Intrinsic Folding Properties of the HLA-B27 Heavy Chain Revealed by Single Chain Trimer Versions of Peptide-Loaded Class I Major Histocompatibility Complex Molecules.

Peptide-loaded Major Histocompatibility Complex (pMHC) class I molecules can be expressed in a single chain trimeric (SCT) format, composed of a specific peptide fused to the light chain beta-2 microglobulin (ß2m) and MHC class I heavy chain (HC) by flexible linker peptides. pMHC SCTs have been used as effective molecular tools to investigate cellular immunity and represent a promising vaccine platform technology, due to their intracellular folding and assembly which is apparently independent of host cell folding pathways and chaperones. However, certain MHC class I HC molecules, such as the Human Leukocyte Antigen B27 (HLA-B27) allele, present a challenge due to their tendency to form HC aggregates. We constructed a series of single chain trimeric molecules to determine the behaviour of the HLA-B27 HC in a scenario that usually allows for efficient MHC class I molecule folding. When stably expressed, a pMHC SCT incorporating HLA-B27 HC formed chaperone-bound homodimers within the endoplasmic reticulum (ER). A series of HLA-B27 SCT substitution mutations revealed that the F pocket and antigen binding groove regions of the HLA-B27 HC defined the folding and dimerisation of the single chain complex, independently of the peptide sequence. Furthermore, pMHC SCTs can demonstrate variability in their association with the intracellular antigen processing machinery.

Correlation between different equations to calculate free testosterone for improved detection of hypogonadism in people living with HIV.

The diagnosis of hypogonadism in people living with HIV (PLWH) remains challenging by the lack of a standardised diagnostic algorithm. Since sexual hormone-binding globulin levels are commonly increased in PLWH, guidelines recommend assessing free testosterone (FT) along with total testosterone levels. We compared different online equations available to estimate FT levels and found a good correlation amongst all algorithms. Estimating FT levels increased diagnostic accuracy of hypogonadism and therefore should be encouraged in clinical practice in PLWH with clinical symptoms of hypogonadism, even when total testosterone levels are normal.

Delivering specialised care to people ageing with HIV in the UK: experience and evolution of services from 2009 to 2019.

BACKGROUND: The introduction of antiretrovirals has resulted in a demographic shift with an increasing proportion of people living with HIV older than 50 years and a change in the spectrum of diseases affecting this population. A specialised clinical service dedicated to older people living with HIV was implemented at Chelsea and Westminster Hospital, London, UK in 2009, following training of health-care providers in HIV, ageing, comorbidity, and polypharmacy management. We report the results of a service evaluation reviewing 10 years of activity of this specialised clinic, including lessons to be applied in routine practice. METHODS: We estimated the prevalence of multimorbidity and polypharmacy and described algorithms devised for use across our HIV outpatient services following implementation of the specialised clinical pathway. The service evaluation was approved by our local clinical governance system and data relative to the period 2009-19 were collected on a secured trust database. FINDINGS: Dedicated time was created for senior and junior doctors, a nurse, and a pharmacy to create clinical appointments for older people living with HIV referred by all service care providers. The team would review different clinical scenarios, book follow-up appointments to review results, refer to different specialists or to complex multidisciplinary teams when necessary. 744 people with HIV aged 50 years and older attended our services (93% [691] male, 7·1% [53] female; mean age 56·5 years [SD 5·5]; 84·2% [622] White, 7·5% [56] Black, 0·9% [7] Asian, 7·5% [56] other race or ethnicity). The prevalence of multimorbidity was 69·3% and of polypharmacy was 46·6%. The most common comorbidities were vitamin D deficiency (428 of 690, 62%), dyslipidaemia (373, 50·1%), hypertension (157, 21·5%), depressive or anxious disorders (117, 15·8%), osteoporosis (91, 12·2%), obesity (98, 13·2%), chronic kidney disease (56, 7·5%), and diabetes (43, 5·7%). Patients with dyslipidaemia, osteoporosis, and metabolic disorders were referred to a live well pathway clinic focusing on targeted lifestyle interventions, including diet and physical exercise, under the supervision of a dietician and a physiotherapist. INTERPRETATION: We have described how our HIV over-50 clinic was organised and implemented, and we reported data showing high rates of comorbidities and polypharmacy, which led to the establishment of a specialised care pathway for all HIV care providers and to the implementation of further joint HIV and specialty clinics (cardiology, metabolic, menopause, nephrology, neurology, and geriatric). FUNDING: None.

