Serum Anti-oligodendrocyte Autoantibodies in Patients With Multiple Sclerosis Detected by a Tissue-Based Immunofluorescence Assay.

Multiple sclerosis (MS), the most prevalent inflammatory disease of the central nervous system (CNS), is characterized by damaged to myelin sheaths and oligodendrocytes. Because MS patients have variable clinical courses and disease severities, it is important to identify biomarkers that predict disease activity and severity. In this study, we assessed the frequencies of serum autoantibodies against mature oligodendrocytes in MS patients using a tissue-based immunofluorescence assay (IFA) to determine whether anti-oligodendrocyte antibodies are associated with the clinical features of MS patients and whether they might be a biomarker to assess CNS tissue damage in MS patients. We assessed the binding of serum autoantibodies to mouse oligodendrocytes expressing Nogo-A, a reliable mature oligodendrocyte marker, by IFA with mouse brain and sera from 147 MS patients, comprising 103 relapsing-remitting MS (RRMS), 22 secondary progressive MS (SPMS), and 22 primary progressive MS (PPMS) patients, 38 neuromyelitis optica spectrum disorder (NMOSD) patients, 23 other inflammatory neurological disorder (OIND) patients, and 39 healthy controls (HCs). Western blotting (WB) was performed using extracted mouse cerebellum proteins and IgG from anti-oligodendrocyte antibody-positive MS patients. Tissue-based IFA showed that anti-oligodendrocyte antibodies were positive in 3/22 (13.6%) PPMS and 1/22 (4.5%) SPMS patients but not in RRMS, NMOSD, and OIND patients or HCs. WB demonstrated the target CNS proteins recognized by serum anti-oligodendrocyte antibodies were approximately 110 kDa and/or 150 kDa. Compared with anti-oligodendrocyte antibody-negative MS patients, MS patients with anti-oligodendrocyte antibodies were significantly older at the time of serum sampling, scored significantly higher on the Expanded Disability Status Scale and the Multiple Sclerosis Severity Score, and had a higher frequency of mental disturbance. Although the clinical significance of anti-oligodendrocyte antibodies is still unclear because of their low frequency, anti-oligodendrocyte autoantibodies are potential biomarkers for monitoring the disease pathology and progression in MS.

Antiplexin D1 Antibodies Relate to Small Fiber Neuropathy and Induce Neuropathic Pain in Animals.

OBJECTIVES: To assess the prevalence of antiplexin D1 antibodies (plexin D1-immunoglobulin G [IgG]) in small fiber neuropathy (SFN) and the effects of these antibodies in vivo. METHODS: We developed an ELISA for plexin D1-IgG using a recombinant extracellular domain of human plexin D1 containing the major epitope and sera from 58 subjects previously studied with a standard tissue-based indirect immunofluorescence assay (TBA). We screened 63 patients with probable SFN and 55 healthy controls (HCs) for serum plexin D1-IgG using ELISA. The results were confirmed by TBA. IgG from 3 plexin D1-IgG-positive patients, 2 plexin D1-IgG-negative inflammatory disease controls, and 2 HCs was intrathecally injected into mice, which were assessed for mechanical and thermal hypersensitivity 24 and 48 hours after injection. RESULTS: The ELISA had 75% sensitivity and 100% specificity using the TBA as a standard, and the coincidence rate of ELISA to TBA was 96.6% (56/58). The frequency of plexin D1-IgG was higher in patients with SFN than in HCs (12.7% [8/63] vs 0.0% [0/55], p = 0.007). Purified IgG from all 3 plexin D1-IgG-positive patients, but not 2 plexin D1-IgG-negative patients, induced significant mechanical and/or thermal hypersensitivity compared with IgG from HCs. In mice injected with plexin D1-IgG-positive but not D1-IgG-negative patient IgG, phosphorylated extracellular signal-regulated protein kinase immunoreactivity, an activation marker, was confined to small dorsal root ganglion neurons and was significantly more abundant than in mice injected with HC IgG. CONCLUSIONS: Plexin D1-IgG is pathogenic but with low prevalence and is a potential biomarker for immunotherapy in SFN.

