PMC5477093_01
Magnetic resonance imaging of intracranial lesions. a Parieto-temporal lesion that was irradiated. T1 weighted MRI after application of Gadolinium-containing contras material. b Presentation of the radiation field that was applied to the lesion. c Progression of irradiated lesion after irradiation and before resection of the lesion
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Fig1
Soon thereafter, however, walking ability deteriorated, and cranial MRI showed a new parieto-temporal lesion in proximity of the formerly irradiated masses (Fig. 1a). Suggestive of further metastatic spread, this new lesion was irradiated with 24 Gray over 7 days (Fig. 1b), and nivolumab continued. MRI demonstrated progression of the newly irradiated lesion (Fig. 1c), whereas extracerebral masses remained stable.
Histological analysis of the resected lesion. H&E stained specimens. a Initial biopsy from bronchial lesion. b Resected cerebral lesion reveals necrotic brain tissue with vasculitic inflammatory infiltrates. Scale bars: 20 mum
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Fig2
Histopathological analysis revealed necrotizing encephalitis with no evidence of metastatic lung cancer (Fig.2a and b).
Immunohistochemical analysis of brain lesion. a Staining with CK22 monoclonal anti-cytokeratin antibody cocktail. b Staining with the astroglial marker anti-GFAP (glial fibrillary acidic protein). Scale bar: 20 mum. c CD45 (leukocyte antigen) staining for the detection of immune cells demonstrates perivascular infiltrates. Scale bar: 50 mum. d Very few CD20-positive B cells are detected. Scale bar: 20 mum. e The perivascular infiltrate are predominantly PD-1 positive T cells. Scale bar: 20 mum. f CD68 staining of macrophages highlights resorptive changes. Scale bar: 50 mum. (g, h) The perivascular T cell infiltrates are mainly CD8 T cells. Scale bar: 20 mum. i Only little PD-L1 staining was detected. Scale bar: 20 mum
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Fig3
Staining for cytokeratins (CK22), performed on all paraffin embedded specimens was negative (Fig. 3a). A high perivascular density of CD45 positive cells was found (Fig. 3c) with predominance of PD-1 positive T cells over B cells (CD20, PD-1, CD4 and CD8 staining, Fig.3d, e, g and h). Staining of CD68 demonstrated accompanying resorptive changes of the brain tissue (Fig. 3f). We also found a predominance of CD8 positive T cells over CD4 positive T cells (Fig. 3g and h). PD-L1 expressing cells were sparse (Fig. 3i).
Chemokine levels over time and detection of anti-vascular endothelial antibodies. a, b Changes in inflammatory chemokine levels that were measured in the serum of the patient by a multiplex bead assay. Chemokines were measured before treatment with nivolumab (time point 1), after 4 weeks (time point 2), after 10 weeks (time point 3), at the diagnosis of the vasculitis/encephalitis (time point 4), and 3 weeks later (time point 5). c Staining of control cerebellum sections with serum from the patient at the time point when the vasculitis/encephalitis was diagnosed. d Staining of cerebellar sections with control serum (left panel) or serum from the patient before PD-1 blockade (right panel)
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Fig4
Measurement of inflammatory chemokines showed an increase of blood levels upon treatment initiation with anti-PD-1 antibody including CCL11, IP-10, and MIP-3alpha (Fig. 4a). Only MIP-1beta and IL-8 were increased at the time point of resection of the encephalitic lesion (Fig. 4b). Moreover, when histological cerebellum sections from an unrelated healthy control individual were incubated with patient's serum taken at the time point when the vasculitis was diagnosed, a strong staining of the endothelial layers of cerebellar vessels was found (Fig. 4c). Testing of control cerebellar sections with control serum or patient's serum before nivolumab treatment showed no staining (Fig. 4d).