Cytokine and T cell responses in post-chikungunya viral arthritis: A cross-sectional study.

OBJECTIVE: To define the relationship between chronic chikungunya post-viral arthritis disease severity, cytokine response and T cell subsets in order to identify potential targets for therapy. METHODS: Participants with chikungunya arthritis were recruited from Colombia from 2019-2021. Arthritis disease severity was quantified using the Disease Activity Score-28 and an Arthritis-Flare Questionnaire adapted for chikungunya arthritis. Plasma cytokine concentrations (interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ and tumor necrosis factor (TNF)) were measured using a Meso Scale Diagnostics assay. Peripheral blood T cell subsets were measured using flow cytometry. RESULTS: Among participants with chikungunya arthritis (N = 158), IL-2 levels and frequency of regulatory T cells (Tregs) were low. Increased arthritis disease activity was associated with higher levels of inflammatory cytokines (IL-6, TNF and CRP) and immunoregulatory cytokine IL-10 (p<0.05). Increased arthritis flare activity was associated with higher Treg frequencies (p<0.05) without affecting T effector (Teff) frequencies, Treg/Teff ratios and Treg subsets. Finally, elevated levels of IL-2 were correlated with increased Treg frequency, percent Tregs out of CD4+ T cells, and Treg subsets expressing immunosuppressive markers, while also correlating with an increased percent Teff out of live lymphocytes (p<0.05). CONCLUSION: Chikungunya arthritis is characterized by increased inflammatory cytokines and deficient IL-2 and Treg responses. Greater levels of IL-2 were associated with improved Treg numbers and immunosuppressive markers. Future research may consider targeting these pathways for therapy.

Clinical profile of children incidentally found to have advanced kidney failure.

INTRODUCTION: No data exist on the epidemiology of children incidentally diagnosed with advanced kidney failure (KF) during evaluation for non-specific symptoms. This is likely related to unrecognized symptoms and signs of CKD. The objective of our study was to evaluate incidentally diagnosed patients with advanced KF requiring long-term kidney replacement therapy (KRT). METHODS: An IRB-approved retrospective chart review of children who started KRT with dialysis (hemo- or peritoneal) was conducted. Included were children with no prior knowledge or diagnosis of underlying kidney disease with chronic kidney disease (CKD) disease stage 4 (GFR 15-29 mL/min/1.73 m2) or 5 (GFR < 15 mL/min/1.73 m2) at initial presentation and started on chronic KRT within 2 months of presentation. RESULTS: Of 177 patients initiating KRT during the study period, 26 (15%) were categorized as incidental advanced KF. This cohort with mean age 12.25 years consisted of 42% males, 54% African Americans included 46% with glomerular, and 54% with non-glomerular etiology for kidney failure. Vomiting (42%) and fatigue (39%) were most common, while growth failure (19%) and hyperkalemia (7%) were less frequent on initial presentation. Anemia (100%), hypertension (96%), hyperparathyroidism (96%), and hyperphosphatemia (92%) were the most frequently seen CKD comorbidities. Chronic KRT was started within 24 h in 62% and within 2 weeks in 88% of the cohort. CONCLUSION: Under-diagnosis of patients with advanced KF is most likely related to milder non-specific clinical symptoms and normal growth in the majority of patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence and correlates of a lifetime cannabis use disorder among pregnant former tobacco smokers.