Liver choline metabolism and gene expression in choline-deficient mice offspring differ with gender.

Choline is an important nutrient during pregnancy and lactation. Maternal choline deficiency in CD-1 mice lowers liver betaine levels in male offspring. By contrast, it increases elovl3 and vanin-1 mRNA levels in female offspring. Taken together, these observations suggest gender-specific responses to a choline-deficient diet.

Painful trigeminal neuropathy associated with anti-Plexin D1 antibody.

OBJECTIVE: To determine whether anti-Plexin D1 antibody (Plexin D1-immunoglobulin G [IgG]), which is associated with limb and trunk neuropathic pain (NP) and binds to pain-conducting small unmyelinated dorsal root ganglion (DRG) neurons, exists in patients with idiopathic painful trigeminal neuropathy (IPTN) and whether Plexin D1-IgG binds to trigeminal ganglion (TG) neurons. METHODS: We enrolled 21 consecutive patients with IPTN and 35 age- and sex-matched controls without NP (25 healthy persons and 10 with neurodegenerative diseases). We measured serum Plexin D1-IgG using a mouse DRG tissue-based indirect immunofluorescence assay (IFA) and by Western blotting (WB) using a recombinant human Plexin D1 (rhPlexin D1) accompanied by immunoadsorption tests with rhPlexin D1. The reactivity of Plexin D1-IgG toward mouse TG, brain, heart, and kidney was assessed by tissue-based IFAs. RESULTS: Serum Plexin D1-IgG was detected more frequently in IPTN than in controls by both IFA and WB (14.3% vs 0%, p = 0.048). Three Plexin D1-IgG-positive patients also had limb or trunk NP and commonly showed tongue pain. In tissue-based IFAs, IgG from 2 Plexin D1-IgG-positive patients immunostained small TG neurons, which was prevented by preincubation with rhPlexin D1. Moreover, Plexin D1-IgG immunostaining mostly colocalized with isolectin B4-positive pain-conducting unmyelinated TG neurons. IFAs of other tissues with the same IgG revealed weak immunoreactivity only in endothelial cells, which was prevented by preincubation with rhPlexin D1. CONCLUSIONS: Plexin D1-IgG, which binds to pain-conducting small TG neurons in addition to DRG neurons, can be present in IPTN as well as limb and trunk NP.

Central nervous system-specific antinuclear antibodies in patients with multiple sclerosis.

BACKGROUND: Nuclear antigen released from central nervous system (CNS) cells undergoing destruction may induce production of antinuclear antibodies (ANA). We characterized the CNS-specific production of ANA in multiple sclerosis (MS). METHODS: We assessed CNS-ANA binding to mouse cerebellar cell nuclei by immunofluorescence assay (IFA) with sera from 104 MS patients (91 relapsing-remitting; 13 secondary progressive), 30 patients with neuromyelitis optica spectrum disorders (NMOSD), and 30 healthy controls (HCs). Conventional ANA (cANA) was detected by IFA using human epithelial type-2 cells. CNS-ANA-positive cANA-negative patients were termed CNS-specific ANA-positive. Western blotting (WB) was performed using mouse cerebellar nuclear fractions. RESULTS: CNS-specific ANA were more frequent in MS than in NMOSD patients or HCs (13.5% vs 0% for both comparisons, both p < .05) and were associated with HLA-DRB1*15:01 (p = .0174). WB revealed a common 55 kDa band in seven MS patients. Compared with CNS-specific ANA-negative MS patients, those with 55 kDa band-immunoreactive CNS-specific ANA showed a higher frequency of secondary progressive MS (42.9% vs 10.0%, p = .0387) and greater Expanded Disability Status Scale scores (4.50 ± 2.02 vs 2.92 ± 2.27, p = .0506). CONCLUSIONS: The CNS-specific ANA was more frequently detected in MS patients than NMOSD patients or HCs. 55 kDa band-reactive CNS-specific ANA may reflect clinical disease progression in MS.