Neutrophils seeking new neighbors: radiotherapy affects the cellular framework and the spatial organization in a murine breast cancer model.

Neutrophils are known to contribute in many aspects of tumor progression and metastasis. The presence of neutrophils or neutrophil-derived mediators in the tumor microenvironment has been associated with poor prognosis in several types of solid tumors. However, the effects of classical cancer treatments such as radiation therapy on neutrophils are poorly understood. Furthermore, the cellular composition and distribution of immune cells in the tumor is of increasing interest in cancer research and new imaging technologies allow to perform more complex spatial analyses within tumor tissues. Therefore, we aim to offer novel insight into intra-tumoral formation of cellular neighborhoods and communities in murine breast cancer. To address this question, we performed image mass cytometry on tumors of the TS/A breast cancer tumor model, performed spatial neighborhood analyses of the tumor microenvironment and quantified neutrophil-extracellular trap degradation products in serum of the mice. We show that irradiation with 2 × 8 Gy significantly alters the cellular composition and spatial organization in the tumor, especially regarding neutrophils and other cells of the myeloid lineage. Locally applied radiotherapy further affects neutrophils in a systemic manner by decreasing the serum neutrophil extracellular trap concentrations which correlates positively with survival. In addition, the intercellular cohesion is maintained due to radiotherapy as shown by E-Cadherin expression. Radiotherapy, therefore, might affect the epithelial-mesenchymal plasticity in tumors and thus prevent metastasis. Our findings underscore the growing importance of the spatial organization of the tumor microenvironment, particularly with respect to radiotherapy, and provide insight into potential mechanisms by which radiotherapy affects epithelial-mesenchymal plasticity and tumor metastasis.

Neoadjuvant concurrent chemoradiotherapy with and without hyperthermia in retroperitoneal sarcomas: feasibility, efficacy, toxicity, and long-term outcome.

PURPOSE: Retroperitoneal (RPS) sarcomas are associated with poor local and abdominal tumor control. However, the benefit of preoperative radio- or chemotherapy alone for these entities is currently unclear. Moreover, as intermediate- and high-grade sarcomas have a tendency toward early metastasis, exploration of neoadjuvant strategies is of high importance. This analysis reports the results of our 20-year single-institution experience with preoperative neoadjuvant concurrent chemoradiation. METHODS: From 2000-2019, 27 patients with intermediate- or high-grade RPS (12 dedifferentiated liposarcoma, 10 leiomyosarcoma, 5 others) were treated with radiotherapy (median dose: 50.4 Gy; range 45-75 Gy) and two cycles of chemotherapy (doxorubicin 50 mg/m2 BSA/d3 q28 and ifosfamide 1.5 g/m2 BSA/d1­5 q28) in neoadjuvant intent. Chemotherapy consisted of doxorubicin alone in two cases and ifosfamide alone in one case. Fifteen patients (56%) additionally received deep regional hyperthermia. RESULTS: The median follow-up time was 53 months (±56.7 months). 92% of patients received two cycles of chemotherapy as planned and 92% underwent surgery. At 5 and 10 years, abdominal-recurrence-free survival was 74.6% (±10.1%) and 66.3% (±11.9%), distant metastasis-free survival was 67.2% (±9.7%) and 59.7% (±11.1%), and overall survival was 60.3% (±10.5%) and 60.3% (±10.5%), respectively. CTC grade III and IV toxicities were leukocytopenia (85%), thrombocytopenia (33%), and anemia (11%). There were no treatment-related deaths. CONCLUSION: Neoadjuvant chemoradiotherapy with and without hyperthermia for retroperitoneal sarcomas is feasible and provided high local control of intermediate- and high-grade sarcoma.

Systemic modulation of stress and immune parameters in patients treated for prostate adenocarcinoma by intensity-modulated radiation therapy or stereotactic ablative body radiotherapy.

