Changes in Cerebrospinal Fluid Proteins across the Spectrum of Untreated and Treated Chronic HIV-1 Infection.

Using the Olink Explore 1536 platform, we measured 1,463 unique proteins in 303 cerebrospinal fluid (CSF) specimens from four clinical centers that included uninfected controls and 12 groups of people living with HIV-1 infection representing the spectrum of progressive untreated and treated chronic infection. We present three initial analyses of these measurements: an overview of the CSF protein features of the sample; correlations of the CSF proteins with CSF HIV-1 RNA and neurofilament light chain protein (NfL) concentrations; and comparison of the CSF proteins in HIV-associated dementia ( HAD ) and neurosymptomatic CSF escape ( NSE ). These reveal a complex but coherent picture of CSF protein changes that includes highest concentrations of many proteins during CNS injury in the HAD and NSE groups and variable protein changes across the course of neuroasymptomatic systemic HIV-1 progression, including two common patterns, designated as lymphoid and myeloid patterns, related to the principal involvement of their underlying inflammatory cell lineages. Antiretroviral therapy reduced CSF protein perturbations, though not always to control levels. The dataset of these CSF protein measurements, along with background clinical information, is posted online. Extended studies of this unique dataset will provide more detailed characterization of the dynamic impact of HIV-1 infection on the CSF proteome across the spectrum of HIV-1 infection, and further the mechanistic understanding of HIV-1-related CNS pathobiology.

IgG and kappa free light chain CSF/serum indices: evaluating intrathecal immunoglobulin production in HIV infection in comparison with multiple sclerosis.

OBJECTIVES: To study intrathecal kappa free light chain (KFLC) synthesis in people living with HIV (PLWH) in comparison with multiple sclerosis (MS). METHODS: Cross-sectional analysis including 56 untreated and 150 well treated PLWH, and compared with 58 controls, and 223 MS patients. RESULTS: Elevated serum/cerebrospinal fluid (CSF) IgG and KFLC indices were observed in untreated PLWH. Seventy percent of untreated PLWH had KFLC index above 6.1, a threshold associated with clinically isolated syndrome/MS diagnosis. No association was found between KFCL index and CSF markers of neuronal injury in either PLWH or MS patients. CONCLUSIONS: HIV-related immune system dysfunction is often associated with an elevated KFLC index akin to those observed in MS. HIV infection should be considered as a differential diagnosis for patients presenting with neurological symptoms and increased intrathecal immunoglobulin synthesis.

Difficult-to-treat HIV in Sweden: a cross-sectional study.

BACKGROUND: Our aim was to examine the prevalence and characteristics of difficult-to-treat HIV in the current Swedish HIV cohort and to compare treatment outcomes between people with difficult and non-difficult-to-treat HIV. METHODS: In this cross-sectional analysis of the Swedish HIV cohort, we identified all people with HIV currently in active care in 2023 from the national register InfCareHIV. We defined five categories of difficult-to-treat HIV: 1) advanced resistance, 2) four-drug regimen, 3) salvage therapy, 4) virologic failure within the past 12 months, and 5) ≥ 2 regimen switches following virologic failure since 2008. People classified as having difficult-to-treat HIV were compared with non-difficult for background characteristics as well as treatment outcomes (viral suppression and self-reported physical and psychological health). RESULTS: Nine percent of the Swedish HIV cohort in 2023 (n = 8531) met at least one criterion for difficult-to-treat HIV. Most of them had ≥ 2 regimen switches (6%), and the other categories of difficult-to-treat HIV were rare (1-2% of the entire cohort). Compared with non-difficult, people with difficult-to-treat HIV were older, had an earlier first year of positive HIV test and lower CD4 counts, and were more often female. The viral suppression rate among people with difficult-to-treat HIV was 84% compared with 95% for non-difficult (p = 0.001). People with difficult-to-treat HIV reported worse physical (but not psychological) health, and this remained statistically significant after adjustment for age, sex, and transmission group. CONCLUSIONS: Although 9% of the HIV cohort in Sweden in 2023 were classified as having difficult-to-treat HIV, a large proportion of these were virally suppressed, and challenges such as advanced resistance and need for salvage therapy are rare in the current Swedish cohort.

COVID-19 Recovery: Consistent Absence of Cerebrospinal Fluid Biomarker Abnormalities in Patients With Neurocognitive Post-COVID Complications.

