Anifrolumab Attenuates Follicular Helper T Cell Activation in Patients with Systemic Lupus Erythematosus

Abstract

Systemic lupus erythematosus (SLE) is a severe autoimmune disease characterized by autoantibody production and multi-organ involvement. Anifrolumab, a monoclonal antibody targeting the type I interferon (IFN) receptor, has been approved for the treatment of SLE. Our aim was to investigate the long-term effects of inhibited type I IFN signaling on circulating follicular helper T subsets (T_FH), follicular regulatory T cells (T_FR), and B lymphocyte subpopulations, reflecting the ongoing germinal center reactions in SLE patients. Peripheral blood samples were obtained from ten SLE patients before the initiation of anifrolumab treatment, and at months 6 and 12 of the intervention period. Flow cytometry analysis was performed to assess the frequencies of circulating T_FH cell subsets, T_FR cells, and certain B cell subpopulations. Serological parameters, including autoantibody levels and complement components, were determined as part of the routine diagnostic evaluation. We observed a significant and sustained reduction in the percentage of activated circulating T_FH cells. Notably, the frequency of CXCR3^-CCR6⁺ T_FH17 cells decreased, whereas the proportion of CXCR3⁺CCR6^- T_FH1 cells increased significantly. Furthermore, the proportion of the IgD^-CD27^- double-negative B lymphocytes was also significantly reduced. These findings suggest that anifrolumab therapy attenuates T_FH cell activation, which may contribute to its clinical efficacy by modulating germinal center responses in SLE.

Keywords: anifrolumab; follicular helper T cells; systemic lupus erythematosus.

Figure 1

Ratios of activated T_FH cells and T_FR cells in SLE patients (n = 10) receiving anifrolumab therapy. Frequency of T_FH cells (a), T_FR cells (b), activated T_FH cells (c), T_FH1 cells (d), T_FH1/17 cells (e), T_FH17 cells (f) and T_FH2 cells (g) were evaluated by flow cytometric analysis. Boxes represent interquartile ranges, horizontal lines show median values, and whiskers show minimum and maximum values. Statistically significant differences are indicated by * p < 0.05; ** p < 0.01.

Figure 2

Ratio of B lymphocyte subsets in SLE patients (n = 10) upon anifrolumab therapy. Frequency of double-negative B cells (a), naive B cells (b), transitional B cells (c), mature naive B cells (d), unswitched B cells (e), switched B cells (f) and primary memory B cells (g) were evaluated by flow cytometric analysis. Boxes represent interquartile ranges, horizontal lines show median values, and whiskers show minimum and maximum values. Statistically significant differences are indicated by * p < 0.05; ** p < 0.01.

Figure 3

Gating strategy for flow cytometric immunophenotyping. Representative dot plots show the identification of follicular regulatory T (T_FR) and follicular helper T (T_FH) cell subtypes (a) and the characterization of B lymphocytes subsets (b). The following cell types were identified: activated T_FH (ICOS⁺PD1⁺), T_FH1 (CXCR3⁺CCR6⁻), T_FH1/17 (CXCR3⁺CCR6⁺), T_FH2 (CXCR3⁻CCR6⁻) and T_FH17 (CXCR3⁻CCR6⁺) and T_FR (CD25⁺CD127⁻) cells, d.n. = double negative (IgD⁻CD27⁻), naive (IgD⁺CD27⁻), u-s.mem. = un-switched memory (IgD⁺CD27⁺), s.mem. = switched memory (IgD⁻CD27⁺), m.n. = mature–naive (CD38^intCD24^int), p.m. = primarily memory (CD38⁻CD24^hi), and trans = transitional (CD38^hiCD24^hi) B cells. Figures were exported from FlowJo v10.0.7 software.