Proteomic and genetic analyses of influenza A viruses identify pan-viral host targets

Influenza A Virus (IAV) is a recurring respiratory virus with limited availability of antiviral therapies. Understanding host proteins essential for IAV infection can identify targets for alternative host-directed therapies (HDTs). Using affinity purification-mass spectrometry and global phosphoproteomic and protein abundance analyses using three IAV strains (pH1N1, H3N2, H5N1) in three human cell types (A549, NHBE, THP-1), we map 332 IAV-human protein-protein interactions and identify 13 IAV-modulated kinases. Whole exome sequencing of patients who experienced severe influenza reveals several genes, including scaffold protein AHNAK, with predicted loss-of-function variants that are also identified in our proteomic analyses. Of our identified host factors, 54 significantly alter IAV infection upon siRNA knockdown, and two factors, AHNAK and coatomer subunit COPB1, are also essential for productive infection by SARS-CoV-2. Finally, 16 compounds targeting our identified host factors suppress IAV replication, with two targeting CDK2 and FLT3 showing pan-antiviral activity across influenza and coronavirus families. This study provides a comprehensive network model of IAV infection in human cells, identifying functional host targets for pan-viral HDT.

AIDE: Adaptive intrapatient dose escalation designs to accelerate Phase I clinical trials

Designing Phase I clinical trials is challenging when accrual is slow or sample size is limited. The corresponding key question is: how to efficiently and reliably identify the maximum tolerated dose (MTD) using a sample size as small as possible? We propose model-assisted and model-based designs with adaptive intrapatient dose escalation (AIDE) to address this challenge. AIDE is adaptive in that the decision of conducting intrapatient dose escalation depends on both the patient's individual safety data, as well as other enrolled patient's safety data. When both data indicate reasonable safety, a patient may perform intrapatient dose escalation, generating toxicity data at more than one dose. This strategy not only provides patients the opportunity to receive higher potentially more effective doses, but also enables efficient statistical learning of the dose-toxicity profile of the treatment, which dramatically reduces the required sample size. Simulation studies show that the proposed designs are safe, robust, and efficient to identify the MTD with a sample size that is substantially smaller than conventional interpatient dose escalation designs. Practical considerations are provided and R code for implementing AIDE is available upon request.

A first-in-human study of mirzotamab clezutoclax as monotherapy and in combination with taxane therapy in relapsed/refractory solid tumors: Dose escalation results

3015

Background: Mirzotamab clezutoclax (ABBV-155) is a first-in-class antibody drug conjugate comprised of a BCL-XL (B-cell lymphoma - extra long) inhibitor, solubilizing linker, and a monoclonal anti-B7H3 antibody. Methods: Patients (pts) with relapsed and/or refractory (R/R) solid tumors were administered mirzotamab clezutoclax with or without paclitaxel. Dose escalation of mirzotamab clezutoclax was guided by Bayesian continual reassessment. Primary outcomes were to determine the maximum tolerated dose (MTD) and the recommended phase 2 dose (RP2D). Secondary outcomes: safety, pharmacokinetics, and overall response rate per RECIST v1.1. Results: As of November 6, 2020, 31 pts received mirzotamab clezutoclax monotherapy (monoTx) and 28 pts received combination therapy with paclitaxel (comboTx). Overall demographics: median age 62 years (range 25–79); 61% female; 86% white; 24% ECOG 0, 76% ECOG 1; 51% had > 3 prior systemic therapies. The median duration of mirzotamab clezutoclax exposure was 3 cycles (range 1–14) for monoTx and 5 cycles (range 1–14) for comboTx. There were no dose limiting toxicities (DLT) reported with monoTx. In comboTx, 2 pts experienced a DLT: Grade 4 neutrophil count decreased and Grade 3 lymphocyte count decreased considered related to paclitaxel. 97% of all pts had adverse events (AEs). The most common AEs (in ≥20% of pts) overall were fatigue (39%), nausea (25%), diarrhea and arthralgia (22% each), vomiting and hypokalemia (20% each). AEs in ≥5 pts related to mirzotamab cleuzutoclax were fatigue (27%), diarrhea (12%), and nausea (9%). Related Grade 3/4 AEs overall (in > 1 patient) included anemia, lymphocyte count decreased, fatigue, and diarrhea (3% each). One patient on monoTx experienced a fatal cardiac arrest. No fatal AEs occurred on comboTx. Responses were observed with comboTx as shown in the Table. Conclusions: Mirzotamab clezutoclax as monotherapy and with paclitaxel demonstrates a tolerable safety profile (MTD not reached) with anti-tumor activity in R/R solid tumors. Further investigation in prospectively-selected B7H3 positive tumors as monoTx in pts with R/R small cell lung cancer and with paclitaxel in pts with R/R breast cancer and docetaxel in pts with R/R non-small cell lung cancer in the dose expansion phase is ongoing. Clinical trial information: NCT03595059. [Table: see text]

Effect of Statin Use on Inflammation and Immune Activation Biomarkers in HIV-Infected Persons on Effective Antiretroviral Therapy

