Severe combined immunodeficiency (SCID) in Canadian children: a national surveillance study

PURPOSE

Severe Combined Immune Deficiency (SCID) is universally fatal unless treated with hematopoietic stem cell transplantation (HSCT). Following the identification of disseminated Bacille Calmette-Guérin (BCG) infections in Canadian First Nations, Métis and Inuit (FNMI) children with unrecognized primary immune deficiencies, a national surveillance study was initiated in order to determine the incidence, diagnosis, treatment and outcome of children with SCID in Canada.

METHODS

Canadian pediatricians were asked to complete a monthly reporting form if they had seen a suspected SCID case, from 2004 to 2010, through the Canadian Paediatric Surveillance Program (CPSP). If the case met CPSP SCID criteria, more detailed data, including demographics and clinical information about investigations, treatment and outcome was collected.

RESULTS

A total of 40 cases of SCID were confirmed for an estimated incidence of SCID in non-FNMI Canadian children of 1.4 per 100,000 live births (95 % CI 1 to 1.9/100,000). The proportion of SCID cases that were FNMI (17.5 %) was almost three times higher than was expected on the basis of proportion of the pediatric population estimated to be FNMI (6.3 %) resulting in an estimated incidence of 4.4 per 100,000 live births (95 % CI 2.1 to 9.2/100,000) in FNMI Canadian children. The mean age at diagnosis for all SCID cases was 4.2 months (range 1–583 days). There were 12 deaths (30 %; 95 % CI 18–46 %); seven died of confirmed or suspected infections before they could receive an HSCT.

CONCLUSIONS

The frequency of SCID cases in FNMI children is higher than in the general Canadian pediatric population. The high mortality rate, due primarily to infection, suggests that early diagnosis by newborn screening followed by HSCT could significantly benefit children with SCID.

A 10-year population based study of 'opt-out' HIV testing of tuberculosis patients in Alberta, Canada: national implications

INTRODUCTION

Compliance with the recommendation that all tuberculosis (TB) patients be tested for human immunodeficiency virus (HIV) has not yet been achieved in Canada or globally.

METHODS

The experience of "opt-out" HIV testing of TB patients in the Province of Alberta, Canada is described over a 10-year period, 2003-2012. Testing rates are reported before and after the introduction of the "opt-out" approach. Risk factors for HIV seropositivity are described and demographic, clinical and laboratory characteristics of TB patients who were newly diagnosed versus previously diagnosed with HIV are compared. Genotypic clusters, defined as groups of two or more cases whose isolates of Mycobacterium tuberculosis had identical DNA fingerprints over the 10-year period or within 2 years of one another, were analyzed for their ability to predict HIV co-infection.

RESULTS

HIV testing rates were 26% before and 90% after the introduction of "opt-out" testing. During the "opt-out" testing years those <15 or >64 years of age at diagnosis were less likely to have been tested. In those tested the prevalence of HIV was 5.6%. In the age group 15-64 years, risk factors for HIV were: age (35-64 years), Canadian-born Aboriginal or foreign-born sub-Saharan African origin, and combined respiratory and non-respiratory disease. Compared to TB patients previously known to be HIV positive, TB patients newly discovered to be HIV positive had more advanced HIV disease (lower CD4 counts; higher viral loads) at diagnosis. Large cluster size was associated with Aboriginal ancestry. Cluster size predicted HIV co-infection in Aboriginal peoples when clusters included all cases reported over 10 years but not when clusters included cases reported within 2 years of one another.

CONCLUSION

"Opt-out" HIV testing of TB patients is effective and well received. Universal HIV testing of TB patients (>80% of patients tested) has immediate (patients) and longer-term (TB/HIV program planning) benefits.

