Human leukocyte antigen expression in paired primary lung tumors and brain metastases in non-small cell lung cancer.

Loss of human leukocyte antigen (HLA) class 1 expression is a mechanism of tumor immune escape and may contribute to resistance to immunotherapy. Patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors can have discordant responses between brain metastases and extracranial sites of disease. We sought to evaluate whether HLA class 1 expression was retained in metastatic NSCLC. Patients with paired primary NSCLC and brain metastases were identified from our institution's tissue registry. HLA class 1 cell membrane expression on tumor cells was determined by immunohistochemistry. Tumors with greater than the median of 10% HLA expression were considered positive. Agreement statistics (κ) were used to assess the congruence of HLA expression. 51 patients with paired primary NSCLC and brain lesions were identified. The median HLA class 1 expression was 20% in the primary tumors (IQR 0-65%) and 10% in the brain metastases (IQR 5-40%). 27 primary tumors and 24 brain metastases were positive for HLA expression. There was disagreement in HLA positivity between paired lesions in 11 patients (22%, 95% CI 12-35%) (κ = 0.57, 95% CI 0.35-0.79) (p = 0.0001). None of the patients received checkpoint inhibitors for treatment of these lesions. The results show that while there is moderate agreement in HLA class 1 expression between primary lung tumor and brain metastasis pairs, HLA expression is incongruent in nearly one quarter of patients. Loss of antigen presentation may represent one of the many potential mechanisms of discordant responses to checkpoint inhibitor therapy.

Safety of Influenza Vaccine in Patients With Cancer Receiving Pembrolizumab.

PURPOSE: There is a concern that influenza vaccination could increase the incidence of immune-related adverse events (irAEs) in patients with cancer receiving immune checkpoint inhibitors. The aim of our study was to determine the safety of influenza vaccination in this patient population. PATIENTS AND METHODS: We retrospectively identified patients who received at least 1 dose of pembrolizumab during any influenza season from September 2014 to August 2017 and reviewed medical records for irAEs. The primary endpoint was the incidence of irAEs. We used multivariable logistic regression and cumulative incidence curve with competing risks for comparison. RESULTS: Among 162 patients with cancer included in this study, 70 patients (43.2%) received at least 1 influenza vaccination. The vaccinated group was significantly older (P = .002) and received more cycles of pembrolizumab (P = .006). The incidence of any grade irAEs in the vaccinated group trended toward being lower (25.7% v 40.2%; P = .07) compared with the nonvaccinated group. Influenza vaccination was independently associated with fewer irAEs, with an odds ratio of 0.4 (95% CI, 0.2 to 0.9; P = .03) in multivariable analyses. The vaccinated group was less likely to have irAEs compared with the nonvaccinated group (24.7% v 34.4% at 12 months; P = .05), with death as a competing risk. The median irAE-free duration in the vaccinated group was longer than the nonvaccinated group (not reached v 28 months; P = .037). CONCLUSION: Influenza vaccination in patients with cancer receiving immune checkpoint inhibitor therapy was not associated with increased irAEs. This supports the safety of influenza vaccination in this patient population.

Biomarkers of hyperprogression and pseudoprogression with immune checkpoint inhibitor therapy.

Hyperprogression and pseudoprogression are two atypical responses to immune checkpoint inhibitor therapy that affect therapeutic decisions and prognosis. Identification of predictive biomarkers for atypical responses either before or during treatment remains a huge unmet need in cancer immunotherapy. Many studies have looked at potential biomarkers, including clinical factors and laboratory findings (e.g., peripheral blood counts, circulating tumor DNA, cytokine levels). The results of these studies have been inconsistent, possibly due to small sample sizes, different tumor types and heterogeneity of the definition of these atypical responses.

Florid dermatopathic lymphadenopathy-A morphological mimic of Langerhans cell histiocytosis.

The histopathology of reactive florid dermatopathic lymphadenopathy shows overlap with Langerhans cell histiocytosis (LCH) involving the lymph node, which may lead to misdiagnosis. These entities can be distinguished by recognition of the sinus-based distribution of Langerhans cells in LCH, in contrast to the paracortical distribution of Langerhans cells, pigment-laden histiocytes, and small lymphocytes in dermatopathic lymphadenopathy.

Lymphocyte-to-monocyte ratio is associated with survival in pembrolizumab-treated metastatic melanoma patients.

The peripheral blood lymphocyte-to-monocyte ratio (LMR) has been associated with prognosis in many malignancies including metastatic melanoma. However, it has not been studied in patients treated with immune checkpoint inhibitors. In this study, we analyzed the baseline LMR with progression-free survival (PFS) and overall survival (OS) in metastatic melanoma patients treated with pembrolizumab. A total of 133 patients with metastatic melanoma treated with pembrolizumab were included in this retrospective study. LMR was calculated from pretherapy peripheral blood counts and the optimal cutoff value was determined by a receiver operator characteristic curve. PFS and OS were evaluated using the Kaplan-Meier method and multivariate Cox proportional hazard modeling. Patients with an LMR of at least 1.7 showed improved PFS (hazard ratio=0.55; 95% confidence interval: 0.34-0.92; P=0.024) and OS (hazard ratio=0.29; 95% confidence interval: 0.15-0.59; P=0.0007). The baseline LMR is associated with PFS and OS in metastatic melanoma patients treated with pembrolizumab, and could represent a convenient and cost-effective prognostic biomarker. Validation of these findings in an independent cohort is needed.

