Objective: To explore the effects of microglial activation on brain function and structure, and its relationship with peripheral inflammatory markers, in treated, HIV-positive individuals, using in vivo [11 C]PBR28 PET (to measure the 18 kDa translocator protein [TSPO]).Methods: Cognitively healthy HIV-positive individuals on suppressive antiretroviral therapy and HIV-negative individuals (controls) underwent brain [ 11 C]PBR28 PET and MRI. HIV-positive patients completed neuropsychological testing and CSF testing for chemokines. The concentration of bacterial ribosomal 16sDNA in plasma was measured as a marker of microbial translocation.Results: HIV-positive individuals showed global increases in TSPO expression compared to controls (corrected p , 0.01), with significant regional increases in the parietal (p 5 0.001) and occipital (p 5 0.046) lobes and in the globus pallidus (p 5 0.035). TSPO binding in the hippocampus, amygdala, and thalamus were associated with poorer global cognitive performance in tasks assessing verbal and visual memory (p , 0.05). Increased TSPO binding was associated with increased brain white matter diffusion MRI mean diffusivity in HIV-positive individuals, a lower CD4/CD8 ratio, and both high pretreatment HIV RNA and plasma concentration ribosomal 16s DNA (p , 0.05).Conclusions: Cognitively healthy HIV-positive individuals show evidence for a chronically activated brain innate immune response and elevated blood markers of microbial translocation despite effective control of plasma viremia. Increased brain inflammation is associated with poorer cognitive performance and white matter microstructural pathology, suggesting a possible role in cognitive impairments found in some HIV-positive patients despite effective treatment.

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Mucosal-associated invariant T (MAIT) cells are tissue-homing T cells recently implicated in HIV pathogenesis. We found that the proportion of MAIT cell in blood and colon of HIV+ patients are reduced in untreated infection. Antiretroviral therapy restored colonic but not blood MAIT cell percentages. We observed a negative correlation between colonic MAIT cells and T-cell activation in blood and suggest mucosal MAIT cell depletion may contribute to systemic immune activation in HIV infection.

Background and aims Infliximab attenuates serological responses to SARS-CoV-2 infection. Whether this is a class effect, or if anti-TNF level influences serological responses, remains unknown. Methods Seroprevalence and the magnitude of SARS-CoV-2 nucleocapsid antibody responses were measured in surplus serum from 11422 (53.3% (6084) male; median age 36.8 years) patients with immune-mediated inflammatory diseases, stored at six therapeutic drug monitoring laboratories between 29 th January and 30 th September 2020. Data were linked to nationally-held SARS-CoV-2 PCR results to 4 th May 2021. Results Rates of PCR confirmed SARS-CoV-2 infection were similar across treatment groups. Seroprevalence rates were lower in infliximab- and adalimumab- than vedolizumab-treated patients (infliximab: 3.0% (178/5893), adalimumab: 3.0% (152/5074), vedolizumab: 6.7% (25/375), p = 0.003). The magnitude of SARS-CoV-2 reactivity was similar in infliximab- vs adalimumab-treated patients (median 4.30 cut-off index (COI) (1.94 – 9.96) vs 5.02 (2.18 – 18.70), p = 0.164), but higher in vedolizumab-treated patients (median 21.60 COI (4.39 - 68.10, p< 0.004). Compared to patients with detectable infliximab and adalimumab drug levels, patients with undetectable drug levels (<0.8 mg/L) were more likely to be seropositive for SARS-CoV-2 antibodies. One-third of patients who had PCR testing prior to antibody testing failed to seroconvert, all were anti-TNF treated. Subsequent positive PCR-confirmed SARS-CoV-2 was seen in 7.9% (12/152) patients after a median time of 183.5 days (129.8 – 235.3), without differences between drugs. Conclusion Anti-TNF treatment is associated with lower SARS-CoV-2 nucleocapsid seroprevalence and antibody reactivity when compared to vedolizumab-treated patients. Higher seropositivity rates in patients with undetectable anti-TNF levels supports a causal relationship, although confounding factors, such as combination therapy with immunomodulator, may have influenced the results.

Loss of Th22 cells and disruption in the balance of Th22 and Treg cells may contribute toward systemic immune activation and mucosal immune deficiency during HIV-1 infection.

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Lab-on-a-Chip (LoC) technology has the potential to revolutionize medical Point-of-Care diagnostics. Currently, considerable research efforts are focused on innovative production technologies that will make commercial upscaling of lab-on-chip products financially viable. Printed circuit board (PCB) manufacturing techniques have several advantages in this field. In this paper we focus on transferring a complete IFN-γ enzyme-linked immune-sorbent assay (ELISA) onto a commercial PCB electrochemical biosensing platform, We adapted a commercially available ELISA to detect the enzyme product TMB/H2O2 using amperometry, successfully reproducing the colorimetry-obtained ELISA standard curve. The results demonstrate the potential for the integration of these components into an automated, disposable, electronic ELISA Lab-on-PCB diagnostic platform.

Rapid advances in clinical technologies, detection sensitivity and analytical throughput have delivered a significant expansion in our knowledge of prognostic and diagnostic biomarkers in many common infectious diseases, such as Tuberculosis (TB). During the last decade, a significant number of approaches to TB diagnosis have been attempted at Point-of-Care (PoC), exploiting a large variation of techniques and materials. In this work, we describe an electronics-based Enzyme-Linked ImmunoSorbent Assay (eELISA), using a Lab-on-a-Printed Circuit Board (LoPCB) approach, for TB diagnosis based on cytokine detection. The test relies upon an electrochemical (amperometric) assay, comprising a high-precision bioinstrumentation board and amperometric sensors, produced exclusively using standard PCB manufacturing processes. Electrochemical detection uses standard Au and Ag electrodes together with a bespoke, low-power, multichannel, portable data-acquisition system. We demonstrate high-performance assay chemistry performed at microfluidic volumes on Au pads directly at the PCB surface with improved limit of detection (~10 pg/mL) over standard colorimetric ELISA methods. The assay has also been implemented in plasma, showing the utility of the system for medical applications. This work is a significant step towards the development of a low-cost, portable, high-precision diagnostic and monitoring technology, which once combined with appropriate PCB-based microfluidic networks will provide complete LoPCB platforms.