Immune activation and inflammation are hallmarks of chronic HIV infection and are etiologically linked to major causes of morbidity and mortality among HIV-infected persons, including coronary artery disease and cancer. Systemic immune activation is dampened, but not resolved, with use of combination antiretroviral therapy (cART). Statins are cardioprotective drugs that also appear to have immunomodulatory and anti-inflammatory properties. We sought to understand the association between statin use, cART, and levels of circulating immune markers in a longitudinal cohort study. From 2004 to 2009, statin use was ascertained in male participants of the Multicenter AIDS Cohort Study (MACS) using interviewer-administered questionnaires. Twenty-four circulating markers of immune activation and inflammation were measured in archived serial samples from a subset of cohort members using multiplex assays. Propensity-adjusted generalized gamma models were used to compare biomarkers' distributions by statin use, and multivariable linear regression models were used to assess the effect of initiating statin on these biomarkers. Overall, 1,031 cART-exposed individuals with HIV infection were included in this study. Statin use was reported by 31.5% of cART-exposed participants. Compared to nonstatin users on cART, statin users on cART had lower levels of IP-10, IL-10, and IL-12p70, and the effect of statin use was decreased in participants using lipophilic statins (atorvastatin, simvastatin, fluvastatin, or lovastatin); these results were statistically significant (p < .05). Among cART users not on aspirin, starting statins decreased levels of high sensitivity c-reactive protein (hsCRP), IL-12p70, and IL-6. Statin therapy is associated with reduced levels of certain biomarkers of immune activation and inflammation in cART users, which may contribute to a lower burden of disease.

1164. Epidemiology of Cryptococcal Infections in Non-HIV Patients: A 20-year Single Center Experience

Background

Cryptococcus has a worldwide distribution, with C. neoformans and C. gattii being two of the most common species causing disease. Despite advances in therapy, disseminated infection often results in significant morbidity and mortality.

Methods

We conducted a single center retrospective cohort study over a twenty-year period spanning from January 2000 through May 2020 to determine epidemiology and outcomes of non-HIV-associated cryptococcosis at Northwestern Memorial Hospital. Cases were identified by positive culture data or positive cryptococcal antigen in the serum or cerebrospinal fluid (CSF). Epidemiology of risk factors, morbidity, and mortality was evaluated.

Results

81 cases were identified of which, 67 had Cryptococcus spp isolated from culture and the remaining patients diagnosed by cryptococcal antigen and/or histopathology. The cohort was primarily Caucasian (56.8%, n=46) and male gender (67.9%, n=55), with a median age of 59.5 (IQR: 52.75-66.25) years old. Common predisposing conditions were diabetes (37%, n=30), chronic kidney disease (34.6%, n=28), and liver disease (28.4%, n=23). Solid organ transplant recipients and use of immunosuppression accounted for, respectively, 32.1% (n=26) and 29.6% (n=24) of the cohort. Sites of infection include lung (65.4%. n=53), central nervous system (33.3%, n=27), blood (30.9%, n=25), peritoneum (6.2%, n=5), musculoskeletal (2.5%, n=2), and prostate (1.2%, n=1). Mean opening pressure on lumbar puncture was 25.3 mmHg (range: 9 -52 mmHg). In hospital mortality at time of diagnosis was 27.2% (n=22), and mortality at 12 months post diagnosis was 51.9% (n=42).

Conclusion

At our center, those with cryptococcosis commonly had risk factors such as immunosuppression either secondary to solid organ transplant or otherwise. Morbidity and mortality remain high.

Disclosures

Sudhir Penugonda, MD, MPH, AbbVie, Inc. (Employee, Other Financial or Material Support, ownership and/or investment interests) Michael Angarone, DO, Abbvie (Other Financial or Material Support, Data Safety Monitoring Board)Allergan (Speaker’s Bureau)

Pharmacodynamic effects in blood and tumor tissue of eftozanermin alfa, a tumor necrosis factor-related apoptosis-inducing ligand receptor agonist

e15668

Background: Eftozanermin alfa (eftoza; formerly known as ABBV-621), a 2nd-generation tumor necrosis factor-related apoptosis-inducing ligand receptor agonist, is being evaluated in previously treated solid and hematologic malignancies (NCT03082209). In a dose-expansion cohort, patients (pts) with KRAS-mutant colorectal cancer (n = 24) and pancreatic cancer (n = 24) were evaluated at 3 dose levels with 12 mandatory paired biopsies per tumor type (pretreatment [Tx] and on-Tx collection). Following eftoza dosing, RNA and protein expression including posttranslational modifications were assessed in tumor biopsies to understand the target engagement and downstream pathway activation. Plasma was evaluated for changes in somatic mutant allele frequency and M30, M65 (circulating apoptotic markers). Methods: Biopsies were collected anytime during the screening period (pre-Tx) and 24±4 h following 2nd or 3rd infusion (on-Tx). Of the requested 4–6 fresh biopsy cores, 1–2 cores were collected as formalin fixed paraffin embedded (FFPE) and the rest were frozen tissue. FFPE tissue was analyzed by multiplex immunohistochemistry (IHC) and RNAseq; reverse phase protein array was used for frozen cores. Plasma was collected at cycle 1 predose and 2, 8, 24, 48, and 168 h postdose and analyzed for M30, M65 (by ELISA) and circulating tumor DNA (64-gene PlasmaSELECT assay). Results: Twenty-five pts consented to biopsies; paired biopsies were obtained from 16 pts at a 64% success rate: FFPE (n = 15) and frozen cores (n = 12). Tumor cells were detected in 11/15 (73%) FFPE and 4/12 (33%) frozen cores. Increase in M30, activated caspases, and cleaved PARP levels was observed in on-Tx biopsy samples compared with pre-Tx, thus serving as evidence for apoptosis induction in tumors following eftoza dosing. Changes in the tumor microenvironment were observed post-Tx by RNAseq and multiplex IHC (eg, CD68 level). Downregulation of prosurvival signaling pathways (eg, AKT/MEK) was also observed following eftoza dosing. Thirteen out of 16 pts showed transient increase in mutant allele fractions post eftoza Tx that correlated with increased plasma circulating tumor markers M30 and M65 at similar time points, suggesting activation of apoptosis pathway. Increase in M30, M65 levels also preceded increase in liver enzymes (ALT/AST) at 2, 48 hr post-Tx. Conclusions: Pharmacodynamic effect of eftoza was successfully demonstrated in blood and tumor tissue, including induction of apoptosis and modulation of PI3K and MEK signaling pathways. Clinical trial information: NCT03082209.

