Computational models can predict response to HIV therapy without a genotype and may reduce treatment failure in different resource-limited settings

OBJECTIVES

Genotypic HIV drug-resistance testing is typically 60%-65% predictive of response to combination antiretroviral therapy (ART) and is valuable for guiding treatment changes. Genotyping is unavailable in many resource-limited settings (RLSs). We aimed to develop models that can predict response to ART without a genotype and evaluated their potential as a treatment support tool in RLSs.

METHODS

Random forest models were trained to predict the probability of response to ART (≤400 copies HIV RNA/mL) using the following data from 14 891 treatment change episodes (TCEs) after virological failure, from well-resourced countries: viral load and CD4 count prior to treatment change, treatment history, drugs in the new regimen, time to follow-up and follow-up viral load. Models were assessed by cross-validation during development, with an independent set of 800 cases from well-resourced countries, plus 231 cases from Southern Africa, 206 from India and 375 from Romania. The area under the receiver operating characteristic curve (AUC) was the main outcome measure.

RESULTS

The models achieved an AUC of 0.74-0.81 during cross-validation and 0.76-0.77 with the 800 test TCEs. They achieved AUCs of 0.58-0.65 (Southern Africa), 0.63 (India) and 0.70 (Romania). Models were more accurate for data from the well-resourced countries than for cases from Southern Africa and India (P < 0.001), but not Romania. The models identified alternative, available drug regimens predicted to result in virological response for 94% of virological failures in Southern Africa, 99% of those in India and 93% of those in Romania.

CONCLUSIONS

We developed computational models that predict virological response to ART without a genotype with comparable accuracy to genotyping with rule-based interpretation. These models have the potential to help optimize antiretroviral therapy for patients in RLSs where genotyping is not generally available.

UK national guideline on safer sex advice

This guideline provides evidence-based guidance on the content of safer sex advice and the provision of brief behaviour change interventions deliverable in genitourinary (GU) medicine clinics. Much of the advice is applicable to other healthcare settings including general practice and clinics providing HIV care. Advice on condom use and effectiveness, oral sex and other sexual practices, testing for sexually transmitted infections (STI) and partner reduction is provided. Advice specific to the transmission of HIV infection including seroadaptive behaviours and negotiated safety is also included. An accompanying review of the evidence supporting the guideline with a complete reference list is available online. A patient information leaflet based on the advice statements developed is also available through the BASHH website.

Pancreatic insufficiency in patients with HIV infection: role of didanosine questioned

OBJECTIVES

The aim of the study was to identify possible causes of pancreatic insufficiency in patients with HIV infection.

METHODS

A retrospective analysis of 233 HIV-positive patients for whom faecal elastase measurement was available was performed to investigate potential associations with core demographic data, HIV infection characteristics, degree of immunosuppresion, exposure to antiretroviral therapy (ART), alcohol misuse, diabetes, hepatitis C virus (HCV) infection, triglyceride and cholesterol levels and symptomatology. The response to pancreatic enzyme replacement for patients with evidence of insufficiency was also evaluated.

RESULTS

Of 233 patients, 104 (45%) had evidence of pancreatic exocrine insufficiency (faecal elastase < 200 mcg/g). A positive association with exocrine pancreatic insufficiency was found for HCV infection (P = 0.007), previous or current HCV treatment (P = 0.003), alcohol misuse history (P = 0.006) and the presence of steatorrhoea (P = 0.03). There was no demonstrated association between exocrine pancreatic insufficiency and didanosine (ddI) exposure (P = 0.43) or stavudine (d4T) exposure (P = 0.62). Seventy-seven per cent of patients who were treated with pancreatic enzymatic supplementation reported a subjective improvement in symptoms.

CONCLUSIONS

Faecal elastase sampling should form part of the routine work-up for HIV-positive patients with chronic diarrhoea even in the absence of 'traditional' risk factors such as ddI exposure. In particular, if the patient has steatorrhoea, a history of alcohol exposure or their HCV serology is positive, they should be considered for investigation. Treatment with pancreatic enzyme supplementation appears to be effective in the treatment of chronic diarrhoea caused by pancreatic insufficiency in the majority of patients.