BACKGROUND: In this exploratory study, the impact of local irradiation on systemic changes in stress and immune parameters was investigated in eight patients treated with intensity-modulated radiation therapy (IMRT) or stereotactic ablative body radiotherapy (SABR) for prostate adenocarcinoma to gain deeper insights into how radiotherapy (RT) modulates the immune system. PATIENTS AND METHODS: RT-qPCR, flow cytometry, metabolomics, and antibody arrays were used to monitor a panel of stress- and immune-related parameters before RT, after the first fraction (SABR) or the first week of treatment (IMRT), after the last fraction, and 3 weeks later in the blood of IMRT (N = 4) or SABR (N = 4) patients. Effect size analysis was used for comparison of results at different timepoints. RESULTS: Several parameters were found to be differentially modulated in IMRT and SABR patients: the expression of TGFB1, IL1B, and CCL3 genes; the expression of HLA-DR on circulating monocytes; the abundance and ratio of phosphatidylcholine and lysophosphatidylcholine metabolites in plasma. More immune modulators in plasma were modulated during IMRT than SABR, with only two common proteins, namely GDF-15 and Tim­3. CONCLUSION: Locally delivered RT induces systemic modulation of the immune system in prostate adenocarcinoma patients. IMRT and SABR appear to specifically affect distinct immune components.

Checkpoint inhibitors and radiation treatment in Hodgkin's lymphoma : New study concepts of the German Hodgkin Study Group.

BACKGROUND: Patients with classical Hodgkin's lymphoma (cHL) have a good prognosis even in advanced stages. However, combined chemo- and radiotherapy, as the standard of care, is also associated with treatment-related toxicities such as organ damage, secondary neoplasias, infertility, or fatigue and long-term fatigue. Many patients suffer from this burden although their cHL was cured. Therefore, the efficacy of immune checkpoint inhibitors like anti-PD1/PD-L1 antibodies in the treatment of solid cancers and also in HL offers new options. A remarkable and durable response rate with a favorable toxicity profile was observed in heavily pretreated cHL patients. METHODS: Planning to perform prospective randomized clinical trials in the content of radio-immune treatment in patients with Hodgkin's lymphoma (HL), we transferred the results of preliminary clinical studies and basic research in clinical relevant study concepts. RESULTS: Based on these promising early phase trial data, the German Hodgkin Study Group (GHSG) will investigate innovative treatment regimens in upcoming phase II trials. CONCLUSION: The therapeutic efficacy and potential synergies of anti-PD1 antibodies in combination with chemo- or radiotherapy will be investigated in various settings of HL.

Clinically significant CMV (re)activation during or after radiotherapy/chemotherapy of the brain : Correlation with neurological deterioration and improvement upon antiviral treatment.

INTRODUCTION: For both patients with high-grade gliomas and multiple cerebral metastases, radio(chemo)therapy is the standard therapy. Neurological decline during treatment is rarely attributed to infections of the brain but to tumor progression or side effects of radiotherapy. CASE REPORTS: We present 4 cases of cytomegalovirus (CMV) viremia associated with neurological deterioration, which occurred during or shortly after radiotherapy and/or chemotherapy of the brain (brain metastases 2, high-grade glioma 1, carcinoma infiltrating brain 1). In all cases, neurological decline was sudden and unexpected, and causes such as increased intracranial pressure or tumor progression could be excluded radiologically. Treatment with dexamethasone and mannitol had no or only very short-term effects. General infections were either excluded or receding before the neurological symptoms occurred. All patients presented with decreasing levels of thrombocytes. In all cases, CMV (re)activation could be proven using blood test for CMV-DNA. The anti-CMV-IgG status suggested reactivation rather than a primary infection. One patient died within 72 h of onset of the symptoms (results of CMV tests were received postmortem). Diagnosis of 3 patients allowed successful administration of antiviral treatment, which greatly improved the general and neurological conditions of the patients within 48 h. DISCUSSION: Neurological deterioration during RT is hardly ever attributed to viral infections. These cases suggest that CMV reactivation and subsequent infection might actually be causative and has to be considered and treated. CONCLUSION: Further prospective studies verifying and investigating this observation in terms of frequency and clinical relevance seem indicated.

Novel technique for high-precision stereotactic irradiation of mouse brains.