Safety and efficacy of chronic suppressive azole therapy for endemic fungal infections in solid organ transplant recipients

BACKGROUND

Although the research is limited, treatment guidelines recommend lifelong suppressive azole therapy for disseminated endemic fungal infection (EFI) after solid organ transplantation (SOT). Suppressive azole therapy may prevent EFI recurrence at the risk of hepatotoxicity and drug interactions. We present real-world safety and effectiveness data of chronic suppressive azole therapy for EFI in SOT recipients over a 10-year period at a single comprehensive transplant center.

METHODS

A retrospective analysis was conducted of SOT recipients diagnosed with EFI from January 1, 2005, to May 1, 2015. Chronic suppressive azole therapy was defined as treatment for more than 12 months after diagnosis. Effectiveness of suppression was defined as preventing EFI reactivation. Safety endpoints included adverse reactions and drug interactions.

RESULTS

Over a 10-year period, 28 SOT recipients were diagnosed with EFI: 16 histoplasmosis, 9 blastomycosis, and 3 coccidioidomycosis. Eighteen (64%) patients were treated with chronic suppressive azole therapy for a median length of 36 months (range 15-90). One patient had an adverse drug interaction requiring azole discontinuation. There were no episodes of azole-related hepatotoxicity, toxicity from antirejection medication, or EFI reactivation.

CONCLUSIONS

Chronic suppressive azole therapy was safe and effective in preventing reactivation of EFI in SOT recipients.

Hepatitis B virus sequencing and liver fibrosis evaluation in HIV/HBV co-infected Nigerians

OBJECTIVES

Molecular characteristics of hepatitis B virus (HBV), such as genotype and genomic mutations, may contribute to liver-related morbidity and mortality. The association of these characteristics with liver fibrosis severity in sub-Saharan Africa is uncertain. We aimed to characterise molecular HBV features in human immunodeficiency virus (HIV)/HBV co-infected Nigerians and evaluate associations between these characteristics and liver fibrosis severity before and after antiretroviral therapy (ART) initiation.

METHODS

HIV/HBV co-infected Nigerians underwent liver fibrosis estimation by transient elastography (TE) prior to and 36 months after ART initiation. Basal core promoter/precore (BCP/PC) and preS1/preS2/S regions of HBV were sequenced from baseline plasma samples. We evaluated associations between HBV mutations and liver fibrosis severity by univariate and multivariable regression.

RESULTS

At baseline, 94 patients underwent TE with median liver stiffness of 6.4 (IQR 4.7-8.7) kPa. Patients were predominantly infected with HBV genotype E (45/46) and HBe-antigen negative (75/94, 79.8%). We identified BCP A1762T/G1764A in 15/35 (43%), PC G1896A in 20/35 (57%), 'a' determinant mutations in 12/45 (26.7%) and preS2 deletions in 6/16 (37.5%). PreS2 mutations were associated with advanced fibrosis in multivariable analysis. At follow-up, median liver stiffness was 5.2 (IQR 4.1-6.6) kPa. No HBV molecular characteristics were associated with lack of fibrosis regression, although HIV virologic control, body mass index (BMI) and baseline CD4+ T-cell count were associated with a decline in fibrosis stage.

CONCLUSION

Frequent BCP/PC and preS1/preS2/S mutations were found in ART-naïve HIV/HBV co-infected Nigerians. Median liver stiffness declined after initiation of ART, regardless of pre-ART HBV mutational pattern or virologic characteristics.

Optimal strategies for the diagnosis of community-onset diarrhea in solid organ transplant recipients: Less is more

BACKGROUND

Diarrhea, a common complication after solid organ transplant (SOT), is associated with allograft failure and death. No evidence-based guidelines exist for the evaluation of diarrhea in SOT recipients. We performed a cost analysis to derive a testing algorithm for the diagnosis of community-onset diarrhea that minimizes costs without compromising diagnostic yields.

DESIGN

A cost analysis was performed on a retrospective cohort of 422 SOT admissions for community-onset diarrhea over an 18-month period. A stepwise testing model was applied on a population level to assess test costs relative to diagnostic yields.

RESULTS

Over an 18-month period, 1564 diagnostic tests were performed and 127 (8.1%) returned positive. Diagnostic testing accounted for $95 625 of hospital costs. The tests with the lowest cost per decrease in the false-omission rate (FOR) were stool Clostridium difficile polymerase chain reaction (PCR) ($156), serum cytomegalovirus quantitative PCR ($1529), stool norovirus (NV) PCR ($4673), and stool culture ($6804). A time-to-event analysis found no significant difference in the length of hospital stay between patients with and without NV testing (P=.520).

CONCLUSIONS

A stepwise testing strategy can reduce costs without compromising diagnostic yields. In the first-stage testing, we recommend assessment for C. difficile, cytomegalovirus, and food-borne bacterial pathogens. For persistent diarrheal episodes, second-stage evaluation should include stool NV PCR, Giardia/Cryptosporidium enzyme immunoassay, stool ova and parasite, reductions in immunosuppressive therapy, and possibly endoscopy. Although NV testing had a relatively low cost per FOR, we recommend NV testing during second-stage evaluation, as an NV diagnosis may not lead to changes in clinical management or further reductions in length of hospital stay.

