Belimumab targeting B cells in lupus treatment

Unlocking Lupus Treatment: How Belimumab Reshapes B Cell Dynamics

Author's portrait.
Lena Voss in Health & Wellness December 2025 • 4 min read.

"A Deep Dive into Belimumab's Impact on CD27+ and CD27- B Cells in Systemic Lupus Erythematosus"


Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease, and finding effective treatments remains a challenge. Belimumab, a human anti-BAFF monoclonal antibody, has emerged as a promising therapy. By inhibiting soluble BAFF (B cell activating factor), Belimumab leads to a partial B cell depletion, but questions remain about which specific B cell subsets are most affected.

A recent study delved into the effects of Belimumab on B cells, focusing on the expression of BAFF receptors (BAFFR). The research tracked changes in BAFFR expression on B cells over a 12-month period of Belimumab treatment in SLE patients, correlating these changes with alterations in B cell subsets.

This article breaks down the key findings of the study, explaining how Belimumab impacts different types of B cells and what this means for the early clinical efficacy of the drug in treating SLE.

Belimumab's Two-Pronged Attack: CD27+ Increase, CD27- Decrease

Belimumab targeting B cells in lupus treatment

The study involved twelve SLE patients (all female, average age 44) undergoing Belimumab therapy. Researchers collected and analyzed blood samples at baseline and at 3, 6, 9, and 12 months to assess changes in B cell subsets and BAFFR expression. All patients were on other immunosuppressants before starting Belimumab, and most continued to take them alongside Belimumab during the study.

The researchers observed a fascinating pattern. There was a transient, statistically significant increase in BAFFR expression on B cells early in the treatment, specifically from baseline to 3 months and baseline to 6 months. This increase then decreased by the 12-month mark. This pattern mirrored the changes seen in a specific B cell subset: CD19+CD27+ cells.

  • CD19+CD27+ Cells: Showed an increase at 3 and 6 months in 9/12 patients.
  • CD19+ Cells: Showed a decrease from baseline to 12 months.
  • CD27- B Cells: Decreased from baseline to 3 and 6 months, persisting to 12 months.
This suggests that Belimumab impacts different B cell subsets in distinct ways. CD19+27+ cells seem able to increase BAFFR and expand early in treatment, while CD19+27- cells are more sensitive to Belimumab deprivation and decrease more rapidly. This differential impact on B cell subsets may be a key factor in the early clinical response observed with Belimumab.

What This Means for Lupus Treatment

The study's findings suggest that Belimumab's effectiveness in treating SLE may be linked to its specific effects on B cell subsets, particularly the CD19+27+ and CD19+27- populations. The ability of CD19+27+ cells to increase BAFFR and transiently expand, coupled with the sensitivity of CD19+27- cells to BAFF deprivation, could explain the early clinical responses observed in patients.

These insights open avenues for further research. Understanding the precise mechanisms by which Belimumab modulates these B cell subsets could lead to more targeted and effective therapies for SLE. Monitoring CD27+ and CD27- B cell levels during Belimumab treatment could potentially help predict treatment response and personalize therapy.

Ultimately, this research highlights the importance of understanding the complex interplay of B cell subsets in SLE and how targeted therapies like Belimumab can reshape these dynamics to improve patient outcomes. The study is a step forward in the ongoing quest to find better treatments for this challenging autoimmune disease.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

Everything You Need To Know

1

How does Belimumab specifically target B cells in Systemic Lupus Erythematosus (SLE) treatment?

Belimumab works by inhibiting soluble BAFF (B cell activating factor). This leads to a partial B cell depletion, but the impact isn't uniform across all B cell subsets. Specifically, it affects CD19+CD27+ and CD19+CD27- cells differently. This targeted approach is what makes it a promising therapy for Systemic Lupus Erythematosus.

2

What changes in BAFFR expression on B cells have been observed during Belimumab treatment, and when do these changes typically occur?

The research indicated a transient increase in BAFFR expression on B cells early in Belimumab treatment, peaking around 3 to 6 months. This increase then decreased by the 12-month mark. This pattern correlates with the changes observed in CD19+CD27+ cells, suggesting these cells are initially responsive to Belimumab's effects by upregulating BAFFR.

3

How do CD19+CD27+ and CD19+CD27- B cells respond differently to Belimumab, and why is this important?

CD19+CD27+ cells appear to increase their BAFFR expression and expand early in Belimumab treatment. Conversely, CD19+CD27- cells are more sensitive to BAFF deprivation caused by Belimumab, leading to a more rapid decrease in their numbers. This differential impact is a key factor in the early clinical response seen with Belimumab.

4

What did the research on Belimumab reveal about its impact on specific B cell populations?

The study, involving twelve female SLE patients with an average age of 44, revealed that Belimumab's effectiveness in treating SLE is likely linked to its specific effects on CD19+CD27+ and CD19+CD27- B cell populations. The ability of CD19+CD27+ cells to transiently expand, coupled with the sensitivity of CD19+CD27- cells to BAFF deprivation, could explain the early clinical responses observed in patients.

5

What further research is needed to fully understand the effects of Belimumab on B cells and its long-term implications for SLE treatment?

While the study highlights the effects of Belimumab on CD19+CD27+ and CD19+CD27- B cells, it does not delve into the long-term consequences of these B cell subset changes. Further research is needed to understand whether these changes lead to sustained clinical benefits and how they affect the overall immune response in SLE patients. Additionally, it's important to investigate how Belimumab interacts with other immunosuppressants commonly used in SLE treatment and whether there are synergistic or antagonistic effects.

Newsletter Subscribe

Subscribe to get the latest articles and insights directly in your inbox.