BACKGROUND: To investigate evidence of residual viral infection, intrathecal immune activation, central nervous system (CNS) injury, and humoral responses in cerebrospinal fluid (CSF) and plasma in patients recovering from coronavirus disease 2019 (COVID-19), with or without neurocognitive post-COVID condition (PCC). METHODS: Thirty-one participants (25 with neurocognitive PCC) underwent clinical examination, lumbar puncture, and venipuncture ≥3 months after COVID-19 symptom onset. Healthy volunteers were included. CSF and plasma severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid and spike antigen (N-Ag, S-Ag), and CSF biomarkers of immune activation and neuronal injury were analyzed. RESULTS: SARS-CoV-2 N-Ag or S-Ag were undetectable in all samples and no participant had pleocytosis. We detected no significant differences in CSF and plasma cytokine concentrations, albumin ratio, IgG index, neopterin, ß2M, or in CSF biomarkers of neuronal injury and astrocytic damage. Furthermore, principal component analysis (PCA1) analysis did not indicate any significant differences between the study groups in the marker sets cytokines, neuronal markers, or anti-cytokine autoantibodies. CONCLUSIONS: We found no evidence of ongoing viral replication, immune activation, or CNS injury in plasma or CSF in patients with neurocognitive PCC compared with COVID-19 controls or healthy volunteers, suggesting that neurocognitive PCC is a consequence of events suffered during acute COVID-19 rather than persistent viral CNS infection or residual CNS inflammation.

Chronic Candida albicans meningitis following critical COVID-19 and serial measurements of (1,3)-ß-D-glucan in cerebrospinal fluid.

Co-infections with invasive candidiasis have been reported to be overrepresented in severe COVID-19. This report presents an unusual case of chronic Candida meningitis following intensive care for COVID-19.

Extracutaneous Kaposi sarcoma risk remains higher in people with HIV in the post-ART era.

OBJECTIVE: To assess Kaposi sarcoma (KS) by HIV-status in Sweden 1983-2017, with particular focus on extracutaneous KS. DESIGN: Population-based study linking the Total Population Registry, the Swedish HIV Registry InfCareHIV, and the Swedish Cancer Registry. METHODS: We included all Swedish residents, born in or outside Sweden between 1940 and 2000 ( n  = 8 587 829), assessing the annual incidence of KS, adjusted hazard ratios (adjHR), and odds ratios (adjOR) in the pre and postcombination antiretroviral therapy (ART) eras. RESULTS: KS was found in 324 individuals of whom 202 (62%) were people with HIV (PWH). While the incidence of KS decreased in PWH, it remained higher compared to HIV-negative at end of follow-up (28 vs. 0.09 per 100 000 person-years, P  < 0.001). In the post-ART era, PWH still had an increased risk of both cutaneous [adjHR 616, 95% confidence interval (CI) 410-926] and extracutaneous KS (adjHR 2068, 95% CI 757-5654), compared to HIV-negative individuals, although there were no cases of extracutaneous disease among virally suppressed PWH. In the post-ART era, the relative risk for KS remained higher in men, particularly men who have sex with men, and viral suppression was associated with lower odds of KS (adjOR 0.05, 95% CI 0.03-0.09). CONCLUSIONS: KS remained increased in PWH in the post-ART era, with a particularly high risk for extracutaneous disease compared to HIV-negative individuals. Notably, there were no cases of extracutaneous disease among virally suppressed PWH, suggesting a less aggressive disease in this population. Further studies on KS in virally suppressed PWH are warranted.

Residual Central Nervous System Immune Activation Is Not Prevented by Antiretroviral Therapy Initiated During Early Chronic HIV Infection.

Background: Antiretroviral therapy (ART) initiated during acute infection can potentially impact the central nervous system (CNS) reservoir, but the differential long-term effects of ART initiation during early or late chronic infection are unknown. Methods: We included neuroasymptomatic people with human immunodeficiency virus (HIV) with suppressive ART initiated during chronic (>1 year since transmission) HIV with archived cerebrospinal fluid (CSF) and serum samples after 1 and/or ≥3 years of ART from a cohort study. CSF and serum neopterin was measured using a commercial immunoassay (BRAHMS, Germany). Results: In total, 185 people with HIV (median, 79 [interquartile range, 55-128] months on ART) were included. A significant inverse correlation was found between CD4+ T-cell count and CSF neopterin only at baseline (r = -0.28, P = .002), but not after 1 (r = -0.026, P = .8) or ≥3 (r -0.063, P = .5) years of ART. No significant differences were seen in CSF or serum neopterin concentrations between different pretreatment CD4+ T-cell strata after 1 or ≥3 (median, 6.6) years of ART. Conclusions: In people with HIV initiating ART during chronic infection, occurrence of residual CNS immune activation was not correlated with pretreatment immune status, even when treatment was initiated at high CD4+ T-cell counts, suggesting that the CNS reservoir, once established, is not differentially affected by the timing of ART initiation during chronic infection.