MicroRNA-related polymorphisms and non-Hodgkin lymphoma susceptibility in the Multicenter AIDS Cohort Study

BACKGROUND

MicroRNAs, small non-coding RNAs involved in gene regulation, are implicated in lymphomagenesis. We evaluated whether genetic variations in microRNA coding regions, binding sites, or biogenesis genes (collectively referred to as miRNA-SNPs) were associated with risk of AIDS-associated non-Hodgkin lymphoma (AIDS-NHL), and serum levels of four lymphoma-related microRNAs.

METHODS

Twenty-five miRNA-SNPs were genotyped in 180 AIDS-NHL cases and 529 HIV-infected matched controls from the Multicenter AIDS Cohort Study (MACS), and real-time polymerase chain reaction was used to quantify serum microRNA levels. Adjusted odds ratios (ORs) estimated using conditional logistic regression evaluated associations between miRNA-SNPs and AIDS-NHL risk. A semi-Bayes shrinkage approach was employed to reduce likelihood of false-positive associations. Adjusted mean ratios (MR) calculated using linear regression assessed associations between miRNA-SNPs and serum microRNA levels.

RESULTS

DDX20 rs197412, a non-synonymous miRNA biogenesis gene SNP, was associated with AIDS-NHL risk (OR=1.34 per minor allele; 95% CI: 1.02-1.75), and higher miRNA-222 serum levels nearing statistical significance (MR=1.21 per minor allele; 95% CI: 0.98-1.49). MiRNA-196a2 rs11614913 was associated with decreased central nervous system (CNS) AIDS-NHL (CT vs. CC OR=0.52; 95% CI: 0.27-0.99). The minor allele of HIF1A rs2057482, which creates a miRNA-196a2 binding site, was associated with systemic AIDS-NHL risk (OR=1.73 per minor allele; 95% CI: 1.12-2.67), and decreased CNS AIDS-NHL risk (OR=0.49 per minor allele; 95% CI: 0.25-0.94).

CONCLUSIONS

This study suggests that a few miRNA-SNPs are associated with AIDS-NHL risk and may modulate miRNA expression. These results support a role for miRNA in AIDS-NHL and may highlight pathways to be targeted for risk stratification or therapeutics.

Identification of Siglec-1 null individuals infected with HIV-1

Siglec-1/CD169 is a myeloid-cell surface receptor critical for HIV-1 capture and infection of bystander target cells. To dissect the role of SIGLEC1 in natura, we scan a large population genetic database and identify a loss-of-function variant (Glu88Ter) that is found in ∼1% of healthy people. Exome analysis and direct genotyping of 4,233 HIV-1-infected individuals reveals two Glu88Ter homozygous and 97 heterozygous subjects, allowing the analysis of ex vivo and in vivo consequences of SIGLEC1 loss-of-function. Cells from these individuals are functionally null or haploinsufficient for Siglec-1 activity in HIV-1 capture and trans-infection ex vivo. However, Siglec-1 protein truncation does not have a measurable impact on HIV-1 acquisition or AIDS outcomes in vivo. This result contrasts with the known in vitro functional role of Siglec-1 in HIV-1 trans-infection. Thus, it provides evidence that the classical HIV-1 infectious routes may compensate for the lack of Siglec-1 in fuelling HIV-1 dissemination within infected individuals.

Binding of virus, HIV-1, to cellular protein Siglec-1 is important for infection of immune cells. Here the authors show that a natural mutation leading to production of truncated Siglec-1 reduces HIV binding and infectivity transfer in vitro, but does not substantially affect infection or AIDS outcome in patients.

Lipid Profiles and APOE4 Allele Impact Midlife Cognitive Decline in HIV-Infected Men on Antiretroviral Therapy

Elevated cholesterol and APOE ε4 genotype were independent risk factors for cognitive decline in antiretroviral therapy–adherent human immunodeficiency virus (HIV)-infected men aged 50–65 years, whereas higher high-density lipoprotein attenuated cognitive decline. Treatment of dyslipidemia may reduce midlife cognitive decline among HIV-infected individuals.

Background. Dyslipidemia and apolipoprotein E4 (APOEϵ4) allele are risk factors for age-related cognitive decline, but how these risks are modified by human immunodeficiency virus (HIV) infection is unclear.

Methods. In a longitudinal nested study from the Multicenter AIDS Cohort Study, 273 HIV type 1–infected (HIV⁺) men aged 50–65 years with baseline HIV RNA <400 copies/mL and on continuous antiretroviral therapy (ART) in ≥95% of follow-up visits were matched by sociodemographic variables to 516 HIV-uninfected (HIV^–) controls. The association between lipid markers (total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides), APOE genotype, and cognitive decline in HIV infection was examined using mixed-effects models.

Results. The median baseline age of participants was 51, 81% were white, and 89% had education >12 years. HIV⁺ men had similar baseline total cholesterol and LDL-C, but lower HDL-C and higher triglycerides than controls (P < .001). Higher total cholesterol and LDL-C were associated with faster rates of cognitive decline (P < .01), whereas higher HDL-C attenuated decline (P = .02) in HIV⁺ men. In HIV⁺ men with elevated cholesterol, statin use was associated with a slower estimated rate of decline (P = .02). APOEϵ4 genotype accelerated cognitive decline in HIV⁺ but not HIV^– men (P = .01), with trajectories diverging from HIV^– ε4 carriers after age 50. Total cholesterol levels did not modify the association of ϵ4 genotype with decline (P = .9).

