Infection and pediatric acute lymphoblastic leukemia

Overexpression of Potential Markers of Regulatory and Exhausted CD8+ T Cells in the Peripheral Blood Mononuclear Cells of Patients with B-Acute Lymphoblastic Leukemia

B-acute lymphoblastic leukemia (B-ALL) is one of the most common pediatric cancers, wherein regulatory T cells (Treg) and exhausted CD8⁺ T cells may be important in its development and maintenance. In this bioinformatics study, we evaluated the expression of 20 Treg/CD8 exhaustion markers and their possible roles in patients with B-ALL. The mRNA expression values of peripheral blood mononuclear cell samples from 25 patients with B-ALL and 93 healthy subjects (HSs) were downloaded from publicly available datasets. Treg/CD8 exhaustion marker expression was normalized with that of the T cell signature and correlated with the expression of Ki-67, regulatory transcription factors (FoxP3, Helios), cytokines (IL-10, TGF-β), CD8⁺ markers (CD8α chain, CD8β chain), and CD8⁺ activation markers (Granzyme B, Granulysin). The mean expression level of 19 Treg/CD8 exhaustion markers was higher in the patients than in the HSs. In patients, the expression of five markers (CD39, CTLA-4, TNFR2, TIGIT, and TIM-3) correlated positively with Ki-67, FoxP3, and IL-10 expression. Moreover, the expression of some of them correlated positively with Helios or TGF-β. Our results suggested that Treg/CD8⁺ T cells expressing CD39, CTLA-4, TNFR2, TIGIT, and TIM-3 favor B-ALL progression, and targeted immunotherapy against these markers could be a promising approach for treating B-ALL.

Early immune stimulation and childhood acute lymphoblastic leukemia in Costa Rica: A comparison of statistical approaches

BACKGROUND

Although epidemiologic studies suggest that early immune stimulation is protective against childhood leukemia, evidence for this relationship is equivocal for Hispanic children, who are disproportionately affected by this disease. The complex biological processes underlying immune stimulation and leukemogenesis may benefit from novel statistical approaches that account for mixed exposures and their nonlinear interactions. In this study, we utilized targeted machine learning and traditional statistical methods to investigate the association of multiple measures of early immune stimulation with acute lymphoblastic leukemia (ALL) in Costa Rican children.

MATERIALS AND METHODS

We used data from a population-based case-control study conducted in Costa Rica (2001-2003). Cases of ALL (n = 240) were diagnosed in 1995-2000 (age >1 year and <15 years at diagnosis) and were identified through the National Cancer Registry and National Children's Hospital. Population controls (n = 578) were frequency-matched to cases by birth year and drawn from the National Birth Registry. Data on surrogate measures of early immune stimulation were collected through in-home interviews. We fitted multivariable models, utilizing targeted causal inference (varimpact), unconditional logistic regression, and latent class analysis (LCA).

RESULTS

In varimpact analysis, contact with any pet [risk difference (RD) = -0.17, 95% CI: -0.25, -0.10)] or any farm animal (RD = -0.07, 95% CI: -0.13, 0.00) and allergies (RD = -0.08, 95% CI: -0.17, 0.01) were associated with a reduced risk of ALL, whereas experiencing a fever longer than one week was associated with an increased risk (RD = 0.23, 95% CI: 0.12, 0.33). In unconditional logistic regression models, contact with any pet or farm animal and a complete vaccination scheme were inversely associated with odds of ALL (OR = 0.44, 95% CI: 0.31, 0.62; OR = 0.66, 95% CI: 0.49, 0.90; OR = 0.45, 95% CI: 0.24, 0.83; respectively), whereas experiencing a fever longer than one week was positively associated with ALL (OR = 2.44, 95% CI: 1.61, 3.70). Two-class and three-class LCA revealed a group with elevated risk for ALL whose exposure profile was mainly characterized by reduced exposure to pets and farm animals.

CONCLUSIONS

Using distinct statistical approaches, we observed that exposure to pets and farm animals was inversely associated with ALL risk, whereas having a fever longer than one week (a putative proxy of severe infection) was associated with an increased risk. For multifactorial diseases such as childhood leukemia, we recommend estimating the joint effects of multiple exposures by applying diverse statistical methods and interpreting their results together. Overall, we found support for the hypothesis that early immune stimulation offers protection against childhood ALL.

