IgA vasculitis nephritis-outcomes in adult-onset disease.

OBJECTIVES: IgA vasculitis (IgAV) in adults has been relatively under-investigated. Since outcomes are worse in other forms of vasculitis with increasing age, we investigated the outcomes of IgAV comparing younger adults (18-34), middle aged adults (35-64) and elderly patients (≥64 years) focusing on kidney outcomes. METHODS: We identified patients with renal biopsy confirmed IgAV nephritis and collected data regarding clinical features and progression to end stage kidney disease (ESKD). The relationship between patient factors and ESKD was analysed by regression. RESULTS: We identified 202 cases, 34% aged 18-34, 43% aged 35-64 and 23% were elderly (>64 years). Median follow up was 44 months. Elderly patients were more likely to present with ESKD (23.9%) compared with middle aged (13.7%) and younger adults (2.9%)(χ2 11.6, p= 0.002). In patients with independent kidney function at biopsy, there was no difference in outcomes between age groups. Male gender, Black ethnicity, diabetes, histological evidence of chronic renal damage and eGFR < 30mls/min were risk factors for development of ESKD. In this observational study 68.3% of patients received glucocorticoids and 56.9% additional immunosuppression. CONCLUSIONS: Elderly patients with IgAV are more likely to have ESKD at presentation, but there is no difference in renal survival between age groups, among those presenting with independent renal function. Renal impairment at biopsy is an independent risk factor for subsequent development of ESKD. There is significant variability in the timing of kidney biopsy and management of these patients among specialist centres. Young adults have outcomes more in keeping with childhood IgAV.

Fluorine labelling of therapeutic human tolerogenic dendritic cells for 19F-magnetic resonance imaging.

Tolerogenic dendritic cell (tolDC) therapies aim to restore self-tolerance in patients suffering from autoimmune diseases. Phase 1 clinical trials with tolDC have shown the feasibility and safety of this approach, but have also highlighted a lack of understanding of their distribution in vivo. Fluorine-19 magnetic resonance imaging (19F-MRI) promises an attractive cell tracking method because it allows for detection of 19F-labelled cells in a non-invasive and longitudinal manner. Here, we tested the suitability of nanoparticles containing 19F (19F-NP) for labelling of therapeutic human tolDC for detection by 19F-MRI. We found that tolDC readily endocytosed 19F-NP with acceptable effects on cell viability and yield. The MRI signal-to-noise ratios obtained are more than sufficient for detection of the administered tolDC dose (10 million cells) at the injection site in vivo, depending on the tissue depth and the rate of cell dispersal. Importantly, 19F-NP labelling did not revert tolDC into immunogenic DC, as confirmed by their low expression of typical mature DC surface markers (CD83, CD86), low secretion of pro-inflammatory IL-12p70, and low capacity to induce IFN-γ in allogeneic CD4+ T cells. In addition, the capacity of tolDC to secrete anti-inflammatory IL-10 was not diminished by 19F-NP labelling. We conclude that 19F-NP is a suitable imaging agent for tolDC. With currently available technologies, this imaging approach does not yet approach the sensitivity required to detect small numbers of migrating cells, but could have important utility for determining the accuracy of injecting tolDC into the desired target tissue and their efflux rate.

Tolerance-inducing medicines in autoimmunity: rheumatology and beyond.

Autoimmunity is currently managed with generalised immunosuppression, which is associated with serious side-effects such as infection and cancer. An ideal treatment strategy would be to induce immune tolerance-ie, to reprogramme the immune system to stop recognising the host itself as a threat. Drug-free remission should follow such an intervention, representing a change in the approach to the treatment of autoimmune disease. Tolerance induction is achievable in animal models of autoimmunity but translation to the clinic has been slow. Nonetheless, progress has been made-eg, restoration of therapeutic responsiveness and drug-free remission have been achieved with stem cell transplantation in refractory autoimmunity, and significant delays in onset of type 1 diabetes in individuals at high risk have been achieved following a brief treatment with anti-CD3 monoclonal antibody. In the future, antigen-specific interventions should provide highly targeted, personalised approaches, avoiding generalised immunosuppression entirely. Such trials have already started, using both direct autoantigenic peptide administration, cellular therapies, and other modalities. In this Series paper, we discuss the history of immune tolerance induction with a focus on rheumatological disease while also highlighting essential data from other specialties. We propose key unanswered questions, which will be covered in other papers in this Series.