Pers Jacques-Olivier, Devauchelle Valérie, Daridon Capucine, Bendaoud Boutahar, Le Berre Rozenn, Bordron Anne, Hutin Pascal, Renaudineau Yves, Dueymes Maryvonne, Loisel Séverine, Berthou Christian, Saraux Alain, Youinou Pierre
Brest University Medical School, Brest, France.
Arthritis Rheum. 2007 May;56(5):1464-77. doi: 10.1002/art.22603.
Treatment with rituximab depletes B cells from the peripheral blood (PB) and salivary glands (SGs) of patients with primary Sjögren's syndrome (SS). The purpose of this study was to track the repopulation of B cell subsets in PB as well as their subsequent homing into SGs in patients with primary SS treated with rituximab.
A series of 4-color flow cytometry experiments delineated B cell subsets in 15 patients with primary SS. All were tested on days 8 and 15 of treatment. Nine of the patients were followed up monthly for 10 months, and the remaining 6 patients were followed up monthly for 24 months. Enzyme-linked immunosorbent assays were developed to measure serum levels of BAFF and rituximab. SGs were biopsied at the start of the study and 4 months after treatment in 15 patients, 12 months after treatment in 3 patients, and 24 months after treatment in 2 patients.
Baseline serum levels of BAFF correlated inversely (r = -0.92, P < 5 x 10(-4)) with the duration of B cell depletion: the higher the BAFF levels, the shorter the duration of B cell depletion. Four B cell subsets repopulated the PB: plasmablasts (CD19+, CD5-,IgD-,CD38++), transitional type 1 (T1) B cells (CD19+,CD5+,IgD+,CD38++), mature Bm2 cells (CD19+,CD5+/-,IgD+,CD38+/-), and memory B cells (CD19+,CD5-,IgD-,CD38-). Increased numbers of Bm2 cells and decreased memory B cells reappeared with time. Sequential SG biopsies revealed that B cells were absent in these glands for 12 months: they were detected 24 months after rituximab treatment. Memory and T1 B cells were the first B cells identified locally.
The timing of B cell repopulation is modulated by BAFF and is followed by reconstitution of the preexisting abnormalities.
利妥昔单抗治疗可使原发性干燥综合征（SS）患者外周血（PB）和唾液腺（SGs）中的B细胞减少。本研究旨在追踪接受利妥昔单抗治疗的原发性SS患者外周血中B细胞亚群的重新增殖情况以及它们随后归巢至唾液腺的情况。
通过一系列四色流式细胞术实验描绘了15例原发性SS患者的B细胞亚群。所有患者均在治疗的第8天和第15天进行检测。9例患者每月随访10个月，其余6例患者每月随访24个月。开发了酶联免疫吸附测定法来测量血清中BAFF和利妥昔单抗的水平。在研究开始时以及治疗后4个月对15例患者、治疗后12个月对3例患者以及治疗后24个月对2例患者进行唾液腺活检。
BAFF的基线血清水平与B细胞耗竭持续时间呈负相关（r = -0.92，P < 5×10⁻⁴）：BAFF水平越高，B细胞耗竭持续时间越短。四种B细胞亚群重新出现在外周血中：浆母细胞（CD19⁺、CD5⁻、IgD⁻、CD38⁺⁺）、过渡1型（T1）B细胞（CD19⁺、CD5⁺、IgD⁺、CD38⁺⁺）、成熟Bm2细胞（CD19⁺、CD5⁺/⁻、IgD⁺、CD38⁺/⁻）和记忆B细胞（CD19⁺、CD5⁻、IgD⁻、CD38⁻）。随着时间的推移，Bm2细胞数量增加，记忆B细胞数量减少。连续的唾液腺活检显示，这些腺体中在12个月内没有B细胞：在利妥昔单抗治疗24个月后检测到B细胞。记忆B细胞和T1 B细胞是最早在局部被识别出的B细胞。
B细胞重新增殖的时间受BAFF调节，随后先前存在的异常得以重建。