DNA methylation and the hygiene hypothesis: connecting respiratory allergy and childhood acute lymphoblastic leukemia

Aim: The hygiene hypothesis states that a lack of infection in early-life suppresses immune system development, and is linked to respiratory allergy (RA) and childhood acute lymphoblastic leukemia (ALL) risk. Little is known about underlying mechanisms, but DNA methylation is altered in RA and ALL, and in response to infection. We investigated if aberrant methylation may be in common between these diseases and associated with infection. Materials & methods: RA and ALL disease-associated methylation signatures were compared and related to exposure-to-infection signatures. Results: A significant number of genes overlapped between RA and ALL signatures (p = 0.0019). Significant overlaps were observed between exposure-to-infection signatures and disease-associated signatures. Conclusion: DNA methylation may be a mediating mechanism through which the hygiene hypothesis is associated with RA and ALL risk.

Consumption of water from ex-mining ponds in Klang Valley and Melaka, Malaysia: A health risk study

Evaluation of health risks due to heavy metals exposure via drinking water from ex-mining ponds in Klang Valley and Melaka has been conducted. Measurements of As, Cd, Pb, Mn, Fe, Na, Mg, Ca, and dissolved oxygen, pH, electrical conductivity, total dissolved solid, ammoniacal nitrogen, total suspended solid, biological oxygen demand were collected from 12 ex-mining ponds and 9 non-ex-mining lakes. Exploratory analysis identified As, Cd, and Pb as the most representative water quality parameters in the studied areas. The metal exposures were simulated using Monte Carlo methods and the associated health risks were estimated at 95th and 99th percentile. The results revealed that As was the major risk factor which might have originated from the previous mining activity. For Klang Valley, adults that ingested water from those ponds are at both non-carcinogenic and carcinogenic risks, while children are vulnerable to non-carcinogenic risk; for Melaka, only children are vulnerable to As complications. However, dermal exposure showed no potential health consequences on both adult and children groups.

A systematic review and meta-analysis of the association between childhood infections and the risk of childhood acute lymphoblastic leukaemia

Background:

To determine whether childhood infections were associated with the development of childhood acute lymphoblastic leukaemia (ALL).

Methods:

We included studies that assessed any infection in childhood prior to the diagnosis of ALL in children aged 0–19 years compared to children without cancer. The primary analysis synthesised any infection against the odds of ALL, and secondary analyses assessed the frequency, severity, timing of infections, and specific infectious agents against the odds of ALL. Subgroup analyses by data source were investigated.

Results:

In our primary analysis of 12 496 children with ALL and 2 356 288 children without ALL from 38 studies, we found that any infection was not associated with ALL (odds ratio (OR)=1.10, 95% CI: 0.95–1.28). Among studies with laboratory-confirmed infections, the presence of infections increased the odds of ALL by 2.4-fold (OR=2.42, 95% CI: 1.54–3.82). Frequency, severity, and timing of infection were not associated with ALL.

Conclusions:

The hypothesis put forward by Greaves and others about an infectious aetiology are neither confirmed nor refuted and the overall evidence remains inadequate for good judgement. The qualitative difference in the subgroup effects require further study, and future research will need to address the challenges in measuring infectious exposures.

[Pathogens of infections in the induction period of childhood acute lymphoblastic leukemia and drug resistance of isolated strains]

OBJECTIVE

To investigate the infections occurring in the induction period of childhood acute lymphoblastic leukemia (ALL), the pathogens of the infections, and drug resistance of isolated strains.

METHODS

A retrospective analysis was performed for the clinical data of 130 children with newly-diagnosed childhood ALL. Infections occurring during the induction chemotherapy, pathogenic strains, and drug-resistance spectrum were analyzed.

RESULTS

The incidence rate of clinical infection and/or microbial infection reached 76.2%. The lungs were the most common infection site (46.2%). The children with severe infection accounted for 52.3%, among whom 60 had pulmonary infection and/or 21 had sepsis. A total of 50 pathogenic strains were detected, which consisted of 29 bacterial strains and 21 fungal strains. Of all the children, 28.5% experienced infections caused by at least one microbe. Among the 29 bacterial strains, there were 19 (65.5%) Gram-negative bacteria and 10 (34.5%) Gram-positive bacteria. The most common Gram-negative bacteria were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa, which were 100% sensitive to imipenem. The most common Gram-positive bacterium was Streptococcus viridans, which was 100% sensitive to vancomycin. The infections caused by fungi accounted for 16.2%, with Candida albicans as the most common fungus. Compared with those with non-severe infections, the children with severe infections had a significantly shorter time to the occurrence of agranulocytosis, a significantly longer duration of agranulocytosis, significantly higher incidence of fever and C-reactive protein (CRP) level, and a significantly longer length of hospital stay (P<0.05).

