Effect of Immunosuppression on the Immune Response to SARS-CoV-2 Infection and Vaccination.

Immunosuppressive treatment in patients with rheumatic diseases can maintain disease remission but also increase risk of infection. Their response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is frequently blunted. In this study we evaluated the effect of immunosuppression exposure on humoral and T cell immune responses to SARS-CoV-2 infection and vaccination in two distinct cohorts of patients; one during acute SARS-CoV-2 infection and 3 months later during convalescence, and another prior to SARS-CoV-2 vaccination, with follow up sampling 6 weeks after vaccination. Results were compared between rituximab-exposed (in previous 6 months), immunosuppression-exposed (in previous 3 months), and non-immunosuppressed groups. The immune cell phenotype was defined by flow cytometry and ELISA. Antigen specific T cell responses were estimated using a whole blood stimulation interferon-γ release assay. A focused post-vaccine assessment of rituximab-treated patients using high dimensional spectral cytometry was conducted. Acute SARS-CoV-2 infection was characterised by T cell lymphopenia, and a reduction in NK cells and naïve CD4 and CD8 cells, without any significant differences between immunosuppressed and non-immunosuppressed patient groups. Conversely, activated CD4 and CD8 cell counts increased in non-immunosuppressed patients with acute SARS-CoV-2 infection but this response was blunted in the presence of immunosuppression. In rituximab-treated patients, antigen-specific T cell responses were preserved in SARS-CoV-2 vaccination, but patients were unable to mount an appropriate humoral response.

Post-Transplant Bone Disease in Kidney Transplant Recipients: Diagnosis and Management.

Kidney transplantation is the preferred gold standard modality of treatment for kidney failure. Bone disease after kidney transplantation is highly prevalent in patients living with a kidney transplant and is associated with high rates of hip fractures. Fractures are associated with increased healthcare costs, morbidity and mortality. Post-transplant bone disease (PTBD) includes renal osteodystrophy, osteoporosis, osteonecrosis and bone fractures. PTBD is complex as it encompasses pre-existing chronic kidney disease-mineral bone disease and compounding factors after transplantation, including the use of immunosuppression and the development of de novo bone disease. After transplantation, the persistence of secondary and tertiary hyperparathyroidism, renal osteodystrophy, relative vitamin D deficiency and high levels of fibroblast growth factor-23 contribute to post-transplant bone disease. Risk assessment includes identifying both general risk factors and kidney-specific risk factors. Diagnosis is complex as the gold standard bone biopsy with double-tetracycline labelling to diagnose the PTBD subtype is not always readily available. Therefore, alternative diagnostic tools may be used to aid its diagnosis. Both non-pharmacological and pharmacological therapy can be employed to treat PTBD. In this review, we will discuss pathophysiology, risk assessment, diagnosis and management strategies to manage PTBD after kidney transplantation.

High rates of psychological distress, mental health diagnoses and suicide attempts in people with chronic kidney disease in Ireland.

BACKGROUND: People with chronic kidney disease (CKD) experience high levels of psychological distress, which is associated with higher mortality and adverse health outcomes. Little is known about the rates of a range of mental health difficulties or rates of suicide attempts in people with CKD. METHODS: Individuals with CKD (n = 268; age range 18-94 years, mean = 49.96 years) on haemodialysis (n = 79), peritoneal dialysis (n = 46), transplant recipients (n = 84) and who were not on renal replacement therapy (RRT; n = 59) were recruited through the Irish Kidney Association social media pages and three Irish hospitals. Participants completed surveys to gather demographics and mental health histories, the Hospital Anxiety and Depression Scale (HADS) and the 12-item Short Form Health Survey (SF-12) to measure health-related quality of life (HRQoL). RESULTS: A total of 23.5% of participants self-reported they had received a mental health diagnosis, with depression (14.5%) and anxiety (14.2%) being the most common, while 26.4% of participants had experienced suicidal ideation and 9.3% had attempted suicide. Using a clinical cut-off ≥8 on the HADS subscales, current levels of clinically significant anxiety and depression were 50.7% and 35.4%, respectively. Depression levels were slightly higher for those on haemodialysis compared with those with a transplant and those not on RRT. Depression, anxiety and having a mental health diagnosis were all associated with lower HRQoL. CONCLUSIONS: People with CKD in Ireland experience high levels of psychological distress, mental health difficulties, suicidal ideation and suicide attempts. The identification of and intervention for mental health difficulties in CKD should be prioritised in clinical care.

Clinical Implementation and Initial Experience of Neutrophil Gelatinase-Associated Lipocalin Testing for the Diagnostic and Prognostic Assessment of Acute Kidney Injury Events in Hospitalized Patients.

