Microfibrillar-associated protein 4 as a potential marker of acute relapse in inflammatory demyelinating diseases of the central nervous system: Pathological and clinical aspects

BACKGROUND

Microfibrillar-associated protein 4 (MFAP4) is an extracellular matrix protein not previously described in the human central nervous system (CNS).

OBJECTIVES

We determined MFAP4 CNS expression and measured cerebrospinal fluid (CSF) and serum levels.

METHODS

Tissue was sampled at autopsy from patients with acute multiple sclerosis (MS) (n = 3), progressive MS (n = 3), neuromyelitis optica spectrum disorder (NMOSD) (n = 2), and controls (n = 9), including 6 healthy controls (HC). MFAP4 levels were measured in 152 patients: 49 MS, 62 NMOSD, 22 myelin oligodendrocyte glycoprotein-associated disease (MOGAD), and 19 isolated optic neuritis (ION).

RESULTS

MFAP4 localized to meninges and vascular/perivascular spaces, intense in the optic nerve. At sites of active inflammation, MFAP4 reactivity was reduced in NMOSD and acute MS and less in progressive MS. CSF MFAP4 levels were reduced during relapse and at the onset of diseases (mean U/mL: MS 14.3, MOGAD 9.7, and ION 14.6 relative to HC 17.9. (p = 0.013, p = 0.000, and p = 0.019, respectively). Patients with acute ON (n = 68) had reduced CSF MFAP4 (mean U/mL: 14.5, p = 0.006). CSF MFAP4 levels correlated negatively with relapse severity (rho = -0.41, p = 0.017).

CONCLUSION

MFAP4 immunoreactivity was reduced at sites of active inflammation. CSF levels of MFAP4 were reduced following relapse and may reflect disease activity.

Clinical spectrum, treatment and outcome of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease in children: a tertiary care experience

Anti-myelin oligodendrocyte glycoprotein antibodies have been associated with a wide range of clinical presentations including monophasic and relapsing disease courses. Lack of a definitive marker for predicting further relapses and the final diagnoses complicates the clinical follow-up and treatment decisions for patients with the first episode. This study retrospectively analyzed the clinical spectrum, treatment protocols and outcome of nine children with MOG antibody-associated demyelinating disease. Diagnoses at first presentation were acute disseminated encephalomyelitis (ADEM) in six cases (67%), optic neuritis in two cases (22%), and clinically isolated syndrome in one case (11%). The disease remained monophasic in five (56%) cases. All cases with a monophasic disease course were negative for anti-MOG antibody titers in the third month. The initial diagnosis of all relapsing cases was ADEM. Three of the four cases with a relapsing disease course were available for anti-MOG antibody testing at the third month and all were positive, however, antibody titers at the sixth month were inconsistent. Cases with a relapsing disease course had no further attacks after monthly intravenous immunoglobulin treatment. Relapsing disease course is not rare in childhood MOG-antibody associated demyelinating disease. Monthly IVIG treatment may be a good alternative for the long-term treatment of relapsing cases with a low side effect profile. Anti-MOG antibody serostatus at remission periods should be interpreted cautiously. Further studies are needed to better understand and predict the clinical course of pediatric patients with MOG-antibody associated diseases.

Inflammatory Demyelinating Lesions: True Sentinel Lesion or Immune-Mediated Response to Lymphoma?

BACKGROUND

Inflammatory demyelinating changes in the absence of malignant cells can sometimes be found on initial biopsies preceding the diagnosis of primary central nervous system lymphoma (PCNSL), resulting in the term "sentinel" lesion. Sentinel lesions have been reported sporadically in literature, resulting in many cases of misdiagnosis and delayed treatment. We aim to address the problem of misdiagnosis in PCNSL presenting as inflammatory demyelinating changes or sentinel lesions on initial biopsies, and to discuss our view of the mechanism underlying this phenomenon.

CASE DESCRIPTION

Herein we report 3 cases of PCNSL that were diagnosed via brain biopsy. We retrospectively reviewed 2 cases of initially misdiagnosed PCNSL presenting with sentinel lesions at our institution. Careful revision of preoperative magnetic resonance imaging (MRI) revealed heterogeneously enhancing tumors with strong peripheral enhancement and hypoenhancing cores. Analysis of our 2 cases revealed that initial biopsy samples in both patients were taken from the hypoenhancing regions on MRI. In the third case, we targeted the peripherally enhancing region for sampling and arrived at the proper diagnosis of PCNSL on initial biopsy.

CONCLUSIONS

Based on our cases and those reported in literature, we speculate that the inflammatory demyelinating changes observed on initial biopsies are immune-mediated responses that coexist with PCNSL in different tumor regions, and that they are the direct result of inadvertent sampling from hypoenhancing regions of the tumor, rather than sentinel lesions, as their name implies. We strongly recommend that biopsy target the most enhanced region on MRI when there is high clinical and radiologic suspicion for PCNSL.

Association Between the Single Nucleotide Polymorphism and the Level of Aquaporin-4 Protein Expression in Han and Minority Chinese with Inflammatory Demyelinating Diseases of the Central Nervous System

The purpose of this study was to determine whether or not aquaporin-4 (AQP4) gene mutations are related to the pathogenesis of inflammatory demyelinating diseases in the central nervous system. Polymorphisms of AQP4 exons 1-5 were determined by sequencing DNA from 67 patients with central nervous system inflammatory demyelinating diseases, including neuromyelitis optica (NMO), multiple sclerosis, recurrent or simultaneous bilateral optic neuritis, and longitudinally extensive transverse myelitis. A plasmid with the identified new missense mutation was constructed, and human embryonic kidney cells (HEK293A) were transfected with either the pEGFP-N1-AQP4-M23 vector (bearing the identified mutated cDNA sequence) or with the plasmid bearing the wild-type AQP4 gene sequence. AQP4 protein expression was analyzed in both experimental groups using Western Blot analysis following protein extraction from transfected cells. A synonymous mutation (rs1839318) was detected on exon 3, and an additional synonymous mutation was detected on the exon 2-2 (rs72557968). Most importantly, a new missense mutation was detected on exon 2-1. According to Western blot analysis, the mutated cDNA sequence yielded increased AQP4 protein expression in comparison with the wild-type cDNA sequence (P < 0.05). AQP4 gene mutations are uncommon, occurring in only 3 out of 67 patients. Although it is possible that the mutations contributed to an increased risk of inflammatory central nervous system disease in these individuals, it is unlikely that mutations are a significant contributor to most patients with NMO spectrum disorders in China.