This controlled study examined the characteristics of serologic abnormalities in 52 patients receiving procainamide for cardiac arrhythmias, who had no symptoms of a connective tissue disease. Antinuclear antibodies occurred in 43 patients (83%). Significant elevation of antibody binding to single-stranded DNA (mean f SEM 30 f 2.6%), double-stranded DNA (13 f l.l%), Z-DNA (optical density 0.54 f 0.06), and p l y A (7.2 2 0.6%) was seen (P < 0.001). Thirty-four patients (65.4%) had antibodies to total histones, most frequently, the J42A/2B dmer. IgG antibodies to H2A/2B correlated with the cumulative procainamide dose. One patient subsequently developed drug-related lupus. Procainamide (PA) is the agent most commonly implicated in drug-related lupus (DRL), with DRL occurring in 30% of patients positive for fluorescent antinuclear antibody (FANA) who take PA. Many of the features of DRL are nonspecific, thus making diagnosis difficult. Autoantibodies have been proposed to be of value in the diagnosis of DRL and, possibly, in the identification of people at risk for the development of DRL (1). Antinuclear and antihistone antibodies (AHA) have been reported to be highly sensitive for DRL (1,2). However, there is little information regarding the prevalence, and type of serologic abnormalities in patients without symptoms of a connective tissue disease. We report here the results of our serologic evaluation of 52 such patients receiving long-term therapy with procainamide.
PATIENTS AND METHODSPatients. Fifty-two patients receiving PA who were attending the outpatient departments of the Veterans Administration (VA) or University of Cincinnati (UC) hospitals were included. There were 50 males (39 Caucasian and 11 black) and 2 females (1 black and 1 Caucasian). Their mean age was 65.8 years (range 47-82). The average daily dose of PA was 3.0 gm (range 0.75-5 gm), and the mean duration of therapy was 40 months (range 1 month to 8 years). Patients with evidence of systemic lupus erythematosus (SLE) at the time of study entry were excluded. Reevaluation of all patients was attempted to determine if evidence of lupus subsequently developed. DRL was diagnosed if patients developed musculoskeletal or pleuropericardial features which resolved upon discontinuation of PA. All 52 of these patients are part of a prospective study (3).Controls. Three groups of control subjects were assessed. One was a group of elderly subjects who were preselected based on age. These were 33 Caucasian individuals who were taking no medications; 28 were men and 5
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