BACKGROUND AND PURPOSE: Small animal irradiation systems were developed for preclinical evaluation of tumor therapy closely resembling the clinical situation. Mostly only clinical LINACs are available, so protocols for small animal partial body irradiation using a conventional clinical system are essential. This study defines a protocol for conformal brain tumor irradiations in mice. MATERIALS AND METHODS: CT and MRI images were used to demarcate the target volume and organs at risk. Three 6 MV photon beams were planned for a total dose of 10 fractions of 1.8 Gy. The mouse position in a dedicated applicator was verified by an X­ray patient positioning system before each irradiation. Dosimetric verifications (using ionization chambers and films) were performed. Irradiation-induced DNA damage was analyzed to verify the treatment effects on the cellular level. RESULTS: The defined treatment protocol and the applied fractionation scheme were feasible. The in-house developed applicator was suitable for individual positioning at submillimeter accuracy of anesthetized mice during irradiation, altogether performed in less than 10 min. All mice tolerated the treatment well. Measured dose values perfectly matched the nominal values from treatment planning. Cellular response was restricted to the target volume. CONCLUSION: Clinical LINAC-based irradiations of mice offer the potential to treat orthotopic tumors conformably. Especially with respect to lateral penumbra, dedicated small animal irradiation systems exceed the clinical LINAC solution.

Low and moderate doses of ionizing radiation up to 2 Gy modulate transmigration and chemotaxis of activated macrophages, provoke an anti-inflammatory cytokine milieu, but do not impact upon viability and phagocytic function.

Benign painful and inflammatory diseases have been treated for decades with low/moderate doses of ionizing radiation (LD-X-irradiation). Tissue macrophages regulate initiation and resolution of inflammation by the secretion of cytokines and by acting as professional phagocytes. Having these pivotal functions, we were interested in how activated macrophages are modulated by LD-X-irradiation, also with regard to radiation protection issues and carcinogenesis. We set up an ex-vivo model in which lipopolysaccharide pre-activated peritoneal macrophages (pMΦ) of radiosensitive BALB/c mice, mimicking activated macrophages under inflammatory conditions, were exposed to X-irradiation from 0·01 Gy up to 2 Gy. Afterwards, the viability of the pMΦ, their transmigration and chemotaxis, the phagocytic behaviour, the secretion of inflammatory cytokines and underlying signalling pathways were determined. Exposure of pMΦ up to a single dose of 2 Gy did not influence their viability and phagocytic function, an important fact regarding radiation protection. However, significantly reduced migration, but increased chemotaxis of pMΦ after exposure to 0·1 or 0·5 Gy, was detected. Both might relate to the resolution of inflammation. Cytokine analyses revealed that, in particular, the moderate dose of 0·5 Gy applied in low-dose radiotherapy for inflammatory diseases results in an anti-inflammatory cytokine microenvironment of pMΦ, as the secretion of the proinflammatory cytokine interleukin (IL)-1ß was reduced and that of the anti-inflammatory cytokine transforming growth factor (TGF)-ß increased. Further, the reduced secretion of IL-1ß correlated with reduced nuclear translocation of nuclear factor (NF)-κB p65, starting at exposure of pMΦ to 0·5 Gy of X-irradiation. We conclude that inflammation is modulated by LD-X-irradiation via changing the inflammatory phenotype of macrophages.

The Erlangen Dose Optimization trial for low-dose radiotherapy of benign painful elbow syndrome. Long-term results.

BACKGROUND AND PURPOSE: To evaluate the long-term efficacy of pain reduction by two dose fractionation schedules used for low-dose radiotherapy of painful elbow syndrome. PATIENTS AND METHODS: Between February 2006 and February 2010, 199 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: Median follow-up was 35 months (range 9-57 months). The overall early, delayed and long-term response rates for all patients were 80, 90 and 94 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 59.6 ± 20.2 and 55.7 ± 18.0 (p = 0.46); 32.1 ± 24.5 and 34.4 ± 22.5 (p = 0.26); 27.0 ± 27.7 and 23.5 ± 21.6 (p = 0.82) and 10.7 ± 15.0 and 21.5 ± 26.9 (p = 0.12), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 8.7 ± 2.9 and 8.1 ± 3.1 (p = 0.21); 4.5 ± 3.2 and 5.0 ± 3.4 (p = 0.51); 3.9 ± 3.6 and 2.8 ± 2.8 (p = 0.19) and 1.5 ± 2.3 and 2.4 ± 3.5 (p = 0.27), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28). CONCLUSION: Low-dose radiotherapy is an effective treatment for the management of benign painful elbow syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy.

The Erlangen Dose Optimization Trial for radiotherapy of benign painful shoulder syndrome. Long-term results.

