From the Research
The presence of mirror pattern oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) does not typically support a diagnosis of multiple sclerosis (MS), and clinicians should consider alternative diagnoses or the possibility of a concurrent systemic inflammatory process. In MS, the characteristic OCB pattern is type 2, which shows unique bands in the CSF that are absent in the serum, indicating intrathecal immunoglobulin production 1. Mirror pattern OCBs, also known as type 4 pattern, show identical bands in both CSF and serum, suggesting that the immunoglobulins originated from the systemic circulation rather than being produced within the central nervous system. This mirror pattern is more commonly associated with systemic inflammatory conditions that affect the nervous system secondarily, such as systemic lupus erythematosus, Sjögren's syndrome, or systemic infections. Some studies have found that a significant proportion of patients with mirror pattern OCBs may still receive a diagnosis of MS, but this is less common than in patients with type 2 OCB patterns 2. Key points to consider in the interpretation of OCB patterns include:
- The technique used for OCB detection, with isoelectric focusing on agarose gels followed by immunoblotting being the recommended method 1
- The importance of analyzing paired undiluted CSF and serum samples to accurately determine the OCB pattern
- The potential for technical issues, such as blot, staining, and IEF reproducibility, to decrease reproducibility and lead to misinterpretations of results 1
- The need for specialized laboratories with expertise in OCB detection and interpretation to ensure accurate results. Given the most recent and highest quality study available, the presence of mirror pattern OCBs should prompt further investigation for other conditions that might explain the patient's neurological symptoms, rather than supporting an MS diagnosis 2.