The IL-33/ST2 axis is crucial in type 2 airway responses induced by Staphylococcus aureus-derived serine protease-like protein D.

BACKGROUND: Chronic airway inflammatory diseases, such as chronic rhinosinusitis with nasal polyps and asthma, show increased nasal Staphylococcus aureus colonization. Staphylococcus aureus-derived serine protease-like protein (Spl) D and other closely related proteases secreted by S aureus have recently been identified as inducers of allergic asthma in human subjects and mice, but their mechanism of action is largely unknown. OBJECTIVE: We investigated the role of recombinant SplD in driving TH2-biased responses and IgE formation in a murine model of allergic asthma. METHODS: Allergic asthma was induced in C57BL/6 J wild-type mice, Toll-like receptor (TLR) 4 knockout (Tlr4-/-) mice, and recombination-activating gene (Rag2) knockout (Rag2-/-) mice by means of repeated intratracheal applications of SplD. Inflammatory parameters in the airways were assessed by means of flow cytometry, ELISA, Luminex, and immunohistochemistry. Serum SplD-specific IgE levels were analyzed by using ELISA. RESULTS: We observed that repeated intratracheal exposure to SplD led to IL-33 and eotaxin production, eosinophilia, bronchial hyperreactivity, and goblet cell hyperplasia in the airways. Blocking IL-33 activity with a soluble ST2 receptor significantly decreased the numbers of eosinophils, IL-13+ type 2 innate lymphoid cells and IL-13+CD4+ T cells and IL-5 and IL-13 production by lymph node cells but had no effect on IgE production. SplD-induced airway inflammation and IgE production were largely dependent on the presence of the functional adaptive immune system and independent of TLR4 signaling. CONCLUSION: The S aureus-derived protein SplD is a potent allergen of S aureus and induces a TH2-biased inflammatory response in the airways in an IL-33-dependent but TRL4-independent manner. The soluble ST2 receptor could be an efficient strategy to interfere with SplD-induced TH2 inflammation but does not prevent the allergic sensitization.

Clinical Utility of ß-Amyloid PET Imaging in People Living With HIV With Cognitive Symptoms.

BACKGROUND: Imaging with ß-amyloid (Aß) positron emission tomography (PET) has the potential to aid the diagnosis of the cause of cognitive impairment affecting people living with HIV (PLWH) when neurodegenerative disorders are considered. We evaluated the clinical utility of [18F]Florbetaben (FBB) in PLWH with cognitive symptoms. METHODS: Imaging with FBB PET was performed in 20 patients with cognitive concerns about dementia. Neuropsychological testing, plasma neurofilament light protein, plasma Aß40, Aß42, and cerebrospinal fluid Aß42, tau, and HIV RNA were obtained. FBB PET images were assessed visually by 3 readers blinded to the clinical diagnosis and quantitatively by obtaining a composite cortical to cerebellar cortex standardized uptake value ratio (SUVR). FBB SUVR from 10 age-matched healthy controls was compared with SUVR of PLWH. RESULTS: Most participants were men (90%) of white ethnicity (90%) with a median age (interquartile range) of 59 (43-79) years. Median CD4 count was 682 (74-1056). All patients were on combination antiretroviral therapy with plasma and cerebrospinal fluid HIV RNA <40 copies/mL. Fourteen patients had objective cognitive impairment including 2 who met clinical criteria for a diagnosis of dementia. No significant differences in composite SUVRs between PLWH and controls [mean (SD): 1.18 (0.03) vs. 1.16 (0.09); P = 0.37] were observed. Four patients were FBB+ with the highest SUVR in the posterior cingulate, superior temporal, and frontal superior lobe. Amyloid PET results contributed to a change in diagnosis and treatment for 10 patients. CONCLUSION: [18F]Florbetaben PET has potential as an adjunctive tool in the diagnosis of PLWH with cognitive impairment, increasing diagnostic certainty and optimizing management.

Assessment and Management of HIV-Associated Cognitive Impairment: Experience from a Multidisciplinary Memory Service for People Living with HIV.

As the HIV population ages, the prevalence of cognitive impairment (CI) is increasing, yet few services exist for the assessment and management of these individuals. Here we provide an initial description of a memory assessment service for people living with HIV and present data from a service evaluation undertaken in the clinic. We conducted an evaluation of the first 52 patients seen by the clinic. We present patient demographic data, assessment outcomes, diagnoses given and interventions delivered to those seen in the clinic. 41 patients (79%) of those seen in the clinic had objective CI: 16 (31%) met criteria for HIV-associated Neurocognitive Disorder (HAND), 2 (4%) were diagnosed with dementia, 14 (27%) showed CI associated with mental illness and/or drugs/alcohol, 7 (13%) had CI which was attributed to factors other than HIV and in 2 (4%) patients the cause remains unclear. 32 (62%) patients showed some abnormality on Magnetic Resonance Imaging (MRI) brain scans. Patients attending the clinic performed significantly worse than normative scores on all tests of global cognition and executive function. Interventions offered to patients included combination antiretroviral therapy modification, signposting to other services, case management, further health investigations and in-clinic advice. Our experience suggests that the need exists for specialist HIV memory services and that such a model of working can be successfully implemented into HIV patient care. Further work is needed on referral criteria and pathways. Diagnostic processes and treatment offered needs to consider and address the multifactorial aetiology of CI in HIV and this is essential for effective assessment and management.