CONCLUSIONS

Pulmonary infections are common in the induction period of childhood ALL. Gram-negative bacteria are the most common pathogenic bacteria. Severe infections can be controlled by carbapenems combined with vancomycin and antifungal agents.

[Pathogens of infections in the induction period of childhood acute lymphoblastic leukemia and drug resistance of isolated strains]

OBJECTIVE

To investigate the infections occurring in the induction period of childhood acute lymphoblastic leukemia (ALL), the pathogens of the infections, and drug resistance of isolated strains.

METHODS

A retrospective analysis was performed for the clinical data of 130 children with newly-diagnosed childhood ALL. Infections occurring during the induction chemotherapy, pathogenic strains, and drug-resistance spectrum were analyzed.

RESULTS

The incidence rate of clinical infection and/or microbial infection reached 76.2%. The lungs were the most common infection site (46.2%). The children with severe infection accounted for 52.3%, among whom 60 had pulmonary infection and/or 21 had sepsis. A total of 50 pathogenic strains were detected, which consisted of 29 bacterial strains and 21 fungal strains. Of all the children, 28.5% experienced infections caused by at least one microbe. Among the 29 bacterial strains, there were 19 (65.5%) Gram-negative bacteria and 10 (34.5%) Gram-positive bacteria. The most common Gram-negative bacteria were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa, which were 100% sensitive to imipenem. The most common Gram-positive bacterium was Streptococcus viridans, which was 100% sensitive to vancomycin. The infections caused by fungi accounted for 16.2%, with Candida albicans as the most common fungus. Compared with those with non-severe infections, the children with severe infections had a significantly shorter time to the occurrence of agranulocytosis, a significantly longer duration of agranulocytosis, significantly higher incidence of fever and C-reactive protein (CRP) level, and a significantly longer length of hospital stay (P<0.05).

CONCLUSIONS

Pulmonary infections are common in the induction period of childhood ALL. Gram-negative bacteria are the most common pathogenic bacteria. Severe infections can be controlled by carbapenems combined with vancomycin and antifungal agents.

Opportunities During Early Life for Cancer Prevention: Highlights From a Series of Virtual Meetings With Experts

Compelling evidence suggests that early life exposures can affect lifetime cancer risk. In 2014, the Centers for Disease Control and Prevention's (CDC's) Cancer Prevention Across the Lifespan Workgroup hosted a series of virtual meetings with select experts to discuss the state of the evidence linking factors during the prenatal period and early childhood to subsequent risk of both pediatric and adult cancers. In this article, we present the results from a qualitative analysis of the meeting transcripts and summarize themes that emerged from our discussions with meeting participants. Themes included the state of the evidence linking early life factors to cancer risk, research gaps and challenges, the level of evidence needed to support taking public health action, and the challenges of communicating complex, and sometimes conflicting, scientific findings to the public. Opportunities for collaboration among public health agencies and other stakeholders were identified during these discussions. Potential next steps for the CDC and its partners included advancing and building upon epidemiology and surveillance work, developing and using evidence from multiple sources to inform decision-making, disseminating and communicating research findings in a clear and effective way, and expanding collaborations with grantees and other partners. As the science on early life factors and cancer risk continues to evolve, there are opportunities for collaboration to translate science into actionable public health practice.

DNA methylation as a potential mediator of environmental risks in the development of childhood acute lymphoblastic leukemia

5-year survival rate for childhood acute lymphoblastic leukemia (ALL) has risen to approximately 90%, yet the causal disease pathway is still poorly understood. Evidence suggests multiple 'hits' are required for disease progression; an initial genetic abnormality followed by additional secondary 'hits'. It is plausible that environmental influences may trigger these secondary hits, and with the peak incidence of diagnosis between 2 and 5 years of age, early life exposures are likely to be key. DNA methylation can be modified by many environmental exposures and is dramatically altered in cancers, including childhood ALL. Here we explore the potential that DNA methylation may be involved in the causal pathway toward disease by acting as a mediator between established environmental factors and childhood ALL development.