Short Communication: Predictive Value of HIV-Related Versus Traditional Risk Factors for Coronary Atherosclerosis in People Aging with HIV.

Cardiovascular disease (CVD) is an important cause of morbidity in people living with HIV (PLWH). We compared the predictive value of HIV-related and traditional CVD risk factors to assess which factors best predict the presence of subclinical coronary atherosclerosis in PLWH. This is a cross-sectional study in PLWH over 50 years of age who performed computed tomography coronary artery calcium (CAC) scoring between 2009 and 2019 at Chelsea and Westminster Hospital. The following outcomes were analyzed: CAC = 0 (no calcification), CAC >0 (any calcification), CAC >100 (moderate calcification), and CAC >400 (severe calcification). Univariate and multivariate logistic regression analyses were performed to assess predictors of coronary calcification. A total of 744 patients were included (mean age 56 ± 5.7 years, 94.8% male, 84% white). A CAC >0 was found in 392 (52.7%), CAC >100 in 90 (12.1%), and CAC >400 in 42 (5.6%) subjects. CAC >100 was strongly associated with hypertension [odds ratio, OR: 2.91, (95% confidence interval: 1.93-4.36), p < .001], dyslipidemia [2.71 (1.81-4.06), p < .001], and diabetes [2.53 (1.29-4.96), p = .01]. Regarding HIV-specific factors, a significant association was found with exposure (>6 years) to protease inhibitors [1.67 (1.06-2.61), p = .05], whereas exposure to tenofovir (>8 years) was negatively associated with CAC >100 [0.54 (0.30-0.98), p = .05]. Despite the high prevalence of hypertension (45.4%) only 21.5% were on antihypertensives, whereas only 29.2% of eligible candidates were receiving lipid-lowering drugs for primary prevention of CVD. Traditional cardiometabolic risk factors remain the strongest predictors of coronary atherosclerosis in PLWH as in the general population. These results underscore the importance of optimizing treatment of hypertension and promoting primary prevention strategies that may be underused in PLWH.

Evaluation of a Clinic Dedicated to People Aging with HIV at Chelsea and Westminster Hospital: Results of a 10-Year Experience.

Successful management of HIV infection as a chronic condition has resulted in a demographic shift where the proportion of people living with HIV (PLWH) older than 50 years is steadily increasing. A dedicated clinic to PLWH older than 50 years was established at Chelsea and Westminster Hospital in January 2009 and then extended to HIV services across the directorate. We report the results of a service evaluation reviewing 10 years of activities of this clinic between January 2009 and 2019. We aimed to estimate the prevalence of major noninfectious comorbidities, polypharmacy (≥5 medications), and multimorbidity (≥2 non-HIV-related comorbidities) and describe algorithms devised for use in HIV outpatient clinics across the directorate. A cohort of 744 PLWH older than 50 years attending this service were analyzed (93% male; mean age of 56 ± 5.5 years; 84% white ethnicity); 97.7% were on antiretroviral treatment and 95.9% had undetectable HIV-RNA at the time of evaluation. The most common comorbidities diagnosed were dyslipidemia (50.1%), hypertension (21.5%), mental health disorders (depression and/or anxiety disorders, 15.7%), osteoporosis (12.2%), obesity (11.9%), chronic kidney disease (7.5%), and diabetes (5.8%). Low vitamin D levels were found in 62% of patients [43% with vitamin D deficiency (<40 mmol/liter) and 57% with vitamin D insufficiency (40-70 mmol/liter)]. The overall prevalence of polypharmacy and multimorbidity was 46.6% and 69.3%, respectively. This study showed significant rates of non-HIV-related comorbidities and polypharmacy in PLWH older than 50 years, leading on to the implementation of clinical care pathways and new joint HIV/specialty clinics (cardiology, nephrology, neurology, metabolic, menopause, and geriatric) to improve prevention, diagnosis, and management of major comorbidities in people aging with HIV.

