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Updated: Aug 20, 2025
Analyses of Proteinuria, Renal Infiltration of Leukocytes, and Renal Deposition of Proteins in Lupus-prone MRL/lpr Mice
Published on: June 8, 2022
Validity of immunoglobulin-binding protein 1 as a biomarker for lupus nephritis
Amany M Ebaid1, Nillie Ezzeldin1, Enas I Abdelhady1
1Faculty of Medicine, Rheumatology & Rehabilitation Department, Faculty of Medicine, 68865Zagazig University, Zagazig, Egypt.
Background:
Lupus nephritis (LN) is a major issue that adds a burden on patients with systemic lupus erythematosus (SLE). Immunoglobulin-binding protein 1 (IGBP1) is identified as a phosphoprotein that has been recently reported to be linked to the B-cell receptor complex and regulates differentiation, proliferation, apoptosis, and tolerance of B cells. Its diagnostic and/or prognostic role in LN has been highlighted only recently.
Objectives:
This study aims to evaluate the relation between serum IGBP1 and SLE disease activity and/or renal activity and to investigate the validity of IGBP1 as a biomarker for LN.
Methods:
96 participants were enrolled and divided into three groups: nephritis, nonnephritis, and control groups. The patients with SLE were diagnosed according to the Systemic Lupus International Collaborating Clinics classification (SLICC) criteria. The serum IGBP1 level was assayed using an enzyme-linked immunosorbent assay (ELISA). Assessments were conducted using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2k) and renal biopsy for LN patients.
Results:
The nephritis and nonnephritis groups had higher IGBP1 levels than the controls; the nephritis group had the highest serum IGBP1 levels (p < .001). Significant correlations were found between IGBP1 levels and proteinuria (r = 0.568, p = .001) and renal SLEDAI (r = 0.475, p = .006) in the nephritis group; on the other hand, the correlation of serum IGBP1 levels with SLEDAI-2K was non-significant for both groups (nephritis and nonnephritis groups). The IGBP1 levels were significantly different among histopathologic classes (p < .001), with class V showing the highest level. Moreover, it showed a significant positive correlation with the pathologic activity index. Compared with renal SLEDAI for identifying active renal affection in patients with SLE, the serum IGBP1 level with a cut-off value of 547.45 ng/mL is a valid biomarker for detecting active nephritis with 93.8% sensitivity and 96.9% specificity.
Conclusion:
The serum IGBP1 levels were high in patients with LN and were positively correlated with the pathologic activity index. The serum IGBP1 level of 547.45 ng/mL is a valid biomarker for detecting active nephritis. Thus, we recommend that clinicians monitor the serum IGBP1 level of patients with SLE to detect LN.