The cardioprotectant 3',4'-dihydroxyflavonol inhibits opening of the mitochondrial permeability transition pore after myocardial ischemia and reperfusion in rats

The study aimed to determine the effect of 3',4'-dihydroxyflavonol (DiOHF) on mitochondrial function, in particular opening of the mitochondrial permeability transition pore (mPTP), respiratory function and reactive oxygen species (ROS) production, in isolated cardiac mitochondria after coronary artery occlusion and reperfusion in vivo. Opening of the mPTP, oxygen consumption and ROS production (assessed by measurement of H2O2) was determined in mitochondria isolated from normal hearts or from the ischemic zone of rat hearts subjected to 30min coronary artery occlusion and 15min reperfusion. Treatment of sham rats with DiOHF (10mgkg(-1) iv) significantly increased the concentration of Ca(2+) required to stimulate mPTP opening. This was accompanied by increased state 3 oxygen consumption and decreased H2O2 release. Ischemia and reperfusion (IR) significantly decreased the concentration of Ca(2+) required to stimulate mPTP opening, decreased state 3 oxygen consumption and increased H2O2 release, when pyruvate plus malate was provided as a substrate. Treatment with DiOHF prevented IR-induced changes in mPTP opening, state 3 oxygen consumption and H2O2 release so that there was no difference compared to sham. In isolated cardiac mitochondria from normal rats DiOHF had no effect on mPTP opening or on state 3 respiration but caused a small increase in state 4 respiration and decreased the respiratory control ratio. DiOHF, administered during ischemia just before reperfusion, inhibits mPTP opening and preserves mitochondrial function through a mechanism likely to be independent of its antioxidant activity or any direct effect on the mPTP.

Sanitoriums and the Canadian colonial legacy: the untold experiences of tuberculosis treatment

Sanitoriums served a much-needed purpose in the age prior to antituberculosis drugs: They removed the infected patient from wider society and created an environment that promoted recovery. We aimed to (a) describe sanitoriums from the perspective of a First Nations reserve community in northern Canada and (b) understand the impact of the sanitorium experience at a community level. Semistructured interviews (n = 15) were conducted in a First Nations reserve community with a high incidence of tuberculosis. Purposive and snowball sampling were used to obtain the sample. Data collection and analysis were iterative, using qualitative content analysis. Participants described the exclusion resulting within and because of sanitoriums. Exclusion within sanitoriums was categorized into (a) the exclusion of Aboriginal culture and practices of healing from the treatment of tuberculosis and (b) the internal exclusion, in which members of the community internally labeled the healed individual postsanitorium as an outsider.

Transmission of Mycobacterium tuberculosis Beijing Strains, Alberta, Canada, 1991-2007

Transmission of Beijing strains posed no more of a public health threat than did non-Beijing strains.

Old Keyam – A Framework for Examining Disproportionate Experience of Tuberculosis Among Aboriginal Peoples of the Canadian Prairies

On the Canadian Prairies, First Nations and Métis peoples are disproportionately affected by tuberculosis (TB) compared to other Canadians. Statistics show enduring transmission and high rates of active TB disease. Despite awareness of the social determinants of TB transmission—such as substance abuse, comorbidities, and basic needs being unmet—transmission and outbreaks continue to occur among Aboriginal people. The Determinants of Tuberculosis Transmission project is a mixed methods, interdisciplinary study that used quantitative questionnaires and qualitative interviews to look more closely at patients’ experiences of TB. Provincial Network Committees (PNCs) comprised of Elders, traditionalists, community-based TB workers, and health researchers in three participating provinces guided the project from inception through to data analysis, interpretation, and dissemination. The collaborative efforts of the patients, the research team, and the PNCs uncovered a continuing influence of colonization in TB transmission. Overwhelming feelings of apathy and despair for the hold that TB continues to have in the lives of patients, families, and communities is captured by the Cree word “keyam,” which may be translated as “to give up” or to ask, “What is the use?” This paper explores the concept of keyam in relation to TB transmission.

Multidrug and extensively drug-resistant tuberculosis in Canada 1997-2008: demographic and disease characteristics

Setting

Nationwide Canadian public health surveillance.

Objective

Description of demographic features and disease characteristics of drug-resistant tuberculosis (TB) in Canada over a 12 year period.

Design

Continuous surveillance of all cases of culture-confirmed TB in Canada. Demographic and microbiologic features were analyzed and comparisons between drug-susceptible, multidrug-resistant (MDR), and drug-resistant not-MDR were made. Cases of extensively drug resistant TB are described.

