Generalized myositis mimicking polymyositis associated with chronic active Epstein-Barr virus infection.

BACKGROUND: Chronic generalized myositis has not so far been reported as a complication of chronic active Epstein-Barr virus infection (CAEBV). We encountered three patients with chronic generalized myositis mimicking polymyositis associated with CAEBV. METHODS: To clarify the pathological character of this myositis, we investigated the distribution, clonality, and the immunophenotype of EBV-infected cells and lymphocytes infiltrating in muscles. RESULTS: Clinically, two patients showed symmetrical proximal weakness and muscle atrophy as the initial and main symptom. Although the condition resembled polymyositis, they had also lingual and/or orbital myositis. The other patient showed generalized myositis at the late phase of CAEBV. In all of them, immunotherapy was ineffective and prognosis was poor. Intramuscular infiltrating lymphocytes in our patients were mainly CD45RO+, CD3+, CD4-, CD8-, TCR betaF1-, TCR deltaTCS1-, CD56-, CD79a-, CD21-, HLA-DR+, ZEBRA -, LMP1-, and EBER+ T cells. Oligoclonal expansion of EBV-infected T cells was shown in the muscles. However, there were no malignant lymphocytes. CONCLUSIONS: This new form of myositis must be distinguished from polymyositis and the other conventional forms of myositis. Careful investigation of hidden CAEBV is recommended when patients present with steroid non-responsive chronic progressive generalized myositis, in particular, with lingual or orbital involvement.

[Different clinical phenotypes of siblings with familial amyotrophic lateral sclerosis showing Cys146Arg point mutation of superoxide dismutase 1 gene].

We reported different clinical phenotypes of siblings with familial amyotrophic lateral sclerosis (FALS) showing Cys146Arg point mutation of superoxide dismutase 1 (SOD1) gene. They showed differences in disease onset of age, progression and severity. The propositus, a 50-year old woman, had muscle wasting and weakness in right lower leg with dysesthesia at the onset, which showed slow progression without other neurological symptoms until 2 years after the onset when bulbar palsy appeared. She has been alive for 3.5 years after the onset. In contrast, a 61-year old man, elder brother of the propositus, had bulbar palsy at the onset, which showed rapid progression along with muscle weakness and wasting of upper extremities. Two years after the onset, he died due to respiratory failure. Detailed clinical features of FALS with Cys146Arg mutation of SOD1 have not been reported. Our cases suggest that FALS with the same SOD1 mutation could show variable clinical feature and course, and that some factors other than SOD1 mutation should be considered for the pathogenesis of FALS.