Cyclic nucleotides (cAMP, cGMP) play a major role in inflammatory processes and may even be involved in the cellular control of immune responses [10,24,25]. The metabolic and kinetic functions of peripheral polymorphonuclear leukocytes (PMNs) in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are modulated, and lymphocyte functions are altered in regard to spontaneous or specific responses of B cells and T cells in such diseases. Thus, a study of cyclic nucleotides in the cells from SLE patients should shed light on the relationship between cyclic nucleotides and alterations in cellular immune responses. Although the data are preliminary, we found significant alterations of intracellular cyclic nucleotides in SLE patients, especially in patients with central nervous system (CNS) involvement. The clinical importance of these changes is also discussed.
Blood was obtained from 12 RA patients, 10 SLE patients, and 10 disease-free subjects. The diagnosis of RA and SLE was made according to the criteria of the American Rheumatism Association [8,9], and all patients satisfied the criteria. The clinical description of the SLE patients studied is given in Table 1. The age of the normal subjects (who were students on the nursing school and medical staffs) ranged between 17 and 24 years; 7 of them were women and 3 were men. All patients with SLE were active and had been treated with prednisolone varying from 10 mg to 60 mg daily. Four patients had CNS involvement. None of them had received cytotoxic agents. Lymphocytes and PMNs were obtained from heparinized venous blood using Boyum's method [5]. Briefly, mononuclear cells and PMNs were obtained by Ficoll-Hypaque gradient centrifugation, and the PMNs were