Indicators of microbial-rich environments and the development of papillary thyroid cancer in the California Teachers Study

BACKGROUND

Little epidemiologic research has focused on the role of immune function in papillary thyroid cancer risk despite scattered observations suggesting it may be important (e.g., hygiene hypothesis). Here we investigate papillary thyroid cancer risk associated with self-reported living environments across the lifespan reflecting immunologically relevant exposures to microbial-rich environments.

METHODS

Among 61,803 eligible participants in the California Teachers Study cohort, 100 were diagnosed with invasive papillary thyroid cancer between 2005 and 2012. Multivariate Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Living in a rural area during early childhood was associated with significantly reduced risk of developing papillary thyroid cancer as an adult (HR=0.51, 95% CI: 0.28-0.94). Specifically, reduced risks were observed for living within a half mile of hoofed animals (HR=0.47, 95% CI: 0.26-0.84), as was having an indoor dog or cat (HR=0.51, 95% CI: 0.32-0.80). Neither sharing a bedroom or living in a rented home as a child nor attending daycare or kindergarten was associated with reduced risk.

CONCLUSIONS

Early childhood exposures to hoofed animals or indoor furry pets were associated with reduced risk of subsequently developing papillary thyroid cancer.

IMPACT

Our findings point to immunologically relevant, early-life exposures to microbial-rich environments as potentially important in reducing thyroid cancer risk, consistent with the hygiene hypothesis and suggesting that certain, possibly animal-derived, microbial exposures may be important to immune calibration or priming.

Childhood acute lymphoblastic leukaemia and indicators of early immune stimulation: the Estelle study (SFCE)

Background:

Factors related to early stimulation of the immune system (breastfeeding, proxies for exposure to infectious agents, normal delivery, and exposure to animals in early life) have been suggested to decrease the risk of childhood acute lymphoblastic leukaemia (ALL).

Methods:

The national registry-based case–control study, ESTELLE, was carried out in France in 2010–2011. Population controls were frequency matched with cases on age and gender. The participation rates were 93% for cases and 86% for controls. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (OR) were estimated using unconditional regression models adjusted for age, gender, and potential confounders.

Results:

In all, 617 ALL and 1225 controls aged ⩾1 year were included. Inverse associations between ALL and early common infections (OR=0.8, 95% confidence interval (CI): 0.6, 1.0), non-first born (⩾3 vs 1; OR=0.7, 95% CI: 0.5, 1.0), attendance of a day-care centre before age 1 year (OR=0.7, 95% CI: 0.5, 1.0), breastfeeding (OR=0.8, 95% CI: 0.7, 1.0), and regular contact with pets (OR=0.8, 95% CI: 0.7, 1.0) in infancy were observed.

Conclusions:

The results support the hypothesis that conditions promoting the maturation of the immune system in infancy have a protective role with respect to ALL.

Exposure to infections and risk of leukemia in young children

BACKGROUND

Epidemiologic studies indicate that infections in early childhood may protect against pediatric acute lymphoblastic leukemia (ALL).

METHODS

We identified 3,402 ALL cases among children 0 to 5 years of age using the California Cancer Registry. From California birth records we randomly selected controls in a 20:1 ratio and frequency matched them to cases by birth year. We investigated markers of exposure to infections, including month of birth, timing of birth in relation to influenza and respiratory syncytial virus (RSV) seasons, and birth order based on data from California birth certificates and national infection surveillance systems.

RESULTS

We observed an increased risk of ALL for spring and summer births, and for those first exposed to an influenza or RSV season at nine to twelve months of age compared with those exposed during the first three months of life, and this association was stronger among first born children [odds ratios (OR), 1.44 and 95% confidence intervals (CI), 1.13-1.82, for influenza exposure at nine to twelve months of age]. Decreased risk was observed with increasing birth order among non-Hispanic whites but not Hispanics (OR, 0.76 and 95% CI, 0.59-096, for fourth or higher birth order among whites).

CONCLUSION

Our results support the hypothesis that infections in early childhood decrease risk of ALL.

IMPACT

Our findings implicate early life exposure to infections as protective factors for ALL in young children.

Patterns of exposure to infectious diseases and social contacts in early life and risk of brain tumours in children and adolescents: an International Case-Control Study (CEFALO)

Background:

Infectious diseases and social contacts in early life have been proposed to modulate brain tumour risk during late childhood and adolescence.

