Ellinor I. B. Peerschke

Background: COVID-19 pathology is associated with exuberant inflammation, vascular damage, and activation of coagulation. In addition, complement activation has been described and is linked to disease pathology. However, few studies have been conducted in cancer patients.Objective: This study examined complement activation in response to COVID-19 in the setting of cancer associated thromboinflammation.Methods: Markers of complement activation (C3a, C5a, sC5b-9) and complement inhibitors (Factor H, C1-Inhibitor) were evaluated in plasma of cancer patients with (n=43) and without (n=43) COVID-19 and stratified based on elevated plasma D-dimer levels (>1.0 μg/ml FEU). Markers of vascular endothelial cell dysfunction and platelet activation (ICAM-1, thrombomodulin, P-selectin) as well as systemic inflammation (pentraxin-3, serum amyloid A, soluble urokinase plasminogen activator receptor) were analyzed to further evaluate the inflammatory response.Results: Increases in circulating markers of endothelial cell dysfunction, platelet activation, and systemic inflammation were noted in cancer patients with COVID-19. In contrast, complement activation increased in cancer patients with COVID-19 and elevated D-dimers. This was accompanied by decreased C1-Inhibitor levels in patients with D-dimers > 5 ug/ml FEU.Conclusion: Complement activation in cancer patients with COVID-19 is significantly increased in the setting of thromboinflammation. These findings support a link between coagulation and complement cascades in the setting of inflammation.

In a stunningly short period of time, the unexpected coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS–CoV-2), has turned the unprepared world topsy-turvy. Although the rapidity with which the virus struck was indeed overwhelming, scientists throughout the world have been up to the task of deciphering the mechanisms by which SARS–CoV-2 induces the multisystem and multiorgan inflammatory responses that, collectively, contribute to the high mortality rate in affected individuals. In this issue of the JCI, Skendros and Mitsios et al. is one such team who report that the complement system plays a substantial role in creating the hyperinflammation and thrombotic microangiopathy that appear to contribute to the severity of COVID-19. In support of the hypothesis that the complement system along with neutrophils and platelets contributes to COVID-19, the authors present empirical evidence showing that treatment with the complement inhibitor compstatin Cp40 inhibited the expression of tissue factor in neutrophils. These results confirm that the complement axis plays a critical role and suggest that targeted therapy using complement inhibitors is a potential therapeutic option to treat COVID-19–induced inflammation.

GC1qR is highly expressed in breast cancer and plays a role in cancer cell proliferation. This study explored therapy with gC1qR monoclonal antibody 60.11, directed against the C1q binding domain of gC1qR, in a murine orthotopic xenotransplant model of triple negative breast cancer. MDA231 breast cancer cells were injected into the mammary fat pad of athymic nu/nu female mice. Mice were segregated into three groups (n = 5, each) and treated with the vehicle (group 1) or gC1qR antibody 60.11 (100 mg/kg) twice weekly, starting at day 3 post-implantation (group 2) or when the tumor volume reached 100 mm³ (group 3). At study termination (d = 35), the average tumor volume in the control group measured 895 ± 143 mm³, compared to 401 ± 48 mm³ and 701 ± 100 mm³ in groups 2 and 3, respectively (p < 0.05). Immunohistochemical staining of excised tumors revealed increased apoptosis (caspase 3 and TUNEL staining) in 60.11-treated mice compared to controls, and decreased angiogenesis (CD31 staining). Slightly decreased white blood cell counts were noted in 60.11-treated mice. Otherwise, no overt toxicities were observed. These data are the first to demonstrate an in vivo anti-tumor effect of 60.11 therapy in a mouse model of triple negative breast cancer.