Results

15,993 cases of culture-confirmed TB were reported during the study period. There were 5 cases of XDR-TB, 177 cases of MDR-TB, and 1,234 cases of first-line drug resistance not-MDR. The majority of drug-resistant cases were reported in foreign-born individuals, with drug-resistant cases diagnosed earlier post-arrival in Canada compared to drug-susceptible cases. In MDR-TB isolates, there was a high rate of drug-resistance to other first- and second-line drugs, making reliable empiric therapeutic recommendations for MDR-TB difficult. There was a statistically significant association between both MDR and drug-resistance not-MDR, and the risk of a negative treatment outcome (defined as treatment failure, absconded, or treatment ongoing >3 yrs).

Conclusion

Drug-resistance complicates TB management even in developed nations with well-established TB control programs. The predominantly international origin of drug-resistant cases highlights the need for global strategies to combat TB.

Increase in multidrug-resistant tuberculosis (MDR-TB) in Alberta among foreign-born persons: implications for tuberculosis management

OBJECTIVES

Globally, the prevalence of anti-tuberculosis drug resistance has been increasing. This study sought to identify trends in multidrug-resistant tuberculosis (MDR-TB) among foreign-born persons in Alberta, a major immigrant-receiving province of Canada.

METHODS

A retrospective cohort study design was used to investigate the prevalence of MDR-TB in foreign-born culture-positive TB cases between 1982 and 2011. Relevant demographic, clinical and laboratory data were abstracted from the TB Registry, individual medical records and the Provincial Laboratory for Public Health.

RESULTS

Of the 2,234 foreign-born culture-positive TB cases in Alberta in 1982-2011, 27 (1.2%) had MDR-TB. Overall, MDR was associated with age &lt;65 years (p=0.025), TB relapse/retreatment, and diagnosis and arrival in the last decade (2002-2011). The prevalence of MDR-TB in 2002-2011 was 2.1%, a significant increase from 0.65% in 1982-1991 (p=0.022) and 0.56% in 1992-2001 (p=0.009). Only immigrants from the Philippines and Vietnam showed a significant increase in the prevalence of MDR-TB between the first two decades and the last. Compared to MDR-TB cases reported in the first two decades, those reported in the last decade were more frequently younger than 35 years of age, new active versus relapse/retreatment cases and diagnosed with non-respiratory versus respiratory TB. In 1992-2011, MDR-TB strains had unique DNA fingerprints.

CONCLUSIONS

Recent trends in the prevalence and clinical characteristics of foreign-born MDR-TB cases have important implications for TB case management in Canada. Early diagnosis of MDR-TB, using genotypic drug susceptibility testing, is suggested in foreign-born TB cases at increased risk of being MDR.

Transcriptome profiling of UPF3B/NMD-deficient lymphoblastoid cells from patients with various forms of intellectual disability

The nonsense-mediated mRNA decay (NMD) pathway was originally discovered by virtue of its ability to rapidly degrade aberrant mRNAs with premature termination codons. More recently, it was shown that NMD also directly regulates subsets of normal transcripts, suggesting that NMD has roles in normal biological processes. Indeed, several NMD factors have been shown to regulate neurological events (for example, neurogenesis and synaptic plasticity) in numerous vertebrate species. In man, mutations in the NMD factor gene UPF3B, which disrupts a branch of the NMD pathway, cause various forms of intellectual disability (ID). Using Epstein Barr virus-immortalized B cells, also known as lymphoblastoid cell lines (LCLs), from ID patients that have loss-of-function mutations in UPF3B, we investigated the genome-wide consequences of compromised NMD and the role of NMD in neuronal development and function. We found that ~5% of the human transcriptome is impacted in UPF3B patients. The UPF3B paralog, UPF3A, is stabilized in all UPF3B patients, and partially compensates for the loss of UPF3B function. Interestingly, UPF3A protein, but not mRNA, was stabilised in a quantitative manner that inversely correlated with the severity of patients' phenotype. This suggested that the ability to stabilize the UPF3A protein is a crucial modifier of the neurological symptoms due to loss of UPF3B. We also identified ARHGAP24, which encodes a GTPase-activating protein, as a canonical target of NMD, and we provide evidence that deregulation of this gene inhibits axon and dendrite outgrowth and branching. Our results demonstrate that the UPF3B-dependent NMD pathway is a major regulator of the transcriptome and that its targets have important roles in neuronal cells.

