Serum deoxyribonuclease I (DNase I) activity in systemic lupus erythematosus (SLE) patients was shown to be lower than that of healthy laboratory personnel, rheumatoid arthritis, and scleroderma patients (P less than 0.001). The decrease in DNase I activity in SLE sera was not due to the effect of various autoantibodies or to heat labile DNase I inhibitor. A relationship between serum DNase I activity and active SLE was demonstrated. Patients with active lupus nephritis had the lowest levels of enzymatic activity.

Diffuse systemic sclerosis and the related syndromes were diagnosed in 115 patients during 1977-1987. Sixty-nine patients were available for clinical evaluation and analysis. These included 46 patients with diffuse systemic sclerosis, 2 with limited cutaneous systemic sclerosis, 2 with linear scleroderma, 18 with overlap syndrome (OS), and one with primary Raynaud's disease. The major clinical manifestations among the diffuse scleroderma patients were the involvement of the following systems; cutaneous (93.3%), musculoskeletal (69.6%), gastrointestinal (54.3%), and pulmonary (43.3%) while renal involvement (4.3%) was less common. Antinuclear antibodies were found in 89.7% with predominating speckle pattern (86.2%) and anti Scl 70 antibody (40.6%). In contrast to the Western series, HLA-DR2 was significantly increased in our diffuse systemic sclerosis patients (p less than 0.01). Among the 18 OS patients, the involvement of pulmonary system (44.4%) was the major cause of morbidity and renal involvement (55.6%) was found frequently although it was clinically mild. In conclusion, our diffuse systemic sclerosis and related diseases patients seem to have milder clinical manifestations than those of the Western series.

A simple radial diffusion technique is described for assaying deoxyribonuclease I (DNase I) activity in whole human plasma and serum. Enzymatic activity was calculated from a standard curve constructed from the studies on the hydrolysis of calf thymus DNA by bovine pancreatic DNase of known concentrations. The assay was shown to be specific for nucleases which are active at neutral pH and require magnesium ions for activation. There was no significant difference in DNase I activity in plasma compared with that in serum from normal individuals (P greater than 0.05). The DNase I activity of 35 normal human sera was 26.1 +/- 9.2 ng/ml and ranged from 10.8-48.5 ng/ml. This technique may prove useful for the evaluation of DNase I activity in crude biological fluids and is not affected by the presence of enzymatic inhibitors and/or activators.

Jaccoud's arthropathy is a syndrome of chronic progressive painless deformity of the hands and feet with surprisingly well preserved functions. The arthropathy has been known to develop subsequently to episodes of rheumatic fever. a patient is presented in this report with a clinical and radiologic finding indistinguishable from that of the Jaccound's arthropathy. However, the only associated illness is chronic lung disease.