Relationship between extremely low total serum IgE levels and rhinosinusitis

Background: The few studies examining clinical manifestations in adults with serum IgE levels less than 2.0 IU/mL provide conflicting information. Objective: To examine self-reported respiratory disease in women with total serum IgE levels less than 2.0 IU/mL to further elucidate previous reports of an association between IgE deficiency and chronic rhinosinusitis. Methods: In a geographically based cohort of 626 pregnant women, total serum IgE levels were measured using a standard assay with a lower limit of detection of 2.0 IU/mL. Sera with IgE levels less than 2.0 IU/mL were assayed again using a low IgE protocol with a detection limit of 0.02 IU/mL. Results: Twenty-one individuals (3.4%) were found to have IgE levels less than 2.0 IU/mL. On repeated assay, 20 of these individuals with available clinical data were found to have detectable IgE levels ranging from 0.5 to 2.1 IU/mL (geometric mean, 1.2 IU/mL). None of these individuals with low IgE levels had physician-diagnosed sinusitis compared with 19.3% (113/585) of those with IgE levels of 2.0 IU/mL or greater (P = .03). Physician-diagnosed asthma was also less prevalent (1/19, 5.3%) in the low IgE group compared with 20.6% in those with higher IgE levels, but this was not significant (P = .14). The low IgE group reported a higher prevalence of hay fever symptoms than the remaining cohort (31.6% vs 24.4%; P = .43) but had less physician-diagnosed hay fever (5.3% vs 15.8%; P = .34). Conclusions: Low serum IgE levels were relatively common in these pregnant women. In contrast to previous studies, a low IgE level was not associated with chronic rhinosinusitis.