Development and Implementation of a Conflict-based Assessment of Pedestrian Safety (CAPS) to Evaluate Accessibility of Complex Intersections

This paper develops and implements the Conflict-based Assessment of Pedestrian Safety (CAPS) methodology for evaluating pedestrian accessibility at complex intersections. In past years, a significant research has been done on pedestrian access to modern roundabouts and other complex intersection forms, including a significant focus on the accessibility for pedestrians who are blind. A majority of these studies have relied on actual street crossings by study participants under supervision of trained Orientation and Mobility (O&M) Specialist. These crossing studies were used to evaluate risk from a measurement of intervention events, where the O&M specialist had to physically stop the participant from crossing. While providing arguably the most accurate data for the crossing risk at a particular intersection, actual street crossings can be dangerous to the study participants, and are further very time consuming and expensive to conduct. The CAPS method presented in this paper emphasizes the use of conflict-based safety factors to quantify risk. The CAPS method relates pedestrian crossing decisions to advanced measurements of vehicle dynamics to estimate lane-by-lane conflicts. CAPS identifies the grade of conflict based on a score generated on a five-criterion rating scale. Each of these criteria or factors has different severity levels, and when combined, provides an overall risk rating of the crossing decision. The CAPS framework was applied to a study of blind pedestrian crossings at a multi-lane roundabout. The resulting risk scores were calibrated from actual O&M interventions observed during the study to give confidence in the CAPS performance. The calibrated CAPS framework correctly matched all (high risk) O&M intervention events, and further identifies other (lower risk) pedestrian-vehicle conflicts. The resulting method has the potential to allow for a faster and most importantly safer evaluation of complex intersections for pedestrian access. Since all factors are measured prior to the pedestrian stepping into the roadway, this approach is compatible with crossing indicator studies, where the participants merely indicate when they would cross, rather than actually stepping into the roadway. The CAPS framework therefore allows for a more objective and consistent safety assessment of pedestrian crossings in a research context without having pedestrians physically step into the roadway.

A population-based cohort study of Mycobacterium tuberculosis Beijing strains: an emerging public health threat in an immigrant-receiving country?

Introduction

Mycobacterium tuberculosis Beijing strains are frequently associated with tuberculosis outbreaks and drug resistance. However, contradictory evidence and limited study generalizability make it difficult to foresee if the emergence of Beijing strains in high-income immigrant-receiving countries poses an increased public health threat. The purpose of this study was to determine if Beijing strains are associated with high risk disease presentations relative to other strains within Canada.

Methods

This was a retrospective population-based study of culture-confirmed active TB cases in a major immigrant-receiving province of Canada in 1991 through 2007. Of 1,852 eligible cases, 1,826 (99%) were successfully genotyped. Demographic, clinical, and mycobacteriologic surveillance data were combined with molecular diagnostic data. The main outcome measures were site of disease, lung cavitation, sputum smear positivity, bacillary load, and first-line antituberculosis drug resistance.

Results

A total of 350 (19%) patients had Beijing strains; 298 (85%) of these were born in the Western Pacific. Compared to non-Beijing strains, Beijing strains were significantly more likely to be associated with polyresistance (aOR 1.8; 95% CI 1.0–3.3; p = 0.046) and multidrug-resistance (aOR 3.4; 1.0–11.3; p = 0.049). Conversely, Beijing strains were no more likely than non-Beijing strains to be associated with respiratory disease (aOR 1.3; 1.0–1.8; p = 0.053), high bacillary load (aOR 1.2; 0.6–2.7), lung cavitation (aOR 1.0; 0.7–1.5), immediately life-threatening forms of tuberculosis (aOR 0.8; 0.5–1.6), and monoresistance (aOR 0.9; 0.6–1.3). In subgroup analyses, Beijing strains only had a significant association with multidrug-resistant tuberculosis (aOR 6.1; 1.2–30.4), and an association of borderline significance with polyresistant tuberculosis (aOR 1.8; 1.0–3.5; p = 0.062), among individuals born in the Western Pacific.