BACKGROUND AND PURPOSE: To evaluate the long-term efficacy of pain reduction by two dose-fractionation schedules for radiotherapy of painful shoulder syndrome. PATIENTS AND METHODS: Between February 2006 and February 2010, 312 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: Median follow-up was 35 months (range 11-57). The overall early, delayed and long-term response rates for all patients were 83, 85 and 82 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 56.8 ± 23.7 and 53.2 ± 21.8 (p = 0.16); 38.2 ± 36.1 and 34.0 ± 24.5 (p = 0.19); 33.0 ± 27.2 and 23.7 ± 22.7 (p = 0.04) and 27.9 ± 25.8 and 32.1 ± 26.9 (p = 0.25), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 9.7 ± 3.0 and 9.5 ± 2.7 (p = 0.31); 6.1 ± 3.6 and 5.4 ± 3.6 (p = 0.10); 5.3 ± 3.7 and 4.1 ± 3.7 (p = 0.05) and 4.0 ± 3.9 and 5.3 ± 4.4 (p = 0.05), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28). CONCLUSION: Radiotherapy is an effective treatment for the management of benign painful shoulder syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy.

Radiotherapy for calcaneodynia. Results of a single center prospective randomized dose optimization trial.

PURPOSE: The aim of this work was to compare the efficacy of two different dose fractionation schedules for radiotherapy of patients with calcaneodynia. PATIENTS AND METHODS: Between February 2006 and April 2010, 457 consecutive evaluable patients were recruited for this prospective randomized trial. All patients received radiotherapy using the orthovoltage technique. One radiotherapy series consisted of 6 single fractions/3 weeks. In case of insufficient remission of pain after 6 weeks a second radiation series was performed. Patients were randomly assigned to receive either single doses of 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before, immediately after, and 6 weeks after radiotherapy using a visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: The overall response rate for all patients was 87 % directly after and 88 % 6 weeks after radiotherapy. The mean VAS values before, immediately after, and 6 weeks after treatment for the 0.5 and 1.0 Gy groups were 65.5 ± 22.1 and 64.0 ± 20.5 (p = 0.188), 34.8 ± 24.7 and 39.0 ± 26.3 (p = 0.122), and 25.1 ± 26.8 and 28.9 ± 26.8 (p = 0.156), respectively. The mean CPS before, immediately after, and 6 weeks after treatment was 10.1 ± 2.7 and 10.0 ± 3.0 (p = 0.783), 5.6 ± 3.7 and 6.0 ± 3.9 (p = 0.336), 4.0 ± 4.1 and 4.3 ± 3.6 (p = 0.257), respectively. No statistically significant differences between the two single dose trial arms for early (p = 0.216) and delayed response (p = 0.080) were found. CONCLUSION: Radiotherapy is an effective treatment option for the management of calcaneodynia. For radiation protection reasons, the dose for a radiotherapy series is recommended not to exceed 3-6 Gy.

Radiotherapy for achillodynia : results of a single-center prospective randomized dose-optimization trial.

BACKGROUND AND PURPOSE: The aim of this study was to compare the efficacy of two different dose-fractionation schedules for radiotherapy of patients with achillodynia. PATIENTS AND METHODS: Between February 2006 and February 2010, 112 consecutive evaluable patients were recruited for this prospective randomized trial. All patients underwent radiotherapy with an orthovoltage technique. One radiotherapy course consisted of 6 single fractions over 3 weeks. In case of insufficient remission of pain after 6 weeks, a second radiation series was performed. Patients were randomly assigned to receive either single doses of 0.5 or 1.0 Gy. The endpoint was pain reduction. Pain was measured before, right after, and 6 weeks after radiotherapy with a visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: The overall response rate for all patients was 84% directly after and 88% 6 weeks after radiotherapy. The mean VAS values before, directly after, and 6 weeks after treatment for the 0.5 and 1.0 Gy groups were 55.7 ± 21.0 and 58.2 ± 23.5 (p = 0.526), 38.0 ± 23.2 and 30.4 ± 22.6 (p = 0.076), and 35.4 ± 25.9 and 30.9 ± 25.4 (p = 0.521), respectively. The mean CPS before, directly after, and 6 weeks after treatment was 8.2 ± 3.0 and 8.9 ± 3.3 (p = 0.239), 5.6 ± 3.1 and 5.4 ± 3.3 (p = 0.756), 4.4 ± 2.6 and 5.3 ± 3.8 (p = 0.577), respectively. No statistically significant differences were found between the two single-dose trial arms for early (p = 0.366) and delayed response (p = 0.287). CONCLUSION: Radiotherapy is an effective treatment option for the management of achillodynia. For radiation protection, the dose of a radiotherapy series is recommended not to exceed 3-6 Gy.