Factors associated with overweight/obesity in a cohort of people living with HIV over 50 years of age.

Changes in body weight in people living with HIV vary by regimen components, timing of therapy introduction (naive, switch) and demographic factors. Our objective was to evaluate weight change and factors associated in an ageing cohort of treated subjects with HIV at Chelsea and Westminster Hospital. We found that the prevalence of obesity was similar to general population and was associated with a number of health conditions, which increase metabolic risk.

The benefits of tenofovir discontinuation with or without bisphosphonate therapy in osteoporotic people living with HIV.

OBJECTIVES: Treatment with bisphosphonates and discontinuation of tenofovir disoproxil fumarate (TDF) are recommended strategies for managing osteoporosis in people living with HIV (PLHIV). This study aimed to compare the effects on bone mineral density (BMD) of TDF discontinuation with and without bisphosphonate therapy in osteoporotic PLHIV. METHODS: The present study is a retrospective cohort analysis of dual-energy X-ray absorptiometry scan results of PLHIV attending Chelsea and Westminster Hospital HIV clinic between 2009 and 2020. Osteoporotic (T-score < -2.5) patients with ≥ 6 months' TDF exposure were included. Changes in BMD and T-scores at the lumbar spine (LS) and femoral neck (FN) were assessed. RESULTS: A total of 84 participants were included, of whom 43 discontinued TDF only (TS) and 41 switched from TDF and received bisphosphonates (TS+): 86.9% were male; 77.4% were white; median (interquartile range, IQR) age was 54.8 (51.0-58.5) years; and median (IQR) TDF exposure was 6.5 (3.5-10.4) years. At a median follow-up of 2 years after TDF-discontinuation, mean spine BMD increased significantly in both groups, but bisphosphonate recipients had greater improvements (4.83% vs. 7.79%; P < 0.019); LS T-scores improved significantly but changes were comparable between groups (TS, 0.5 vs. TS+, 0.6; P = 0.270). At the FN, no significant increases in BMD were observed (TS, 3.05% vs. TS+, 2.71%; P = 0.205); T-scores significantly improved in bisphosphonate recipients only (+0.2; P = 0.003). A greater proportion recovered from osteoporosis in the TS+ group (34.9% vs. 43.9%), although differences between groups were not significant (P = 0.503). CONCLUSIONS: Our real-world data indicate that although TDF discontinuation significantly improved bone health in osteoporotic PLHIV, combining bisphosphonates with TDF discontinuation resulted in greater improvements in BMD.

Histopathology and immunophenotyping of late onset cutaneous manifestations of COVID-19 in elderly patients: Three case reports.

BACKGROUND: Several cutaneous manifestations such as urticarial rash, erythematous patches and chilblain-like lesions have been described in young adults with coronavirus disease 2019 (COVID-19) and are present in up to 20% patients, but few reports exist describing histopathological and immunophenotypic characteristics of dermatological lesions in older patients. Our aim was to characterize skin lesions in elderly patients during late stages of COVID-19 from clinical, histological and immunophenotypic perspectives. CASE SUMMARY: Three patients, admitted for COVID-19, and who developed cutaneous manifestations underwent skin biopsies. Immunophenotypic analysis for CD20, CD3, CD4 and CD8 was performed on skin biopsies to assess immune cell infiltrates. CD1a was used as a marker of Langerhans cells, and CD31 as a marker of endothelial cells. In the three study patients, cutaneous manifestations were evident in the late-stage of COVID-19 (mean time from the first positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) swab to rash onset was 35 d). Skin biopsies showed a similar pattern of T lymphocyte infiltration in all patients. Indeed, a chronic dermatitis with perivascular lymphocytic infiltrate was observed with predominance of CD3+ T-cell (CD3+). CONCLUSION: Our study confirms previous reports. Histological and immunophenotypic patterns in our patients confirm results described in the two previous reported experiences. This pattern is similar to what is found in some lympho-proliferative disorders. Therefore, since these findings are non-specific, SARS-CoV-2 infection should be suspected.

