The Association Between Atopy and Childhood/Adolescent Leukemia: A Meta-Analysis

Abstract

Atopic disease is hypothesized to be protective against several malignancies, including childhood/adolescent leukemia. To summarize the available epidemiologic evidence, the authors performed a meta-analysis of associations between atopy/allergies, asthma, eczema, hay fever, and hives and childhood/adolescent leukemia, acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML). They searched MEDLINE literature (1952-March 2009) and queried international experts to identify eligible studies. Ten case-control studies were included. Summary odds ratios and 95% confidence intervals were computed via random-effects models. Odds ratios for atopy/allergies were 1.42 (95% confidence interval (CI): 0.60, 3.35) for 3 studies of leukemia overall, 0.69 (95% CI: 0.54, 0.89) for 6 studies of ALL, and 0.87 (95% CI: 0.62, 1.22) for 2 studies of AML, with high levels of heterogeneity detected for leukemia overall and ALL. Inverse associations were observed for ALL and asthma (odds ratio (OR) = 0.79, 95% CI: 0.61, 1.02), eczema (OR = 0.74, 95% CI: 0.58, 0.96), and hay fever (OR = 0.55, 95% CI: 0.46, 0.66) examined separately. Odds ratios for ALL differed by study design, exposure data source, and latency period, indicating that these factors affect study results. These results should be interpreted cautiously given the modest number of studies, substantial heterogeneity, and potential exposure misclassification but are useful in designing future research.

The Safety of Specific Immunotherapy for Patients Allergic to House-Dust Mites and Pollen in Relation to the Development of Neoplasia and Autoimmune Disease: A Long-Term, Observational Case-Control Study

“…The association of atopy with cancer risk has been explored but only in limited studies [11,12,13,14]; however, a positive association between asthma and lung cancer has been confirmed. In contrast, there is some evidence that the immune systems of allergy patients can display anticancer activity, including significantly stronger NK cell activity against other cells (e.g.…”

Allergy and risk of hematologic malignancies: Associations and mechanisms

“…There have been several investigations regarding definition and measurement of allergies and the subtypes of HM assessed, however, an inverse association with history of allergies has been reported for HM as a group [4], lymphoma overall [5,6], Hodgkin's lymphoma (HL), Non Hodgkin lymphoma (NHL) [7][8][9][10], Acute Lymphoblastic Leukemia (ALL) [11,12], and multiple myeloma (MM) [13] (Table 1) [14]. The study indicates a moderately increased risk of HMs in women but not in men with a history of allergies to airborne allergens, especially to plants, grass, or trees.…”

“…The presence of an allergic condition could be a surrogate marker of increased vigilance of the immune system in scrutinizing, identifying, and destroying cancer cells [11].…”

Association of asthma with the risk of acute leukemia and non-Hodgkin lymphoma

“…According to the cancer immune surveillance hypothesis, the immune system identifi�� ��� ���������� �b������ ����� �� ��� body, ��u� �v������ ��� ��v���p���� �� � �u�b�� �� p�������� malignancies (34). The occurrence of asthma may be a surro-���� ���k�� �� �� increased ability of ��� immune system �� recogniz� and destroy malignant cells (23). By contrast, ��� antigenic stimulation hypothesis �u������ ���� ��� ������� inflammatory state in asthma��� patients may result in an inflammatory cytokine cascade and lead to tissue damage ���, ultimately, lymphoid malignancies (35).…”

“…By contrast, ��� ��������� ����u������ hypothesis suggest� ���� ���u��-����u������ ���������� may p�����p��� �� ������, �u� �� �� ���������� �u�b�� �� ������ mutations in activated dividing immune cells (9)(10)(11)(12). P��v��u� ��u���� �u������� ���� ������ w�� p�������v� ������� ��uk���� and lymphoma (13)(14)(15)(16), whereas other studies indicated asthma �� a risk factor (17)(18)(19), or ��p����� no association (20)(21)(22)(23).…”