HIV-associated gastric natural killer/T-cell lymphoma

Natural killer (NK)/T-cell lymphoma is a rare form of non-Hodgkin's lymphoma that is seen with increased frequency in HIV infection and in transplant recipients. This case report describes an unusual case of extranodal NK/T-cell lymphoma in a patient with advanced HIV disease in which gastric involvement was a significant feature.

The MONET trial: week 144 analysis of the efficacy of darunavir/ritonavir (DRV/r) monotherapy versus DRV/r plus two nucleoside reverse transcriptase inhibitors, for patients with viral load < 50 HIV-1 RNA copies/mL at baseline

BACKGROUND

In the MONotherapy in Europe with Tmc114 (MONET) trial, darunavir/ritonavir (DRV/r) monotherapy showed noninferior efficacy vs. two nucleoside reverse transcriptase inhibitors (NRTIs) plus DRV/r at the primary 48-week analysis. The trial was continued to week 144 to assess the durability of the results.

METHODS

A total of 256 patients with viral load < 50 HIV-1 RNA copies/mL on current highly active antiretroviral therapy (HAART) for at least 6 months switched to DRV/r 800/100 mg once daily, either as monotherapy (n=127) or with two NRTIs (n=129). Treatment failure was defined as two consecutive HIV RNA levels above 50 copies/mL [time to loss of virological response (TLOVR)] by week 144, or discontinuation of study drugs.

RESULTS

Eighty-one per cent of patients were male and 91% were Caucasian, and they had a median baseline CD4 count of 575 cells/uL. More patients in the DRV/r monotherapy arm had hepatitis C virus coinfection at baseline than in the control arm (18% vs. 12%, respectively). By week 144, the percentage of patients with HIV RNA < 50 copies/mL [intent to treat (ITT), TLOVR, switch=failure method] was 69% vs. 75% in the DRV/r monotherapy and triple therapy arms [difference= -5.9%; 95% confidence interval (CI) -16.9%, +5.1%]; by a strict ITT analysis (switches not considered failures), the percentage of patients with HIV RNA < 50 copies/mL was 84% vs. 83.5%, respectively (difference= +0.5%; 95% CI -8.7%, +9.7%). Twenty-one and 13 patients had two consecutive HIV RNA results above 50 copies/mL in the DRV/r monotherapy arm and triple therapy arm, respectively, of whom 18 of 21 (86%) and 10 of 13 (77%) had HIV RNA < 50 copies/mL at week 144.

CONCLUSIONS

In this study, for patients with HIV RNA < 50 copies/mL at baseline, switching to DRV/r monotherapy showed noninferior efficacy to DRV/r plus two NRTIs in a strict ITT (switches not considered failures) analysis, but not in a TLOVR switch equals failure analysis.

Severe vitamin D deficiency in a patient treated for hepatitis B with tenofovir

With the increasing use of tenofovir disoproxil in the management of HIV and hepatitis B, serious adverse effects, such as renal dysfunction, will inevitably increase in frequency. We describe a case of a patient presenting with hypophosphataemia suggestive of Fanconi's syndrome, but in fact explicable by simple vitamin D deficiency. This emphasizes that while monitoring for adverse effects is recommended, physicians must consider all alternative causes for biochemical abnormalities prior to discontinuing tenofovir and delaying appropriate management.

Chemoradiotherapy for anal cancer in HIV patients causes prolonged CD4 cell count suppression

BACKGROUND

Despite the advent of highly active antiretroviral therapy, anal cancer remains a significant health problem in human immunodeficiency virus (HIV) patients. We present the clinical features and treatment outcomes of anal cancer in 60 HIV-positive patients over a 20-year period.

PATIENTS AND METHODS

A prospective database of all HIV-positive individuals managed in a specialist unit since 1986 includes 11 112 patients (71 687 person-years of follow-up). Sixty patients with anal cancer were identified. Their clinicopathological and treatment details were analysed.

