Granzyme K+ CD8 T cells form a core population in inflamed human tissue.

T cell-derived pro-inflammatory cytokines are a major driver of rheumatoid arthritis (RA) pathogenesis. Although these cytokines have traditionally been attributed to CD4 T cells, we have found that CD8 T cells are notably abundant in synovium and make more interferon (IFN)-γ and nearly as much tumor necrosis factor (TNF) as their CD4 T cell counterparts. Furthermore, using unbiased high-dimensional single-cell RNA-seq and flow cytometric data, we found that the vast majority of synovial tissue and synovial fluid CD8 T cells belong to an effector CD8 T cell population characterized by high expression of granzyme K (GzmK) and low expression of granzyme B (GzmB) and perforin. Functional experiments demonstrate that these GzmK+ GzmB+ CD8 T cells are major cytokine producers with low cytotoxic potential. Using T cell receptor repertoire data, we found that CD8 GzmK+ GzmB+ T cells are clonally expanded in synovial tissues and maintain their granzyme expression and overall cell state in blood, suggesting that they are enriched in tissue but also circulate. Using GzmK and GzmB signatures, we found that GzmK-expressing CD8 T cells were also the major CD8 T cell population in the gut, kidney, and coronavirus disease 2019 (COVID-19) bronchoalveolar lavage fluid, suggesting that they form a core population of tissue-associated T cells across diseases and human tissues. We term this population tissue-enriched expressing GzmK or TteK CD8 cells. Armed to produce cytokines in response to both antigen-dependent and antigen-independent stimuli, CD8 TteK cells have the potential to drive inflammation.

Single Ascending Dose Study of a Short Interfering RNA Targeting Lipoprotein(a) Production in Individuals With Elevated Plasma Lipoprotein(a) Levels.

Importance: Lipoprotein(a) (Lp[a]) is an important risk factor for atherothrombotic cardiovascular disease and aortic stenosis, for which there are no treatments approved by regulatory authorities. Objectives: To assess adverse events and tolerability of a short interfering RNA (siRNA) designed to reduce hepatic production of apolipoprotein(a) and to assess associated changes in plasma concentrations of Lp(a) at different doses. Design, Setting, and Participants: A single ascending dose study of SLN360, an siRNA targeting apolipoprotein(a) synthesis conducted at 5 clinical research unit sites located in the US, United Kingdom, and Australia. The study enrolled adults with Lp(a) plasma concentrations of 150 nmol/L or greater at screening and no known clinically overt cardiovascular disease. Participants were enrolled between November 18, 2020, and July 21, 2021, with last follow-up on December 29, 2021. Interventions: Participants were randomized to receive placebo (n = 8) or single doses of SLN360 at 30 mg (n = 6), 100 mg (n = 6), 300 mg (n = 6), or 600 mg (n = 6), administered subcutaneously. Main Outcomes and Measures: The primary outcome was evaluation of safety and tolerability. Secondary outcomes included change in plasma concentrations of Lp(a) to a maximum follow-up of 150 days. Results: Among 32 participants who were randomized and received the study intervention (mean age, 50 [SD, 13.5] years; 17 women [53%]), 32 (100%) completed the trial. One participant experienced 2 serious adverse event episodes: admission to the hospital for headache following SARS-CoV-2 vaccination and later for complications of cholecystitis, both of which were judged to be unrelated to study drug. Median baseline Lp(a) concentrations were as follows: placebo, 238 (IQR, 203-308) nmol/L; 30-mg SLN360, 171 (IQR, 142-219) nmol/L; 100-mg SLN360, 217 (IQR, 202-274) nmol/L; 300-mg SLN360, 285 (IQR, 195-338) nmol/L; and 600-mg SLN360, 231 (IQR, 179-276) nmol/L. Maximal median changes in Lp(a) were -20 (IQR, -61 to 3) nmol/L, -89 (IQR, -119 to -61) nmol/L, -185 (IQR, -226 to -163) nmol/L, -268 (IQR, -292 to -189) nmol/L, and -227 (IQR, -270 to -174) nmol/L, with maximal median percentage changes of -10% (IQR, -16% to 1%), -46% (IQR, -64% to -40%), -86% (IQR, -92% to -82%), -96% (IQR, -98% to -89%), and -98% (IQR, -98% to -97%), for the placebo group and the 30-mg, 100-mg, 300-mg, and 600-mg SLN360 groups, respectively. The duration of Lp(a) lowering was dose dependent, persisting for at least 150 days after administration. Conclusions and Relevance: In this phase 1 study of 32 participants with elevated Lp(a) levels and no known cardiovascular disease, the siRNA SLN360 was well tolerated, and a dose-dependent lowering of plasma Lp(a) concentrations was observed. The findings support further study to determine the safety and efficacy of this siRNA. Trial Registration: ClinicalTrials.gov Identifier: NCT04606602; EudraCT Identifier: 2020-002471-35.

Familial hypercholesterolaemia and cascade testing in general practice

THE COVID-19 pandemic highlights the key role of general practice in Australian health service delivery, especially for our most vulnerable patients.1 While terms such as 'index case' (defined as the first identified case in a group of related cases of a particular communicable or heritable disease) and 'cascade testing' (the extension of genetic testing to individuals at risk of inheriting a pathogenic variant previously identified in a biological relative) have long been associated with genetic testing for hereditary conditions among families, the recent increased public awareness of and experience with epidemiological concepts such as contact tracing offers new potential to improve detection and management of familial hypercholesterolaemia (FH) in the community.On 1 May 2020, new Medicare Benefits Schedule (MBS) item numbers relating to genetic testing for FH were introduced in Australia,2 offering a timely opportunity for general practice to collaborate with lipid specialists to facilitate improved detection and management. While an infectious disease such as COVID-19 cannot be directly compared with inherited conditions such as FH, lessons learned from the pandemic and developments in remote consulting can be applied to the management of FH.

The Knowns and Unknowns of Contemporary Statin Therapy for Familial Hypercholesterolemia.

PURPOSE OF REVIEW: Statins are first-line therapy for lowering low-density lipoprotein (LDL) cholesterol in familial hypercholesterolemia (FH), particularly in heterozygous patients. We review advances and new questions on the use of statins in FH. RECENT FINDINGS: Cumulative evidence from registry data and sub-analyses of clinical trials mandates the value of statin therapy for prevention of atherosclerotic cardiovascular disease (ASCVD) in FH. Statins are safe in children and adolescents with FH, with longer term cardiovascular benefits. The potentially toxic effects of statins in pregnancy need to be considered, but no association has been reported in prospective cohort studies with birth defects. There is no rationale for discontinuation of statins in elderly FH unless indicated by adverse events. FH is undertreated, with > 80% of statin-treated FH patients failing to attain LDL cholesterol treatment targets. This may relate to adherence, tolerability, and genetic differences in statin responsiveness. Statin treatment from childhood may reduce the need for stringent cholesterol targets. Combination of statins with ezetimibe and PCSK9 inhibitors significantly improves the efficacy of treatment. Whether statin use could improve the clinical course of FH patients with COVID-19 and other respiratory infections remains an unsolved issue for future research. Statins are the mainstay for primary and secondary prevention of ASCVD in FH. Sustained long-term optimal statin treatment from an early age can effectively prevent ASCVD over decades of life. Despite their widespread use, statins merit further investigation in FH.