confidence interval 0.15, 1.15; P = 0.08. Higher rates of grade 3-5 adverse events (96.9 vs. 89.7%) and serious adverse events (35.4 vs. 22.4%) were observed with G-chemo vs R-chemo, respectively. Neutropenia was frequent in the Japanese subgroup (92.3% G-chemo; 79.3% R-chemo). Overall, the results in the Japanese subgroup were consistent with those in the global GALLIUM population.

The 1,3-beta-D-Glucan (BDG) assay is widely used for the diagnosis of fungal infections, especially in patients with hematologic malignancies. Some antimicrobials have been reported to cause false-positive results for BDG, but there has been no report on the effect of penicillin G (PCG) on BDG levels. We experienced a patient who developed false-positive BDG elevation during the administration of PCG for osteomyelitis due to Streptococcus pneumoniae infection. The serum BDG level increased up to 81.0 pg/ml during the continuous administration of PCG at 24 million units per day. However, chest and paranasal CT scan showed no evidence of fungal infection. The BDG level decreased to 38.0 pg/ml at 14 hours after the discontinuation of PCG. The amount of BDG in one vial of PCG inferred from these serum BDG levels is very similar to the actual BDG concentration in a vial of PCG. Therefore, during the administration of PCG, elevated BDG levels should be interpreted with caution, as they may be false-positive results.

<p>CD19に対するキメラ抗原受容体を発現させた遺伝子改変T細胞が再発・難治性のB細胞性腫瘍に対して有効であることが注目を集めている。2011年にCLLをはじめとした進行の遅い腫瘍のおよそ半数に有効であることが報告された。2012年にはB-NHLのおよそ8割に対しても同様に有効であることが報告された。2013年には治療が最も難しいと考えられていたB-ALLのおよそ9割に劇的な効果が報告された。つい最近では，通常CD19を発現していない多発性骨髄種に対しても自家移植と併用すると分子生物学的寛解を期待できる治療であることが報告された。一方で，サイトカイン放出症候群と中枢神経毒性は重篤な副作用として認識されている。本邦での臨床試験は昨年始まったばかりであるが，この分野の大きなブレークスルーになると期待されている新規治療法である。</p>

Bone marrow mononuclear cells from 93 patients with hematological malignancies after allogeneic hematopoietic stem cell transplantation (AHSCT) were analyzed using flow cytometry (FCM). The disease was acute myeloblastic leukemia (50 patients), acute lymphoblastic leukemia, and others. Conditioning was myeloablative (80 patients) or reduced intensity. The stem cell source was bone marrow (75 patients), peripheral blood stem cells, or cord blood. After AHSCT, granulocyte colony-stimulating factor was given to all patients. All patients showed engraftment of the donor cells. FCM was conducted on a median of 22 days after AHSCT. The gate was set around a granulocytic region consisting of immature granulocytes. The positivity rates of CD13, CD14, CD15, CD33, CD34, CD56, and HLA-DR in the cells were 59.9 ± 27.4%, 5.8 ± 8.8%, 98.3 ± 1.9%, 92.3 ± 12.4%, 2.6 ± 5.8%, 24.3 ± 16.7%, and 9.1 ± 6.6%, respectively. The greatest value of CD56 positivity was 73.1%. On the basis of CD56 expression, cases of more than 24% CD56 positivity were assigned to the CD56-high group (39 patients), while the rest were assigned to the CD56-low/negative group. There were no significant differences between the two groups in terms of disease status, sex, donor, hematopoietic stem cells, days of FCM analysis, or peripheral blood cell counts around the days of performing FCM. These results indicate that CD56 can be expressed in normal immature granulocytes at a variety of expression levels in regenerative bone marrow. Attention should be paid when evaluating aberrant antigen expression of CD56 in granulocytes. [J Clin Exp Hematop 53(3) : 247-250, 2013]