Objective:

To investigate the efficacy and safety of belimumab in pediatric patients with lupus nephritis and hypogammaglobulinemia, particularly focusing on the safety concerns related to infection risk associated with low serum IgG levels.

Key Findings:

• Hypogammaglobulinemia was present in 81.5% of participants prior to treatment, indicating a high prevalence.
• The belimumab group had a significantly higher incidence of infections compared to the control group, raising safety concerns.
• Serum IgG levels were significantly lower in the belimumab group, which may contribute to increased infection risk.
• Belimumab treatment resulted in lower ESR and higher C3 levels at specific time points, suggesting some therapeutic benefits.

Interpretation:

Belimumab may exacerbate hypogammaglobulinemia and increase infection risk in pediatric patients with lupus nephritis, highlighting the need for careful monitoring and consideration of IgG replacement therapy.

Limitations:

• Small sample size of 27 patients limits generalizability.
• Lack of long-term follow-up data beyond 52 weeks may overlook late-onset effects.

Conclusion:

Monitoring IgG levels in pediatric lupus nephritis patients on belimumab is crucial, and aggressive IgG replacement therapy may be required for those with low serum IgG levels to mitigate infection risks.