INTRODUCTION: The use of novel kidney injury biomarkers has been shown to improve diagnostic assessment and prognostic prediction in various populations with acute kidney injury (AKI), but their use in a standard clinical practice have been rarely reported. METHODS: We reported the clinical implementation of neutrophil gelatinase-associated lipocalin (NGAL) measurement for routine AKI diagnostic workup of patients receiving nephrology consultation in a tertiary academic centre. Specific focus was made on the diagnostic performance to discriminate functional ("pre-renal") from intra-renal AKI and to predict AKI progression. RESULTS: Forty-five urine NGAL (uNGAL) and 25 plasma NGAL (pNGAL) samples in the first 50 consecutive patients were analysed. KDIGO Stage 1, 2, 3 AKI, and renal replacement therapy occurred in 10%, 40%, 50%, and 24% of cases, respectively. The uNGAL was lower in patients with transient AKI (<48 h) and no sign of urinary tract infections (37 [25-167] ng/mL) than sustained or progressive AKI (298 [74-1,308] ng/mL) (p = 0.016), while pNGAL did not discriminate transient (264 [100-373] ng/mL) from persistent AKI (415 [220-816] ng/mL) (p = 0.137). The median uNGAL level was 63 (35-1,123) ng/mL for functional/pre-renal AKI and 451 (177-1,315) ng/mL for intra-renal AKI (p = 0.043), while the pNGAL was 264 (114-468) and 415 (230-816) ng/mL (p = 0.235), respectively. CONCLUSION: NGAL, as part of the routine workup, is useful for diagnostic and prognostic assessment of new-onset AKI in clinical practice. Interpretation of an increased NGAL level should be clinically evaluated in its clinical context, particularly considering concomitant infection (urinary or systemic). Clinical adoption of emerging AKI biomarkers as diagnostic tests in clinical practice should be further encouraged.

Transparent Poly(methyl methacrylate) Composites Based on Bacterial Cellulose Nanofiber Networks with Improved Fracture Resistance and Impact Strength.

Cellulose nanofibers are often explored as biobased reinforcement for the production of high-performance composite materials. In this work, we fabricated transparent poly(methyl methacrylate) (PMMA) composites consisting of two-dimensional and three-dimensional bacterial cellulose (BC) nanofiber networks. Three different composite designs consisting of 1 vol % BC loading were fabricated and studied: (i) composites with a three-dimensional BC nanofiber network embedded uniformly throughout the PMMA matrix; (ii) sandwich-structured construction consisting of three-dimensional BC-PMMA sandwiched between two neat PMMA sheets; and (iii) dried and well-consolidated two-dimensional BC nanofiber network embedded in a PMMA matrix. All fabricated model BC-PMMA composites were found to be optically transparent, but PMMA composites consisting of the two-dimensional BC nanofiber network possessed higher light transmittance (73% @550 nm) compared to the three-dimensional BC nanofiber network counterparts (63% @550 nm). This is due to the higher specific surface area of the three-dimensional BC nanofiber network, which led to more light scattering. Nevertheless, it was found that both two-dimensional and three-dimensional BC nanofiber networks serve as excellent stiffening agents for PMMA matrix, improving the tensile modulus of the resulting composites by up to 30%. However, no improvement in tensile strength was observed. The use of three-dimensional BC nanofiber network led to matrix embrittlement, reducing the tensile strain-at-failure, fracture resistance, and Charpy impact strength of the resulting BC-PMMA composites. When the BC nanofiber network was used as two-dimensional reinforcement, cracks were observed to propagate through the debonding of BC nanofiber network, leading to higher fracture toughness and Charpy impact strength. These novel findings could open up further opportunities in the design of novel optically transparent polymeric composite laminates based on the two-dimensional BC nanofiber network for impact protection.

Obscure gastrointestinal bleeding resulting from small bowel neoplasia; A case series.

INTRODUCTION: Undiagnosed gastrointestinal bleeding may originate in the small bowel. This presents a diagnostic challenge despite the advancement in contemporary imaging. We report two cases which highlight the limitations of routine investigation for obscure gastrointestinal bleeding. PRESENTATION OF CASE: Patient A presented with a history of rectal bleeding, treated with interventional embolisation of caecal angiodysplasia. A diagnosis of neuroendocrine tumour (NET) was reached two years after presentation following intraoperative right hemicolectomy resection of a presumed recurrent angiodysplastic bleed. Patient B presented with recurrent melaena labelled as non-steroidal anti-inflammatory drug (NSAID) induced gastritis. After multiple endoscopic and radiological investigations, a 4.5 cm mass was visualised on imaging after three years, which was histologically proven as gastrointestinal stromal tumour (GIST) of the small bowel. Both patients experienced a delayed diagnosis despite multiple investigations and careful follow-up. DISCUSSION: Our case series discusses the benefits and limitations of investigation for gastrointestinal bleeding and suggests a need for continued multidisciplinary input in situations where the patient presumed diagnosis remains in question. CONCLUSION: OGIB remains a diagnostic challenge and is attributable to small bowel pathology in 75% of cases. This suggests a need for continued investigation in situations where the patient presents multiple times despite adequate treatment for the presumed underlying condition.