Pathology Features of Immune and Inflammatory Myopathies, Including a Polymyositis Pattern, Relate Strongly to Serum Autoantibodies.

We asked whether myopathology features of immune or inflammatory myopathies (IIM), without reference to clinical or laboratory attributes, correlate with serum autoantibodies. Retrospective study included 148 muscle biopsies with: B-cell inflammatory foci (BIM), myovasculopathy, perimysial pathology (IMPP), myofiber necrosis without perimysial or vessel damage or inflammation (MNec), inflammation and myofiber vacuoles or mitochondrial pathology (IM-VAMP), granulomas, chronic graft-versus-host disease, or none of these criteria. 18 IIM-related serum autoantibodies were tested.

Sarcopenia, age, atrophy, and myopathy: Mitochondrial oxidative enzyme activities.

Introduction: We studied mitochondrial impairment as a factor in the pathologic equivalent of sarcopenia, muscle fiber atrophy associated with increased age.

Methods: Mitochondrial oxidative enzyme activities and coenzyme Q10 levels were measured in frozen human proximal limb muscles with combined age and atrophy, age alone, atrophy alone, denervation, immune myopathies, and mitochondrial disorders with ophthalmoplegia.

Results: Sarcopenia (age and atrophy) had reduced mean activities of mitochondrial Complexes I, II, and II+III, with severe reduction of Complex I activity in 54% of patients.

Myopathy with anti-HMGCR antibodies: Perimysium and myofiber pathology.

Objective: To analyze clinical features and myopathology changes in muscle fibers, connective tissue, and vessels in 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibody-associated myopathies.

Methods: Retrospective review of records and myopathologic features of 49 consecutive patients with myopathies and serum HMGCR antibodies.

Results: Clinical features included onset age from 12 to 83 years, female predominance (67%), proximal, symmetric weakness (84%), muscle discomfort (78%), dysphagia (35%), systemic features, including skin rash and interstitial lung disease (37%), statin use (38%), and a high serum creatine kinase (83%).

Myelinated and unmyelinated endoneurial axon quantitation and clinical correlation.

Introduction: Different disease patterns result from loss of myelinated and unmyelinated axons, but quantitation to define their loss has been difficult.

Methods: We measured large and small endoneurial axons in axonal neuropathies by staining them with peripherin and comparing their area to that of nonmyelinating Schwann cells stained with neural cell adhesion molecule (NCAM).

Results: Loss of myelinated and unmyelinated axons was typically proportional, with predominant myelinated or unmyelinated axon loss in a few patients.

Regional ischemic immune myopathy: a paraneoplastic dermatomyopathy.

Necrosis and regeneration of scattered muscle fibers are common features of many active acquired and immune myopathies. We studied a series of patients with acquired myopathies with an unusual pattern of regional, rather than scattered, muscle fiber necrosis and regeneration. Retrospective review of records of 7 patients with acquired myopathies having regional muscle fiber necrosis on muscle biopsy.

Clinical and laboratory features of neuropathies with serum IgM binding to TS-HDS.

Introduction: In this investigation we studied clinical and laboratory features of polyneuropathies in patients with serum IgM binding to the trisulfated disaccharide IdoA2S-GlcNS-6S (TS-HDS).

Methods: We retrospectively compared 58 patients with selective IgM binding to TS-HDS to 41 consecutive patients with polyneuropathies without TS-HDS binding.

Results: Patients with IgM vs.

Motor neuropathies and serum IgM binding to NS6S heparin disaccharide or GM1 ganglioside.

Background: Serum IgM binding to GM1 ganglioside (GM1) is often associated with chronic acquired motor neuropathies. This study compared the frequency and clinical associations of serum IgM binding to a different antigen, a disulphated heparin disaccharide (NS6S), with results of IgM binding to GM1.

Methods: Serums and clinical features were retrospectively compared from 75 patients with motor neuropathies and 134 controls with amyotrophic lateral sclerosis (ALS), chronic immune demyelinating polyneuropathy (CIDP) and sensory neuropathies.

Vascular pathology in dermatomyositis and anatomic relations to myopathology.

The causes of perifascicular myofiber atrophy and capillary pathology in dermatomyositis are incompletely understood. We studied 11 dermatomyositis muscles by histochemistry, immunohistochemistry, and ultrastructure. We found that endomysial capillaries within regions of perifascicular atrophy are not entirely lost, but they have reduced size, endothelial loss, C5b9 complement deposits, and relatively preserved connective tissue molecules and pericytes.

Sensory neuropathy with monoclonal IgM binding to a trisulfated heparin disaccharide.

We studied clinical and serological features of five patients with polyneuropathy and serum immunoglobulin M (IgM) binding to the trisulfated disaccharide IdoA2S-GlcNS-6S (TS-HDS), the most abundant disaccharide component of heparin oligosaccharides. The patients all had painful, predominantly sensory polyneuropathies. Sensory loss was distal and panmodal.

Severe sensory ataxia and demyelinating polyneuropathy with IgM anti-GM2 and GalNAc-GD1A antibodies.

Several polyneuropathy syndromes have been described with polyclonal serum immunoglobulin G (IgG) or immunoglobulin M (IgM) binding to gangliosides GM2 and GalNAc-GD1a that contain the terminal trisaccharide moiety GalNAc(beta1-4)Gal(alpha2-3)NeuAc. We describe the clinical and electrodiagnostic features in two patients with serum IgM monoclonal anti-GM2 and anti-GalNAc-GD1a antibodies. These patients had slowly progressive, panmodal sensory loss with severe sensory ataxia.