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Various immune-related adverse events can frequently occur, which may be life-threatening if programmed death 1 or its ligand is blocked. Here, we report a rare case of concomitant autoimmune hemolytic anemia and hemophagocytic lymphohistiocytosis caused by atezolizumab plus chemotherapy in a patient with lung adenocarcinoma and autoantibodies. Dramatic and lasting tumor regression in response to only one therapy cycle was achieved. Nevertheless, this case suggests that careful management is required when using immunotherapy in patients with autoantibodies.

Recent studies indicate that lipid metabolic changes affect the survival of multiple myeloma (MM) cells. Time-of-flight secondary ion mass spectrometry (TOF-SIMS), an imaging mass spectrometry technique, is used to visualize the subcellular distribution of biomolecules including lipids. We therefore applied this method to human clinical specimens to analyze the membrane fatty acid composition and determine candidate molecules for MM therapies. We isolated MM cells and normal plasma cells (PCs) from bone marrow aspirates of MM patients and healthy volunteers, respectively, and these separated cells were analyzed by TOF-SIMS. Multiple ions including fatty acids were detected and their ion counts were estimated. In MM cells, the mean intensity of palmitic acid was significantly lower than the mean intensity in PCs. In a cell death assay, palmitic acid reduced U266 cell viability dose-dependently at doses between 50 and 1000 μM. The percentage of apoptotic cells increased from 24 h after palmitic acid administration. In contrast, palmitic acid had no effect on the viability of normal peripheral blood mononuclear cells (PBMCs). The results of this study indicated that palmitic acid is a potential candidate for novel therapeutic agents that specifically attack MM cells.

Lipids comprise the primary component of cell membranes. Imaging mass spectrometry is increasingly being used to visualize membranous lipids in clinical specimens, and it has revealed that abnormal lipid metabolism is related to the development of diseases. To characterize cell populations which are rare and sparsely localized in tissues, we conducted time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses of individual cells sorted by fluorescence activated cell sorting (FACS) and applied the method to analyze breast cancer stem cells (CSCs). TOF-SIMS analyses visualized phosphoric acids and four fatty acid (FA) species in the sorted CD45 − /CD44 + /CD24 − CSCs, and these ions are suspected to have originated from membranous phospholipids as they were uniformly detected from the locus where the cells attached. Integrated ion intensity of palmitoleic acids [FA(16:1)] normalized by phosphoric acid signals were decreased significantly in CSCs as compared to that of CD45 − /CD44 − /CD24 + non-stem cancer cells (NSCCs). This finding was supported by liquid chromatography coupled electrospray ionization-tandem mass spectrometry analysis, which revealed phosphatidylcholine (PC)(16:0/16:1) to be less abundant and PC(16:0/16:0) to be more abundant in CSCs as compared to NSCCs. Therefore, our novel method successfully provided lipid composition analysis of individual cells classified by the expression of a complex combination of cell-surface markers. The lipid compositions of CSCs originating from the heterogeneous cellular populations of clinical specimens were successfully characterized by this method.