The deoxyribonucleic acid (DNA) skin test in systemic lupus erythematosus. I. Clinical evaluation

DNA skin tests in patients with definite or suspected systemic lupus erythematosus and in dermatological control patients. A long-term follow-up study

This study presents a long-term clinical and immunological follow-up of 62 patients during 1971 and 1973, tested intradermally with DNA derived from calf thymus. The DNA skin test is positive in almost all clear-cut cases of SLE. In addition, the DNA skin test was positive in 16 patients, but the criteria for SLE were not met at the time of testing. During the follow-up, 7 out of these 16 patients developed definite SLE, 2 developed subacute cutaneous LE and 3 developed ANA-negative SLE. This suggests that a positive DNA skin test may precede the development of SLE or some of its subtypes. All our SLE patients with skin test reactivity presented cutaneous disease manifestations suggesting that similar pathogenetic mechanisms may be involved in DNA tests and natural SLE skin lesions. Because the positive DNA skin test showed correlation with ANA, anti-DNA antibodies, cryoglobulins, lupus anticoagulant and depressed C3 and C4 values, humoral factors may be partly responsible. However, DNA skin test reactivity was also positive in ANA-negative SLE, suggesting that other mechanisms may also be involved.

Skin response to intradermal DNA and RNA in systemic lupus erythematosus

The local response of 18 patients with active systemic lupus erythematosus to 0.1 ml of intradermally injected 0.1% polymerized calf thymus DNA and synthetic double-stranded polyinosinic-polycytidylic acid was studied. In 14 patients positive for DNA, 61 +/- 8% of the inflammatory cells in the subepidermis at 24 hours were acid alpha-naphthyl acetate esterase-positive T lymphocytes. A leukocytoclastic vasculitis was observed in the deeper dermis. Rheumatoid arthritis patients and acne patients had negative responses. These results indicated an abnormal cellular and humoral in vivo response by patients with systemic lupus to DNA. It is suggested that the epidermal Langerhans cells were responsible for the topographic dichotomy of the local DNA response. Test results were positive for polyinosinic-polycytidylic acid in 12 patients, for DNA in 14 patients, and for both in 9 patients. In the 9 patients with positive results for both tests, comparison of responses to each test indicated that the reaction intensity was dependent on the patient and not on the type of polynucleotide acid that was injected.

The ribonucleic acid (RNA) skin test in systemic lupus erythematosus and other connective tissue diseases

A series of 65 patients with different autoimmune diseases was examined using different RNA-solutions for intradermal skin tests. Clinically positive results were obtained most often in patients with mixed connective tissue disease but quite often also in patients with systemic lupus erythematosus and progressive systemic sclerosis or with some symptoms of an automimmune nature. The histological examination of the biopsies from the test sites revealed that there was no correlation between the clinically positive tests and the histological criteria usually used as a sign of a positive test.