BACKGROUND: Following tobacco and alcohol, cannabis is the most commonly used substance during pregnancy. Given the high prevalence of concurrent cannabis and tobacco use as well as the health consequences associated with prenatal substance use, we sought to document the relative contributions of psychosocial and psychiatric factors commonly associated with cannabis use in predicting a lifetime cannabis use disorder (CUD) among women who had quit smoking tobacco as a result of pregnancy. METHODS: Pregnant former tobacco smokers (n=273) enrolled in a larger randomized controlled trial for postpartum tobacco relapse prevention completed semi-structured psychiatric interviews and self-reported demographic, pregnancy, health, psychosocial, and tobacco use factors during their third trimester of pregnancy. RESULTS: In total, 14% (n=38) of women met criteria for a lifetime CUD. The strongest predictors of a lifetime CUD were a history of having multiple psychiatric disorders (OR=36.44; 95% CI=5.03-264.27; p<0.001) followed by a lifetime alcohol use disorder (OR=3.54; 95% CI=1.27-9.87; p<0.05). In addition, more frequent attempts to quit smoking tobacco (OR=1.12; 95% CI=1.01-1.25; p<0.05) and lower self-efficacy about weight management after quitting smoking tobacco (OR=0.78; 95% CI=0.62-0.97; p<0.05) also were significantly associated with a lifetime CUD. CONCLUSIONS: Women with a history of both cannabis and tobacco dependence may represent a subset of women who need more specialized treatment during the perinatal period to improve substance use outcomes.

Molecular basis for differential elongation of omega-3 docosapentaenoic acid by the rat Elovl5 and Elovl2.

Functional characterization of the rat elongases, Elovl5 and Elovl2, has identified that Elovl2 is crucial for omega-3 docosahexaenoic acid (DHA) (22:6n-3) synthesis. While the substrate specificities of the rat elongases had some overlap, only Elovl2 can convert the C22 omega-3 PUFA docosapentaenoic acid (DPA) (22:5n-3) to 24:5n-3, which is the penultimate precursor of DHA. In order to better understand the potential for these elongases to be involved in DHA synthesis, we have examined the molecular reasons for the differences between Elovl5 and Elovl2 in their ability to elongate DPA to 24:5n-3. We identified a region of heterogeneity between Elovl5 and Elovl2 spanning transmembrane domains 6 and 7. Using a yeast expression system, we examined a series of Elovl2/Elovl5 chimeras and point mutations to identify Elovl2 residues within this region which are responsible for DPA substrate specificity. The results indicate that the cysteine at position 217 in Elovl2 and a tryptophan at the equivalent position in Elovl5 explain their differing abilities to elongate DPA to 24:5n-3. Further studies confirmed that Elovl2 C217 is a critical residue for elongation of DPA at the level observed in the native protein. Understanding the ability of elongases to synthesize 24:5n-3 may provide a basis for using sequence data to predict their ability to ultimately support DHA synthesis.

Fatty acid desaturase 2 promoter mutation is not responsible for Δ6-desaturase deficiency.

Dietary essential polyunsaturated fatty acids (PUFAs) require fatty acid desaturases (FADS) for conversion to long-chain PUFAs (LCPUFAs), which are critical for many aspects of human health. A Δ6-desaturase deficiency in a single patient was attributed to an insertion mutation in the FADS2 promoter. Later population studies have shown this thymidine nucleotide (T) insertion to be a common polymorphism (rs3834458). We examined correlations between rs3834458 variants and fatty acid evidence of FADS2 activity in a cohort of rheumatoid arthritis patients selected for low or nil consumption of n-3 LCPUFA as fish or fish oil. The presence of the T allele was associated with higher FADS2 activity, as indicated by higher conversion of plasma n-3 PUFA to LCPUFA. However, the T-insertion/deletion polymorphism did not affect FADS2 promoter activity in luciferase reporter assays in HepG2 or NIH/3T3 cells. Our results indicate that the polymorphism rs3834458 does not appear to directly affect FADS2 promoter activity and is not responsible for a previously reported Δ6-desaturase deficiency.

Development of a fish cell culture model to investigate the impact of fish oil replacement on lipid peroxidation.

