Interleukin 2 receptors and responsiveness to recombinant human interleukin 2 in patients with systemic lupus erythematosus

Phenotypic and functional similarities between 5-azacytidine-treated T cells and a T cell subset in patients with active systemic lupus erythematosus

OBJECTIVE

Antigen-specific CD4+ T cells treated with DNA methylation inhibitors become autoreactive, suggesting a novel mechanism for autoimmunity. To test whether this mechanism might be involved in systemic lupus erythematosus (SLE), phenotypic markers for the autoreactive cells were sought.

METHODS

Cloned normal T cells were treated with the DNA methylation inhibitor 5-azacytidine (5-azaC) and studied for altered gene expression. T cells from patients with active SLE were then studied for a similar change in gene expression, and cells expressing the marker were tested for autoreactivity.

RESULTS

5-azaC-treated normal T cells had increased CD11a (leukocyte function-associated antigen 1 alpha) expression relative to other membrane molecules. A T cell subset with similar CD11a expression was found in patients with active SLE. This subset contained cells that spontaneously lysed autologous macrophages, with a specificity similar to that of 5-azaC-treated cells.

Serum soluble interleukin 2 receptor in systemic lupus erythematosus: effects of disease activity and infection

Serum soluble interleukin 2 receptor (sIL2R) was measured in patients with active and inactive systemic lupus erythematosus (SLE). The concentration of sIL2R was higher in inactive SLE than in normal controls and was significantly increased in active compared with inactive SLE. When patients with active SLE were followed up serially it was found that the sIL2R concentration fell when the disease became inactive. There was no statistically significant association between sIL2R and the grades of disease activity, however. In patients with either active or inactive SLE and infection the sIL2R concentration was much higher than in those without infection. Chronic infection (tuberculosis or candida) was associated with a much higher concentration of sIL2R than pyogenic or herpes zoster infection. The sIL2R concentration helps to distinguish infection in patients with SLE.

Natural killer cell activity in Sjögren's syndrome and systemic lupus erythematosus: stimulation with interferons and interleukin-2 and correlation with immune complexes

Natural killer (NK) cell activity and its stimulation by interferons (IFNs) and interleukin-2 (IL-2) are diminished in Sjögren's syndrome and systemic lupus erythematosus (SLE). Serum samples of these patients often contain circulating immune complexes, which may influence NK cell activity. Sixteen patients with Sjögren's syndrome (14/16 immune complex positive), 14 with SLE (9/14 immune complex positive), and 11 controls (immune complex negative) were studied. Mononuclear cells collected from a Percoll gradient were preincubated with recombinant IFN-alpha (rIFN-alpha) (100 U/ml), rIFN-gamma (1000 U/ml), rIL-2 (100 U/ml), or without cytokine. Natural killer cell activity was determined by incubating the mononuclear cells with carboxyfluorescein labelled K562 cells, and the percentage decrease of fluorescence was measured on an FACS Analyzer. In patients with Sjögren's syndrome and SLE NK cell activity and the numbers of cells expressing the NK cell associated antigens CD16 and Leu7 were diminished compared with the controls. Interleukin-2 stimulated NK cell activity significantly in comparison with the non-stimulated value in all studied groups, whereas IFN-gamma only stimulated NK cell activity in both patient groups and IFN-alpha only in patients with Sjögren's syndrome. There was no correlation between NK cell activity, with or without stimulation, and the immune complex concentrations. It is concluded that NK cell activity is decreased in Sjögren's syndrome and SLE and that it may be partially restored by IL-2 and IFN-gamma in both diseases, and by IFN-alpha in Sjögren's syndrome. The decrease of NK cell activity did not correlate with immune complex concentrations; on the other hand, decreased numbers of NK cells (CD16+ or Leu7+) and of cytokine concentrations might be important in the impaired NK cell activity in both diseases.

Rheumatoid arthritis: clinical considerations in diagnosis and management

Advances in the understanding of the immune response, in immunogenetics, and in better identification of microbial agents that produce arthritis have made possible more accurate diagnosis of rheumatoid arthritis. Epidemiologic study of groups of rheumatoid patients and their response to therapy has provided a broader perspective of the disease's course and management. Therapy must be guided by the acute or chronic phase of the disease and must embrace chemical, psychologic, and physical modalities to achieve the goals of pain relief and the restoration of immune balance. Rheumatoid arthritis can no longer be considered benign since it impairs the duration as well as the quality of life. Therapy should be aggressive depending upon the predictors of more destructive disease.