Markedly upregulated serum semaphorin 4A as a novel activity marker of myasthenia gravis.

Myasthenia gravis (MG) is an autoantibody-mediated disease of the neuromuscular junction. Semaphorin 4A (Sema4A) is involved in the activation of T cells in various inflammatory disorders. In this study, we aimed to investigate whether Sema4A is involved in the pathogenesis of MG. We measured serum Sema4A concentrations in 30 treatment-naïve MG patients with acetylcholine receptor (AChR) antibodies, 7 with muscle-specific tyrosine kinase (MuSK) antibodies and 21 normal controls. As a result, serum Sema4A levels were significantly higher in patients with AChR antibody-positive MG and MuSK antibody-positive MG than in controls (p ≤ 0.0001 for both MG groups). Serum Sema4A levels were correlated with AChR antibody levels (Spearman's ρ = 0.39, p = 0.03) and MG Foundation of America clinical classification classes (Spearman's ρ = 0.38, p = 0.04) in patients with AChR antibody-positive MG. In conclusion, high serum Sema4A levels may reflect T-cell activation, and this molecule could be a potential marker of disease activity in MG.

Neurosarcoidosis with enlargement of the dorsal root ganglia: A case report.

We report the case of a woman in her 40s who presented with sensory disturbances in all 4 limbs and left facial palsy. MRI revealed asymmetric enlargement of the dorsal root ganglia, which was enhanced by gadolinium-a chest CT scan identified enlarged supraclavicular, mediastinal, and hilar lymph nodes. A biopsy of a hilar lymph node showed noncaseating epithelioid granulomas, confirming a sarcoidosis diagnosis. Prednisolone treatment led to symptomatic improvements. In sarcoidosis of the peripheral nervous system, there might be observable enlargement of the dorsal root ganglion alongside enhanced gadolinium contrast. Obtaining a biopsy from the dorsal root ganglion poses challenges, and radiologists should be mindful of this specific imaging characteristic.