Targeting Inflammation and Immunosenescence to Improve Vaccine Responses in the Elderly.

One of the most appreciated consequences of immunosenescence is an impaired response to vaccines with advanced age. While most studies report impaired antibody responses in older adults as a correlate of vaccine efficacy, it is now widely appreciated that this may fail to identify important changes occurring in the immune system with age that may affect vaccine efficacy. The impact of immunosenescence on vaccination goes beyond the defects on antibody responses as T cell-mediated responses are reshaped during aging and certainly affect vaccination. Likewise, age-related changes in the innate immune system may have important consequences on antigen presentation and priming of adaptive immune responses. Importantly, a low-level chronic inflammatory status known as inflammaging has been shown to inhibit immune responses to vaccination and pharmacological strategies aiming at blocking baseline inflammation can be potentially used to boost vaccine responses. Yet current strategies aiming at improving immunogenicity in the elderly have mainly focused on the use of adjuvants to promote local inflammation. More research is needed to understand the role of inflammation in vaccine responses and to reconcile these seemingly paradoxical observations. Alternative approaches to improve vaccine responses in the elderly include the use of higher vaccine doses or alternative routes of vaccination showing only limited benefits. This review will explore novel targets and potential new strategies for enhancing vaccine responses in older adults, including the use of anti-inflammatory drugs and immunomodulators.

Use of Coronary Artery Calcium Scoring to Improve Cardiovascular Risk Stratification and Guide Decisions to Start Statin Therapy in People Living With HIV.

BACKGROUND: Cardiovascular disease (CVD) risk assessment remains a critical step in guiding decisions to initiate primary prevention interventions in people living with HIV (PLWH). SETTING: We investigated whether coronary artery calcium (CAC) scoring allowed a more accurate selection of patients who may benefit from statin therapy, compared with current risk assessment tools alone. METHODS: Cross-sectional analysis of PLWH over 50 years old who underwent CAC scoring between 2009 and 2019. Framingham Risk score (FRS), QRISK2 and D:A:D scores were calculated for each participant at the time of CAC scoring and statin eligibility determined based on current European guidelines on the prevention of CVD in PLWH. RESULTS: A total of 739 patients were included (mean age 56 ± 5, 92.8% male, 84% white). Among 417 (56.4%) candidates for statin therapy based on FRS ≥10%, 174 (23.5%) had no detectable calcification (CAC = 0). Conversely, 145 (19.6%) patients with detectable calcification (CAC > 0) were identified as low-risk (FRS < 10%). When compared with FRS, CAC scoring reclassified CVD risk in 43.1% of patients, 145 (19.6%) to a higher risk group that could benefit from statin therapy and 174 (23.5%) statin candidates to a lower risk group. QRISK2 and D:A:D scores performed similarly to FRS, underestimating the presence of significant coronary calcification in 21.1% and 24.9% respectively and overestimating risk in 16.9% and 18.8% patients with CAC = 0. CONCLUSIONS: Establishing a decision-model based on the combination of conventional risk tools and CAC scoring improves risk assessment and the selection of PLWH who would benefit from statin therapy.

Sestrins induce natural killer function in senescent-like CD8+ T cells.

Aging is associated with remodeling of the immune system to enable the maintenance of life-long immunity. In the CD8+ T cell compartment, aging results in the expansion of highly differentiated cells that exhibit characteristics of cellular senescence. Here we found that CD27-CD28-CD8+ T cells lost the signaling activity of the T cell antigen receptor (TCR) and expressed a protein complex containing the agonistic natural killer (NK) receptor NKG2D and the NK adaptor molecule DAP12, which promoted cytotoxicity against cells that expressed NKG2D ligands. Immunoprecipitation and imaging cytometry indicated that the NKG2D-DAP12 complex was associated with sestrin 2. The genetic inhibition of sestrin 2 resulted in decreased expression of NKG2D and DAP12 and restored TCR signaling in senescent-like CD27-CD28-CD8+ T cells. Therefore, during aging, sestrins induce the reprogramming of non-proliferative senescent-like CD27-CD28-CD8+ T cells to acquire a broad-spectrum, innate-like killing activity.

