Persistent Off-Season Dysregulation of Memory B Cell Subsets in Allergic Rhinitis.

INTRODUCTION

Allergic rhinitis (AR) is a common allergic airway disease. Although B cells play essential roles in AR pathogenesis, their subset distribution outside the allergen exposure period remains poorly characterized.

OBJECTIVE

To profile peripheral blood B cell subsets in AR patients during the pollen-free season and compare them with healthy controls (HC), aiming to identify persistent immunological alterations and potential biomarkers.

METHODS

Peripheral blood mononuclear cells (PBMCs) were collected from a total of 28 participants, 14 patients with allergic rhinitis (AR) and 14 healthy controls (HC) during the off-season. B cell subsets were identified using flow cytometry based on IgD and CD27 expression, classifying cells as naïve (IgDCD27), unswitched memory (IgDCD27), switched/conventional memory (IgDCD27), and unconventional memory B cells (IgDCD27). CD38 and CD24 were utilized to further distinguish transitional, naïve, memory, and plasma cell phenotypes. Immunoglobulin isotypes (IgG1-4, IgA1/IgA2) were assessed specifically within conventional memory B cells, while CD86 expression was evaluated on IgM memory-like and naïve B cells. Additionally, kappa (κ) and lambda (λ) light chain usage was analyzed to assess light chain distribution.

RESULTS

AR patients displayed lower frequencies of IgG1, IgG2, and IgA1/IgA2 memory B cells, along with elevated frequencies of IgG4 and κ B cells. Additionally, CD86IgM memory-like B cells were significantly reduced in AR, suggesting altered activation dynamics. No significant differences were observed in CD24/CD38 profiling.

CONCLUSION

Even outside allergen exposure, AR patients exhibit systemic B cell dysregulation, characterized by skewed class switching, altered subset distribution, and reduced activation markers expression. These findings underscore persistent immune imbalance in AR, identify potential off-season biomarkers of allergic inflammation.