Steven B. Welch

Biallelic hypomorphic mutations in a linear deubiquitinase define otulipenia, an early-onset autoinflammatory disease

Significance We describe a human disease linked to mutations in the linear deubiquitinase (DUB) OTULIN, which functions as a Met1-specific DUB to remove linear polyubiquitin chains that are assembled by the linear ubiquitin assembly complex (LUBAC). OTULIN has a role in regulating Wnt and innate immune signaling complexes. Hydrolysis of Met1-linked ubiquitin chains attenuates inflammatory signals in the NF-κB and ASC-mediated pathways. OTULIN-deficient patients have excessive linear ubiquitination of target proteins, such as NEMO, RIPK1, TNFR1, and ASC, leading to severe inflammation. Cytokine inhibitors have been efficient in suppressing constitutive inflammation in these patients. This study, together with the identification of haploinsufficiency of A20 (HA20), suggests a category of human inflammatory diseases, diseases of dysregulated ubiquitination. Systemic autoinflammatory diseases are caused by mutations in genes that function in innate immunity. Here, we report an autoinflammatory disease caused by loss-of-function mutations in OTULIN (FAM105B), encoding a deubiquitinase with linear linkage specificity. We identified two missense and one frameshift mutations in one Pakistani and two Turkish families with four affected patients. Patients presented with neonatal-onset fever, neutrophilic dermatitis/panniculitis, and failure to thrive, but without obvious primary immunodeficiency. HEK293 cells transfected with mutated OTULIN had decreased enzyme activity relative to cells transfected with WT OTULIN, and showed a substantial defect in the linear deubiquitination of target molecules. Stimulated patients’ fibroblasts and peripheral blood mononuclear cells showed evidence for increased signaling in the canonical NF-κB pathway and accumulated linear ubiquitin aggregates. Levels of proinflammatory cytokines were significantly increased in the supernatants of stimulated primary cells and serum samples. This discovery adds to the emerging spectrum of human diseases caused by defects in the ubiquitin pathway and suggests a role for targeted cytokine therapies.

Availability and Use of Molecular Microbiological and Immunological Tests for the Diagnosis of Tuberculosis in Europe

Introduction Currently only limited data exist regarding the availability and clinical use of molecular and immunological tests for tuberculosis (TB) in the European setting. Methods Web-based survey of Paediatric-Tuberculosis-Network-European-Trialsgroup (ptbnet) and Tuberculosis-Network-European-Trialsgroup (TBnet) members conducted June to December 2013. Both networks comprise clinicians, microbiologists, epidemiologists and researchers predominately based in Europe. Results 191 healthcare professionals from 31 European countries participated. Overall, 26.8% of respondents did not have access to the Xpert MTB/RIF assay; only 44.6% had access to the assay in-house. However, a substantial proportion had access to other commercial and/or non-commercial PCR-based assays for TB (68.8% and 31.8%, respectively). Only 6.4% did not have access to any PCR-based assays for TB. A large proportion of participants with access to the Xpert MTB/RIF assay had used it for the analysis of non-respiratory samples [pleural fluid: 36.5%, gastric aspirates: 34.7%, cerebrospinal fluid: 34.7%, stool samples: 4.3%, blood/serum: 2.6%, ‘other samples’ (which included biopsy/tissue samples, lymph node aspirates, joint aspirates and urine samples): 16.5%]. Regarding interferon-gamma release assays, a greater proportion of respondents had access to the QuantiFERON-TB Gold assay (84.7%) than to the T-SPOT.TB assay (52.2%). Conclusions Both immunological and molecular TB tests are widely available across Europe. The QuantiFERON-TB Gold assay is more widely used than the T-SPOT.TB assay, which may reflect the difficulties of integrating an ELISPOT assay into the routine laboratory setting. Although Xpert MTB/RIF assays are optimised and solely licensed for the analysis of sputum samples, in clinical practice they are commonly used for non-respiratory samples. Further research is needed to establish how current molecular TB tests impact on patient care and outcome in the routine clinical setting.