Polypharmacy and evaluation of anticholinergic risk in a cohort of elderly people living with HIV.

: As a consequence of ageing, the number of prescribed medications for people living with HIV is increasing. Concomitant use of different drugs and their potential interactions may increase anticholinergic exposure and escalate the risk for side effects. We conducted an analysis in our cohort of people living with HIV over 50 years of age to evaluate the overall anticholinergic risk, as it is useful to identify, prevent, and manage increased side effect risks.

Senescent cells evade immune clearance via HLA-E-mediated NK and CD8+ T cell inhibition.

Senescent cells accumulate in human tissues during ageing and contribute to age-related pathologies. The mechanisms responsible for their accumulation are unclear. Here we show that senescent dermal fibroblasts express the non-classical MHC molecule HLA-E, which interacts with the inhibitory receptor NKG2A expressed by NK and highly differentiated CD8+ T cells to inhibit immune responses against senescent cells. HLA-E expression is induced by senescence-associated secretary phenotype-related pro-inflammatory cytokines, and is regulated by p38 MAP kinase signalling in vitro. Consistently, HLA-E expression is increased on senescent cells in human skin sections from old individuals, when compared with those from young, and in human melanocytic nevi relative to normal skin. Lastly, blocking the interaction between HLA-E and NKG2A boosts immune responses against senescent cells in vitro. We thus propose that increased HLA-E expression contributes to persistence of senescent cells in tissues, thereby suggesting a new strategy for eliminating senescent cells during ageing.

Convergence of Innate and Adaptive Immunity during Human Aging.

Aging is associated with profound changes in the human immune system, a phenomenon referred to as immunosenescence. This complex immune remodeling affects the adaptive immune system and the CD8+ T cell compartment in particular, leading to the accumulation of terminally differentiated T cells, which can rapidly exert their effector functions at the expenses of a limited proliferative potential. In this review, we will discuss evidence suggesting that senescent αßCD8+ T cells acquire the hallmarks of innate-like T cells and use recently acquired NK cell receptors as an alternative mechanism to mediate rapid effector functions. These cells concomitantly lose expression of co-stimulatory receptors and exhibit decreased T cell receptor signaling, suggesting a functional shift away from antigen-specific activation. The convergence of innate and adaptive features in senescent T cells challenges the classic division between innate and adaptive immune systems. Innate-like T cells are particularly important for stress and tumor surveillance, and we propose a new role for these cells in aging, where the acquisition of innate-like functions may represent a beneficial adaptation to an increased burden of malignancy with age, although it may also pose a higher risk of autoimmune disorders.

Rickettsia slovaca infection in humans, Portugal.

Fifteen years after the initial detection of Rickettsia slovaca in ticks in Portugal, 3 autochthonous cases of R. slovaca infection were diagnosed in humans. All patients had an eschar on the scalp and lymphadenopathy; 2 patients had facial edema. R. slovaca infection was confirmed by serologic testing, culture, and PCR.

Sowing the seeds of cancer: telomeres and age-associated tumorigenesis.

PURPOSE OF REVIEW: Advances in the health system and medical sciences are continuously pushing the barrier of life-expectancy. As a consequence, humans are being increasingly afflicted by age-associated diseases, such as cancer. The challenge now lies in understanding the mechanisms underlying ageing in order to reduce the lifetime risk for cancer. RECENT FINDINGS: In long-lived mammals, telomere length and restriction of telomerase activity are important barriers preventing the uncontrolled cell division. Absence of telomerase dictates the continuous telomere erosion with each cell division, thus restraining the proliferation of incipient tumour cells. However, recent findings have revealed the unintended consequences of telomere control of cell division. Cells with short telomeres accumulate in older individuals increasing the risk of telomere depletion. Loss of telomere protection results in tetraploidization and genomic instability characteristic of epithelial cancers. Additionally, telomere shortening blocks cell proliferation and induces cell senescence. Senescent cells secrete proinflammatory factors and reactive oxygen species that increase the likelihood of cellular transformation and create the perfect soil for cancer development. SUMMARY: Telomere shortening thus provides an example of antagonist pleiotropy, in which a beneficial characteristic that acts during the reproductive years of an organism may, later in life, contain the seed to its demise.

