Increased anti-KIR4.1 antibodies in multiple sclerosis: could it be a marker of disease relapse?
BACKGROUND
Screening of putative autoimmune targets in multiple sclerosis (MS) revealed a proportion of patients carrying antibodies (Abs) against KIR4.1, a potassium channel that shares functional properties with AQP4. Both are localized at the perivascular astrocytic processes.


OBJECTIVE
To measure anti-KIR4.1 Abs in the serum of MS and neuromyelitis optica (NMO) patients, and to identify the clinical and laboratory characteristics of patients harboring anti-KIR4.1 Abs.


METHODS
We measured anti-KIR4.1 Abs in serum, using the peptide KIR4.1 (83-120) enzyme-linked immunosorbent assay (ELISA).


RESULTS
Serum levels of anti-KIR4.1 Abs were significantly higher in MS and NMO patients than in healthy controls (HCs); with Abs detected in 21 of 80, 10 of 45, and 2 of 32 individuals, respectively (MS versus HC, p < 0.05). The level of anti-KIR4.1 Abs was significantly higher during MS relapse, versus remission (p = 0.04). The clinical characteristics of our study patients did not vary based on KIR4.1 positivity.


CONCLUSIONS
Anti-KIR4.1 Abs were found in similar proportions of patients with MS and NMO, at a significantly higher level than observed in HCs; consequently, the presence of Abs does not discriminate between these demyelinating diseases. However, anti-KIR4.1 Ab levels differed in MS patients during relapse and remission; as such, they may represent a marker of disease exacerbation.
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Livnat
L
Brill
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Lotem
L
Goldberg
Neuroimmunology Laboratory, Department of Neurology, Tel Aviv Sourasky Medical Center, and 2Sackler's Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Arnon
A
Karni
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Panayiota
P
Petrou
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Oded
O
Abramsky
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Haim
H
Ovadia
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Tamir
T
Ben-Hur
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel.
Dimitrios
D
Karussis
Department of Neurology and Laboratory of Neuroimmunology, and the Agnes-Ginges Center for Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel adembinsky@gmail.com.
Adi
A
Vaknin-Dembinsky
D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis*; D002648:Child; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000276:immunology*; D009471:Neuromyelitis Optica / Q000276:immunology; D024661:Potassium Channels, Inwardly Rectifying / Q000276:immunology*; D011379:Prognosis; D012008:Recurrence; D015203:Reproducibility of Results; D000098854:Kcnj10 Channel
D001323:Autoantibodies; D015415:Biomarkers; D000098854:Kcnj10 Channel; D024661:Potassium Channels, Inwardly Rectifying
Autoimmune disease; KIR4.1; biomarker; immunoassay; immunology; multiple sclerosis; neuromyelitis optica; potassium channel; relapse