Conclusions. Elevated cholesterol and APOEϵ4 genotype are independent risk factors for cognitive decline in ART-adherent HIV⁺ men aged >50 years. Treatment of dyslipidemia may be an effective strategy to reduce cognitive decline in older HIV⁺ individuals.

Role of APOBEC3F Gene Variation in HIV-1 Disease Progression and Pneumocystis Pneumonia

Human APOBEC3 cytidine deaminases are intrinsic resistance factors to HIV-1. However, HIV-1 encodes a viral infectivity factor (Vif) that degrades APOBEC3 proteins. In vitro APOBEC3F (A3F) anti-HIV-1 activity is weaker than A3G but is partially resistant to Vif degradation unlike A3G. It is unknown whether A3F protein affects HIV-1 disease in vivo. To assess the effect of A3F gene on host susceptibility to HIV- acquisition and disease progression, we performed a genetic association study in six well-characterized HIV-1 natural cohorts. A common six-Single Nucleotide Polymorphism (SNP) haplotype of A3F tagged by a codon-changing variant (p. I231V, with allele (V) frequency of 48% in European Americans) was associated with significantly lower set-point viral load and slower rate of progression to AIDS (Relative Hazards (RH) = 0.71, 95% CI: 0.56, 0.91) and delayed development of pneumocystis pneumonia (PCP) (RH = 0.53, 95% CI: 0.37-0.76). A validation study in the International Collaboration for the Genomics of HIV (ICGH) showed a consistent association with lower set-point viral load. An in vitro assay revealed that the A3F I231V variant may influence Vif mediated A3F degradation. Our results provide genetic epidemiological evidence that A3F modulates HIV-1/AIDS disease progression.

The role of KIR and HLA polymorphism in HIV acquisition: association and in vitro functional studies (VIR1P.1159)

Polymorphism in the genes that encode the HLA antigens and the KIR receptors on NK cells influence both adaptive and innate immunity. We analyzed the role of HLA and KIR polymorphisms in HIV acquisition by comparing 405 HIV+ and 523 HIV- men in the Chicago MACS cohort. We found no significant association with any HLA allele, in contrast to the well established strongly protective effect of HLA-B*57:01 for HIV disease progression. The inhibitory KIR ligands are HLA class I epitopes and fall into the groups: HLA-C1,C2, HLA-Bw4, and HLA-A3/A11. Association analyses of individual KIR genes in the presence/absence of their cognate HLA ligand revealed that one KIR/HLA ligand genotype combination was protective for HIV acquisition. The HLA ligand genotype C1/C1 was protective compared to C1/C2 and C2/C2 but only with genotype KIR2DL3+/KIR2DL2- (OR = 1.76, p = 0.007). This KIR genotype marks homozygosity for the centromeric KIR A haplotype, which is more inhibitory, has fewer genes, and less diverse than KIR B haplotypes. Since C2 is the ligand for the KIR2DL1 receptor, and C1 is the ligand for the KIR2DL3 receptor, the protective association observed with C1/C1 homozygotes suggests that a lack of signaling via the strongly inhibitory KIR2DL1 receptor in addition to signaling via the KIR2DL3 receptor is protective. In vitro assays of NK cells from KIR2DL3 homozygous individuals demonstrate that C1/C1 vs C1/C2 and C2/C2 (C2+) genotypes are more active in terms of cytokine release.

The association between APOL1 risk alleles and longitudinal kidney function differs by HIV viral suppression status

BACKGROUND

Existing data suggest that human immunodeficiency virus (HIV)-infected African Americans carrying 2 copies of the APOL1 risk alleles have greater risk of kidney disease than noncarriers. We sought to determine whether HIV RNA suppression mitigates APOL1-related kidney function decline among African Americans enrolled in the Multicenter AIDS Cohort Study.

METHODS

We genotyped HIV-infected men for the G1 and G2 risk alleles and ancestry informative markers. Mixed-effects models were used to estimate the annual rate of estimated glomerular filtration rate (eGFR) decline, comparing men carrying 2 (high-risk) vs 0-1 risk allele (low-risk). Effect modification by HIV suppression status (defined as HIV type 1 RNA level <400 copies/mL for >90% of follow-up time) was evaluated using interaction terms and stratified analyses.

RESULTS

Of the 333 African American men included in this study, 54 (16%) carried the APOL1 high-risk genotype. Among HIV-infected men with unsuppressed viral loads, those with the high-risk genotype had a 2.42 mL/minute/1.73 m(2) (95% confidence interval [CI], -3.52 to -1.32) faster annual eGFR decline than men with the low-risk genotype. This association was independent of age, comorbid conditions, baseline eGFR, ancestry, and HIV-related factors. In contrast, the rate of decline was similar by APOL1 genotype among men with sustained viral suppression (-0.16 mL/minute/1.73 m(2)/year; 95% CI, -.59 to .27; P for interaction <.001).

CONCLUSIONS

Unsuppressed HIV-infected African Americans with the APOL1 high-risk genotype experience an accelerated rate of kidney function decline; HIV suppression with antiretroviral therapy may reduce these deleterious renal effects.

Clinical Outcomes of Carbapenem-Resistant Acinetobacter baumannii Bloodstream Infections: Study of a 2-State Monoclonal Outbreak

Objective.

To characterize the clinical outcomes of patients with bloodstream infection caused by carbapenem-resistant Acinetobacter baumannii during a 2-state monoclonal outbreak.

Design.

Multicenter observational study.

Setting.

Four tertiary care hospitals and 1 long-term acute care hospital.

Methods.

A retrospective medical chart review was conducted for all consecutive patients during the period January 1, 2005, through April 30, 2006, for whom 1 or more blood cultures yielded carbapenem-resistant A. baumannii.