Fish oils are rich in omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), predominantly 20:5n-3 and 22:6n-3, whereas vegetable oils contain abundant C(18)-PUFA, predominantly 18:3n-3 or 18:2n-6. We hypothesized that replacement of fish oils with vegetable oils would increase the oxidative stability of fish lipids. Here we have used the long established and easily cultivated FHM cell line derived from the freshwater fish species fathead minnow (Pimephales promelas) to test this hypothesis. The FHM cells were readily able to synthesize 20:5n-3 and 24:6n-3 from 18:3n-3 but 22:6n-3 synthesis was negligible. Also, they were readily able to synthesize 20:3n-6 from 18:2n-6 but 20:4n-6 synthesis was negligible. Mitochondrial ß-oxidation was greatest for 18:3n-3 and 20:5n-3 and the rates for 16:0, 18:2n-6, 22:6n-3 and 18:1n-9 were significantly lower. Fatty acid incorporation was predominantly into phospholipids (79-97%) with very little incorporation into neutral lipids. Increasing the fatty acid concentration in the growth medium substantially increased the concentrations of 18:3n-3 and 18:2n-6 in the cell phospholipids but this was not the case for 20:5n-3 or 22:6n-3. When they were subjected to oxidative stress, the FHM cells supplemented with either 20:5n-3 or 22:6n-3 (as compared with 18:3n-3 or saturated fatty acids) exhibited significantly higher levels of thiobarbituric reactive substances (TBARS) indicating higher levels of lipid peroxidation. The results are discussed in relation to the effects of fatty acid unsaturation on the oxidative stability of cellular lipids and the implications for sustainable aquaculture.

Genetically modified dendritic cells in cancer immunotherapy: a better tomorrow?

IMPORTANCE OF THE FIELD: Dendritic cells (DC) are powerful antigen-presenting cells that induce and maintain primary cytotoxic T lymphocyte (CTL) responses directed against tumor antigens. Consequently, there has been much interest in their application as antitumor vaccines. AREAS COVERED IN THIS REVIEW: A large number of DC-based vaccine trials targeting a variety of cancers have been conducted; however, the rate of reported clinically significant responses remains low. Modification of DC to express tumor antigens or immunostimulatory molecules through the transfer of genes or mRNA transfection offers a logical alternative with potential advantages over peptide- or protein antigen-loaded DC. In this article, we review the current results and future prospects for genetically modified DC vaccines for the treatment of cancer. WHAT THE READER WILL GAIN: Genetically-modified dendritic cell-based vaccines represent a powerful tool for cancer therapy. Numerous preclinical and clinical studies have demonstrated the potential of dendritic cell vaccines alone or in combination with other therapeutic modalities. TAKE HOME MESSAGE: Genetically modified DC-based anti-cancer vaccination holds promise, perhaps being best employed in the adjuvant setting with minimal residual disease after primary therapy, or in combination with other antitumor or immune-enhancing therapies.

Application of a flow cytometric cytotoxicity assay for monitoring cancer vaccine trials.

In this study, we evaluated the applicability of a flow cytometry-based cytotoxicity (FC) assay previously developed by our laboratory, for monitoring cancer vaccine trials. The assay simultaneously measures effector cell degranulation and target cell death. Clinically relevant samples consisted of frozen peripheral blood mononuclear cells (PBMC) from vaccinated melanoma patients with known response to the melanoma peptide g209. Both PBMC and 7 day in vitro-stimulated lymphocyte from patient samples were used as effector cells in the FC assay. Activity against the relevant g209 and the control g280 peptide measured in the FC assay was directly compared with results obtained from the Granzyme B enzyme-linked immunosorbent spot assay and the standard 51Cr-release assay run in tandem. The FC assay detected low or no activity when PBMC were used as effector cells. Using cytotoxic T lymphocytes as effector cells, little or no effector cell degranulation or cytotoxicity was measured in the FC assay in prevaccination samples. After vaccination, an increase in both degranulation and target cell death could be determined when target cells were pulsed with g209. No or low reactivity was found against g280 at any time point. Our findings exhibited excellent correlation between CD107a expression and GrB secretion and also Annexin V binding to target cells and specific lysis measured in the 51Cr-release assay. Results obtained from the FC assay were highly reproducible. Therefore, the FC assay may be applied to vaccine trial monitoring and allows the measurement of effector cell degranulation and target cell death simultaneously in a single sample.