B cells drive neuropathic pain-related behaviors in mice through IgG-Fc gamma receptor signaling.

Neuroimmune interactions are essential for the development of neuropathic pain, yet the contributions of distinct immune cell populations have not been fully unraveled. Here, we demonstrate the critical role of B cells in promoting mechanical hypersensitivity (allodynia) after peripheral nerve injury in male and female mice. Depletion of B cells with a single injection of anti-CD20 monoclonal antibody at the time of injury prevented the development of allodynia. B cell-deficient (muMT) mice were similarly spared from allodynia. Nerve injury was associated with increased immunoglobulin G (IgG) accumulation in ipsilateral lumbar dorsal root ganglia (DRGs) and dorsal spinal cords. IgG was colocalized with sensory neurons and macrophages in DRGs and microglia in spinal cords. IgG also accumulated in DRG samples from human donors with chronic pain, colocalizing with a marker for macrophages and satellite glia. RNA sequencing revealed a B cell population in naive mouse and human DRGs. A B cell transcriptional signature was enriched in DRGs from human donors with neuropathic pain. Passive transfer of IgG from injured mice induced allodynia in injured muMT recipient mice. The pronociceptive effects of IgG are likely mediated through immune complexes interacting with Fc gamma receptors (FcγRs) expressed by sensory neurons, microglia, and macrophages, given that both mechanical allodynia and hyperexcitability of dissociated DRG neurons were abolished in nerve-injured FcγR-deficient mice. Consistently, the pronociceptive effects of IgG passive transfer were lost in FcγR-deficient mice. These data reveal that a B cell-IgG-FcγR axis is required for the development of neuropathic pain in mice.

Subcutaneous Injection of Allogeneic Adipose-Derived Mesenchymal Stromal Cells in Psoriasis Plaques: Clinical Trial Phase I.

OBJECTIVE: Mesenchymal stromal cells (MSCs) play immunomodulatory role in various autoimmune diseases. Previous pre-clinical and clinical studies have shown that MSCs could be a therapeutic modality for psoriasis. However, the mechanisms of treatment and its possible side effects are under investigation. In this study, the safety and probable efficacy of injecting allogeneic adipose-derived mesenchymal stromal cells (ADSCs) in psoriatic patients were evaluated. MATERIALS AND METHODS: In this phase I clinical study with six months of follow-up, total number of 1×106 or 3×106 cells/cm2 of ADSCs were injected into the subcutaneous tissue of each plaque as a single dose in three males and two females (3M/2F) with a mean age of 32.8 ± 8.18. The primary outcome was safety. Changes in clinical and histological indexes, the number of B and T lymphocytes in local and peripheral blood, and serum levels of inflammatory cytokines were assessed. Paired t test was used to compare variables at two time points (baseline and six months after injection) and repeated measures ANOVA test was utilized for variables at three time points in follow-up visits. RESULTS: No major adverse effects such as burning, pain, itching, or any systemic side effects were observed following ADSCs injection, and the lesions showed slight to considerable improvement after injection. The mRNA expression levels of pro-inflammatory factors were reduced in the dermis of the patients after injection. The increased expression level of Foxp3 transcription factor in the patient blood samples suggested modulation of inflammation after ADMSCs administration. Six months after the intervention, no major side effects were reported, but skin thickness, erythema, and scaling of the plaques, as well as the PASI score, were decreased in majority of patients. CONCLUSION: Our study suggested that ADSC injection could be considered as a safe and effective therapeutic approach for psoriatic plaques (registration number: IRCT20080728001031N24).

Generalized Pustular Psoriasis Flare-Up after Both Doses of BBIBP-CorV Vaccination in a Patient under Adalimumab Treatment: A Case Report.

Generalized pustular psoriasis is a possibly serious condition that can be triggered by various factors. Previous studies show a slight likelihood of disease exacerbation subsequent to COVID-19 vaccination. Here, we present the first (to the best of our knowledge) case of pustular psoriasis flare after each one of the two shots of the BBIBP-CorV (Sinopharm) vaccine despite adalimumab treatment.