Clinical significance of a single cerebrospinal fluid immunoglobulin band: A retrospective study

Paraneoplastic cerebellar and brainstem disorders

Paraneoplastic cerebellar and brainstem disorders are a heterogeneous group that requires prompt recognition and treatment to help prevent irreversible neurologic injury. Paraneoplastic cerebellar degeneration is best characterized by Yo antibodies in patients with breast or ovarian cancer. Tr (DNER) antibodies in patients with Hodgkin lymphoma can also present with a pure cerebellar syndrome and is one of the few paraneoplastic syndromes found with hematological malignancy. Opsoclonus-myoclonus-ataxia syndrome presents in both pediatric and adult patients with characteristic clinical findings. Other paraneoplastic brainstem syndromes are associated with Ma2 and Hu antibodies, which can cause widespread neurologic dysfunction. The differential for these disorders is broad and also includes pharmacological side effects, infection or postinfectious processes, and neurodegenerative diseases. Although these immune-mediated disorders have been known for many years, mechanisms of pathogenesis are still unclear, and optimal treatment has not been established.

The contribute of cerebrospinal fluid free light-chain assay in the diagnosis of multiple sclerosis and other neurological diseases in an Italian multicenter study

BACKGROUND

Cerebrospinal fluid (CSF) free light chains (FLCs) can be an alternative assay to oligoclonal bands (OCBs) in inflammatory neurological disorders, but threshold has no consensus.

OBJECTIVE

To assess the diagnostic accuracy of CSF FLCs in multiple sclerosis (MS) and other neurological diseases.

METHODS

A total of 406 patients from five Italian centers. FLCs were measured in CSF and serum using Freelite MX assays on Optilite.

RESULTS

A total of 171 patients were diagnosed as MS, 154 non-inflammatory neurological diseases, 48 inflammatory central nervous system (CNS) diseases, and 33 peripheral neurological diseases. Both kFLC and λFLC indices were significantly higher in patients with MS compared to other groups (p < 0.0001). The kFLC index ⩾ 6.4 is comparable to OCB for MS diagnosis (area under the receiver operating characteristic curve (AUC) = 0.876; sensitivity 83.6% vs 84.2%; specificity 88.5% vs 90.6%). λFLC index ⩾ 5 showed an AUC of 0.616, sensitivity of 33.3% and specificity of 90.6%. In all, 12/27 (44.4%) MS patients with negative OCB had kFLC index ⩾ 6.4. Interestingly, 37.5% of 24 patients with a single CSF IgG band showed high kFLC index and 12.5% positive λFLC index.

CONCLUSION

Our findings support the diagnostic utility of FLC indices in MS and other CNS inflammatory disorders, suggesting a combined use of FLC and OCB to help clinicians with complementary information.