Scleroderma Peripheral B Lymphocytes Secrete Interleukin-6 and Transforming Growth Factor [beta] and Activate Fibroblasts

• Published in: Arthritis & rheumatology (Hoboken, N.J.) Vol. 69; no. 5; pp. 1078 - 1089
• Main Authors: Dumoitier, Nicolas, Chaigne, Benjamin, Regent, Alexis, Lofek, Sébastien, Mhibik, Maissa, Dorfmuller, Peter, Terrier, Benjamin, London, Jonathan, Berezne, Alice, Tamas, Nicolas, Varin-Blank, Nadine, Mouthon, Luc
• Format: Journal Article
• Language: English
• Published: Atlanta Wiley Subscription Services, Inc 01.05.2017
• Subjects: Bromodeoxyuridine; CD5 antigen; CD69 antigen; CD86 antigen; CD95 antigen; Cell proliferation; Collagen; Cytokines; Cytometry; Fibroblasts; Flow cytometry; Growth factors; In vitro methods and tests; Incubation; Interleukin 6; Interleukin 6 receptors; Interleukins; Lymphocyte receptors; Lymphocytes; Lymphocytes B; Males; Multiplexing; Patients; Scleroderma; Subpopulations; Systemic sclerosis; Transforming growth factor-b
• ISSN: 2326-5191; 2326-5205
• DOI: 10.1002/art.40016

Objective To study the role of B lymphocytes in systemic sclerosis (SSc). Methods Peripheral B cell subpopulations and the production of interleukin-6 (IL-6) and transforming growth factor [beta] (TGF[beta]) were analyzed using flow cytometry and multiplex assay. The fibroblast proliferation rate upon incubation with supernatants from B cells isolated from SSc patients or healthy controls was assessed using XTT, bromodeoxyuridine, and Ki-67. Collagen production was assessed using a collagen assay. Results Ninety untreated patients (12 males) fulfilling the American College of Rheumatology/European League Against Rheumatism criteria for SSc (23 with diffuse cutaneous SSc [dcSSc] and 67 with limited cutaneous SSc [lcSSc]) and 30 healthy controls were recruited. Increased proportions of B cells expressing CD69 and CD95 were identified among the patients with SSc. B lymphocytes from dcSSc patients versus lcSSc patients and healthy controls expressed increased proportion of cells positive for CD5 (mean±SD 24.12±7.93% versus 14.09±6.58% [P=0.03] and 14.21±5.34% [P=0.01]), CD86 (39.89±22.11% versus 17.72±13.98% [P=0.0007] and 11.68±11.09% [P<0.001]), IL-6 receptor (IL-6R; 33.64±23.12% versus 17.91±13.62% [P<0.0001] and 12.08±8.68% [P=0.0009]), or IL-21R (32.55±20.19% versus 5.76±4.40% [P<0.0001] and 5.93±3.29% [P<0.0001]). In addition, the levels of IL-6 (mean±SD 314.3±317.8 pg/ml versus 6.10±2.58 pg/ml; P=0.0007) and TGF[beta] (mean±SD 1,020±569 pg/ml versus 163.8±98.69 pg/ml; P=0.001) secreted by B lymphocytes from patients with SSc were increased compared to healthy controls. Fibroblast proliferation and collagen production were also significantly increased in the presence of B cell supernatant from SSc patients as compared to healthy controls. Conclusion The numbers of activated B cells were increased in SSc patients, and the up-regulation of CD5, CD86, IL-6R, and IL-21R discriminated between patients with dcSSc and those with lcSSc. Peripheral B lymphocytes from SSc patients secreted both IL-6 and TGF[beta], and they activated fibroblasts in vitro.