The Role of Tumor Microenvironment in the Pathogenesis of Sézary Syndrome

Sézary syndrome is an aggressive leukemic variant of cutaneous T-cell lymphomas, characterized by erythroderma, lymphadenopathy, and peripheral blood involvement by CD4+ malignant T-cells. The pathogenesis of Sézary syndrome is not fully understood. However, the course of the disease is strongly influenced by the tumor microenvironment, which is altered by a combination of cytokines, chemokines, and growth factors. The crosstalk between malignant and reactive cells affects the immunologic response against tumor cells causing immune dysregulation. This review focuses on the interaction of malignant Sézary cells and the tumor microenvironment.

873. A Retrospective Cohort Study on Treatment Outcomes of Patients on Third-Line Therapy at the HIV Advanced Treatment Centre, University Teaching Hospital, Zambia

Background In Zambia, third-line regimens consist of a switch to darunavir/ritonavir (DRV/r) and/or raltegravir (RAL) and/or etravirine (ETV), and as of 2017, dolutegravir (DTG), from a failing second-line therapy.5 We assessed virologic suppression (HIV viral load (VL) ≤1000 copies/ml per Zambian national guidelines), immunological response, and patterns of HIV drug resistance mutation among patients on third-line ART at the University Teaching Hospital (UTH) in Lusaka, Zambia. Methods A retrospective evaluation of adults ≥18 years old on third-line ART regimens at UTH between January 2012 to June 30, 2020 was conducted. Patients were referred for second-line virologic failure defined as HIV RNA VL > 1000 copies/mL on two consecutive measurements after 6 months on second-line ART.5 We assessed virologic suppression VL ≤1000 copies/ml, CD4, mutations, and third-line regimens of this cohort. Patients were excluded if they were on third-line ART < 6 months or received RAL and/or ETV and/or DTG before starting third-line ART. Results A total of 539 patients were included; 231 males (42.9%) and 308 (57.1%) females. The mean age of third-line initiation was 29.8 years; mean time from ART initiation to third-line initiation was 9.9 years. Out of 25 combination 349 (64.7%) received DTG, 272 (50.5%) DRV/r, 85(15.8%) ETR, and 49 (9.1%) RAL. There were 215 (39.9%) genotypes; common mutations were to zidovudine (80%), non-nucleoside reverse transcriptase inhibitors (NNRTIs) (78%), and protease inhibitors (PIs) (41%). Patients with at least one viral load and CD4 upon third-line initiation was 296 (54.9%) and 350 (64.9%), respectively. Among patients with sufficient data (21%, n=115), VL suppression increased from 44 (38%) patients at baseline to 53 (46%) at next available follow-up; with mean baseline VL and follow-up VL of log10 3.60 and 3.33, respectively. The immunologic response revealed 49 (56.3%) had CD4 increase with mean increase of 61.1 cells/mm3. (See Table 1.) Conclusion We found moderate improvements in VL suppression and immunologic response. Nearly all third-line patients had genotypic resistance to first-line NNRTI and nearly half to second-line PI regimens. Quality improvement measures are needed to improve viral load timing following ART changes to better assess regimen efficacy. Disclosures All Authors: No reported disclosures

The immunologic response to severe acute respiratory syndrome coronavirus 2

Background: The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has precipitated the worst global pandemic in a century, which has caused millions of infections and deaths as well as massive economic repercussions. Objective: As with any pathogenic virus, it is crucial to understand its unique interactions with the human immune system so that pharmaceutical and prophylactic interventions can be deployed to effectively control the pandemic. Methods: A literature search by using PubMed was conducted in 2020 with variants of the terms “COVID-19,” “SARS-CoV-2,” and “immunological response.” English language articles that presented original data about the immunologic response to coronavirus disease 2019 (COVID-19) were selected for review. This article reviewed the current understanding of the innate and adaptive immune responses to SARS-CoV-2 infection, including their relationship to current therapeutic and diagnostic strategies. Results: SARS-CoV-2 uses several unique molecular techniques to evade detection by the innate immune system early in the course of infection, and upregulation of these innate immune pathways may possibly accelerate the time to recovery and prevent severe disease. Although the majority of cases results in the patients' recovery, a significant proportion of infections result in deaths prompted by the host's inflammatory overreaction to the infection, a response that can be attenuated with corticosteroids and potentially other immune modulators. Conclusion: Current work by the scientific community to further understand how SARS-CoV-2 interacts with the human immune system will be invaluable to our response and preparedness for future coronavirus pandemics.