RESULTS

At anal cancer diagnosis, the mean age was 44 years (range: 28-75 years) and the median CD4 cell count was 305 mm(-3) (range: 16-1252 mm(-3)). Fifty (83%) had chemoradiotherapy (CRT). Forty-six (92%) responded, of whom 10 (22%) subsequently relapsed with locoregional (70%), metastatic disease (10%) or both (20%). The overall 5-year survival is 65% (95% confidence interval 51% to 78%). The median CD4 count fell from 289 mm(-3) before CRT to 132 mm(-3) after 3 months and to 189 mm(-3) after 1 year (P<0.05). Six patients in remission of anal cancer died of acquired immunodeficiency syndrome defining illnesses.

CONCLUSIONS

The management of anal cancer with CRT achieves similar outcomes as the general population. CRT is associated with significant prolonged CD4 suppression that may contribute to late deaths of patients in remission.

Non-cirrhotic portal hypertension in HIV-infected individuals

Non-cirrhotic portal hypertension (NCPH) has been associated with didanosine (ddI) exposure. We aimed to determine the number of individuals with NCPH within our cohort and define their characteristics. We identified individuals within our cohort with NCPH and performed a retrospective case note review. Cumulative antiretroviral therapy (ART) use was calculated and a statistical analysis performed to compare exposure to the rest of the clinic cohort for the same time period. Where available, data was collated on FibroScan®, echocardiography and coagulation profile. Seventeen patients were identified. Upper gastrointestinal bleeding was the most common presenting feature. Liver biopsy showed mild portal or periportal fibrosis in 13 (81%) and four with features of nodular regenerative hyperplasia. There was significantly greater exposure to ddl in this group (59.5 months) compared to the rest of the HIV cohort (21.1 months) P = <0.001. Eleven subjects has a liver elastography performed, six (55%) had a result greater than 9.6 kPa (consistent with greater than F2 disease by Metavir scoring). Echocardiography was performed in seven patients: four met criteria for pulmonary hypertension. This is consistent with other cohorts demonstrating an association between the didanosine exposure and NCPH. Our data also suggest an increased risk of pulmonary hypertension.

The effects of enfuvirtide therapy on body composition and metabolic parameters over 48 weeks in the TORO body imaging substudy

OBJECTIVE

The aim of the study was to compare the metabolic and morphological effects of enfuvirtide plus an optimized background (OB) regimen vs. OB alone (control group) in treatment-experienced patients in the T-20 vs. Optimized Regimen Only (TORO) studies.

METHODS

Body composition and metabolic changes were investigated in patients over 48 weeks, based on fasting chemistries, body weight, and other anthropometric measurements. Dual-energy X-ray absorptiometry (DEXA) and computed tomography (CT) scans were performed in a patient subgroup (n=155) at baseline and at weeks 24 and 48.

RESULTS

At week 48, mean changes from baseline were similar between treatment groups for glucose, insulin, C-peptide, total cholesterol, low-density lipoprotein (LDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglyceride levels. The enfuvirtide group experienced a significant increase in body weight [mean change from baseline +0.99 kg; 95% confidence interval (CI) +0.54, +1.44] and, in those who had body scans, there was a significant increase in truncal fat (by DEXA: median change +419.4 g; 95% CI+71.3, +767.5) and total fat [visceral adipose tissue (VAT)+subcutaneous adipose tissue (SAT) by single-slice abdominal CT scan: median change +25.5 cm(2) ; 95% CI+8.9, +42.0] over 48 weeks; significant increases in these parameters were not seen in the control group. There was no significant change in truncal:peripheral fat ratio in either the enfuvirtide or the control group.

CONCLUSION

The addition of enfuvirtide to an OB regimen does not appear to have unfavourable effects on fat distribution or metabolic parameters.

