Clinical, laboratory, and pathologic observations in six patients with sensory motor peripheral neuropathy associated with the acquired immunodeficiency syndrome (AIDS) are presented. Blood and urine testing failed to reveal other causes for peripheral neuropathy. Distinctive CSF findings included elevated human immunodeficiency virus-specific indices. Peripheral nerve pathology confirmed the results of electrodiagnostic studies and revealed axonal loss and demyelination. Epineurial and endoneurial mononuclear infiltrates were present in three patients, and in one with early neuropathy, retroviral-like particles were present in peripheral nerve axoplasm. The findings indicate that in some patients with AIDS, neuropathy may be the direct result of a viral insult, although the causes are likely multifactorial.

A case of myasthenia gravis with histopathologic confirmation of spindle cell thymoma and pure red blood cell aplasia is reported. This is the twelfth case in the literature in which a simultaneous occurrence of all three disorders, with documented thymic pathology, is noted. Immunologic observations in this patient include an elevated acetylcholine receptor antibody and antinuclear antibody titer, agglutination of mouse red blood cells when combined with the patient's serum, and lack of inhibition of binding of radioactive erythropoietin to mouse red cell receptors when combined with the patient's serum. Although both myasthenia with thymoma and pure red blood cell aplasia may have a common immunologic denominator, our findings in this case indicate that inhibition of erythropoiesis is unrelated to erythropoietin receptor blockade. An alternative hypothesis is offered based on defective T-cell function.

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Clinical, electrodiagnostic, and biopsy findings in a family with infantile facioscapulohumeral muscular dystrophy are reported. Four of eight family members having the disorder, all with onset in infancy, developed severe weakness leading to death in adolescence. The clinical course and prognosis of infantile facioscapulohumeral muscular dystrophy may, therefore, be as devastating as that of Duchenne muscular dystrophy. The unusual infantile presentation and high mortality in our affected family members suggest that the gene coding for this disorder may be different from that responsible for conventional facioscapulohumeral muscular dystrophy.

Amyloid fibrils were isolated from the myocardium of two patients with familial amyloid polyneuropathy. The solubilized amyloid fibril whole protein shared immunologic determinants with normal human serum prealbumin (transthyretin), but revealed subtle differences on immunoelectrophoresis and radial immunodiffusion. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, amyloid fibril whole protein was resolved into numerous bands that reacted with antitransthyretin on immunoblots. The whole protein also contained peptide fragments of fibronectin, but was devoid of amyloid P protein. An antiserum raised against the whole protein was suitable for immunocytochemistry of amyloid in paraffin sections. In contrast, commercial antitransthyretin, raised against the intact tetrameric protein failed to react with tissue amyloid. Immunochemical and immunocytochemical results support the concept that familial amyloid polyneuropathy with cardiomyopathy is due to infiltration of susceptible tissues by an anomalous transthyretin.