Immune checkpoint inhibitors (ICIs) are a newly developed component of cancer care that expands the treatment possibilities for patients. Their use has been associated with several immune-related adverse events, including ICI-induced sarcoidosis-like reactions. This article reviews the data concerning ICI-induced sarcoidosis-like reactions currently available in the medical literature. These reactions have been reported in three classes of ICIs: anti-cytotoxic T-lymphocyte associated protein 4 antibodies, programmed death 1 inhibitors and programmed death ligand 1 inhibitors. These reactions are indistinguishable from sarcoidosis with a similar histology, pattern of organ involvement, and pattern of clinical manifestations. The most common locations to observe granulomatous inflammation from these reactions is in intrathoracic locations (the lung and/or mediastinal lymph nodes) and the skin. The median time between initiation of an ICI and the development of a sarcoidosis-like reaction averaged 14 weeks. Clinicians have opted to use corticosteroids and/or discontinue the ICI, or take no action when these reactions have developed. Regardless of whether the clinician performed an intervention or not, these reactions have uniformly improved or resolved after ICI-treatment, which provides additional temporal evidence supporting the presence of a sarcoidosis-like reaction as opposed to sarcoidosis. There is even evidence that the development of an ICI-induced sarcoidosis-like reaction suggests that the ICI is effective as an anti-tumor agent and should be continued. As is the case for sarcoidosis, sarcoidosis-like reactions do not mandate antisarcoidosis therapy, especially if the condition is asymptomatic. When treatment of sarcoidosis-like reaction is required, it may be prudent to continue ICI therapy and add antisarcoidosis therapy because standard antisarcoidosis regimens seem to be effective. Further research into the mechanisms involved in the development of ICI-induced sarcoidosis-like reactions may give insights into the immunopathogenesis of sarcoidosis.

A key unknown of the functional space in tumor immunity is whether CD4 T cells depend on intratumoral MHCII cancer antigen recognition. MHCII-expressing, antigen-presenting cancer-associated fibroblasts (apCAFs) have been found in breast and pancreatic tumors and are considered to be immunosuppressive. This analysis shows that antigen-presenting fibroblasts are frequent in human lung non-small cell carcinomas, where they seem to actively promote rather than suppress MHCII immunity. Lung apCAFs directly activated the TCRs of effector CD4 T cells and at the same time produced C1q, which acted on T cell C1qbp to rescue them from apoptosis. Fibroblast-specific MHCII or C1q deletion impaired CD4 T cell immunity and accelerated tumor growth, while inducing C1qbp in adoptively transferred CD4 T cells expanded their numbers and reduced tumors. Collectively, we have characterized in the lungs a subset of antigen-presenting fibroblasts with tumor-suppressive properties and propose that cancer immunotherapies might be strongly dependent on in situ MHCII antigen presentation.

Clara cell secretory protein (CC16) is associated with Th2 modulation. Surfactant protein D (SPD) plays an important role in surfactant homeostasis and eosinophil chemotaxis. We measured CC16 and SPD in sputum supernatants of 84 asthmatic patients and 12 healthy controls. In 22 asthmatics, we additionally measured CC16 and SPD levels in BAL and assessed smooth muscle area (SMA), reticular basement membrane (RBM) thickness, and epithelial detachment (ED) in bronchial biopsies. Induced sputum CC16 and SPD were significantly higher in patients with severe asthma (SRA) compared to mild-moderate and healthy controls. BAL CC16 and SPD levels were also higher in SRA compared to mild-moderate asthma. CC16 BAL levels correlated with ED, while SPD BAL levels correlated with SMA and RBM. Severity represented a significant covariate for these associations. CC16 and SPD levels are upregulated in SRA and correlate with remodeling indices, suggesting a possible role of these biomarkers in the remodeling process.

Background Accurate predictions of tumor dissemination risks and medical treatment outcomes are critical to personalize therapy. Patient-derived xenograft (PDX) models in mice have demonstrated high accuracy in predicting therapeutic outcomes, but methods for predicting tumor invasiveness and early stages of vascular/lymphatic dissemination are still lacking. Here we show that a zebrafish tumor xenograft (ZTX) platform based on implantation of PDX tissue fragments recapitulate both treatment outcome and tumor invasiveness/dissemination in patients, within an assay time of only 3 days. Methods Using a panel of 39 non-small cell lung cancer PDX models, we developed a combined mouse-zebrafish PDX platform based on direct implantation of cryopreserved PDX tissue fragments into zebrafish embryos, without the need for pre-culturing or expansion. Clinical proof-of-principle was established by direct implantation of tumor samples from four patients. Results The resulting ZTX models responded to Erlotinib and Paclitaxel, with similar potency as in mouse-PDX models and the patients themselves, and resistant tumors similarly failed to respond to these drugs in the ZTX system. Drug response was coupled to elevated expression of EGFR, Mdm2, Ptch1 and Tsc1 (Erlotinib), or Nras and Ptch1 (Paclitaxel) and reduced expression of Egfr, Erbb2 and Foxa (Paclitaxel). Importantly, ZTX models retained the invasive phenotypes of the tumors and predicted lymph node involvement of the patients with 91% sensitivity and 62% specificity, which was superior to clinically used tests. The biopsies from all four patient tested implanted successfully, and treatment outcome and dissemination were quantified for all patients in only 3 days. Conclusions We conclude that the ZTX platform provide a fast, accurate, and clinically relevant system for evaluation of treatment outcome and invasion/dissemination of PDX models, providing an attractive platform for combined mouse-zebrafish PDX trials and personalized medicine.

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