Conclusion

Other than an increased risk of polyresistant or multidrug-resistant tuberculosis, Beijing strains appear to pose no more of a public health threat than non-Beijing strains within a high-income immigrant-receiving country.

A population-based study of tuberculosis epidemiology and innovative service delivery in Canada

OBJECTIVE

To compare and interpret tuberculosis (TB) incidence rates in a Canadian population across two decennials (1989-1998 and 1999-2008) as a benchmark for World Health Organization targets and the long-term goal of TB elimination. The population under study was served by two urban clinics in the first decennial and two urban and one provincial clinic in the second.

METHODS

TB rates among Status Indians, Canadian-born 'others' and the foreign-born were estimated using provincial and national databases. Program performance was measured in on-reserve Status Indians in each decennial.

RESULTS

In each decennial, the incidence rate in Status Indians and the foreign-born was greater than that in the Canadian-born 'others'; respectively 27.7 and 33.0 times in Status Indians, and 8.0 and 20.9 times in the foreign-born. Between decennials, the rate fell by 56% in Status Indians, 58% in Canadian-born 'others', and 18% in the foreign-born. On-reserve Status Indians had higher rates than off-reserve Status Indians, and the three-clinic model out-performed the two-clinic model among those on-reserve. Rates in the foreign-born varied by World Bank region, and were highest among those from Africa and Asia.

CONCLUSION

Status Indians and the foreign-born are at increased risk of TB in Canada. Significant progress towards TB elimination has been made in Status Indians but not in the foreign-born.

Nonvisual Cues for Aligning to Cross Streets

Accurately aligning to the crosswalk is an important component of safe street crossing for pedestrians who are blind. Six alignment cues were evaluated in a simulated crosswalk environment in which crosswalk angle was not always in line with ramp slope. The effectiveness of each cue is reported and implications are discussed.

Common functional polymorphisms of DISC1 and cortical maturation in typically developing children and adolescents

Disrupted-in-schizophrenia-1 (DISC1), contains two common non-synonymous single-nucleotide polymorphisms (SNPs)--Leu607Phe and Ser704Cys--that modulate (i) facets of DISC1 molecular functioning important for cortical development, (ii) fronto-temporal cortical anatomy in adults and (iii) risk for diverse psychiatric phenotypes that often emerge during childhood and adolescence, and are associated with altered fronto-temporal cortical development. It remains unknown, however, if Leu607Phe and Ser704Cys influence cortical maturation before adulthood, and whether each SNP shows unique or overlapping effects. Therefore, we related genotype at Leu607Phe and Ser704Cys to cortical thickness (CT) in 255 typically developing individuals aged 9-22 years on whom 598 magnetic resonance imaging brain scans had been acquired longitudinally. Rate of cortical thinning varied with DISC1 genotype. Specifically, the rate of cortical thinning was attenuated in Phe-carrier compared with Leu-homozygous groups (in bilateral superior frontal and left angular gyri) and accelerated in Ser-homozygous compared with Cys-carrier groups (in left anterior cingulate and temporal cortices). Both SNPs additively predicted fixed differences in right lateral temporal CT, which were maximal between Phe-carrier/Ser-homozygous (thinnest) vs Leu-homozygous/Cys-carrier (thickest) groups. Leu607Phe and Ser704Cys genotype interacted to predict the rate of cortical thinning in right orbitofrontal, middle temporal and superior parietal cortices, wherein a significantly reduced rate of CT loss was observed in Phe-carrier/Cys-carrier participants only. Our findings argue for further examination of Leu607Phe and Ser704Cys interactions at a molecular level, and suggest that these SNPs might operate (in concert with other genetic and environmental factors) to shape risk for diverse phenotypes by impacting on the early maturation of fronto-temporal cortices.

Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data. Case counts and rates were analysed in relation to demographics, immigration period and time since arrival. Pre-1986 immigrants (n=3,860,853) and 1986-2002 immigrants (n=3,463,283) contributed 8,662 and 9,613 TB cases, respectively. Immigrants arriving ≤ 5 yrs ago and those arriving >10 yrs ago contributed almost equally to the annual foreign-born TB case count despite a 3.5-fold difference in in-country person-yrs. Remarkably stable and relatively low TB incidence was observed among immigrants >10 yrs post-arrival. Conversely, TB incidence within 5 yrs of arrival was dynamic, demonstrating a strong inverse association with time since arrival and higher sensitivity to changes in immigration level than shifts toward higher incidence source countries. Relative constancy in foreign-born TB incidence is explained by a complex convergence of several factors. Immigrants born in high-incidence countries who arrived ≤ 2 yrs ago and were aged 15-34 yrs upon arrival constitute high-yield targets for preventive therapy.

Impact of pharmacotherapy on the incidence of transurethral prostatectomy for benign prostatic hyperplasia and the implications for surgical training

Medical therapy has become first line treatment for Benign Prostatic Hypertrophy (BPH) and in many cases TURP may no longer be required. Proof and quantification of this evolution in practice has been somewhat elusive and provided the principle impetus for this study. This is a retrospective study of BPH management in Republic of Ireland from 1995 to 2008. National treatment databases were sourced for numbers undergoing TURP and pharmacotherapy prescribing data was obtained from individual pharmaceutical companies. A total of 28,240 TURP's were performed nationally between 1995 and 2008. TURP's performed annually, decreased by 1,494 (51%), alpha-blocker prescriptions increased from 8,710 to 302,159 units and the number of urology trainees increased by 10 (60%). Clear association between decreases in TURP's and increases in pharmacotherapy for BPH is demonstrated. Implications on training likely exist and will require proper evaluation in order to maintain future standards in this surgical practice.

High HIV-TB co-infection rates in marginalized populations: evidence from Alberta in support of screening TB patients for HIV

Heretofore we have not seen strong evidence of synergy between HIV and tuberculosis (TB) in Canada. This may simply reflect a lack of concurrent surveillance for the two diseases. To date, the goal of universal HIV testing of TB patients (> 80% tested) in Canada has not been achieved, despite the existence of two national advisories recommending universal HIV testing of TB patients. In response to these advisories, we recently undertook to demonstrate the feasibility of using an 'opt-out' approach to achieve universal HIV testing of TB patients in Alberta--see the Canadian Journal of Public Health 2009;100(2):116-20. In the present commentary, we add two more years of data (2007-2008) to our earlier report and demonstrate for the first time that HIV co-infection is significantly greater in middle-aged (35-64 years) compared to young adult (15-34 years) TB patients and in Aboriginal and sub-Saharan African, compared to Canadian-born non-Aboriginal and foreign-born 'other' TB patients. Our findings underscore the need for universal concurrent testing as well as greater interaction between TB and HIV programs.

Factors associated with treatment adherence in a randomised trial of latent tuberculosis infection treatment

SETTING

Randomised controlled trial of latent tuberculosis infection (LTBI) treatment in 10 clinics in Canada, Saudi Arabia and Brazil.

OBJECTIVE

To identify early predictors of LTBI treatment adherence, including pre-treatment characteristics.

DESIGN

Patients randomised to 4 months of rifampicin (RMP; n = 420) or 9 months of isoniazid (n = 427) were monitored for adherence using an electronic device. Outcomes were 1) treatment completion, defined as intake of >or=80% of the prescribed doses, and further categorised as completed within the allotted time or not; and 2) treatment regularity, measured by the time interval between doses. Relative risk (RR) and adjusted odds ratios (aOR) of patients' pre-treatment characteristics and adherence at first follow-up visit were calculated.

RESULTS

Completion of treatment was higher with RMP (aOR 4.3, 95%CI 2.7-6.8). Early predictors (first follow-up visit) of non-adherence were late first visit attendance (RR for completion in time 0.9, 95%CI 0.8-0.98), >20% of missed doses (RR 0.4, 95%CI 0.3-0.6) and greater variation of hours between doses (0.209 vs. 0.131, P < 0.001). Serious adverse events were not associated with irregularity of treatment.

CONCLUSION

The shorter RMP regimen was associated with better adherence. Patients with poor adherence could be identified at the first follow-up visit from their punctuality in follow-up, missed doses and variability of pill-taking.