Amyloid myopathy masquerading as polymyositis.

OBJECTIVE: It is not well appreciated that the clinical presentation of amyloid myopathy can mimic that of polymyositis. By retrospective clinicopathologic analysis we determined distinctive features of amyloid myopathy that differentiate the 2 diseases. METHODS: Two patients with clinical and histologic evidence of an inflammatory myopathy had fatal outcomes despite appropriate treatment for polymyositis. Their clinical course and original pathologic specimens were reviewed. In addition, original tissue samples were obtained and analyzed using Congo red staining and immunoperoxidase. RESULTS: The initial diagnosis of polymyositis was supported in both cases by muscle biopsies showing inflammatory infiltrates and elevations of creatine phosphokinase and by classic electromyography. Retrospective evaluation of the initial muscle biopsies disclosed subtle but incontrovertible evidence of vascular amyloid. Further analysis of the original specimens confirmed the presence of immunoglobin light chain (AL) amyloid. CONCLUSION: Amyloid myopathy can mimic polymyositis. Both can have similar clinical symptoms, as well as inflammatory infiltrates on muscle biopsy. Failure to recognize amyloid myopathy deprives patients of potentially life prolonging treatment. Congo red staining and immunohistochemical analysis of tissue could prevent misdiagnosis.

Hypocomplementemic urticarial vasculitis syndrome. Clinical and serologic findings in 18 patients.

We identify and describe clinical findings in hypocomplementemic urticarial vasculitis syndrome (HUVS), an uncommon to rare illness related to systemic lupus erythematosus (SLE). A patient with recurrent, idiopathic urticaria-like lesions was diagnosed as having HUVS if a lesional biopsy showed leukocytoclastic vasculitis, the serum C1q was markedly decreased, and antibody to C1q was detected in the patient's serum. The clinical characteristics, serologic findings, and outcome of patients who met these criteria were determined from prospective and retrospective data, including hospital and office records, patient interviews, previously banked serum samples, and freshly drawn sera. Eighteen patients with HUVS were identified, and high incidences of angioedema, ocular inflammation, glomerulonephritis, and obstructive pulmonary disease were found. Renal and lung biopsies showed mesangial or membranoproliferative glomerulonephritis and severe pulmonary emphysema without vasculitis. Pulmonary function was measured in 17 patients, 11 of whom had dyspnea. All dyspneic patients had moderate to severe airflow obstruction, which progressed in all 11 and subsequently improved in only 1. Six of these 11 patients died of respiratory failure, 1 underwent lung transplantation, and 3 of the remaining 4 have moderately severe to life-threatening respiratory insufficiency. Treatment did not appear to alter the progression of obstructive lung disease. In contrast, renal insufficiency improved with treatment in 2 of 2 patients. Angioedema, ocular inflammation, obstructive lung disease, and glomerulonephritis appear to be common in HUVS, and lung disease causes substantial morbidity and mortality. The pathogenesis of HUVS may involve humoral autoimmunity, although it is not clear how autoimmunity would participate in development of obstructive lung disease. Cigarette smoking appears to be a risk factor for fatal lung disease in HUVS. All patients with HUVS should be made aware of this possibility and should be advised, encouraged, and helped to avoid tobacco smoke.

Simple immuno bead labeling of leukemic cell clusters cultured in methylcellulose.

In studies of in vitro leukemic clonogenic cells it is of importance to determine the cell lineage of individual clusters grown in culture. A method is described for the in-situ identification of leukemic cell clusters in methylcellulose cultures. Whole cultures are dried and incubated with various monoclonal antibodies, followed by incubation with beads coated with secondary antibody. Clusters containing antibody-positive cells are heavily labeled with beads which simplifies the recognition and scoring of clusters using normal light microscopy. This method has general applications and can also be used to identify normal myeloid and lymphoid clusters depending on the availability of lineage specific monoclonal antibodies.