The impact of BCG vaccination on tuberculin skin test responses in children is age dependent: evidence to be considered when screening children for tuberculosis infection

Background Following exposure to TB, contacts are screened to target preventive treatment at those at high risk of developing TB. The UK has recently revised its recommendations for screening and now advises a 5 mm tuberculin skin test (TST) cut-off irrespective of age or BCG status. We sought to evaluate the impact of BCG on TST responses in UK children exposed to TB and the performance of different TST cut-offs to predict interferon γ release assay (IGRA) positivity. Methods Children <15 years old were recruited from 11 sites in the UK between January 2011 and December 2014 if exposed in their home to a source case with sputum smear or culture positive TB. Demographic details were collected and TST and IGRA undertaken. The impact of BCG vaccination on TST positivity was evaluated in IGRA-negative children, as was the performance of different TST cut-offs to predict IGRA positivity. Results Of 422 children recruited (median age 69 months; IQR: 32–113 months), 300 (71%) had been vaccinated with BCG. BCG vaccination affected the TST response in IGRA-negative children less than 5 years old but not in older children. A 5 mm TST cut-off demonstrated good sensitivity and specificity in BCG-unvaccinated children, and an excellent negative predictive value but was associated with low specificity (62.7%; 95% CI 56.1% to 69.0%) in BCG-vaccinated children. For BCG-vaccinated children, a 10 mm cut-off provided a high negative predictive value (97.7%; 95% CI 94.2% to 99.4%) with the positive predictive value increasing with increasing age of the child. Discussion BCG vaccination had little impact on TST size in children over 5 years of age. The revised TST cut-off recommended in the recent revision to the UK TB guidelines demonstrates good sensitivity but is associated with impaired specificity in BCG-vaccinated children.

Efficacy and safety of darunavir/ritonavir at 48 weeks in treatment-naïve, HIV-1-infected adolescents: results from a phase 2 open-label trial (DIONE).

Background: Twice-daily darunavir/ritonavir is indicated in treatment-experienced children (≥3 years). This study assessed once-daily administration in treatment-naïve adolescents. Methods: Phase 2, 48-week, open-label, single-arm study evaluating pharmacokinetics, safety and efficacy of once-daily darunavir/ritonavir 800/100 mg in treatment-naïve, HIV-1–infected adolescents (≥12 to <18 years, ≥40 kg) with zidovudine/lamivudine or abacavir/lamivudine. Results: Twelve patients (67% female; median 14.4 years) were enrolled. After 24 and 48 weeks, respectively, 11 of 12 (92%) and 10 of 12 (83%) patients achieved viral load <50 copies/mL (intent-to-treat time-to-loss of virologic response); all had ≥1 log10 drop in viral load versus baseline. Median CD4+ cell count increased by 175 and 221 cells/mm3 (intent-to-treat-noncompleter = failure) after 24 and 48 weeks, respectively. Eighty-three percent of patients were adherent to darunavir/ritonavir. One patient was never suppressed and 1 patient rebounded. No patients developed darunavir resistance-associated mutations or lost phenotypic susceptibility to any commercially available protease inhibitor or any background nucleoside reverse transcriptase inhibitor. Eleven patients (92%) reported ≥1 adverse event (AE), considered in 2 patients to be at least possibly related to darunavir (gastrointestinal-related events and dizziness). Four patients had ≥1 serious AE. Three patients reported ≥1 grade 3/4 AE; no serious or grade 3/4 AEs were considered darunavir related. No patients discontinued because of AEs. Conclusions: Over 48 weeks, once-daily darunavir/ritonavir 800/100 mg plus NRTIs was effective and well-tolerated for treatment of HIV-1–infected, antiretroviral-naïve adolescents (≥12 to <18 years). These findings support use of once-daily darunavir/ritonavir 800/100 mg in this population.

Prevalence, incidence, and associated risk factors of tuberculosis in children with HIV living in the UK and Ireland (CHIPS): a cohort study

BACKGROUND Tuberculosis is the most common serious co-infection in people living with HIV worldwide, but little is known about its incidence in HIV-infected children living in high-resource settings with low tuberculosis prevalence. We aimed to assess the incidence and prevalence of tuberculosis in children with HIV living in the UK and Ireland to understand rates, risk factors, and outcomes of the disease in this group. METHODS We did an analysis of children enrolled in CHIPS, an observational multicentre cohort of children receiving HIV care in the UK and Ireland. We assessed characteristics and prevalence of tuberculosis at baseline, measured incidence of disease through the follow-up period using the CHIPS database, and calculated associated risk factors in these children with multivariable logistic and Cox regression models. FINDINGS Between Jan 1, 1996, to Sept 18, 2014, data for 1848 children with 14 761 years of follow-up were reported to CHIPS. 57 (3%) children were diagnosed with tuberculosis: 29 children had tuberculosis at presentation (prevalent tuberculosis) and 29 had the disease diagnosed during follow-up (incident tuberculosis), including one child with recurrent tuberculosis events. Median age at diagnosis was 9 years (IQR 5-12). 25 (43%) children had pulmonary tuberculosis, 24 (41%) had extrapulmonary tuberculosis with or without pulmonary involvement, and the remainder (n=9; 16%) had unspecified-site tuberculosis. The overall incidence rate for the follow-up period was 196 cases per 100 000 person-years (95% CI 137-283). In our multivariable model, tuberculosis at presentation was associated with more severe WHO immunological stage at baseline (odds ratio 0·25, 95% CI 0·08-0·74; p=0·0331; for none vs severe) and being born abroad (odds ratio 0·28, 0·10-0·73; p=0·0036; for UK and Ireland vs abroad). Incident tuberculosis was associated with time-updated more severe WHO immunological stage (hazard ratio 0·15, 95% CI 0·06-0·41; p=0·0056; for none vs severe) and older age at baseline (1·11, 0·47-2·63; p=0·0027; for age >10 years vs 5-9 years). INTERPRETATION Tuberculosis rates in HIV-infected children in the UK and Ireland were higher than those reported in the general paediatric population. Further study is warranted of tuberculosis screening and preventive treatment for children at high-risk of this disease to avoid morbidity and mortality in this population. FUNDING NHS England, PENTA Foundation.

