Opinion
Video
Biomarkers in CIDP
Author(s):
Panelists discuss how biomarkers, such as neurofilament light chain (NfL), autoantibodies, and inflammatory markers, have potential in enhancing chronic inflammatory demyelinating polyneuropathy (CIDP) diagnosis and treatment monitoring, but emphasize that their use remains experimental, and a comprehensive approach integrating clinical assessments and electrophysiological findings is essential for optimal patient care.
Summary for Physicians:
This segment discusses the role of biomarkers in the diagnosis and treatment of CIDP, focusing on how they can aid in diagnosis and help assess treatment response.
Key Points:
1. Role of Biomarkers in the Diagnosis of CIDP:
- No Universal Biomarker: Currently, there is no single biomarker that can definitively diagnose CIDP. The diagnosis is primarily clinical, based on symptoms, nerve conduction studies, and electrophysiological findings. However, biomarkers may provide supportive information, especially when the clinical presentation is atypical or when differentiating CIDP from other similar neuropathies.
- Neurofilament Light Chain (NfL): NfL is a promising biomarker in neurodegenerative and inflammatory neurological diseases, including CIDP. Elevated NfL levels in the cerebrospinal fluid and serum are indicative of neuronal damage and axonal injury. In CIDP, NfL may correlate with disease activity, severity, and progression. However, NfL is not yet routinely used in clinical practice but remains an area of active research.
- Anti–Myelin Protein Antibodies: Autoantibodies targeting myelin-related proteins (eg, myelin basic protein or GM1 ganglioside) have been proposed as potential biomarkers in CIDP. However, their diagnostic value is still unclear, as these antibodies are not present in all patients and may also be found in other neuropathies or autoimmune disorders.
- Cytokines and Inflammatory Markers: Elevated levels of proinflammatory cytokines, such as TNF-α, interleukin-6, and interleukin-1β, have been observed in patients with CIDP, reflecting immune system activation. These markers are not specific for CIDP, but they may help in understanding disease activity and inflammation. They are also being investigated for use in monitoring response to treatment.
2. Biomarkers for Assessing Treatment Response:
- Neurofilament Light Chain (NfL) as a Marker for Treatment Response: Since NfL levels reflect neuronal damage, measuring NfL before and after treatment could provide insight into how well a therapy is working. A reduction in NfL levels over time would suggest that treatment is effectively controlling disease activity and limiting axonal damage.
- Electrophysiological Improvement: Although not a traditional biomarker, improvements in nerve conduction velocity and electrophysiological tests can serve as indicators of treatment efficacy. For instance, patients showing improvement in nerve conduction tests (eg, reduced latencies and better conduction velocities) likely have a favorable response to therapies such as intravenous immunoglobulin (IVIg) or plasmapheresis.
- Immunoglobulin Levels: In patients receiving IVIg or subcutaneous immunoglobulin, measuring immunoglobulin levels could provide indirect evidence of the effectiveness of the treatment. A reduction in the frequency of relapses and improvements in clinical scales can also serve as indirect markers of success.
- Autoantibodies and Immune Markers: In some cases, monitoring levels of specific autoantibodies involved in the disease process can help assess treatment efficacy. For example, a decrease in anti–myelin protein antibodies could indicate a positive response to immunomodulatory treatments. Similarly, changes in cytokine profiles could reflect how well the immune system is responding to therapy.
3. Challenges and Limitations:
- Biomarkers Are Not Fully Established: While promising, biomarkers are still not fully validated for routine clinical use in CIDP. Much of the research is still in the experimental phase, and more studies are needed to establish standardized cutoff values and to determine their utility in everyday clinical practice.
- Variability in Biomarker Levels: Biomarker levels can vary widely among individuals and may be influenced by factors other than CIDP, such as other comorbid conditions or external variables like infections or other inflammatory diseases. This variability can limit the specificity and reliability of biomarkers in CIDP.
- Biomarker Integration Into Clinical Practice: Biomarkers, when used, should be integrated with clinical symptoms, electrophysiological findings, and patient history to make accurate clinical decisions. Biomarkers alone are not sufficient for diagnosing or monitoring CIDP in isolation.
In conclusion, biomarkers in CIDP have the potential to enhance diagnosis and monitoring of treatment response, but their use remains an evolving area of research. While NfL, autoantibodies, and inflammatory markers show promise, they are not yet standard in clinical practice. Clinicians should continue to rely on a comprehensive approach, combining biomarkers with clinical assessments and electrophysiological findings, to optimize care for patients with CIDP.