Results.

We identified 86 patients from the 16-month study period. Their mortality rate was 41%; of the 35 patients who died, one-third (13) had positive blood culture results for carbapenem-resistant A. baumannii at the time of death. Risk factors associated with mortality were intensive care unit stay, malignancy, and presence of fever and/or hypotension at the time blood sample for culture was obtained. Only 5 patients received adequate empirical antibiotic treatment, but the choice of treatment did not affect mortality.

Fifty-seven patients (66.2%) had a single positive blood culture result for carbapenem-resistant A. baumannii; the only factor associated with a single positive blood culture result was the presence of decubitus ulcers. Interestingly, during the study period, a transition from single to multiple positive blood culture results was observed. Four patients, 3 of whom were in a burn intensive care unit, were bacteremic for more than 30 days (range, 36–86 days).

Conclusions.

To our knowledge, this is the first time a study has described 2 patterns of bloodstream infection with A. baumannii: single versus multiple positive blood culture results, as well as a subset of patients with prolonged bacteremia.

No association between Apoε4 alleles, HIV infection, age, neuropsychological outcome, or death

The ε4 allele of the apolipoprotein E (ApoE) gene may have important interactions with physical health and cognitive function among individuals with HIV disease. The purpose of this study is to examine the relationships between ε4, HIV disease, age, neuropsychological impairment, and death in a large, well-characterized study sample. A total of 2846 men participating in the Multicenter AIDS Cohort Study had ApoE genotyping and neuropsychological test data available for analysis. We found a significant association between HIV infection and time to death (from any cause), as well as older age, race, and education. But, ApoE status was not significantly associated with time to death. Similarly, we found a significant association between HIV infection and time to incident cognitive impairment, as well as age, education, and HIV serostatus; Apoε4 status was not related to incident cognitive impairment. There were no significant interactions between ApoE, HIV infection, and age on cognitive impairment. These data replicate and strengthen prior findings of the lack of association between ApoE ε4 and cognitive outcomes in HIV disease. We conclude that within the specific constraints of an exclusively male study in which the majority of participants were less than 65 years of age (range 22-87 years), it appears reasonable to conclude that the ε4 allele is not significantly interacting with HIV serostatus.

Diagnostic yields in solid organ transplant recipients admitted with diarrhea

BACKGROUND

Although diarrhea is a frequent complaint among solid organ transplant recipients, the contribution of infectious etiologies remains incompletely defined. We sought to define the etiologies of diarrhea and the yields of testing at our institution.

METHODS

We performed a retrospective analysis over an 18-month period of hospitalized solid organ transplant recipients. We stratified diarrhea by community onset vs hospital onset of diarrhea.

RESULTS

We identified 422 admissions (representing 314 unique patients) with community-onset diarrhea, and 112 admissions (representing 102 unique patients) with hospital-onset diarrhea. The majority of community- and hospital-onset diarrheal episodes had no identified etiology (60.9% and 75.9%, respectively; P = .03), yet were also self-limited (91% and 91%, respectively; P = .894). Thereafter, the most frequently encountered infectious etiologies were Clostridium difficile infection (13.3% and 11.8%, respectively), norovirus enteritis (8.2% and 3%), cytomegalovirus disease or colitis (6.3% and 2.7%), and bacterial enterocolitis (0.9% and 0%) (P = .03). In aggregate, these entities represented 93.7% and 90.5% of the identified infectious etiologies, respectively. Protozoan causes were rarely seen. Coinfection, or the simultaneous detection of ≥2 pathogens, occurred in 8 (1.9%) and 2 (1.8%) community- and hospital-onset diarrheal admissions, respectively (P = .99).

CONCLUSIONS

In solid organ transplant recipients who presented at our institution with diarrhea, approximately one-third had infectious etiologies identified, consisting predominantly of C. difficile, norovirus, cytomegalovirus, and bacterial enterocolitis. Other infectious etiologies were rare.

Human APOBEC3 induced mutation of human immunodeficiency virus type-1 contributes to adaptation and evolution in natural infection

Human APOBEC3 proteins are cytidine deaminases that contribute broadly to innate immunity through the control of exogenous retrovirus replication and endogenous retroelement retrotransposition. As an intrinsic antiretroviral defense mechanism, APOBEC3 proteins induce extensive guanosine-to-adenosine (G-to-A) mutagenesis and inhibit synthesis of nascent human immunodeficiency virus-type 1 (HIV-1) cDNA. Human APOBEC3 proteins have additionally been proposed to induce infrequent, potentially non-lethal G-to-A mutations that make subtle contributions to sequence diversification of the viral genome and adaptation though acquisition of beneficial mutations. Using single-cycle HIV-1 infections in culture and highly parallel DNA sequencing, we defined trinucleotide contexts of the edited sites for APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H. We then compared these APOBEC3 editing contexts with the patterns of G-to-A mutations in HIV-1 DNA in cells obtained sequentially from ten patients with primary HIV-1 infection. Viral substitutions were highest in the preferred trinucleotide contexts of the edited sites for the APOBEC3 deaminases. Consistent with the effects of immune selection, amino acid changes accumulated at the APOBEC3 editing contexts located within human leukocyte antigen (HLA)-appropriate epitopes that are known or predicted to enable peptide binding. Thus, APOBEC3 activity may induce mutations that influence the genetic diversity and adaptation of the HIV-1 population in natural infection.