Impact of pre-antiretroviral treatment HIV-RNA on time to successful virological suppression and subsequent virological failure - two nationwide, population-based cohort studies.

BACKGROUND: The impact of pre-antiretroviral treatment (ART) HIV-RNA on time to successful virological suppression and subsequent failure in HIV patients remains poorly investigated. METHODS: We used the Swedish InfCareHIV database and the Danish HIV Cohort Study to evaluate impact of pre-ART HIV-RNA on primary virological suppression (HIV-RNA < 50 copies/ml) and risk of secondary virological failure (two consecutive HIV-RNA > 200 copies/ml or one >1000 copies/ml). The study included 3366 Swedish and 2050 Danish ART naïve individuals who initiated ART in the period 2000-2018. We used Kaplan-Meier estimates and Cox regression analyses to estimate absolute risks and hazard ratios. RESULTS: In both cohorts, more than 95% of patients with a pre-ART HIV-RNA <100 000 copies/ml obtained virological suppression within the first year after ART initiation contrasting 74% (Sweden) and 86% (Denmark) in those with HIV-RNA >1 000 000 copies/ml. Almost all patients obtained virological suppression after four years irrespective of pre-ART HIV-RNA. In contrast, we observed no substantial impact of pre-ART HIV-RNA on risk of virological failure once virological suppression was obtained. CONCLUSION: High pre-ART HIV-RNA is strongly associated with increased time to successful virological suppression, but pre-ART HIV-RNA has no impact on risk of subsequent virological failure.

The effect of vitamin B supplementation on neuronal injury in people living with HIV: a randomized controlled trial.

Effective antiretroviral therapy has radically changed the course of the HIV pandemic. However, despite efficient therapy, milder forms of neurocognitive symptoms are still present in people living with HIV. Plasma homocysteine is a marker of vitamin B deficiency and has been associated with cognitive impairment. People living with HIV have higher homocysteine concentrations than HIV-negative controls, and we have previously found an association between plasma homocysteine concentration and CSF concentration of neurofilament light protein, a sensitive marker for ongoing neuronal injury in HIV. This prompted us to perform this randomized controlled trial, to evaluate the effect of vitamin B supplementation on neuronal injury in a cohort of people living with HIV on stable antiretroviral therapy. At the Department of Infectious Diseases at Sahlgrenska University Hospital in Gothenburg, Sweden, 124 virally suppressed people living with HIV were screened to determine eligibility for this study. Sixty-one fulfilled the inclusion criteria by having plasma homocysteine levels at or above 12 µmol/l. They were randomized (1:1) to either active treatment (with cyanocobalamin 0.5 mg, folic acid 0.8 mg and pyridoxine 3.0 mg) q.d. or to a control arm with a cross over to active treatment after 12 months. Cognitive function was measured repeatedly during the trial, which ran for 24 months. We found a significant correlation between plasma neurofilament light protein and plasma homocysteine at screening (n = 124, r = 0.35, P < 0.0001). Plasma homocysteine levels decreased by 35% from a geometric mean of 15.7 µmol/l (95% confidence interval 14.7-16.7) to 10.3 µmol/l (95% confidence interval 9.3-11.3) in the active treatment arm between baseline and Month 12. No significant change was detected in the control arm during the same time period [geometric mean 15.2 (95% confidence interval 14.3-16.2) versus geometric mean 16.5 µmol/l (95% confidence interval 14.7-18.6)]. A significant difference in change in plasma homocysteine levels was seen between arms at 12 months [-40% (95% confidence interval -48 to -30%), P < 0.001]. However, no difference between arms was seen in either plasma neurofilament light protein levels [-6.5% (-20 to 9%), P = 0.39], or cognitive measures [-0.08 (-0.33 to 0.17), P = 0.53]. Our results do not support a vitamin B-dependent cause of the correlation between neurofilament light protein and homocysteine. Additional studies are needed to further elucidate this matter.

