More Evidence that Kir4.1 is not the causal target for MS

Brill L, Goldberg L, Karni A, Petrou P, Abramsky O, Ovadia H, Ben-Hur T, Karussis D, Vaknin-Dembinsky A.Increased anti-KIR4.1 antibodies in multiple sclerosis: Could it be a marker of disease relapse? Mult Scler. 2014 Nov. pii: 1352458514551779. [Epub ahead of print]

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.
AIMS: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.


It had been suggested that 50% of MSers have antibodies but this observation has not been replicated by a number of labs, and this adds one more nail in that coffin. However it was found in about 25% o MSers and NMOers, but was more common than in non MSers and were more common in relapse. Is this a marker of disease exacerbation but do we need a  marker for something that you are sensing..maybe but there is more negative data on the way about the likelihood that that anti-bodies against this potassium channel are highly expressed in MS.

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