Temporal stability of serum concentrations of cytokines and soluble receptors measured across two years in low-risk HIV-seronegative men

BACKGROUND

Prospective cohort studies often quantify serum immune biomarkers at a single time point to determine risk of cancer and other chronic diseases that develop years later. Estimates of the within-person temporal stability of serum markers partly assess the utility of single biomarker measurements and may have important implications for the design of prospective studies of chronic disease risk.

METHODS

Using archived sera collected from 200 HIV-seronegative men at three visits spaced over approximately 2 years, concentrations of 14 biomarkers (ApoA1, sCD14, sgp130, sIL-6R, sIL-2Rα, sTNFR2, BAFF/BLyS, CXCL13, IFN-γ, interleukin [IL]-1β, IL-6, IL-8, IL-10, and TNF-α) were measured in a single laboratory. Age- and ethnicity-adjusted intraclass correlation coefficients (ICC) were calculated for each biomarker, and mixed linear regression models were used to examine the influence of age, ethnicity, season, and study site on biomarker concentrations.

RESULTS

Across all three study visits, most biomarkers had ICC values indicating fair to excellent within-person stability. ApoA1 (ICC = 0.88) and TNF-α (ICC = 0.87) showed the greatest stability; the ICC for IL-8 (ICC = 0.33) was remarkably less stable. The ICCs were similar when calculated between pairs of consecutive visits. The covariables did not influence biomarker levels or their temporal stability. All biomarkers showed moderate to strong pairwise correlations across visits.

CONCLUSIONS

Serum concentrations of most evaluated immune biomarkers displayed acceptable to excellent within-person temporal reliability over a 2-year period. Further investigation may be required to clarify the stability of IL-8.

IMPACT

These findings lend support to using these serologic immune biomarkers in prospective studies investigating associations with chronic diseases.

BK virus replication and nephropathy after alemtuzumab-induced kidney transplantation

BK virus nephropathy (BKVN) is a recognized cause of graft failure in kidney transplant recipients. There are limited data on the epidemiology of BK virus (BKV) infection after alemtuzumab induction. By clinical protocol, the kidney transplant recipients at our center were screened with BKV plasma PCR monthly for the first 4 months posttransplant then every 2-3 months for 2 years. A single center retrospective cohort study of all kidney transplant recipients from January 2008 to August 2010 was conducted to determine incidence and outcomes of BKV infection. Descriptive statistics and Kaplan-Meier analysis was performed. Of 666 recipients, 250 (37.5%) developed viruria, 80 (12%) developed viremia and 31 (4.7%) developed BKVN at a median of 17, 21 and 30 weeks, respectively. Induction with alemtuzumab did not significantly affect incidence of BKVN. Increased recipient age, African American race, acute graft rejection and CMV infection were significantly associated with the development of BKVN in multivariate analysis. The incidence of BK viruria, viremia and nephropathy was not significantly different among kidney transplant recipients who received alemtuzumab induction compared to patients receiving less potent induction.

Monitoring seasonal influenza A evolution: rapid 2009 pandemic H1N1 surveillance with an reverse transcription-polymerase chain reaction/electro-spray ionization mass spectrometry assay

BACKGROUND

The emergence of the pandemic H1N1 influenza strain in 2009 reinforced the need for improved influenza surveillance efforts. A previously described influenza typing assay that utilizes RT-PCR coupled to electro-spray ionization mass spectrometry (ESI-MS) played an early role in the discovery of the pandemic H1N1 influenza strain, and has potential application for monitoring viral genetic diversity in ongoing influenza surveillance efforts.

OBJECTIVES

To determine the analytical sensitivity of RT-PCR/ESI-MS influenza typing assay for identifying the pandemic H1N1 strain and describe its ability to assess viral genetic diversity.

STUDY DESIGN

Two sets of pandemic H1N1 samples, 190 collected between April and June of 2009, and 69 collected between October 2009 and January 2010, were processed by the RT-PCR/ESI-MS influenza typing assay, and the spectral results were compared to reference laboratory results and historical sequencing data from the Nucleotide Database of the National Center for Biotechnology Information (NCBI).

RESULTS

Strain typing concordance with reference standard testing was 100% in both sample sets, and the assay demonstrated a significant increase in influenza genetic diversity, from 10.5% non-wildtype genotypes in early samples to 69.9% in late samples (P<0.001). An NCBI search demonstrated a similar increase, from 13.4% to 45.2% (P<0.001).

CONCLUSIONS

This comparison of early versus late influenza samples analyzed by RT-PCR/ESI-MS demonstrates the influenza typing assay's ability as a universal influenza detection platform to provide high-fidelity pH1N1 strain identification over time, despite increasing genetic diversity in the circulating virus. The genotyping data can also be leveraged for high-throughput influenza surveillance.

Suboptimal etravirine activity is common during failure of nevirapine-based combination antiretroviral therapy in a cohort infected with non-B subtype HIV-1

OBJECTIVE

The primary objective of this study was to estimate etravirine activity in a cohort of patients infected with non-B subtype HIV-1 and failing nevirapine-based therapy.

MATERIALS AND METHODS

Genotypic resistance testing was performed if viral load was >OR= 1,000 copies/ml after receiving at least six months of therapy. Suboptimal response to etravirine was predicted by a score >OR= 2.5 on the Tibotec weighting schema, >OR= 4 in the Monogram schema, or classification as high to low-level resistant by a modification of the Stanford HIVdb algorithm (Version 5.1.2). Bivariate and multivariate analyses were conducted to determine the risk factors for suboptimal etravirine activity.

