Clinical characteristics of IgE deficiency among patients with primary immunodeficiencies: Findings from the United States Immunodeficiency Network (USIDNET) registry.

BACKGROUND

IgE has been recognized to be involved in immune regulation and tumor surveillance. Nevertheless, the prevalence and clinical significance of IgE deficiency (IED; IgE ≤ 2 kU/L) in primary immunodeficiencies (PIDs) remain poorly defined.

OBJECTIVE

To evaluate the frequency, laboratory features, and clinical features of patients with IED and PID.

METHODS

We analyzed data of 1593 patients with PID from the United States Immunodeficiency Network registry who had available IgE levels. Demographic, laboratory, and clinical characteristics were compared between the IED and non-IED (nIED) groups.

RESULTS

In total, IED was identified in 363 patients (22.8%). The highest proportion of IED was observed in ataxia-telangiectasia (73%), hyper-IgM syndrome (38.5%), X-linked agammaglobulinemia (38.3%), and common variable immunodeficiency (34%). IED patients had higher frequencies of reduced IgA (61% vs 21.7%; P < .001), IgM (49.6% vs 21%; P < .001), and low cluster of differentiation 4 counts (23.8% vs 19.4%; P = .01), and were more likely to receive immunoglobulin replacement therapy than nIED patients (odds ratio [OR], 2.49; 95% CI, 1.79-3.47; P < .001). Moreover, IED was associated with increased odds of splenomegaly (OR, 2.76; 95% CI, 1.89-4.03; P < .001), neutropenia (OR, 1.80; 95% CI, 1.13-2.87; P = .01), and thrombocytopenia (OR, 3.13; 95% CI, 1.82-5.38; P < .001). The proportions and odds of infections and sepsis were similar between the groups. In common variable immunodeficiency, IED was associated with increased odds of malignancy (9.4% vs 3.5%; OR, 2.89; 95% CI, 1.13-7.46; P = .03).

CONCLUSION

The results indicate that IED may identify a subgroup of patients with PID who have greater immune dysregulation than those with nIED. Further prospective studies are needed to determine whether IED has prognostic or risk stratification value among patients with PID.