A high κ-free light chain (κ-FLC) index may predict early disease activity in multiple sclerosis (MS) and, compared to determination of cerebrospinal fluid (CSF)-restricted oligoclonal band (OCB), has a prognostic value, according to study results published in Neurology Neuroimmunology & Neuroinflammation.
For patients with multiple sclerosis, the timing of starting treatment and whether moderately or highly efficacious disease-modifying therapies should be used are often debated, leading to the need for biomarkers to predict disease activity.
While the number of brain magnetic resonance imaging (MRI) lesions and OCBs in CSF provide some prognostic value, FLC in CSF is emerging as an improved biomarker in MS. To better understand this, a team of investigators conducted a study to determine whether κ- and λ-FLC index may predict early disease activity independent of demographics, clinical, and MRI characteristics.
Study investigators included a total of 88 patients (mean age, 33 years; 68% women) in the analysis with prospective follow-up for 3 to 4 years, at which time they tabulated the occurrence of a second clinical attack and the initiation of a disease-modifying therapy. OCBs were positive in 79 of the patients.
On follow-up (median, 47 months), 38 patients experienced a second clinical attack and were converted to clinically definite MS. At baseline, the κ-FLC index was 36.5 and positive in 76 of 88 patients. κ-FLC index was significantly related to white blood cell count (P <.001). Compared with patients who did not convert to clinically definite MS, those who did had a significantly elevated κ-FLC index during follow-up.
Conversely, the baseline λ-FLC index was a median 12.9 and positive in 55 of 88 patients. There were no significant relations between λ-FLC index and white blood cell count and number of T2 hyperintense and contrast-enhancing T1 lesions on MRI. λ-FLC index was higher, however, in patients who were positive for OCBs compared to those who were negative (P =.001).
Among patients who had a κ-FLC index greater than 100 at baseline, the probability for a second attack within 12 months was twice as likely compared with patients who had a lower κ-FLC index.
The likelihood of a second attack increased by 4 within 24 months for patients with a high κ-FLC index compared with those with a low index. The median time for a second attack among patients with high κ-FLC index was 11 months compared to 36 months for patients with a low κ-FLC index.
“Current evidence suggests that κ-FLC index is a reliable prognostic biomarker that might replace OCB determination taking us one step closer to tailored medicine in MS,” the study authors concluded. They added that “further studies in a multicenter setting including a higher number of patients are required to replicate the independent prognostic value of κ-FLC index in early MS. Also, besides clinical end points such as time to second clinical attack, it might be of interest to investigate how κ-FLC index performs for predicting MRI activity in the early MS disease course.”
Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.
Berek K, Bsteh G, Auer M, et al. Kappa-free light chains in CSF rredict early multiple sclerosis disease activity. Neurol Neuroimmunol Neuroinflamm. 2021;8(4):e1005. doi:10.1212/NXI.0000000000001005