RESULTS

The patients (n=91) were receiving nevirapine and lamivudine plus stavudine (57.1%) or zidovudine (42.9%). Median duration of nevirapine exposure was 53 weeks (IQR 46-101 weeks). The most common etravirine resistance associated mutations were Y181C (42.9%), G190A (25.3%), H221Y (19.8%), A98G (18.7%), K101E (16.5%), and V90I (12.1%). Suboptimal etravirine activity was predicted in 47.3 to 56.0%. There were disparities in mutations listed in Tibotec versus Monogram Schemas. Predicted suboptimal activity was not associated with nucleoside reverse transcriptase inhibitor (NRTI) used, gender, pretreatment or current CD4 cell count or viral load, subtype or NRTI mutations.

CONCLUSION

Etravirine has compromised activity in approximately half of the patients failing nevirapine-based first-line treatment in this cohort, which supports guidelines that caution against using it with NRTIs alone in such patients.

Prevalence of hepatitis B and C seropositivity in a Nigerian cohort of HIV-infected patients

INTRODUCTION

The clinical and public health implications of the convergence of the human immunodeficiency virus (HIV) epidemic and chronic viral hepatitis in sub-Saharan Africa are poorly understood. This study was designed to determine the seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV), and the impact of co-infection on baseline serum alanine transaminase (ALT), CD4+ T lymphocyte (CD4) count, and plasma HIV-RNA (viral load) in a cohort of HIV-infected Nigerians.

METHODS

A retrospective study was conducted, on eligible treatment-naive patients who presented between August 2004 and February 2007 to the University College Hospital (UCH), Ibadan, Nigeria. Demographic data and pre-treatment laboratory results (hepatitis B surface antigen (HBsAg), HCV antibodies (anti-HCV), ALT, CD4 count and viral load) were retrieved from the medical records. Fisher's exact, two sample t-tests, and the Wilcoxon rank sum tests were used to compare groups. A logistic regression model was fitted to explore characteristics associated with co-infection status.

RESULTS

A total of 1779 HIV-infected patients (male: female ratio, 1:2) met inclusion criteria. HBsAg was present in 11.9%, anti-HCV in 4.8% and both markers in 1%. HBsAg was more common among males than females (15.4% vs 10.1%, respectively p = 0.001) while anti-HCV was detected in a similar proportion of males and females (5.3% versus 4.6%, respectively p = 0.559). HIV-infected patients with anti-HCV alone had a lower mean baseline CD4 count compared to those without anti-HCV or HBsAg (197 cells/mm3 vs 247 cells/mm3, respectively p = 0.008). Serum ALT was higher among patients with HBsAg compared to those without HBsAg or anti-HCV (43 International Units (IU) vs. 39 IU, respectively p = 0.015). Male gender was associated with HBV co-infection on logistic regression (OR1.786; 95% CI, 1.306-2.443; p < 0.005).

CONCLUSION

More HIV-infected females than males presented for care in this cohort. We identified a relatively high prevalence of HBV and HCV co-infection in general, and a higher rate of HBV co-infection among males than females. Pre-treatment CD4 count was significantly lower among those with HCV co-infection, while ALT was slightly higher among those with HBV co-infection. Triple infection with HIV, HBV and HCV was present in a small but significant proportion of patients. These findings underscore the importance of testing for HBV and HCV in all HIV-infected persons in our setting.

A case of peroneal neuropathy-induced footdrop. Correlated and compensatory lower-extremity function

This article reports on the case of a man with peroneal neuropathy-induced footdrop who was seen at the authors' institution 3 years after open reduction and internal fixation of a proximal fibular fracture and a distal, spiral, oblique tibial fracture of the right leg. A comprehensive gait analysis was conducted. A significant footdrop in gait resulted in a "reverse check mark" center-of-pressure pattern, an increased transverse-plane rotation of the foot, and excessive knee and hip flexion in the sagittal plane. These objective findings documented significant dysfunction within the involved lower extremity; in addition, aberrant biomechanics were observed in structures other than the site of initial injury within both limbs.

Proteoglycan composition in the human sclera during growth and aging

PURPOSE

Scleral proteoglycans were characterized from human donor eyes aged 2 months to 94 years to identify age-related changes in the synthesis and/or accumulation of these extracellular matrix components.

METHODS

Newly synthesized proteoglycans (previously radiolabeled with 35SO4) and total accumulated scleral proteoglycans were extracted with 4 M guanidine hydrochloride and separated by molecular sieve chromatography on a Sepharose CL-4B column. The elution positions of newly synthesized and total accumulated proteoglycans were determined by assaying each fraction for radioactivity and glycosaminoglycans, respectively. Regression analyses were performed on the three major proteoglycan peaks to identify age-related changes in scleral proteoglycan composition. Scleral proteoglycans were further purified by anion-exchange chromatography and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses.

RESULTS

Human scleral proteoglycans were apparent as three major peaks after chromatography on Sepharose CL-4B. The two faster eluting peaks contained alternative forms of the cartilage proteoglycan, aggrecan, whereas the third peak contained the small proteoglycans biglycan and decorin. The relative percentage of newly synthesized and total accumulated aggrecan increased approximately two- to sixfold from infancy to 94 years. In contrast, the relative percentage of newly synthesized and total accumulated biglycan and decorin decreased by approximately 25%. Chromatography and Western blot results indicated that the absolute amounts of all three proteoglycans significantly increased in concentration within the sclera from birth to the fourth decade. Beyond the fourth decade, decorin and biglycan decreased in all scleral regions and were present in lowest concentrations by the ninth decade. In contrast, aggrecan, which was present in highest concentration in the posterior sclera, was not significantly reduced with increasing age.

CONCLUSIONS

The age-related changes in scleral proteoglycan composition observed in the present study are likely to contribute to the regional alterations in biomechanical properties of the sclera associated with growth and aging.