Methods:

CEFALO is an interview-based case–control study in Denmark, Norway, Sweden and Switzerland, including children and adolescents aged 7–19 years with primary intracranial brain tumours diagnosed between 2004 and 2008 and matched population controls.

Results:

The study included 352 cases (participation rate: 83%) and 646 controls (71%). There was no association with various measures of social contacts: daycare attendance, number of childhours at daycare, attending baby groups, birth order or living with other children.

Cases of glioma and embryonal tumours had more frequent sick days with infections in the first 6 years of life compared with controls. In 7–19 year olds with 4+ monthly sick day, the respective odds ratios were 2.93 (95% confidence interval: 1.57–5.50) and 4.21 (95% confidence interval: 1.24–14.30).

Interpretation:

There was little support for the hypothesis that social contacts influence childhood and adolescent brain tumour risk. The association between reported sick days due to infections and risk of glioma and embryonal tumour may reflect involvement of immune functions, recall bias or inverse causality and deserve further attention.

Infectious illness in children subsequently diagnosed with acute lymphoblastic leukemia: modeling the trends from birth to diagnosis

Although there is increasing evidence that immune dysregulation in children who develop acute lymphoblastic leukemia (ALL) is detectable from birth, debate about the role of infectious exposures in infancy continues. With the aim of quantifying children's infectious exposures, investigators have used a number of infection exposure proxies, but there is a lack of consistency in findings, with some markers indicating increased ALL risks and others decreased risks, the disparity being evident both within and between studies. Accordingly, the authors conducted an in-depth analysis of key infection exposure proxies used in the United Kingdom Childhood Cancer Study, a national population-based case-control study conducted over the period 1991-1996, which combined data from medical records, parental interview, and population census. This longitudinal approach revealed the marked deterioration in immune response that emerged around 5 months prior to ALL diagnosis and confirmed that infectious diagnoses in the first year of life were significantly increased (P < 0.05) in children who developed leukemia between 2 and 14 years of age, as well as in those who had birth orders >1, were not breastfed, lived in deprived areas, or were diagnosed with eczema. By contrast, no association between infectious illness and preschool activity was detected, the lower infection levels among controls whose mothers reported attendance contributing to a significantly reduced ALL odds ratio.

Acute hepatitis A induction of precursor B-cell acute lymphoblastic leukemia: a causal relationship?

Background

Precursor B-cell acute lymphoblastic leukemia accounts for 2% of all lymphoid neoplasms in the United States and occurs most frequently in childhood, but can also occur in adults with a median age of 39 years. It is more commonly seen in males and in Caucasians.

Case Report

We present a case of a 51-year-old Caucasian female with the development of precursor B-cell acute lymphoblastic leukemia after suffering acute hepatitis A 4 weeks prior to her diagnosis. She presented with malaise for a month without spontaneous bruising/bleeding, infections, or B-symptoms, such as fevers, night sweats, or unintentional weight loss.

Conclusion

Nonspecific viral transformation of bone marrow has been discussed in the literature, but we specifically describe hepatitis A-induced adult-onset precursor B-cell acute lymphoblastic leukemia, which is the first reported case in the literature.

Risk of lymphoma and leukaemia after bacille Calmette-Guérin and smallpox vaccination: a Danish case-cohort study

Vaccines may have non-specific effects as suggested mainly in mortality studies from low-income countries. The objective was to examine the effects of BCG and smallpox vaccinations on subsequent risk of lymphoma and leukaemia in a Danish population experiencing rapid out-phasing of these vaccines. In a background cohort (N=47,622) from the Copenhagen School Health Records Register, cases of leukaemia (N=20) and lymphoma (N=51) were identified through the Danish Cancer Registry. The vaccination status of the cases was compared with the vaccination status of a 5% random sample (N=2073) of the background cohort and analysed in a case-cohort design. BCG vaccination reduced the risk of lymphomas (HR=0.49 (95% CI: 0.26-0.93)), whereas smallpox vaccination did not (HR=1.32 (0.56-3.08)). With the small number of leukaemia cases, the analysis of leukaemia had limited power (BCG vaccination HR=0.81 (0.31-2.16); smallpox vaccination HR=1.32 (0.49-3.53)). The present study with very reliable vaccine history information indicates a beneficial effect of BCG vaccination on the risk of lymphomas.