Efficacy and Safety of Subcutaneous Immunotherapy for Local Allergic Rhinitis: A Meta-Analysis of Randomized Controlled Trials

Background Subcutaneous immunotherapy (SCIT) has been used for treating local allergic rhinitis (LAR) patients. However, the clinical efficacy and safety were still questioned. Objective This study was designed to estimate the efficacy and safety of SCIT for treating LAR patients through meta-analysis. Methods We systemically searched MEDLINE, Cochrane Library, and Embase publications. Randomized, double-blind, clinical trials for the efficacy and safety of Allergen Immunotherapy (AIT) for LAR were included. A meta-analysis of 4 clinical endpoints (combined symptom and medication scores [CSMS], symptom scores [SS], medication scores [MS] and rhinoconjunctivitis quality of life questionnaire [RQLQ]) and adverse events (AEs)) was performed after bias and heterogeneity assessments. The immunologic response results were summarized. Results Four RCTs with 134 patients were included. Four studies for analyzing primary outcomes (CSMS, SS, MS) and AEs, three for RQLQ results. The results indicated an important significant difference between SCIT and placebo groups, list as follows: CSMS (SMD = −2.42, 95% CI: −3.60 to −1.25, P < .0001), SS (SMD = −2.08, 95% CI −3.68 to −0.48, P = .01), MS (SMD = −1.43, 95% CI: −2.65 to −0.21, P = 0.02), RQLQ (SMD = −0.70, 95% CI −1.29 to −0.12, P = .02), Local AEs (RR = 4.13, 95% CI 1.08 to 15.77, P = .04). For immunologic response, significantly increased serum sIgG4 levels and improvements of allergen tolerance was observed after SCIT. Conclusions Our meta-analysis suggests that SCIT has a significant effect on improving symptoms and reducing medicine consumption for LAR patients. Larger and multicenter clinical trials are needed to clarify the safety and long-term efficacy.

Time-dependent evolution of IgG antibody levels after first and second dose of mRNA-based SARS-CoV-2 vaccination in hemodialysis patients: a multicenter study

Background Vaccination programs are essential for the containment of the COVID-19 pandemic, which has affected hemodialysis populations especially hard. Early reports suggest a reduced immunologic response to SARS-Cov-2 vaccines in dialysis patients, in spite of a high degree of seroconversion. We aimed to identify risk factors for a reduced efficacy of an mRNA vaccine in a cohort of hemodialysis patients. Method In a multicenter study, including 294 Portuguese hemodialysis patients who had received 2 doses of BNT162b2 with a three week interval, IgG-class antibodies against the SARS-CoV-2 spike protein were determined 3 weeks after the first dose (M1) and 6 weeks after the second dose (M2). The threshold for seroconversion was 10UR/mL. Demographic and clinical data was retrieved from a quality registry. Adverse events were registered using a questionnaire. Results At M2, seroconversion was 93.1% with a median antibody level of 197.5U/mL (1.2–3237.0) and a median increase of 180.0U/mL (-82.9–2244.6) from M1. Age (beta -8.9; 95%CI: -12.88 to -4.91; P &lt; 0.0001), ferritin &gt; 600ng/mL (beta 183.93; 95%CI: 74.75 to 293.10; P = 0.001) and physical activity (beta 265.79; 95%CI: 30.7 to 500.88; P = 0.03) were independent predictors of SARS-Cov-2 antibody levels after two vaccine doses. Plasma albumin &gt; 3.5g/dL independently predicted the increase of antibody levels between both doses (OR 14.72; 95%CI: 1.38 to 157.45; P = 0.03). Only mild adverse reactions were observed in 10.9% of patients. Conclusions The SARS-Cov-2 vaccine BNT162b2 is safe and effective in hemodialysis patients. Besides age, iron status and nutrition are possible modifiable modulators of the immunologic response to SARS-Cov-2 mRNA vaccines. This data suggests the need for an early identification of populations at higher risk for diminished antibody production and the potential advantage of the implementation of oriented strategies to maximize the immune response to vaccination in these patients.