A rapid method for assessment of natural killer cell function after multiple receptor crosslinking

NK cell function is regulated by the integration of signals from activating and inhibitory receptors. We developed an assay to study the effect of co-crosslinking NK cell receptors in pair-wise combinations without the need to purify NK cells. Monoclonal antibodies recognising inhibitory and activating receptors were coated to flat bottomed tissue culture plates and degranulation was measured within unfractionated, freshly isolated resting or cytokine activated peripheral blood mononuclear cells by flow cytometric analysis of CD107a expression. Measured degranulation responses were NK cell specific, since no expression of CD107a was induced in gated T cells. We detected enhancement of degranulation in response to combinations of antibodies against activating NK cell receptors, including CD16, NKG2D, NKp30 and NKp46 compared to each antibody when combined with an isotype matched control antibody. Co-crosslinking of NKG2A resulted in the inhibition of degranulation measured in response to anti-NKp30 or anti-NKp46 alone in both resting or cytokine pre-activated NK cells, but had no effect on CD16 or NKG2D mediated responses. Interferon gamma production was assayed by intracellular cytokine staining and in cell culture supernatants after receptor crosslinking. No IFN-γ could be detected from resting NK cells after receptor crosslinking whereas the pattern of IFN-γ production in cytokine pre-activated NK cells reflected that observed for degranulation. We conclude that this assay is suitable for the analysis of the impact of NK cell receptor co-crosslinking on multiple NK cell functions and has the potential for application to pathologic conditions where limited numbers of cells are available for study.

Anti-inflammatory activity of tetracyclines: applications to human disease

Tetracyclines possess anti-inflammatory characteristics which are largely independent of their antibacterial activity. A variety of in vitro biologic effects have been reported for tetracyclines in both immune and non-immune cells. The in vivo therapeutic efficacy of tetracyclines in diseases such as rheumatoid arthritis, multiple sclerosis, and stroke has also been demonstrated in both animal models and clinical studies. This review describes the experimental evidence which demonstrates the various non-antibacterial anti-inflammatory activities of tetracyclines and discusses possible mechanisms of action of these drugs.

A randomized controlled trial of the effect of school food and dining room modifications on classroom behaviour in secondary school children

BACKGROUND/OBJECTIVES

Adequate nutrition is considered important for learning, but there is little robust research on the association between diet and learning in school-aged children in industrialized countries. This study investigated the effect of tailored modifications to the food and dining experience in secondary schools on learning-related behaviours.

SUBJECTS/METHODS

In 2008, 12 co-educational secondary schools in England were recruited. Schools were randomly allocated to receive a tailored action plan and support to modify their food provision and dining environment over a 15-week period (intervention or to control). Learning-related behaviours were systematically observed during post-lunchtime classes at all schools. Observations were made by trained observers using a validated protocol to determine whether pupils were 'on-task' (concentrating and alert) or 'off-task' (disruptive or disengaged).

RESULTS

In total, 156 pupils were observed (control n = 58, intervention n = 98) at baseline (12,210 and 20,560 observations, control and intervention, respectively) and at follow-up (16,846 and 23,462, respectively). On-task and off-task behaviours were similar across treatment groups at baseline. At follow-up, intervention group pupils were 18% more likely to be on-task (odds ratio (OR) 1.18, 95% confidence interval ((95% CI) 1.05-1.33) and 14% less likely to be off-task (OR 0.86, 95% CI 0.75-0.98) compared with control group pupils.

CONCLUSIONS

This study suggests that modifying food provision and the dining environment can improve learning-related behaviours of secondary school pupils in the post-lunch period. This finding supports ongoing investment and interventions by local authorities across the United Kingdom to improve school food and lunchtime dining facilities.

School lunch and learning behaviour in primary schools: an intervention study

BACKGROUND/OBJECTIVES

In addition to the nutritional benefits of healthier school food, anecdotes describe improvements in children's behaviour and educational outcomes when school food or the school dining room environment is improved. This study hypothesized that a school food and dining room intervention would improve pupils' learning-related classroom behaviour.

SUBJECTS/METHODS

A controlled intervention trial involving six primary schools matched in triplets and randomly assigned to a 12-week intervention (promotion of healthier school food at lunchtime and changes in the school dining environment) or 12-week wait-listed control group. Study outcome was learning-related behaviours measured in a random sample of 146 pupils in years 3-5.