No effect of remdesivir or betamethasone on upper respiratory tract SARS-CoV-2 RNA kinetics in hospitalised COVID-19 patients: a retrospective observational study.

BACKGROUND: The viral kinetics of SARS-CoV-2 has been considered clinically important. While remdesivir and corticosteroids are recommended for COVID-19 patients requiring oxygen support, there is a limited number of published reports on viral kinetics in hospitalised patients with COVID-19 treated with remdesivir or corticosteroids. METHODS: We conducted a retrospective study by collecting longitudinal samples from the nasopharynx/throat of 123 hospitalised patients (median age 55 years, 74% male) with COVID-19, to evaluate the effects of remdesivir and corticosteroid treatment on viral RNA levels. The subjects were divided into four groups: those receiving remdesivir (n = 25), betamethasone (n = 41), both (n = 15), or neither (n = 42). Time to viral RNA clearance was analysed using Kaplan-Meier plots, categorical data were analysed using Fisher's exact test, and Kruskal-Wallis for continuous data. Viral RNA decline rate was analysed using a mixed effect model. RESULTS: We found no significant difference in SARS-CoV-2 RNA decline rate or time to SARS-CoV-2 RNA clearance between the groups. Moreover, clinical status at baseline was not correlated with time to viral clearance. CONCLUSIONS: Since SARS-CoV-2 RNA kinetics was not affected by treatment, repeated sampling from the upper respiratory tract cannot be used to evaluate treatment response.

Viral Antigen and Inflammatory Biomarkers in Cerebrospinal Fluid in Patients With COVID-19 Infection and Neurologic Symptoms Compared With Control Participants Without Infection or Neurologic Symptoms.

Importance: Neurologic symptoms are common in COVID-19, but the central nervous system (CNS) pathogenesis is unclear, and viral RNA is rarely detected in cerebrospinal fluid (CSF). Objective: To measure viral antigen and inflammatory biomarkers in CSF in relation to neurologic symptoms and disease severity. Design, Setting, and Participants: This cross-sectional study was performed from March 1, 2020, to June 30, 2021, in patients 18 years or older who were admitted to Sahlgrenska University Hospital, Gothenburg, Sweden, with COVID-19. All patients had CSF samples taken because of neurologic symptoms or within a study protocol. Healthy volunteer and prepandemic control groups were included. Exposure: SARS-CoV-2 infection. Main Outcomes and Measures: Outcomes included CSF SARS-CoV-2 nucleocapsid antigen (N-Ag) using an ultrasensitive antigen capture immunoassay platform and CSF biomarkers of immune activation (neopterin, ß2-microglobulin, and cytokines) and neuronal injury (neurofilament light protein [NfL]). Results: Forty-four patients (median [IQR] age, 57 [48-69] years; 30 [68%] male; 26 with moderate COVID-19 and 18 with severe COVID-19 based on the World Health Organization Clinical Progression Scale), 10 healthy controls (median [IQR] age, 58 [54-60] years; 5 [50%] male), and 41 patient controls (COVID negative without evidence of CNS infection) (median [IQR] age, 59 [49-70] years; 19 [46%] male) were included in the study. Twenty-one patients were neuroasymptomatic and 23 were neurosymptomatic (21 with encephalopathy). In 31 of 35 patients for whom data were available (89%), CSF N-Ag was detected; viral RNA test results were negative in all. Nucleocapsid antigen was significantly correlated with CSF neopterin (r = 0.38; P = .03) and interferon γ (r = 0.42; P = .01). No differences in CSF N-Ag concentrations were found between patient groups. Patients had markedly increased CSF neopterin, ß2-microglobulin, interleukin (IL) 2, IL-6, IL-10, and tumor necrosis factor α compared with controls. Neurosymptomatic patients had significantly higher median (IQR) CSF interferon γ (86 [47-172] vs 21 [17-81] fg/mL; P = .03) and had a significantly higher inflammatory biomarker profile using principal component analysis compared with neuroasymptomatic patients (0.54; 95% CI, 0.03-1.05; P = .04). Age-adjusted median (IQR) CSF NfL concentrations were higher in patients compared with controls (960 [673-1307] vs 618 [489-786] ng/L; P = .002). No differences were seen in any CSF biomarkers in moderate compared with severe disease. Conclusions and Relevance: In this study of Swedish adults with COVID-19 infection and neurologic symptoms, compared with control participants, viral antigen was detectable in CSF and correlated with CNS immune activation. Patients with COVID-19 had signs of neuroaxonal injury, and neurosymptomatic patients had a more marked inflammatory profile that could not be attributed to differences in COVID-19 severity. These results highlight the clinical relevance of neurologic symptoms and suggest that viral components can contribute to CNS immune responses without direct viral invasion.