Benign painful elbow syndrome. First results of a single center prospective randomized radiotherapy dose optimization trial.

BACKGROUND AND PURPOSE: The goal of the present study was to evaluate the efficacy of two different dose-fractionation schedules for radiotherapy (RT) of patients with painful elbow syndrome. PATIENTS AND METHODS: Between February 2006 and February 2010, 199 consecutive evaluable patients were recruited for this prospective randomized trial. All patients received RT in orthovoltage technique. One RT course consisted of 6 single fractions/3 weeks. In case of insufficient remission of pain after 6 weeks a second radiation series was performed. Patients were randomly assigned to receive either single doses of 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before, right after, and 6 weeks after RT by a visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: The overall response rate for all patients was 80% direct after and 91% 6 weeks after RT. The mean VAS values before, after and 6 weeks after treatment for the 0.5 and 1.0 Gy groups were 59.6 ± 20.2 and 55.7 ± 18.0 (p = 0.463), 32.1 ± 24.5 and 34.4 ± 22.5 (p = 0.256), and 27.0 ± 27.7 and 23.5 ± 21.6 (p = 0.818). The mean CPS before, after, and 6 weeks after treatment was 8.7 ± 2.9 and 8.1 ± 3.1 (p = 0.207), 4.5 ± 3.2 and 5.0 ± 3.4 (p = 0.507), 3.9 ± 3.6 and 2.8 ± 2.8 (p = 0.186), respectively. No statistically significant differences between the two single dose trial arms for early (p = 0.103) and delayed response (p = 0.246) were found. CONCLUSION: RT is an effective treatment option for the management of benign painful elbow syndrome. For radiation protection reasons the dose for a RT series is recommended not to exceed 3.0 Gy.

Benign painful shoulder syndrome: initial results of a single-center prospective randomized radiotherapy dose-optimization trial.

BACKGROUND AND PURPOSE: To compare the efficacy of two different dose-fractionation schedules for radiotherapy of patients with benign painful shoulder syndrome. PATIENTS AND METHODS: Between February 2006 and February 2010, 312 consecutive evaluable patients were recruited for this prospective randomized trial. All patients received radiotherapy with an orthovoltage technique. One radiotherapy course consisted of 6 single fractions in 3 weeks. In case of insufficient remission of pain after 6 weeks, a second radiation series was performed. Patients were randomly assigned to receive either single doses of 0.5 or 1.0 Gy. The endpoint was pain reduction. Pain was measured before, right after, and 6 weeks after radiotherapy using a visual analogue scale (VAS) and a comprehensive pain score (CPS). RESULTS: The overall response rate for all patients was 83% directly after and 85% 6 weeks after radiotherapy. The mean VAS values before, directly after, and 6 weeks after treatment for the 0.5 and 1.0 Gy groups were 56.8 ± 23.7 and 53.2 ± 21.8 (p = 0.158), 38.2 ± 26.1 and 34.0 ± 24.5 (p = 0.189), and 33.0 ± 27.2 and 23.7 ± 22.7 (p = 0.044), respectively. The mean CPS before, directly after, and 6 weeks after treatment was 9.7 ± 3.0 and 9.5 ± 2.7 (p = 0.309), 6.1 ± 3.6 and 5.4 ± 3.6 (p = 0.096), 5.3 ± 3.7 and 4.1 ± 3.7 (p = 0.052), respectively. Despite a slight advantage in the VAS analysis for the 1.0 Gy group for delayed response, the CPS analysis revealed no statistically significant differences between the two single-dose trial arms for early (p = 0.652) and delayed response quality (p = 0.380). CONCLUSION: Radiotherapy is an effective treatment option for the management of benign painful shoulder syndrome. Concerning radiation protection, the dose for a radiotherapy series is recommended not to exceed 3-6 Gy.

