Altered Peripheral B-Lymphocyte Subsets in Type 1 Diabetes and Latent Autoimmune Diabetes in Adults

Abstract

Objective: B lymphocytes play an important role in the immunopathogenesis of autoimmune diabetes. We hypothesized that the altered B-cell subset phenotype is associated with autoimmune diabetes.

Research design and methods: Patients with type 1 diabetes (T1D) (n = 81), latent autoimmune diabetes in adults (LADA) (n = 82), or type 2 diabetes (T2D) (n = 95) and healthy control subjects (n = 218) with normal glucose tolerance (NGT) were recruited. We determined the percentage of circulating B-lymphocyte subsets, including CD19(+)CD23(-)CD21(+) (marginal zone B [MZB]), CD19(+)CD23(+)CD21(-) (follicular B [FoB]), and CD19(+)CD5(+)CD1d(hi) (interleukin-10-producing regulatory B [B10]) cells by flow cytometry.

Results: Patients with T1D or LADA had increased percentages of MZB cells and decreased percentages of FoB cells compared with healthy control subjects with NGT and patients with T2D. Moreover, patients with T1D showed the lowest frequency of B10 cells compared with patients with LADA or T2D, whereas healthy control subjects expressed the highest frequency of B10 cells. Of note, the frequency of MZB cells was negatively associated and the frequency of FoB cells was positively associated with fasting C-peptide (FCP). The frequency of B10 cells was positively correlated with FCP and negatively correlated with hemoglobin A(1c).

Conclusions: The data show that patients with T1D or LADA express an altered frequency of B-cell subsets, which is associated with islet function and glycemia. These findings suggest that B lymphocytes may be involved in loss of self-tolerance and β-cell destruction and could be used as a biomarker and potential target for immunological intervention.

Figure 1

Flow cytometry analysis of peripheral B-cell subsets. A: The initial CD19⁺ gate was derived from a lymphocyte gate (defined on FSC and SSC) followed by single-cell discrimination. B: Representative dot plot showing the gating strategy for MZB, FoB, and T2-MZP B cells gated on CD19⁺ B cells. C: Representative dot plot showing the gating strategy for B10 cells gated on CD19⁺ B cells.

Figure 2

The frequency of B-cell subsets in subtypes of diabetes and control subjects. The frequency of MZB (A), FoB (B), T2-MZP B (C), and B10 (D) cells gated on CD19⁺ B cells. P values refer to comparison of data after adjustment for age, sex, and BMI. Each point represents the percentage of B-cell subsets of an individual. Horizontal lines show medians. *P < 0.05, **P < 0.01, ***P < 0.001.