Pembrolizumab-related Immune Thrombocytopenia in a Patient with Lung Adenocarcinoma Treated by Radiotherapy: Potential Immune-related Adverse Event Elicited by Radiation Therapy.

The effect of radiotherapy during immunotherapy on immune-related adverse events (irAEs) is not fully understood. We herein report a 74-year-old woman diagnosed with lung adenocarcinoma with programmed death ligand 1 expression ≥50% and treated with pembrolizumab. She developed fatal immune thrombocytopenia associated with pembrolizumab immediately following radiotherapy. A flow cytometry analysis of peripheral blood detected an increased expression of programmed death-1 (PD-1) and Ki-67 in CD4+ and CD8+ T cells after radiotherapy, compared with pre-irradiation measurements. This case suggests that radiotherapy may evoke irAEs during treatment with anti-PD-1 antibodies, which physicians should consider when using radiotherapy in patients treated with these drugs.

Heterogeneous Tumor-Immune Microenvironments between Primary and Metastatic Tumors in a Patient with ALK Rearrangement-Positive Large Cell Neuroendocrine Carcinoma.

Evolution of tumor-immune microenviroments (TIMEs) occurs during tumor growth and dissemination. Understanding inter-site tumor-immune heterogeneity is essential to harness the immune system for cancer therapy. While the development of immunotherapy against lung cancer with driver mutations and neuroendocrine tumors is ongoing, little is known about the TIME of large cell neuroendocrine carcinoma (LCNEC) or anaplastic lymphoma kinase (ALK) rearrangement-positive lung cancer. We present a case study of a 32-year-old female patient with ALK-rearrangement-positive LCNEC, who had multiple distant metastases including mediastinal lymph-node, bilateral breasts, multiple bones, liver and brain. Multiple biopsy samples obtained from primary lung and three metastatic tumors were analyzed by fluorescent multiplex immunohistochemistry. Tissue localizations of tumor-infiltrating lymphocytes in the tumor nest and surrounding stroma were evaluated. T cell and B cell infiltrations were decreased with distance from primary lung lesion. Although each tumor displayed a unique TIME, all tumors exhibited concomitant regression after treatment with an ALK-inhibitor. This study provides the first evidence of the coexistence of distinct TIME within a single individual with ALK-rearrangement-positive LCNEC. The present study contributes to our understanding of heterogeneous TIMEs between primary and metastatic lesions and provides new insights into the complex interplay between host-immunity and cancer cells in primary and metastatic lesions.

Non-small-cell Lung Cancer with Severe Skin Manifestations Related to Radiation Recall Dermatitis after Atezolizumab Treatment.

Radiation recall dermatitis (RRD) is an inflammatory reaction that occurs at previously irradiated skin regions after drug administration. We herein report a patient with non-small-cell lung cancer treated previously with thoracic radiotherapy who developed severe RRD induced by atezolizumab [anti-programmed death 1 ligand 1 (PD-L1) antibody]. Immunohistochemistry of the skin biopsy showed dermatitis with infiltration of CD8+ lymphocytes, suggesting that atezolizumab might provoke an immune-related inflammatory reaction at previously irradiated skin regions. When administering anti-PD-L1 antibody to patients who have undergone radiotherapy previously, physicians should carefully monitor the irradiated skin for the potential occurrence of RRD.

Trousseau's syndrome triggered by an immune checkpoint blockade in a non-small cell lung cancer patient.

PD-1 blockade therapy activates T cells by blocking the interaction between PD-1 and PD-L1 and promotes IFN-γ and Th1 cytokine production. In turn, IFN-γ and Th1 cytokines produced by activated T cells promote TF synthesis in monocytes/macrophages, which results in hypercoagulability leading to thrombosis.