Cardiac dysfunction and mortality in critically ill patients with COVID-19: A Swedish multicentre observational study.

BACKGROUND: The prevalence and importance of cardiac dysfunction in critically ill patients with COVID-19 in Sweden is not yet established. The aim of the study was to assess the prevalence of cardiac dysfunction and elevated pulmonary artery pressure (PAP), and its influence on mortality in patients with COVID-19 in intensive care in Sweden. METHODS: This was a multicentre observational study performed in five intensive care units (ICUs) in Sweden. Patients admitted to participating ICU with COVID-19 were examined with echocardiography within 72 h from admission and again after 4 to 7 days. Cardiac dysfunction was defined as left ventricular (LV) dysfunction (ejection fraction <50% and/or regional hypokinesia) or right ventricular (RV) dysfunction (defined as TAPSE <17 mm or visually assessed moderate/severe RV dysfunction). RESULTS: We included 132 patients, of whom 127 (96%) were intubated. Cardiac dysfunction was found in 42 (32%) patients. Most patients had cardiac dysfunction at the first assessment (n = 35) while a few developed cardiac dysfunction later (n = 7) and some changed type of dysfunction (n = 3). LV dysfunction was found in 21 and RV dysfunction in 19 patients, while 5 patients had combined dysfunction. Elevated PAP was found in 34 patients (26%) and was more common in patients with RV dysfunction. RV dysfunction and elevated PAP were independently associated with an increased risk of death (OR 3.98, p = .013 and OR 3.88, p = .007, respectively). CONCLUSIONS: Cardiac dysfunction occurs commonly in critically ill patients with COVID-19 in Sweden. RV dysfunction and elevated PAP are associated with an increased risk of death.

Failure to restore CD4+ cell count associated with infection-related and noninfection-related cancer.

OBJECTIVE: To assess incidence and relative risk of cancer in Sweden, by HIV status, from 1988 to 2017. DESIGN: Population-based register study. METHODS: From the Swedish Total Population Register, all people born between 1940 and 2000 (n = 8 587 629), and resident in Sweden sometime 1983-2017 were identified and linked to National HIV Register InfCareHIV, National Cancer Register, and LISA database. We present incidence and adjusted hazard ratios (adjHR) of infection and noninfection-related cancer for three periods between 1988 and 2017. RESULTS: Incidence and relative risk of infection-related cancer decreased but remained higher in people with HIV (PWH) than in HIV-negative. The proportion attributable to infection remained higher in PWH than in HIV-negative (44 vs. 9%). Women with HIV had lower risk of infection-related cancer than men with HIV [adjusted hazard ratio (adjHR) 0.6, 95% CI 0.4-0.9], mainly driven by lower incidence of Kaposi's sarcoma (adjHR 0.1, 95% CI 0.0-0.4). Current viral suppression (adjHR 0.3, 95% CI 0.2-0.5) was associated with lower risk of infection-related cancer. Current CD4+ cell count less than 200 cells/µl was associated with both infection-related (adjHR 15.3, 95% CI 10.7-21.8) and noninfection-related cancer (adjHR 2.5, 95% CI 1.5-4.1), as was CD4+ cell count increases less than 100 cells/µl post antiretroviral therapy (ART) (infection-related cancer adjHR 6.6, 95% CI 4.2-10.6, noninfection-related cancer adjHR 2.0, 95% CI 1.2-3.3). CONCLUSION: Current CD4+ cell count and failure to restore CD4+ cell count both associated with infection and noninfection-related cancer. Viral suppression associated with lower risk of infection-related cancer. Early HIV detection and early adherent ART remain essential for cancer prevention.

Effect of antiretroviral treatment on blood-brain barrier integrity in HIV-1 infection.