F18-FDG PET/CT imaging early predicts pathologic complete response to induction chemoimmunotherapy of locally advanced head and neck cancer: preliminary single-center analysis of the checkrad-cd8 trial.

AIM: In the CheckRad-CD8 trial patients with locally advanced head and neck squamous cell cancer are treated with a single cycle of induction chemo-immunotherapy (ICIT). Patients with pathological complete response (pCR) in the re-biopsy enter radioimmunotherapy. Our goal was to study the value of F-18-FDG PET/CT in the prediction of pCR after induction therapy. METHODS: Patients treated within the CheckRad-CD8 trial that additionally received FDG- PET/CT imaging at the following two time points were included: 3-14 days before (pre-ICIT) and 21-28 days after (post-ICIT) receiving ICIT. Tracer uptake in primary tumors (PT) and suspicious cervical lymph nodes (LN +) was measured using different quantitative parameters on EANM Research Ltd (EARL) accredited PET reconstructions. In addition, mean FDG uptake levels in lymphatic and hematopoietic organs were examined. Percent decrease (Δ) in FDG uptake was calculated for all parameters. Biopsy of the PT post-ICIT acquired after FDG-PET/CT served as reference. The cohort was divided in patients with pCR and residual tumor (ReTu). RESULTS: Thirty-one patients were included. In ROC analysis, ΔSUVmax PT performed best (AUC = 0.89) in predicting pCR (n = 17), with a decline of at least 60% (sensitivity, 0.77; specificity, 0.93). Residual SUVmax PT post-ICIT performed best in predicting ReTu (n = 14), at a cutpoint of 6.0 (AUC = 0.91; sensitivity, 0.86; specificity, 0.88). Combining two quantitative parameters (ΔSUVmax ≥ 50% and SUVmax PT post-ICIT ≤ 6.0) conferred a sensitivity of 0.81 and a specificity of 0.93 for determining pCR. Background activity in lymphatic organs or uptake in suspected cervical lymph node metastases lacked significant predictive value. CONCLUSION: FDG-PET/CT can identify patients with pCR after ICIT via residual FDG uptake levels in primary tumors and the related changes compared to baseline. FDG-uptake in LN + had no predictive value. TRIAL REGISTRY: ClinicalTrials.gov identifier: NCT03426657.

Photopheresis with UV-A light and 8-methoxypsoralen leads to cell death and to release of blebs with anti-inflammatory phenotype in activated and non-activated lymphocytes.

BACKGROUND: Extracorporeal photopheresis is a therapy for treatment of autoimmune diseases, cutaneous T-cell lymphoma, organ graft rejection as well as graft-versus-host diseases. The exact mechanism how the combination of 8-methoxypsoralen plus UV-A irradiation (PUVA) acts is still unclear. We investigated the cell death of activated and non-activated lymphocytes after PUVA treatment as well as the rate of released blebs and their antigen composition. RESULTS: In presence of 8-MOP, UV-A light highly significantly increased the cell death of activated lymphocytes. The same was observed to a lesser extent in non-activated cells. Blebs derived from activated lymphocytes after PUVA treatment showed the highest surface exposition of phosphatidylserine. These blebs also displayed a high exposure of the antigens CD5 and CD8 as well as a low exposure of CD28 and CD86. CONCLUSION: PUVA treatment exerts anti-inflammatory effects by inducing apoptosis and apoptotic cell-derived blebs with immune suppressive surface composition.

After shrinkage apoptotic cells expose internal membrane-derived epitopes on their plasma membranes.

Apoptosis and phagocytosis of apoptotic cells are crucial processes. At best the phagocytic machinery detects and swallows all apoptotic cells in a way that progression to secondary necrosis is avoided. Otherwise, inflammation and autoimmune diseases may occur. Most apoptotic cells are phagocytosed instantaneously in a silent fashion; however, some dying cells escape their clearance. If the cells are not cleared early, they lose membranes due to extensive shedding of membrane surrounded vesicles (blebbing) and shrink. It is unclear how apoptotic cells compensate their massive loss of plasma membrane. Here, we demonstrate that endoplasmic reticulum- (ER) resident proteins (calnexin, the KDEL receptor and a dysfunctional immunoglobulin heavy chain) were exposed at the surfaces of shrunken late apoptotic cells. Additionally, these cells showed an increased binding of lectins, which recognize sugar structures predominantly found as moieties of incompletely processed proteins in ER and Golgi. In addition the ER resident lipophilic ER-Tracker Blue-White DPX, and internal GM1 were observed to translocate to the cell surfaces during late apoptosis. We conclude that during blebbing of apoptotic cells the surface membrane loss is substituted by immature membranes from internal stores. This mechanism explains the simultaneous appearance of preformed recognition structures for several adaptor proteins known to be involved in clearance of dead cells.

