Intensity of CD23 expression on IgG₁ ⁺ B cells reflects serum IgE level in asthma

IgE plays a key role in asthma pathogenesis. To produce high-affinity IgE, B cells can undergo IgE class switching through an IgG₁ intermediate stage with repeated antigenic stimulation. Nonetheless, the phenotype of B cells that holds IgE response in asthma patients remains to be fully investigated.

We investigated whether IgG₁ ⁺ B cells reflect the magnitude of the IgE response and correlate with asthma phenotype and disease severities in adult asthma patients.

The frequencies of IgG₁ ⁺, CD23⁺, and CD23⁺IgG₁ ⁺ B cells, along with surface CD23 expression levels in the blood of adult asthma patients (n = 40), were compared with those of nonasthmatic control subjects (n = 24). We then investigated whether the frequencies of individual B-cell populations and their surface CD23 expression levels were linked to serum IgE concentrations, eosinophil counts, and lung functions. Additionally, we also investigated whether serum IgE could affect the frequencies of these B-cell populations in patients with moderate-to-severe asthma (n = 16).

Serum IgE concentrations correlated with CD23 expression levels on CD23⁺IgG₁ ⁺ B cells, but not their numbers that were linked to blood eosinophil counts and lung functions (forced expiratory volume in 1 second). Neither the frequency of CD23⁺IgG₁ ⁺ B cells nor the CD23 expression levels were affected by steroid treatment or leukotriene inhibitors. Neutralizing IgE with omalizumab did not alter the frequency of CD23⁺, IgG₁ ⁺, or CD23⁺IgG₁ ⁺ B cells in asthma patients.

Surface CD23 expression levels on CD23⁺IgG₁ ⁺ B cells, but not their numbers, correlate with the magnitude of IgE response in adult asthma patients.