False Positive EBV and CMV IgM in Systemic Lupus Erythematosus
Yes, patients with Systemic Lupus Erythematosus (SLE) can show false positive IgM antibodies for both Epstein-Barr Virus (EBV) and Cytomegalovirus (CMV) due to their activated immune systems. 1
Mechanism of False Positivity
- False positive CMV IgM results commonly occur in patients with activated immune systems, including those with SLE 1
- EBV infection itself can cause false positive CMV IgM results, creating additional complexity in interpretation 1, 2
- The immune dysregulation in SLE can produce serologic profiles that mimic primary or reactivated viral infections, even without active viral replication 3
Clinical Implications
- CMV antigenaemia has been reported in 18-44% of SLE patients, with higher antigen concentrations in those treated with pulse methylprednisolone and cyclophosphamide 1
- Serological testing for viral infections in SLE patients should be interpreted with caution due to these known cross-reactivities 2
- CMV infection may mimic active SLE, making differentiation between disease flare and infection challenging 1
Diagnostic Considerations
- When CMV IgM is positive in an SLE patient, confirmation with another technique is necessary before making clinical decisions 2
- NAAT (Nucleic Acid Amplification Test) or viral load testing provides more reliable evidence of active viral infection than antibody testing in SLE patients 1, 4
- In a study of adolescents with SLE who had serologic patterns suggesting primary or reactivated EBV infection, most did not have detectable active EBV infection despite the serologic findings 3
Monitoring Recommendations
- Testing for CMV (antigenaemia) should be considered in SLE patients with active disease undergoing therapy with high-dose glucocorticoids 1
- When interpreting viral serologies in SLE patients, consider the possibility of false positivity due to immune dysregulation 3
- Research suggests that disease flares may precede EBV reactivation, rather than viral reactivation causing flares 4
Relationship Between Viral Infections and SLE
- EBV-specific CD8+ T cell responses are functionally impaired in SLE patients, which may contribute to higher viral loads 4
- Both inactive and active SLE patients have significantly elevated EBV viral loads compared to healthy controls 4
- Some evidence suggests that EBV may play a role in SLE pathogenesis or exacerbation, though the exact mechanism remains unclear 5
When evaluating positive EBV or CMV IgM results in SLE patients, clinicians should consider the high likelihood of false positivity and confirm active infection through viral load testing or other methods before making treatment decisions based solely on antibody results 1, 2, 3.