IgG autoantibodies bound to surfaces of necrotic cells and complement C4 comprise the phagocytosis promoting activity for necrotic cells of systemic lupus erythaematosus sera.

OBJECTIVE: Accumulation of dying and dead cells is thought to be involved in the etiopathogenesis of systemic lupus erythaematosus (SLE). Clearance has been described mainly for apoptotic cells; however, the knowledge of serum factors participating in the phagocytosis of necrotic cells is limited. PATIENTS AND METHODS: Sera from 18 patients with SLE and 10 normal healthy donors (NHD), and macrophages from 3 NHD were included. Autoantibodies and complement were measured by ELISA and phagocytosis by flow cytometry. Binding of serum IgG to necrotic cells was assessed by flow cytometry and confocal microscopy. RESULTS: Sera from patients with SLE and NHD generally promoted the phagocytosis of necrotic cells by macrophages isolated from NHD. Five independent experiments with macrophages from three different NHD led to similar results. The sera from healthy controls displayed a homogeneous activity, whereas sera from patients with SLE showed a dichotomic behaviour. Only sera containing autoantibodies binding to the surfaces of necrotic cells and sufficient complement showed increased phagocytosis promoting activities. In SLE sera, C4 turned out to be the critical complement component in this process. Sera de-complemented by heat treatment strongly reduced phagocytosis of necrotic cells. CONCLUSIONS: Serum components influence the uptake of necrotic cells by phagocytosis competent macrophages from NHD. Complement is required for this process and autoantibodies binding to the surfaces of necrotic cells additionally promote their phagocytosis.

Inefficient clearance of dying cells and autoreactivity.

Dying cells were basically unnoticed by scientists for a long time and only came back into the spotlight roughly 10 years ago. The process of recognition and uptake of apoptotic and necrotic cells is complex and failures in this process can contribute to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Here, we discuss the recognition and uptake molecules which are involved in an efficient clearance of dying cells in early and late phases of cell death. The exposure of phosphatidylserine (PS) is an early surface change of apoptosing cells recognized by several receptors and adaptor molecules. We demonstrated that dying cells have cell membranes with high lateral mobility of PS, which contribute to their efficient clearance. Changes of the glycoprotein composition of apoptotic cells occur later than the exposure of PS. We further observed that complement binding is an early event in necrosis and a rather late event in apoptosis. Complement, C-reactive protein (CRP), and serum DNase I act as back-up molecules in the clearance process. Finally, we discuss how the accumulation of secondary necrotic cells and cellular debris in the germinal centers of secondary lymph organs can lead to autoimmunity. It is reasonable to argue that clearance defects are major players in the development of autoimmune diseases such as SLE.

Clearance of apoptotic cells in human SLE.

Systemic lupus erythematosus (SLE) is characterized by a diverse array of autoantibodies, particularly against nuclear antigens, thought to derive from apoptotic and necrotic cells. Impaired clearance functions for dying cells may explain accumulation of apoptotic cells in SLE tissues, and secondary necrosis of these cells may contribute to the chronic inflammation in this disease. The exposure of phosphatidylserine (PS) and altered carbohydrates on dying cells are important recognition signals for macrophages. Furthermore, serum factors such as complement, DNase I, pentraxins (e.g. C-reactive protein) and IgM contribute to efficient opsonization and uptake of apoptotic and necrotic cells. Defects in these factors may impact the development of SLE in humans and mice in a variety of ways. We observed impaired clearance of apoptotic cells in lymph nodes and skin biopsies of humans with lupus, as well as intrinsic defects of macrophages differentiated in vitro from SLE patients' CD34+ stem cells, demonstrating that apoptotic cells are not properly cleared in a subgroup of patients with SLE. This altered mechanism for the clearance of dying cells may represent a central pathogenic process in the development and acceleration of this autoimmune disease.