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Publications

Journal Article Ahead of print 1 citation

PubMed: 42091137 DOI: 10.1177/13524585261442020

Kappa free light chain index or oligoclonal bands testing in clinical practice for multiple sclerosis diagnosis: An algorithm comparative study.

Mult Scler

Authors: Michaël Levraut, Mikael Cohen, Delphine Sterlin, Xavier Ayrignac, Kévin Bigaut, Hélène Zéphir, Jonathan Ciron, Jean-Philippe Camdessanché, Olivier Casez, Thibault Moreau, Elisabeth Maillart, Aude Maurousset, David Laplaud, Edith Bigot, Jean Pelletier, Eric Thouvenot, Christine Lebrun-Frénay

Affiliations

  • Unité de Recherche Clinique Côte d"Azur (UR2CA-URRIS), Centre Hospitalier Universitaire de Nice, Centre de Ressources et de Compétences Sclérose en Plaques (CRC-SEP), Nice, France.
  • Unité de Recherche Clinique Côte d"Azur (UR2CA-URRIS), Centre Hospitalier Universitaire de Nice, Centre de Ressources et de Compétences Sclérose en Plaques (CRC-SEP), Nice, France; Département de Neurologie, CRC-SEP, Centre Hospitalier Universitaire de Nice, Nice, France.
  • Laboratoire d'Immunologie, Assistance Publique des Hôpitaux de Paris, Centre Hospitalier Universitaire de la Pitié-Salpêtrière, Paris, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Montpellier, Montpellier, France.
  • Département de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
  • Université de Lille, Inserm U1172, CHU de Lille, Lille, France.
  • Département de Neurologie, CRC-SEP, Centre Hospitalier Universitaire de Toulouse, Toulouse Cédex, France.
  • Université Toulouse III, Infinity, Inserm UMR1291 - CNRS UMR5051, Toulouse Cédex, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Etienne, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Grenoble, Grenoble, France.
  • Département de Neurologie, Centre Hospitalier de Dijon, Dijon, France.
  • Département de Neurologie, Assistance Publique des Hôpitaux de Paris, Centre Hospitalier Universitaire de la Pitié-Salpêtrière, Paris, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Tours, Tours, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Nantes, Nantes, France.
  • Département de Biochimie, Centre Hospitalier Universitaire de Nantes, Nantes, France.
  • Département de Neurologie, Assistance publique des Hôpitaux de Marseille, Centre Hospitalier Universitaire de La Timone, Marseille, France.
  • Département de Neurologie, Centre Hospitalier Universitaire de Nîmes, Nîmes, France.

Abstract

BACKGROUND

Limited evidence exists on how to use kappa free light chains (κFLCs) and oligoclonal bands (OCBs) in diagnosing intrathecal immunoglobulin synthesis (IgS).

OBJECTIVE

To compare different algorithms to define IgS.

METHODS

A retrospective analysis of the 2022 French cohort study was conducted. Patients were considered to have IgS if (1) the κFLC index was ⩾6.1, (2) OCB was positive, (3) the κFLC index was ⩾6.1 or OCB was positive, (4) the κFLC index was ⩾20 or OCB was positive, regardless of the κFLC index value, or (5) the κFLC index was ⩾20 or OCB was positive (with OCB tested only when the κFLC index was between 3.5 and 20). People with multiple sclerosis (MS) were compared with controls and with a subgroup of age- and sex-matched MS-mimicking disorders.

RESULTS

Of 1531 patients, 675 had MS and 856 were controls (133 MS mimics). Agreement between OCB and κFLC index (⩾6.1) was high (89%). All tested algorithms demonstrated high accuracy in separating groups. Using the sequential approach (5) achieves higher specificity and a significant reduction in OCB testing.

CONCLUSION

Using a simple cut-off point of 6.1 for routine screening is accurate, but testing for OCB when the κFLC index is between 3.5 and 20 increases specificity and should be prospectively studied in challenging cases.

MeSH

Research Design, Sclerosis, Multiple Sclerosis, Oligoclonal Bands, Algorithms, Demyelinating Diseases, Diagnosis