Effects of commonly used chronic medications on the outcomes of ipilimumab therapy in patients with metastatic melanoma.

Ipilimumab can induce long-term survival in 20% of patients with metastatic melanoma. Concurrent chronic medications may impact the patient's immune system, possess antimelanoma properties, and potentially affect clinical outcomes. This retrospective study sought to describe the efficacy and toxicity effects of 12 classes of chronic medications in metastatic melanoma patients treated with ipilimumab. A total of 159 adults who received ipilimumab for metastatic melanoma at Mayo Clinic (Rochester, Minnesota, USA) from 1 March 2011 through 31 December 2014 were included. Classes of chronic medications included statins, metformin, ß-blockers, angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers, calcium channel blockers, aspirin, non-steroidal anti-inflammatory drugs, H1 and H2 receptor antagonists, proton pump inhibitors (PPIs), antidepressants, and vitamin D supplements. Of the 12 medication classes, only PPIs were found to have an increased odds of experiencing a partial response or a complete response to ipilimumab [odds ratio: 3.73; confidence interval (CI): 1.26-11.04; P=0.02] on the basis of a case-control analysis. Although not significant, PPI use also trended toward improved overall survival and progression-free survival (hazard ratio: 0.44; CI: 0.17-1.15; P=0.09; and hazard ratio: 0.6; CI: 0.34-1.06; P=0.08, respectively) on the basis of Kaplan-Meier and Cox proportional hazard modeling. No medication class was associated with an increased risk of grades 3-5 immune-related adverse events with ipilimumab on the basis of case-control analysis. In summary, patients on PPIs may be more likely to experience a partial response/complete response following ipilimumab therapy. Because of the small sample size and the retrospective nature of this work, these findings are only descriptive and further study should be carried out. Other classes of chronic medications did not produce statistically significant effects for any of the measured outcomes.

Characterization and use of a rabbit-anti-mouse VPAC1 antibody by flow cytometry.

Vasoactive intestinal peptide receptor-1 signaling in lymphocytes has been shown to regulate chemotaxis, proliferation, apoptosis and differentiation. During T cell activation, VPAC1 mRNA is downregulated, but the effect on its protein levels is less clear. A small number of studies have reported measurement of human VPAC1 by flow cytometry, but murine VPAC1 reagents are unavailable. Therefore, we set out to generate a reliable and highly specific α-mouse VPAC1 polyclonal antibody for use with flow cytometry. After successfully generating a rabbit α-VPAC1 polyclonal antibody (α-mVPAC1 pAb), we characterized its cross-reactivity and showed that it does not recognize other family receptors (mouse VPAC2 and PAC1, and human VPAC1, VPAC2 and PAC1) by flow cytometry. Partial purification of the rabbit α-VPAC1 sera increased the specific-activity of the α-mVPAC1 pAb by 20-fold, and immunofluorescence microscopy (IF) confirmed a plasma membrane subcellular localization for mouse VPAC1 protein. To test the usefulness of this specific α-mVPAC1 pAb, we showed that primary, resting mouse T cells express detectable levels of VPAC1 protein, with little detectable signal from activated T cells, or CD19 B cells. These data support our previously published data showing a downregulation of VPAC1 mRNA during T cell activation. Collectively, we have established a well-characterized, and highly species specific α-mVPAC1 pAb for VPAC1 surface measurement by IF and flow cytometry.

Radical reversal of vasoactive intestinal peptide (VIP) receptors during early lymphopoiesis.

Successful thymocyte maturation is essential for normal, peripheral T cell function. Vasoactive intestinal peptide (VIP) is a neuropeptide which is highly expressed in the thymus that has been shown to modulate thymocyte development. VIP predominantly binds two G protein coupled receptors, termed vasoactive intestinal peptide receptor 1 (VPAC1) and VPAC2, but their expression profiles in CD4(-)/CD8(-) (double negative, DN) thymocyte subsets, termed DN1-4, have yet to be identified. We hypothesized that a high VPAC1:VPAC2 ratio in the earliest thymocyte progenitors (ETP cells) would be reversed during early lymphopoiesis as observed in activated, peripheral Th(2) cells, as the thymus is rich in Th(2) cytokines. In support of this hypothesis, high VPAC1 mRNA levels decreased 1000-fold, accompanied with a simultaneous increase in VPAC2 mRNA expression during early thymocyte progenitor (ETP/DN1)→DN3 differentiation. Moreover, arrested DN3 cells derived from an Ikaros null mouse (JE-131 cells) failed to completely reverse the VIP receptor ratio compared to wild type DN3 thymocytes. Surprisingly, VPAC2(-/-) mice did not show significant changes in relative thymocyte subset numbers. These data support the notion that both VPAC1 and VPAC2 receptors are dynamically regulated by Ikaros, a master transcriptional regulator for thymocyte differentiation, during early thymic development. Moreover, high VPAC1 mRNA is a novel marker for the ETP population making it enticing to speculate that the chemotactic VIP/VPAC1 signaling axis may play a role in thymocyte movement. Also, despite the results that VPAC2 deficiency did not affect thymic subset numbers, future studies are necessary to determine whether downstream T cell phenotypic changes manifest themselves, such as a propensity for a Th(1) versus Th(2) polarization.