Management of paediatric tuberculosis in leading UK centres: unveiling consensus and discrepancies.

SETTING Large specialist paediatric TB clinics in the UK. OBJECTIVE To evaluate clinical practice and compare with national and international guidelines. DESIGN A survey based on an electronic questionnaire on the management of latent tuberculous infection (LTBI) and tuberculosis (TB) disease was conducted in 13 specialist paediatric TB clinics. The consensus and discrepancies were evaluated by descriptive analysis. RESULTS Practice was reportedly different when choosing age limits for preventive treatment for TB contacts with initially negative tuberculin skin tests (TSTs), interpretation of TST results and use of interferon-gamma release assays (IGRAs) in the context of LTBI. In relation to management of children with TB disease, practices varied for duration of treatment of osteoarticular TB, monitoring for ethambutol ocular toxicity and use of pyridoxine. There was limited experience with multidrug-resistant TB (MDR-TB), and over half of the clinics monitored MDR-TB contacts without giving preventive treatment. CONCLUSIONS The survey showed heterogeneity in several aspects of clinical care for children with TB. Available paediatric TB guidelines differ substantially, explaining the wide variations in management of childhood TB. Prospective paediatric studies are urgently required to inform and standardise clinical practice, especially in the context of evolving drug resistance.

Evaluating UK National Guidance for Screening of Children for Tuberculosis. A Prospective Multicenter Study

Rationale: To identify infected contacts of tuberculosis (TB) cases, the UK National Institute for Health and Care Excellence (NICE) recommended the addition of IFN‐&ggr; release assays (IGRA) to the tuberculin skin test (TST) in its 2006 TB guidelines. Treatment for TB infection was no longer recommended for children who screened TST‐positive but IGRA‐negative. Objectives: We performed a cohort study to evaluate the risk of TB disease in this group. Methods: Children exposed to an infectious case of TB in their household were recruited from 11 pediatric TB clinics. TST and IGRA were performed at baseline, with IGRA repeated at 8 weeks and TST repeated if initially negative. Children were treated according to 2006 NICE guidelines and followed for 24 months. Measurements and Main Results: Of 431 recruited children, 392 completed the study. We diagnosed 48 (12.2%) cases of prevalent TB disease, 105 (26.8%) with TB infection, and 239 (60.9%) without TB infection or disease. Eighteen children aged 2 years and above had a positive TST but persistently negative IGRA. None received TB infection treatment and none developed TB disease. Ninety (26.1%) children qualified for TB infection treatment according to 2006 NICE guidelines. In contrast, 147 (42.7%) children would have qualified under revised NICE guidance, issued in 2016. Conclusions: In this low‐prevalence setting we saw no incident cases of TB disease in children who were TST‐positive but IGRA‐negative and did not receive treatment for TB infection. Following the latest NICE guidance, significantly more children will require medication.

Weekends-off efavirenz-based antiretroviral therapy in HIV-infected children, adolescents and young adults (BREATHER): Extended follow-up results of a randomised, open-label, non-inferiority trial.