Prevalence of etravirine resistance associated mutations in HIV-1 strains isolated from infected individuals failing efavirenz: comparison between subtype B and non-B genetic variants.

Etravirine (ETR) is a non-nucleoside analogue reverse transcriptase inhibitor (NNRTI) with a high genetic barrier to the development of resistance and with potential activity against Human immunodeficiency virus type 1 (HIV-1) strains resistant to first-generation NNRTIs. The objective of this study was to investigate the prevalence of ETR resistance associated mutations (RAMs) in HIV-1 strains isolated from infected individuals failing efavirenz (EFV), as well as to evaluate possible differences in the distribution of ETR RAMs between subtype B and non-B genetic variants. Nucleotide sequences of the protease and partial reverse transcriptase (RT) coding regions of the pol gene of 55 HIV-1 strains isolated from infected individuals failing EFV on regular follow-up at a reference center in Portugal, were retrospectively analyzed. The most prevalent ETR RAMs observed were L100I, V90I, and K101E, with a prevalence of 16.4% (n = 9), 9.1% (n = 5), and 5.5% (n = 3), respectively. Overall, 47.3% (n = 26) of the nucleotide sequences had at least one ETR RAM: 38.2% (n = 21) had one ETR RAM, 7.3% (n = 4) had two ETR RAMs and 1.8% (n = 1) had three ETR RAMs. No statistically significant differences were found in the distribution of ETR RAMs between subtype B and non-B genetic variants. The results demonstrate that ETR rescue therapy is a viable option in treatment-experienced individuals failing EFV and suggests that ETR may be equally useful in HIV-1 infections caused by different genetic variants.

Predictors of in-hospital mortality in elderly patients with bacteraemia admitted to an Internal Medicine ward.

BACKGROUND: Infectious diseases are a common cause of increased morbidity and mortality in elderly patients. Bacteraemia in the elderly is a difficult diagnosis and a therapeutic challenge due to age-related vicissitudes and to their comorbidities. The main purpose of the study was to assess independent risk factors for in-hospital mortality among the elderly with bacteraemia admitted to an Internal Medicine Ward. METHODS: Overall, a cohort of 135 patients, 65 years of age and older, with bacteraemia were retrospectively studied. Data related to demographic information, comorbidities, clinical parameters on admission, source and type of infection, microorganism isolated in the blood culture, laboratory data and empirical antibiotic treatment was recorded from each patient. Multivariate logistic regression was performed to identify independent predictors of all-cause in-hospital mortality. RESULTS: Of these 135 patients, 45.9% were women. The most common infections in this group of patients were urinary tract infections (46.7%). The main microorganisms isolated in the blood cultures were Escherichia coli (14.9%), Methicillin-resistant Staphylococcus aureus (MRSA) (12.0%), non-MRSA (11.4%), Klebsiella pneumoniae (9.1%) and Enterococcus faecalis (8.0%). The in-hospital mortality was 22.2%. Independent prognostic factors associated with in-hospital mortality were age ≥ 85 years, chronic renal disease, bacteraemia of unknown focus and cognitive impairment at admission (OR, 2.812 [95% CI, 1.039-7.611; p = 0.042]; OR, 6.179 [95% CI, 1.840-20.748; p = 0.003]; OR, 8.673 [95% CI, 1.557-48.311; p = 0.014] and OR, 3.621 [95% CI, 1.226-10.695; p = 0.020], respectively). By multivariate analysis appropriate antibiotic therapy was not associated with lower odds of mortality. CONCLUSION: Bacteraemia in the elderly has a high mortality rate. There are no set of signs or clinical features that can predict bacteraemia in the elderly. However, older age (≥ 85 years), chronic renal disease, bacteraemia of unknown focus and severe cognitive impairment adversely affects the outcome of elderly patients with bacteraemia admitted to an Internal Medicine ward.