T cell receptor-engineered T cells derived from target human leukocyte antigen-DPB1-specific T cell can be a potential tool for therapy against leukemia relapse following allogeneic hematopoietic cell transplantation.

Human leukocyte antigen (HLA)-DPB1 antigens are mismatched in approximately 70% of allogeneic hematopoietic stem cell transplantations (allo-HSCT) from HLA 10/10 matched unrelated donors. HLA-DP-mismatched transplantation was shown to be associated with an increase in acute graft-versus-host disease (GVHD) and a decreased risk of leukemia relapse due to the graft-versus-leukemia (GVL) effect. Immunotherapy targeting mismatched HLA-DP is considered reasonable to treat leukemia following allo-HCT if performed under non-inflammatory conditions. Therefore, we isolated CD4+ T cell clones that recognize mismatched HLA-DPB1 from healthy volunteer donors and generated T cell receptor (TCR)-gene-modified T cells for future clinical applications. Detailed analysis of TCR-T cells expressing TCR from candidate clone #17 demonstrated specificity to myeloid and monocytic leukemia cell lines that even expressed low levels of targeted HLA-DP. However, they did not react to non-hematopoietic cell lines with a substantial level of targeted HLA-DP expression, suggesting that the TCR recognized antigenic peptide is only present in some hematopoietic cells. This study demonstrated that induction of T cells specific for HLA-DP, consisting of hematopoietic cell lineage-derived peptide and redirection of T cells with cloned TCR cDNA by gene transfer, is feasible when using careful specificity analysis.

Utility of cerebrospinal fluid liquid biopsy in distinguishing CNS lymphoma from cerebrospinal infectious/demyelinating diseases.

BACKGROUND: Distinguishing between central nervous system lymphoma (CNSL) and CNS infectious and/or demyelinating diseases, although clinically important, is sometimes difficult even using imaging strategies and conventional cerebrospinal fluid (CSF) analyses. To determine whether detection of genetic mutations enables differentiation between these diseases and the early detection of CNSL, we performed mutational analysis using CSF liquid biopsy technique. METHODS: In this study, we extracted cell-free DNA from the CSF (CSF-cfDNA) of CNSL (N = 10), CNS infectious disease (N = 10), and demyelinating disease (N = 10) patients, and performed quantitative mutational analysis by droplet-digital PCR. Conventional analyses were also performed using peripheral blood and CSF to confirm the characteristics of each disease. RESULTS: Blood hemoglobin and albumin levels were significantly lower in CNSL than CNS infectious and demyelinating diseases, CSF cell counts were significantly higher in infectious diseases than CNSL and demyelinating diseases, and CSF-cfDNA concentrations were significantly higher in infectious diseases than CNSL and demyelinating diseases. Mutation analysis using CSF-cfDNA detected MYD88L265P and CD79Y196 mutations in 60% of CNSLs each, with either mutation detected in 80% of cases. Mutual existence of both mutations was identified in 40% of cases. These mutations were not detected in either infectious or demyelinating diseases, and the sensitivity and specificity of detecting either MYD88/CD79B mutations in CNSL were 80% and 100%, respectively. In the four cases biopsied, the median time from collecting CSF with the detected mutations to definitive diagnosis by conventional methods was 22.5 days (range, 18-93 days). CONCLUSIONS: These results suggest that mutation analysis using CSF-cfDNA might be useful for differentiating CNSL from CNS infectious/demyelinating diseases and for early detection of CNSL, even in cases where brain biopsy is difficult to perform.

A simple method to distinguish residual elotuzumab from monoclonal paraprotein in immunofixation assays for multiple myeloma patients.

Negative immunofixation electrophoresis (IFE) of serum and/or urine is a diagnostic marker for determining a complete response (CR) after immunotherapy for multiple myeloma (MM). However, residual therapeutic antibodies such as elotuzumab (IgG-κ), can compromise IFE evaluation when the affected immunoglobulins belong to the same IgG-κ subclass. We thus sought to develop a simple and rapid method to treat patient serum before IFE to distinguish the residual elotuzumab. Serum samples from patients receiving elotuzumab were treated with a predetermined amount of soluble signaling lymphocyte activation molecule F7 (SLAMF7) protein and then subjected to conventional IFE testing. We tested our method in samples from 12 patients. The IgG-κ band in IFE disappeared or shifted after elotuzumab treatment in four patients with no bone marrow minimal residual disease and normalized free light chain, whereas seven patients with any sign of residual MM showed a remaining IgG-κ band after treatment. One-hour incubation of samples with 6-9 molar excess soluble SLAMF7 before IFE was sufficient to distinguish residual elotuzumab in 11 of 12 samples. This simple method does not require special reagents, can be performed in most clinical laboratories, and enables differentiation between patients with a CR and those requiring further treatment.