Mesothelioma is an aggressive cancer of the serous membranes with poor prognosis despite combination therapy consisting of surgery, radiotherapy, and platinum-based chemotherapy. Targeted therapies, including immunotherapies, have reported limited success, suggesting the need for additional therapeutic targets. This study investigates a potential new therapeutic target, gC1qR/HABP1/p32 (gC1qR), which is overexpressed in all morphologic subtypes of mesothelioma. gC1qR is a complement receptor that is associated with several cellular functions, including cell proliferation and angiogenesis. In vitro and in vivo experiments were conducted to test the hypothesis that targeting gC1qR with a specific gC1qR monoclonal antibody 60.11 reduces mesothelioma tumor growth, using the biphasic mesothelioma cell line MSTO-211H (MSTO). In vitro studies demonstrate cell surface and extracellular gC1qR expression by MSTO cells, and a modest 25.3 ± 1.8% (n = 4) reduction in cell proliferation by the gC1qR blocking 60.11 antibody. This inhibition was specific for targeting the C1q binding domain of gC1qR at aa 76–93, as a separate monoclonal antibody 74.5.2, directed against amino acids 204–218, had no discernable effect. In vivo studies, using a murine orthotopic xenotransplant model, demonstrated an even greater reduction in MSTO tumor growth (50% inhibition) in mice treated with the 60.11 antibody compared to controls. Immunohistochemical studies of resected tumors revealed increased cellular apoptosis by caspase 3 and TUNEL staining, in 60.11 treated tumors compared to controls, as well as impaired angiogenesis by decreased CD31 staining. Taken together, these data identify gC1qR as a potential new therapeutic target against mesothelioma with both antiproliferative and antiangiogenic properties.

Background: Cell-free DNA (cfDNA) analysis using peripheral blood represents an exciting, minimally invasive technology for cancer diagnosis and monitoring. The reliability of testing is dependent on the accuracy and sensitivity of specific molecular analyses to detect tumor-associated genomic variants and on the quantity and quality of cfDNA available for testing. Specific guidelines for standardization and design of appropriate quality programs focused specifically on cfDNA isolation are lacking, as are standardized quality control reagents. Content: This report describes and illustrates quality control and quality assurance processes, supported by generation of in-house quality control material, to ensure the reliability of the preanalytical phase of cfDNA analysis. Summary: We have developed a robust quality program to support high-volume automated cfDNA extraction from peripheral blood by implementing processes and procedures designed to monitor the adequacy of specimen collection, specimen stability, efficiency of cfDNA extraction, and cfDNA quality.

Introduction: Globular C1q receptor (gC1qR/p32/HABP1) is overexpressed in a variety of cancers, particularly adenocarcinomas. This study investigated gC1qR expression in malignant pleural mesothelioma (MPM) and its pathophysiologic correlates in a surgical patient cohort. Methods: Tissue microarrays comprising 6 tumoral and 3 stromal cores from 265 patients with MPM (216 epithelioid, 26 biphasic, and 23 sarcomatoid; 1989–2010) were investigated by immunohistochemistry for gC1qR expression (intensity and distribution by H-score, range 0–300), and immune cell infiltration. Overall survival (OS) was analyzed by the Kaplan-Meier method (high vs. low gC1qR expression delineated by median score) in the whole cohort and by neoadjuvant chemotherapy (NAC) status. Multivariable Cox analysis included stage, chemotherapy, and immune cell infiltration. Results: gC1qR was overexpressed in all histological types of MPMs (263/265, 99.2%) compared to normal pleura. In epithelioid MPM, high gC1qR expression was associated with better OS (median 25 vs. 11 months; p = 0.020) among NAC patients, and among patients without NAC (No-NAC) but who received post-operative chemotherapy (median OS 38 vs. 19 months; p = 0.0007). In multivariable analysis, high gC1qR expression was an independent factor for improved OS in patients treated with NAC. In the No-NAC cohort, high gC1qR expression correlated with lower tumor stage. Moreover, the influence of Ki67 and CD4 T-cell infiltration on OS were more pronounced among patients with high gC1qR expression. Conclusion: This is the first description of gC1qR expression in MPM. The data identify gC1qR as a potential new prognostic factor in patients treated with surgery and chemotherapy.

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The use of antithrombotic agents, including anticoagulants, antiplatelet agents, and thrombolytics has increased over the last decade and is expected to continue to rise. Although antithrombotic-associated intracranial hemorrhage can be devastating, rapid reversal of coagulopathy may help limit hematoma expansion and improve outcomes.