RESULTS

On-task and off-task behaviours were observed and used as proxy measures for concentration and disengagement (disruption), respectively. Teacher-pupil on-task engagement was 3.4 times more likely in the intervention schools compared with the control schools (adjusted model odds ratio (OR)=3.40 (95% confidence interval (CI)=1.56, 7.36), P=0.009). However, on-task pupil-pupil behaviour was less likely in the intervention group (adjusted model OR=0.45 (95% CI=0.28, 0.70), P<0.001). Similarly, off-task pupil-pupil behaviour was more likely in the intervention group than in the control group in both the unadjusted model (OR=2.18 (95% CI=1.52, 3.13), P<0.001) and the adjusted model (OR=2.28 (95% CI=1.25, 4.17), P=0.007).

CONCLUSIONS

This study offers some support for the hypothesis that a school food and dining room intervention can have a positive impact on pupils' alertness. However, if raised alertness is not channelled and supervised, it may result in increased off-task behaviour when pupils are working together.

Safety and immunogenicity of a Shigella flexneri 2a Invaplex 50 intranasal vaccine in adult volunteers

Shigellosis is a leading cause of diarrhea worldwide prompting vaccine development. The Shigella flexneri Invaplex 50 is a macromolecular complex containing IpaB, IpaC, and LPS, formulated from an aqueous extract of virulent Shigella delivered via nasal administration. Preclinical vaccine testing demonstrated safety, immunogenicity and efficacy. An open-label dose-escalating phase 1 study evaluated a 3-dose (2-week intervals) regimen via nasal pipette delivery. Thirty-two subjects were enrolled into one of four vaccine dose groups (10, 50, 240, or 480 microg). The vaccine was well tolerated with minor short-lived nasal symptoms without evidence of dose effect. Antibody-secreting cell (ASC) responses were elicited at doses > or =50 microg with the highest IgG ASC, Invaplex 50 (100%) and S. flexneri 2a LPS (71%), as well as, serologic responses (43%) occurring with the 240 microg dose. Fecal IgA responses, Invaplex 50 (38.5%) and LPS (30.8%), were observed at doses > or =240 microg. The Invaplex 50 nasal vaccine was safe with encouraging mucosal immune responses. Follow-on studies will optimize dose, delivery mechanism and assess efficacy in a S. flexneri 2a challenge study.

Intercalation of sea urchin proteins in calcite: study of a crystalline composite material

Sea urchin skeletal elements are composed of single crystals of calcite. Unlike their synthetic counterparts, these crystals do not have well-developed cleavage and are consequently much more resistant to fracture. This phenomenon is due in part to the presence of acidic glycoproteins occluded within the crystals. By means of x-ray diffraction with synchrotron radiation, it is shown that the presence of the protein in synthetic calcite only slightly decreases the coherence length but significantly increases the angular spread of perfect domains of the crystals. In biogenic calcite, the coherence length is 1/3 to 1/4 as much as that in synthetic calcite and the angular spread is 20 to 50 times as wide. It is proposed that the presence of macromolecules concentrated at mosaic boundaries that are oblique to deavage planes is responsible for the change in fracture properties. These results may be important in the material sciences, because of the unusual nature of this material, namely, a composite based on the controlled intercalation of macromolecules inside single-crystal lattices.

Severe septic-shock like reaction to co-trimoxazole in an HIV-positive man

Adverse drug reactions occur at a greater frequency in HIV-infected individuals. A 38-year-old Eritrean man was treated with outpatient co-trimoxazole for confirmed Pneumocystis jirovecii pneumonia, but was switched to clindamycin and primaquine due to nausea and vomiting. Following development of methaemaglobinaemia, he was recommenced on prophylactic co-trimoxazole. He was later found moribund with features resembling septic shock and required invasive respiratory support. The diagnosis of a rare, but severe reaction to co-trimoxazole did not become apparent until he was rechallenged with prophylactic co-trimoxazole after recovery from his initial severe reaction. In an era of polypharmacy and an increasing availability of novel drugs, this case is a timely reminder to clinicians of the ongoing need for pharmacovigilance, especially in HIV-infected individuals who may have unusual presentations of an adverse drug reaction.