Relationship between low serum immunoglobulin E levels and malignancies in 9/11 World Trade Center responders.

BACKGROUND

Individuals with very low immunoglobulin E (IgE) levels have a high risk of developing malignancy. Previous studies have revealed that World Trade Center (WTC) responders exposed to carcinogens have an elevated risk of some cancers.

OBJECTIVE

To evaluate the association between low-serum IgE levels and cancer development in WTC-exposed responders.

METHODS

IgE levels were measured in 1851 WTC responders after September 11, 2001. This is the first pilot study in humans comparing the odds of developing cancer in this high-risk population, between the "low-IgE" (IgE in the lowest third percentile) vs "non-low-IgE" participants.

RESULTS

A significantly higher proportion of hematologic malignancies was found in low-IgE (4/55, 7.3%) compared with non-low-IgE (26/1796, 1.5%, P < .01) responders. The proportion of solid tumors were similar in both groups (5.5% vs 11.4%, P > .05). After adjustment for relevant confounders (race, sex, age at blood draw, WTC arrival time, smoking status), the low-IgE participants had 7.81 times greater odds (95% confidence interval, 1.77-29.35) of developing hematologic cancer when compared with non-low-IgE participants. The hematologic cancers found in this cohort were leukemia (n = 1), multiple myeloma (n = 1), and lymphoma (n = 2). No statistical significance was found when estimating the odds ratio for solid tumors in relation to IgE levels.

CONCLUSION

WTC responders with low serum IgE levels had the highest odds of developing hematologic malignancies. This hypothesis-generating study suggests that low serum IgE levels might be associated with the development of specific malignancies in at-risk individuals exposed to carcinogens. Larger, multicenter studies with adequate follow-up of individuals with different IgE levels are needed to better evaluate this relationship.