BackgroundInflammatory mediators, including acute phase reactants and cytokines, have been reported to be associated with clinical efficacy in patients with melanoma and other cancers receiving immune checkpoint inhibitors (ICI). Analyses of patient sera from three large phase II/III randomized ICI trials, one of which included a chemotherapy arm, were performed to assess whether baseline levels of C-reactive protein (CRP), interleukin-6 (IL-6) or neutrophil/lymphocyte (N/L) ratios were prognostic or predictive.Patients and methodsBaseline and on-treatment sera were analyzed by multiplex protein assays from immunotherapy-naïve patients with metastatic melanoma randomized 1:1 on the Checkmate-064 phase II trial of sequential administration of nivolumab followed by ipilimumab or the reverse sequence. Baseline sera, and peripheral blood mononuclear cells using automated cell counting, were analyzed from treatment-naïve patients who were BRAF wild-type and randomly allocated 1:1 to receive nivolumab or dacarbazine on the phase III Checkmate-066 trial, and from treatment-naïve patients allocated 1:1:1 to receive nivolumab, ipilimumab or both ipilimumab and nivolumab on the phase III Checkmate-067 trial.ResultsHigher baseline levels of IL-6 and the N/L ratio, and to a lesser degree, CRP were associated with shorter survival in patients receiving ICI or chemotherapy. Increased on-treatment levels of IL-6 in patients on the Checkmate-064 study were also associated with shorter survival. IL-6 levels from patients on Checkmate-064, Checkmate-066 and Checkmate-067 were highly correlated with levels of CRP and the N/L ratio.ConclusionIL-6, CRP and the N/L ratio are prognostic factors with higher levels associated with shorter overall survival in patients with metastatic melanoma receiving ICI or chemotherapy in large randomized trials. In a multi-variable analysis of the randomized phase III Checkmate-067 study, IL-6 was a significant prognostic factor for survival.

The latent TGF-β binding proteins (LTBP) −1, −3, and −4 are extracellular proteins that assist in the secretion and localization of latent TGF-β. The null mutation of LTBP-4S in mice causes defects in the differentiation of terminal air-sacs, fragmented elastin, and colon carcinomas. We investigated lung development from embryonic day 14.5 (E14.5) to day 7 after birth (P7) in order to determine when the defects in elastin organization initiate and to further examine the relation of TGF-β signaling levels and air-sac septation in Ltbp4S −/− lungs. We found that defects in elastogenesis are visible as early as E14.5 and are maintained in the alveolar walls, in blood vessel media, and subjacent air-way epithelium. The air-sac septation defect was associated with excessive TGF-β signaling and was reversed by lowering TGF-β2 levels. Thus, the phenotype is not directly reflective of a change in TGF-β1, the only TGF-β isoform known to complex with LTBP-4. Reversal of the air-sac septation defect was not associated with normalization of the elastogenesis indicating two separate functions of LTBP-4 as a regulator of elastic fiber assembly and TGF-β levels in lungs.

Mice deficient in Latent TGFβ Binding Protein 4 (Ltbp4) display a defect in lung septation and elastogenesis. The lung septation defect is normalized by genetically decreasing TGFβ2 levels. However, the elastic fiber assembly is not improved in Tgfb2−/−;Ltbp4S−/− compared to Ltbp4S−/− lungs. We found that decreased levels of TGFβ1 or TGFβ3 did not improve lung septation indicating that the TGFβ isoform elevated in Ltbp4S−/− lungs is TGFβ2. Expression of a form of Ltbp4 that could not bind latent TGFβ did not affect lung phenotype indicating that normal lung development does not require the formation of LTBP4-latent TGFβ complexes. Therefore, the change in TGFβ-level in the lungs is not directly related to Ltbp4 deficiency but probably is a consequence of changes in the extracellular matrix. Interestingly, combination of the Ltbp4S−/− mutation with a fibulin-5 null mutant in Fbln5−/−;Ltbp4S−/− mice improves the lung septation compared to Ltbp4S−/− lungs. Large globular elastin aggregates characteristic for Ltbp4S−/− lungs do not form in Fbln5−/−;Ltbp4S−/− lungs and EM studies showed that elastic fibers in Fbln5−/−;Ltbp4S−/− lungs resemble those found in Fbln5−/− mice. These results are consistent with a role for TGFβ2 in lung septation and for Ltbp4 in regulating fibulin-5 dependent elastic fiber assembly.

BackgroundHigh C reactive protein (CRP) levels have been reported to be associated with a poor clinical outcome in a number of malignancies and with programmed cell death protein 1 immune checkpoint blockade in patients with advanced cancer. Little is known about the direct effects of CRP on adaptive immunity in cancer. Therefore, we investigated how CRP impacted the function of T cells and dendritic cells (DCs) from patients with melanoma.MethodsThe effects of CRP on proliferation, function, gene expression and phenotype of patient T cells and DCs, and expansion of MART-1 antigen-specific T cells were analyzed by multicolor flow cytometry and RNA-seq. Additionally, serum CRP levels at baseline from patients with metastatic melanoma treated on the Checkmate-064 clinical trial were assessed by a Luminex assay.ResultsIn vitro, CRP inhibited proliferation, activation-associated phenotypes and the effector function of activated CD4+ and CD8+ T cells from patients with melanoma. CRP-treated T cells expressed high levels of interleukin-1β, which is known to enhance CRP production from the liver. CRP also suppressed formation of the immune synapse and inhibited early events in T-cell receptor engagement. In addition, CRP downregulated the expression of costimulatory molecules on mature DCs and suppressed expansion of MART-1-specific CD8+ T cells in a dose-dependent manner by impacting on both T cells and antigen-presenting cells. High-serum CRP levels at baseline were significantly associated with a shorter survival in both nivolumab-treated and ipilimumab-treated patients.ConclusionsThese findings suggest that high levels of CRP induce an immunosuppressivemilieuin melanoma and support the blockade of CRP as a therapeutic strategy to enhance immune checkpoint therapies in cancer.Trial registration numberNCT01783938andNCT02983006.

Schneck is entitled to a share of royalty received by the university on sales of products described in this article. He is also a founder of NexImmune and owns equity in the company and he serves as a member of NexImmune's Scientific Advisory Board. The terms of these arrangements have been reviewed and approved by The Johns Hopkins University in accordance with its conflict of interest policies.