BACKGROUND: Blood-brain barrier (BBB) injury is prevalent in patients with HIV-associated dementia (HAD) and is a frequent feature of HIV encephalitis. Signs of BBB damage are also sometimes found in neuroasymptomatic HIV-infected individuals without antiretroviral therapy (ART). The aim of this study was to investigate the integrity of the BBB before and after initiation of ART in both neuroasymptomatic HIV infection and in patients with HAD. METHODS: We determined BBB integrity by measuring cerebrospinal fluid (CSF)/plasma albumin ratios in archived CSF samples prior to and after initiation of ART in longitudinally-followed neuroasymptomatic HIV-1-infected individuals and patients with HAD. We also analyzed HIV RNA in blood and CSF, IgG Index, CSF WBC counts, and CSF concentrations of ß2-micoglobulin, neopterin, and neurofilament light chain protein (NfL). RESULTS: We included 159 HIV-infected participants; 82 neuroasymptomatic individuals and 77 with HAD. All neuroasymptomatic individuals (82/82), and 10/77 individuals with HAD, were longitudinally followed with a median (interquartile range, IQR) follow-up of 758 (230-1752) days for the neuroasymptomatic individuals, and a median (IQR) follow-up of 241 (50-994) days for the individuals with HAD. Twelve percent (10/82) of the neuroasymptomatic individuals and 80% (8/10) of the longitudinally-followed individuals with HAD had elevated albumin ratios at baseline. At the last follow-up, 9% (7/82) of the neuroasymptomatic individuals and 20% (2/10) of the individuals with HAD had elevated albumin ratios. ART significantly decreased albumin ratios in both neuroasymptomatic individuals and in patients with HAD. CONCLUSION: These findings indicate that ART improves and possibly normalizes BBB integrity in both neuroasymptomatic HIV-infected individuals and in patients with HAD.

Longitudinal Follow Up of Immune Responses to SARS-CoV-2 in Health Care Workers in Sweden With Several Different Commercial IgG-Assays, Measurement of Neutralizing Antibodies and CD4+ T-Cell Responses.

Background: The risk of SARS-CoV-2 infection among health care workers (HCWs) is a concern, but studies that conclusively determine whether HCWs are over-represented remain limited. Furthermore, methods used to confirm past infection vary and the immunological response after mild COVID-19 is still not well defined. Method: 314 HCWs were recruited from a Swedish Infectious Diseases clinic caring for COVID-19 patients. IgG antibodies were measured using two commercial assays (Abbot Architect nucleocapsid (N)-assay and YHLO iFlash-1800 N and spike (S)-assays) at five time-points, from March 2020 to January 2021, covering two pandemic waves. Seroprevalence was assessed in matched blood donors at three time-points. More extensive analyses were performed in 190 HCWs in September/October 2020, including two additional IgG-assays (DiaSorin LiaisonXL S1/S2 and Abbot Architect receptor-binding domain (RBD)-assays), neutralizing antibodies (NAbs), and CD4+ T-cell reactivity using an in-house developed in vitro whole-blood assay based on flow cytometric detection of activated cells after stimulation with Spike S1-subunit or Spike, Membrane and Nucleocapsid (SMN) overlapping peptide pools. Findings: Seroprevalence was higher among HCWs compared to sex and age-matched blood donors at all time-points. Seropositivity increased from 6.4% to 16.3% among HCWs between May 2020 and January 2021, compared to 3.6% to 11.9% among blood donors. We found significant correlations and high levels of agreement between NAbs and all four commercial IgG-assays. At 200-300 days post PCR-verified infection, there was a wide variation in sensitivity between the commercial IgG-assays, ranging from <30% in the N-assay to >90% in the RBD-assay. There was only moderate agreement between NAbs and CD4+ T-cell reactivity to S1 or SMN. Pre-existing CD4+ T-cell reactivity was present in similar proportions among HCW who subsequently became infected and those that did not. Conclusions: HCWs in COVID-19 patient care in Sweden have been infected with SARS-CoV-2 at a higher rate compared to blood donors. We demonstrate substantial variation between different IgG-assays and propose that multiple serological targets should be used to verify past infection. Our data suggest that CD4+ T-cell reactivity is not a suitable measure of past infection and does not reliably indicate protection from infection in naive individuals.

Correction: Serum-IgG responses to SARS-CoV-2 after mild and severe COVID-19 infection and analysis of IgG non-responders.

[This corrects the article DOI: 10.1371/journal.pone.0241104.].

No difference in biomarkers of ischemic heart injury and heart failure in patients with COVID-19 who received treatment with chloroquine phosphate and those who did not.