Bone Morphogenetic Protein-2 Rapidly Heals Two Distinct Critical Sized Segmental Diaphyseal Bone Defects in a Porcine Model

ABSTRACT Introduction Segmental bone defects (SBDs) are devastating injuries sustained by warfighters and are difficult to heal. Preclinical models that accurately simulate human conditions are necessary to investigate therapies to treat SBDs. We have developed two novel porcine SBD models that take advantage of similarities in bone healing and immunologic response to injury between pigs and humans. The purpose of this study was to investigate the efficacy of Bone Morphogenetic Protein-2 (BMP-2) to heal a critical sized defect (CSD) in two novel porcine SBD models. Materials and Methods Two CSDs were performed in Yucatan Minipigs including a 25.0-mm SBD treated with intramedullary nailing (IMN) and a 40.0-mm SBD treated with dual plating (ORIF). In control animals, the defect was filled with a custom spacer and a bovine collagen sponge impregnated with saline (IMN25 Cont, n = 8; ORIF40 Cont, n = 4). In experimental animals, the SBD was filled with a custom spacer and a bovine collage sponge impregnated with human recombinant BMP-2 (IMN25 BMP, n = 8; ORIF40 BMP, n = 4). Healing was quantified using monthly modified Radiographic Union Score for Tibia Fractures (mRUST) scores, postmortem CT scanning, and torsion testing. Results BMP-2 restored bone healing in all eight IMN25 BMP specimens and three of four ORIF40 BMP specimens. None of the IMN25 Cont or ORIF40 Cont specimens healed. mRUST scores at the time of sacrifice increased from 9.2 (±2.4) in IMN25 Cont to 15.1 (±1.0) in IMN25 BMP specimens (P &lt; .0001). mRUST scores increased from 8.2 (±1.1) in ORIF40 Cont to 14.3 (±1.0) in ORIF40 BMP specimens (P &lt; .01). CT scans confirmed all BMP-2 specimens had healed and none of the control specimens had healed in both IMN and ORIF groups. BMP-2 restored 114% and 93% of intact torsional stiffness in IMN25 BMP and ORIF40 BMP specimens. Conclusions We have developed two porcine CSD models, including fixation with IMN and with dual-plate fixation. Porcine models are particularly relevant for SBD research as the porcine immunologic response to injury closely mimics the human response. BMP-2 restored healing in both CSD models, and the effects were evident within the first month after injury. These findings support the use of both porcine CSD models to investigate new therapies to heal SBDs.

Inflammatory Mediators Leading to Edema Formation through Plasma Membrane Receptors

Edema is a swelling from liquid accumulation in body tissues. Injuries in tissues or organs may cause this disorder leading to chemical mediators releasing and triggering the inflammatory process. Inflammatory mediators, when released in response to injuries, promote biological reactions at the affected site. Furthermore, plasma membrane receptors modulate the inflammatory chemical agent synthesis and release. Pattern recognition receptors, such as Toll Like is an example of plasma membrane receptors associated with chemical agents recognizing and cascade amplification. Therefore, these plasma membrane proteins exhibit essential roles during injuries and immunologic response. Thus, this review discusses the plasma membrane receptors modulation in the inflammatory area, focusing on edema formation.