Background Weekends off antiretroviral therapy (ART) may help engage HIV-1-infected young people facing lifelong treatment. BREATHER showed short cycle therapy (SCT; 5 days on, 2 days off ART) was non-inferior to continuous therapy (CT) over 48 weeks. Planned follow-up was extended to 144 weeks, maintaining original randomisation. Methods BREATHER was an open-label, non-inferiority trial. Participants aged 8-24yrs with virological suppression on efavirenz-based first-line ART were randomised 1:1, stratified by age and African/non-African sites, to remain on CT or change to SCT. The Kaplan-Meier method was used to estimate the proportion of participants with viral rebound (confirmed VL≥50 copies/mL) under intent-to-treat at 48 weeks (primary outcome), and in extended follow-up at 96, 144, and 192 weeks. SCT participants returned to CT following viral rebound, 3 VL blips or discontinuation of efavirenz. Findings Of 199 participants (99 SCT, 100 CT), 97 per arm consented to extended follow-up. Median follow-up was 185.3 weeks (IQR 160.9–216.1). 69 (70%) SCT participants remained on SCT at last follow-up. 105 (53%) were male, baseline median age 14 years (IQR 12–18), median CD4 count 735 cells/μL (IQR 576–968). 16 SCT and 16 CT participants had confirmed VL≥50 copies/mL by the end of extended follow-up (HR 1.00, 95% CI 0.50–2.00). Estimated difference in percentage with viral rebound (SCT minus CT) by week 144 was 1.9% (90% CI -6.6–10.4; p = 0.72) and was similar in a per-protocol analysis. There were no significant differences between arms in proportions of participants with grade 3/4 adverse events (18 SCT vs 16 CT participants; p = 0.71) or ART-related adverse events (10 vs 12; p = 0.82). 20 versus 8 serious adverse events (SAEs) were reported in 16 SCT versus 4 CT participants, respectively (p = 0.005 comparing proportions between groups; incidence rate ratio 2.49, 95%CI 0.71–8.66, p = 0.15). 75% of SAEs (15 SCT, 6 CT) were hospitalisations for a wide range of conditions. 3 SCT and 6 CT participants switched to second-line ART following viral failure (p = 0.50). Conclusions Sustainable non-inferiority of virological suppression in young people was shown for SCT versus CT over median 3.6 years. Standard-dose efavirenz-based SCT is a viable option for virologically suppressed HIV-1 infected young people on first-line ART with 3-monthly VL monitoring. Trial registration EudraCT 2009-012947-40 ISRCTN 97755073 ClinicalTrials.gov NCT01641016

P91 Incorporating tuberculosis strain typing data into routine contact tracing investigations: experience from the field

Strain typing of tuberculosis (TB) isolates by 24 loci mycobacterial interspersed repetitive unit-variable number tandem repeats (MIRU-VNTRs) is now a routine laboratory tool for TB control, but its utility in informing contact tracing and public health action has not been well reported in the United Kingdom. Since November 2011 we have routinely held typing meetings and undertaken cluster investigation. Over 18 months, 68 clusters were discussed. Fifty-five (81%) clusters were small (2–5 patients), 7 (10%) were medium (6–14 patients) and 6 (9%) were large (>15 patients, median = 42, IQR = 26–52). Enhanced epidemiological investigation was undertaken in 27/68 (40%) clusters. Typing meetings alone readily identified 20 definite epidemiological links between 46/458 (10%) cases. In 15 cases, 9 definite or probable links were not supported by genotyping, leading to expanded screening in one workplace. 112 extended interviews were done. A further 23 definite links between 77 (17%) cases, 2 probable links between 5 (1%) cases and 24 possible links between 72 (16%) cases were found. Expanded screening as a direct result of strain typing and cluster investigation occurred in 4/6 settings where non-household transmission was identified (a factory, 2 places of worship, a hospital, a hostel and a pub). An additional 124 contacts were identified. 65 attended screening, 21 latent TB cases were treated and 1 active TB case was found. Routine incorporation of strain typing data in contact tracing improves diagnosis of latent and active infection but requires investment in data management systems and human resource for enhanced epidemiological investigation.

P99 Impact of TB cluster investigation in a new migrant community

In a high incidence area of tuberculosis (TB), clinicians and nurses identified a sharp increase in the number of TB cases originating from a single country in March 2012 (average 3 per year in 2006–2008, 9 per year in 2009–2010, 20 cases in 2011 and 13 cases to March 2012). We undertook a social network approach to identify whether recent transmission had occurred. 56/66 (85%) cases from 2009 onwards were interviewed in their homes and perceptions of TB were explored. Median number of years in the UK was 4 years (IQR 2–5). Socialisation occured mainly in private homes and places of worship, with 44/56 (78%) attending 9 places of worship. Twenty-three cases could be epidemiologically linked to an index case who was a prominent community member who had been symptomatic for 10 months. 24 loci mycobacterial interspersed repetitive unit-variable number tandem repeats (MIRU-VNTRs) strain typing was available in 19/24 (79%). Twelve had identical strain type to the index case. Six cases unexpectedly clustered in 4 other strain types. As a result of the cluster investigation the TB service were invited to talk at a religious service and two community members became crucial in raising awareness. An additional 77 contacts identified themselves for screening with 59 (77%) completing investigations. Sixteen latent TB cases were treated, 7 were given BCG vaccination and 13 are still undergoing assessment. Cluster investigation builds relationships and trust to provide accessible TB services in diverse communities. This new migrant community now has a high awareness of TB and future delays in TB diagnosis can be avoided.