BACKGROUND: Chloroquine was promoted as a COVID-19 therapeutic early in the pandemic. Most countries have since discontinued the use of chloroquine due to lack of evidence of any benefit and the risk of severe adverse events. The primary aim of this study was to examine if administering chloroquine during COVID-19 imposed an increased risk of ischemic heart injury or heart failure. METHODS: Medical records, laboratory findings, and electrocardiograms of patients with COVID-19 who were treated with 500 mg chloroquine phosphate daily and controls not treated with chloroquine were reviewed retrospectively. Controls were matched in age and severity of disease. RESULTS: We included 20 patients receiving chloroquine (500 mg twice daily) for an average of five days, and 40 controls. The groups were comparable regarding demographics and biochemical analyses including C-reactive protein, thrombocytes, and creatinine. There were no statistically significant differences in cardiac biomarkers or in electrocardiograms. Median troponin T was 10,8 ng/L in the study group and 17.9 ng/L in the control group, whereas median NT-proBNP was 399 ng/L in patients receiving chloroquine and 349 ng/L in the controls. CONCLUSIONS: We found no increased risk of ischemic heart injury or heart failure as a result of administering chloroquine. However, the use of chloroquine to treat COVID-19 outside of clinical trials is not recommended, considering the lack of evidence of its effectiveness, as well as the elevated risk of fatal arrythmias.

Increased immune activation and signs of neuronal injury in HIV-negative people on preexposure prophylaxis.

OBJECTIVE: Persistent immune activation in the central nervous system and systemically are common in people living with HIV (PLHIV) despite antiretroviral therapy. It is not known whether this is generated by HIV replication or by other components such as coinfections and lifestyle-related factors. DESIGN: The aim of this study was to determine the importance of different factors; it is crucial to find well matched HIV-negative controls. In this context, HIV-negative persons on preexposure prophylaxis (PrEP) may constitute a suitable control group to PLHIV with similar lifestyle-related factors. METHODS: Cerebrospinal fluid (CSF) and blood were collected from 40 HIV-negative persons on PrEP and 20 controls without PrEP. Biomarkers of immune activation, blood--brain barrier (BBB) integrity and neuronal injury were analysed. RESULTS: CSF and serum ß2-microglobulin, serum neopterin and CSF neurofilament light protein were higher in persons on PrEP compared with controls. Furthermore, persons on PrEP had higher CSF/plasma albumin ratio, and matrix metalloproteinase-3 concentrations, indicating BBB dysfunction. Of persons on PrEP, 90% were cytomegalovirus (CMV)-positive compared to 65% of the controls. CMV-positive individuals as a group had higher levels of serum ß2-microglobulin than CMV-negative individuals (P < 0.05). Drug users had higher serum ß2-microglobulin compared to nonusers (P < 0.01). CONCLUSION: HIV-negative persons on PrEP had higher levels of biomarkers for immune activation, BBB impairment and neuronal injury, compared with volunteers without PrEP. Moreover, serum ß2-microglobulin was higher in CMV-positive than in CMV-negative individuals and in drug users compared with nonusers. These findings are important to consider when analysing immune activation and CNS injury in PLHIV, and emphasize the importance of appropriate controls.

Proteomic blood profiling in mild, severe and critical COVID-19 patients.

The recent SARS-CoV-2 pandemic manifests itself as a mild respiratory tract infection in most individuals, leading to COVID-19 disease. However, in some infected individuals, this can progress to severe pneumonia and acute respiratory distress syndrome (ARDS), leading to multi-organ failure and death. This study explores the proteomic differences between mild, severe, and critical COVID-19 positive patients to further understand the disease progression, identify proteins associated with disease severity, and identify potential therapeutic targets. Blood protein profiling was performed on 59 COVID-19 mild (n = 26), severe (n = 9) or critical (n = 24) cases and 28 controls using the OLINK inflammation, autoimmune, cardiovascular and neurology panels. Differential expression analysis was performed within and between disease groups to generate nine different analyses. From the 368 proteins measured per individual, more than 75% were observed to be significantly perturbed in COVID-19 cases. Six proteins (IL6, CKAP4, Gal-9, IL-1ra, LILRB4 and PD-L1) were identified to be associated with disease severity. The results have been made readily available through an interactive web-based application for instant data exploration and visualization, and can be accessed at https://phidatalab-shiny.rosalind.kcl.ac.uk/COVID19/ . Our results demonstrate that dynamic changes in blood proteins associated with disease severity can potentially be used as early biomarkers to monitor disease severity in COVID-19 and serve as potential therapeutic targets.