Invited commentary: childhood acute lymphoblastic leukemia and allergies: biology or bias?

Genetic polymorphisms of Th2 interleukins, history of asthma or eczema and childhood acute lymphoid leukaemia: Findings from the ESCALE study (SFCE)

BACKGROUND

Previous studies on the putative role of allergy in the aetiology of childhood leukaemia have reported contradictory results. The present study aimed to analyse the relation between a medical history of asthma or eczema and childhood acute lymphoid leukaemia (ALL) in light of potential candidate gene-environment interactions.

METHODS

Analyses were based on a subset of 434 cases of ALL and 442 controls successfully genotyped and of European ancestry children enrolled in a French population-based case-control study conducted in 2003-2004. Information about medical history was obtained during a standardized interview with the mothers. Candidate polymorphisms in genes of the Th2 cytokines IL4, IL10, IL13 and IL4-receptor, were genotyped or imputed.

RESULTS

None of the variant alleles were directly associated with childhood acute lymphoid leukaemia. A medical history of asthma or eczema was reported more often in the control group (OR = 0.7 [0.5-1.0]). This association was mostly seen in the group of children not carrying the IL13-rs20541 variant allele (Interaction Odds Ratio IOR 1.9, p-interaction = 0.07) and in those carrying the IL10 triple variant haplotype (IOR 0.5, p-interaction = 0.04). No interaction was observed with the candidate polymorphisms in IL4 and IL4R.

CONCLUSION

This study provides a new insight into the relationship between allergic symptoms and childhood acute lymphoid leukaemia, by suggesting this inverse association could be limited to children carrying certain genetic polymorphisms. If confirmed, these results could help better understand the biological mechanisms involved in the development of childhood acute lymphoid leukaemia.

Association of atopic diseases and parvovirus B19 with acute lymphoblastic leukemia in childhood and adolescence in the northeast of Brazil

BACKGROUND

Several factors related to the immune system, such as a history of allergies and virus infections, may be associated with acute lymphoblastic leukemia (ALL). The purpose of this study was to analyze whether the presence of atopic diseases and previous infection with parvovirus B19 and Epstein-Barr virus (EBV) are associated with the development of ALL.

METHODS

This case-control study was performed in two tertiary hospitals located in northeastern Brazil. The study population included 60 patients who were diagnosed with non-T-cell ALL using myelogram and immunophenotyping and 120 patients in the control group. Atopy was evaluated via a parent questionnaire and medical records. Total immunoglobulin (Ig)E and IgG levels of parvovirus B19 and EBV were measured in the serum. Logistic regression was performed to assess the association between variables and odds of ALL.

RESULTS

We identified a significant inverse association between rhinitis, urticaria and elevated IgE serum levels with ALL. A history of parvovirus B19 infection showed a significant association with this type of cancer [OR (95 % CI) 2.00 (1.94-4.26); P = 0.050]. In logistic regression, the presence of atopy was a protective factor [OR (95 % CI) 0.57 (0.38-0.83); P = 0.004], and the presence of IgG for parvovirus B19 was an important risk factor for ALL [OR (95 % CI) 2.20 (1.02-4.76); P = 0.043].

CONCLUSIONS

These results suggest that atopic diseases and elevated total IgE levels are associated with a potential protective effect on the development of ALL. Previous infection with parvovirus B19 contributed to ALL susceptibility.

Allergies, atopy, immune-related factors and childhood rhabdomyosarcoma: a report from the Children's Oncology Group

Rhabdomyosarcoma (RMS) is a highly malignant tumor of developing muscle that can occur anywhere in the body. Due to its rarity, relatively little is known about the epidemiology of RMS. Atopic disease is hypothesized to be protective against several malignancies; however, to our knowledge, there have been no assessments of atopy and childhood RMS. Therefore, we explored this association in a case-control study of 322 childhood RMS cases and 322 pair-matched controls. Cases were enrolled in a trial run by the Intergroup Rhabdomyosarcoma Study Group. Controls were matched to cases on race, sex and age. The following atopic conditions were assessed: allergies, asthma, eczema and hives; in addition, we examined other immune-related factors: birth order, day-care attendance and breastfeeding. Conditional logistic-regression models were used to calculate an odds ratio (OR) and 95% confidence interval (CI) for each exposure, adjusted for age, race, sex, household income and parental education. As the two most common histologic types of RMS are embryonal (n=215) and alveolar (n=66), we evaluated effect heterogeneity of these exposures. Allergies (OR=0.60, 95% CI: 0.41-0.87), hives (OR = 0.61, 95% CI: 0.38-0.97), day-care attendance (OR=0.48, 95% CI: 0.32-0.71) and breastfeeding for ≥ 12 months (OR=0.36, 95% CI: 0.18-0.70) were inversely associated with childhood RMS. These exposures did not display significant effect heterogeneity between histologic types (p>0.52 for all exposures). This is the first study indicating that atopic exposures may be protective against childhood RMS, suggesting additional studies are needed to evaluate the immune system's role in the development of this tumor.