Association between levels of serum and urinary B cell-activating factor and systemic lupus erythematosus disease activity

Maryam Rezazadeh1, Mohammad Hasan Jokar1, Seyedeh Mehrnaz Aghili2, Zahra Mirfeizi1, Mahmoud Mahmoudi3, Negar Morovatdar4, Kamila Hashemzadeh1

1Mashhad University of Medical Sciences, Rheumatic Diseases Research Center, Mashhad, Iran
2Division of Rheumatology, Allergy and Immunology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
3Mashhad University of Medical Sciences, Bu-Ali Research Institute, Mashhad, Iran
4Mashhad University of Medical Sciences, Clinical Research Unit, Mashhad, Iran

Keywords: B cell-activating factor, SLEDAI-2K, systemic lupus erythematosus.

Abstract

Objectives: This study investigated the correlation between serum and urinary B cell-activating factor (BAFF) levels and systemic lupus erythematosus (SLE) disease activity.

Patients and methods: This case-control study was conducted with 87 participants between December 2020 and September 2021. Sixty-two SLE patients who fulfilled the eligibility criteria were enrolled. SLE patients were categorized into active (n=34) and inactive (n=28) groups based on their Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores. The control group consisted of 25 healthy subjects. Serum and urine samples were collected for the measurement of BAFF levels. Finally, the relationship between these variables and SLE disease activity was investigated.

Results: The mean age of active (SLEDAI-2K >4) and inactive (SLEDAI-2K ≤4) SLE patients and healthy individuals were 32.8±7.8, 32.5±6.8, and 31.7±7.8 years, respectively (p=0.62). The median serum BAFF (s-BAFF) and urinary BAFF (u-BAFF) in active lupus patients (10.4 [2.3] ng/mL and 8.2 [3.7] ng/mL, respectively) were significantly higher than in inactive lupus patients (6 (7.1) ng/mL and 1.7 (4.7) ng/mL, respectively; p<0.001) and the control group (3 (3.7) ng/mL and 1.6 (2.2) ng/mL, respectively; p<0.001). However, s-BAFF (p=0.07) and u-BAFF (p=0.43) did not significantly differ between the inactive group and the control group. A significant positive correlation was observed between s-BAFF (r=0.41 and p=0.001) and u-BAFF (r=0.78 and p<0.001) levels and the SLEDAI-2K score.

Conclusion: There is a significant positive correlation between serum and urinary BAFF levels and SLE disease activity. Furthermore, significantly higher levels of s-BAFF and u-BAFF have been observed in patients with active lupus compared to inactive and healthy subjects, indicating a possible role for BAFF in the pathogenesis of SLE disease activity.

Citation: Rezazadeh M, Jokar MH, Aghili SM, Mirfeizi Z, Mahmoudi M, Morovatdar N, et al. Association between levels of serum and urinary B cell-activating factor and systemic lupus erythematosus disease activity. Arch Rheumatol 2023;38(3):429-440.

Ethics Committee Approval

The study protocol was approved by the Mashhad University of Medical Science’s Ethics Committee (date: February 2020, no: 980828). The study was conducted in accordance with the principles of the Declaration of Helsinki.

Author Contributions

Conceptualization, methodology, formal analysis, writing-review & editing: M.R.; Conceptualization, writing-review & editing: M.H.J.; Methodology, formal analysis, writing-original draft: S.M.A.; Methodology, writing-review & editing: Z.M.; Methodology, writing-review & editing: M.M.; Conceptualization, writing-review & editing: N.M.; Conceptualization, methodology, writing-review & editing: K.H.

Conflict of Interest

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Financial Disclosure

The authors received no financial support for the research and/or authorship of this article.

Acknowledgments

The authors express their gratitude to all colleagues who assisted them in this work.

Data Sharing Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.