Immune cell-antibody interactions in health and disease

An approach based on a combination of toxicological experiments and in silico predictions to investigate the adverse outcome pathway (AOP) of paraquat neuro-immunotoxicity

Paraquat (PQ) exposure is strongly associated with neurotoxicity. However, research on the neurotoxicity mechanisms of PQ varies in terms of endpoints of toxic assessment, resulting in a great challenge to understand the early neurotoxic effects of PQ. In this study, we developed an adverse outcome pathway (AOP) to investigate PQ-induced neuro-immunotoxicity from an immunological perspective, combining of traditional toxicology methods and computer simulations. In vivo, PQ can microstructurally lead to an early synaptic loss in the brain mice, which is a large degree regarded as a main reason for cognitive impairment to mice behavior. Both in vitro and in vivo demonstrated synapse loss is caused by excessive activation of the complement C1q/C3-CD11b pathway, which mediates microglial phagocytosis dysfunction. Additionally, the interaction between PQ and C1q was validated by molecular simulation docking. Our findings extend the AOP framework related to PQ neurotoxicity from a neuro-immunotoxic perspective, highlighting C1q activation as the initiating event for PQ-induced neuro-immunotoxicity. In addition, downstream complement cascades induce abnormal microglial phagocytosis, resulting in reduced synaptic density and subsequent non-motor dysfunction. These findings deepen our understanding of neurotoxicity and provide a theoretical basis for ecological risk assessment of PQ.

Role of macrophage polarisation in skin wound healing

Skin wound healing is a complex pathophysiological change that is driven by macrophages and their secreted related factors. Depending on the stimuli, macrophages can be polarised into two subtypes of macrophages with completely different phenotypes and functions, namely M1 and M2. The aim of this study was to explore the role of M1 and M2 macrophages in skin healing in order to develop new drugs for the treatment of refractory wounds. Primary bone marrow-derived macrophages (BMDMs) were isolated from rats and expanded in vitro using macrophage colony stimulating factor. In addition, the BMDMs were polarised into the M1 and M2 subtypes using lipopolysaccharides (LPS) and interleukin-4 (IL-4), respectively. Cytokine levels in the culture supernatants were measured by an enzyme linked immunosorbent assay. Epidermal wounds were made on the dorsal surface of rats, and treated with M1 or M2 cell suspensions or phosphate buffered saline. Wound healing was recorded on days 1, 3, 7, 10, and 14 after stamping, and the wound healing rate was measured by haematoxylin-eosin and Masson staining. A total of 3 to 4 × 107 bone marrow cells were extracted from each rat femur. The BMDM culture had 87.1% CD45+ cells, 89.2% CD68+ cells, and 86.5% CD45+ CD68+ cells. Furthermore, IL-12 (P < .05) and IL-10 (P ≥ .05) levels, respectively, increased and decreased in the culture supernatants of the M1 cells after LPS stimulation compared with those in the M0 (unstimulated) group. Likewise, IL-4 stimulation led to a significant increase in IL-10 levels (P < .01) in the conditioned media of M2 cells, while that of IL-12 decreased slightly (P ≥ .05). In the rat model, the infusion of M2 cells accelerated wound healing and tissue regeneration, whereas the M1 cells delayed the recruitment of inflammatory cells, granulation growth, and collagen deposition, which impaired wound healing. Macrophage polarisation and activation are critical for skin wound healing. While exogenous M1 cell infusion delayed wound healing, the M2 cells promoted wound healing in a rat model.

Investigation of the causal relationship between breast cancer and autoimmune diseases: A bidirectional mendelian randomization study

A clear bidirectional relationship exists between malignant cancers including breast cancer and different autoimmune diseases. However, none of the studies have assessed whether this association is causal and none have used Mendelian randomization for determining this relationship. This study therefore investigated the causal relationship between autoimmune diseases and breast cancer using the Mendelian randomization approach. Summary statistical data were obtained from genome-wide association studies to investigate the causal relationship between different autoimmune diseases including Graves' disease, Sjögren's syndrome, Crohn disease, systemic sclerosis, and psoriasis and breast cancer risk. The results revealed no strong evidence to support the causal relationship between Graves disease (odds ratio [OR] = 0.9958; 95% confidence interval [CI]: 0.9982-1.0035), Sjögren's syndrome (OR = 1.0018; 95% CI: 0.9950-1.0087), Crohn disease (OR = 2.1195, 95% CI: 0.1872-23.9978), systemic sclerosis (OR = 1.0024; 95% CI: 0.997-1.0079), and psoriasis (OR = 1.0016; 95% CI: 0.9913-1.0121) to breast cancer risk. A similar result was obtained in the reverse Mendelian randomization analysis. Our study provides evidence that autoimmune diseases might not have a causal relationship with breast cancer risk in the European population and concludes that shared genetic effects or environmental confounders.

Lymphedema of the Arm after COVID-19 Vaccination in a Patient with Hidden Breast Cancer and Paraneoplastic Dermatomyositis

The pandemic outbreak of Coronavirus Disease 2019 (COVID-19) led to the development of mRNA vaccines. With the extensive vaccination campaign performed worldwide, many adverse reactions to these drugs have been reported in the literature. Although most of them are mild and self-limiting, they may sometimes cause psychological stress and require efforts to make a differential diagnosis with other conditions. This is the case of lymphadenopathies and lymphedema in patients with a history of cancer. Herein we present a case of lymphedema of the arm developed ten days after a VAXZEVRIA COVID-19 vaccine shot in a patient who had concomitant signs and symptoms compatible with a diagnosis of dermatomyositis. It was later classified as paraneoplastic as instrumental investigation revealed a breast carcinoma contralateral to the site of vaccine injection. With this report we ponder an adverse reaction to COVID-19 vaccination with the aim of bringing new data for clinicians who face similar clinical presentations, particularly controversial for radiologists and oncologists.