CD4 cytopenia and occasional expansion of CD4+CD8+lymphocytes in Sjögren's syndrome.

OBJECTIVES: To define whether Sjögren's syndrome (SS) patients have lymphocytopenia compared to healthy controls, and to assess which lymphocyte subset might be involved. The presence of any concurrent infection was recorded. METHODS: A cohort of ten consecutive patients with SS was studied, and the results were compared with ten sex- and age-matched controls (C). RESULTS: In SS, a significant cytopenia of CD4+ (679 +/- 339 vs 1110 +/- 222 cells/mm3, p < 0.005) and an even more impressive decrease in the CD4+CD45 RA+ (242 +/- 154 vs 491 +/- 190 cells/mm3, p < 0.005) subset was observed. An absolute CD4 lymphocytopenia (CD4+ < 300 cells/mm3) was seen in two patients. In one patient an unusual finding was the expansion of a double positive population of CD4+CD8+ lymphocytes. No striking relationship with any particular infection was shown. A retrospective review of the absolute CD4+ cytopenia in 54 consecutive SS cases revealed a prevalence of 5.5%. CONCLUSION: Some SS patients have T lymphocytopenia which mainly affects the CD4+CD45 RA+ subset. Occasional cases with absolute CD4 lymphocytopenia may also be observed. These patients show some evidence of mild recurrent or chronic, but never severe, opportunistic infections.

Autoimmune connective tissue disease, chronic polyarthritides and B cell expansion: risks and perspectives with immunosuppressive drugs.

Several autoimmune diseases, including Sjögren's syndrome (SS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), are characterized by B cell hyperactivity, polyclonal activation, and autoantibody synthesis. Overt B cell clonal expansion occurs in a minority of the patients, while at the tissue level clonotypic B cells may be more easily detected in the majority of patients. The data available suggests that antigen-driven B cell expansion, eventually leading to somatic mutation and transformation, is the main event. Immunosuppressive drugs known to increase chromosomal damage and to lead to earlier transformation should therefore be avoided, unless strictly necessary to preserve vital organ functioning. New immunosuppressive drugs such as methotrexate, cyclosporine A, and Rapamycin are promising for they seem to offer effective control of disease-related organ damage with acceptable side effects. The B cell lymphoproliferative diseases occurring under treatment seem to remit spontaneously after prompt drug withdrawal. Close surveillance, employing new techniques capable of detecting early B or T cell clonal expansion, may allow better monitoring of possible complications. Biological agents such as alpha-interferon and monoclonal antibodies (which are directed against specific immunological mediators and thus target-selected steps of the immune-inflammatory process) have opened promising new research topics in all these diseases.

Sod and GSH inhibit the high glucose-induced oxidative damage and the PDGF increased secretion in cultured human endothelial cells.

Poor control of blood glucose has been established as a key pathogenetic mechanism in the vascular complications of diabetes. It has been reported that glucose may autooxidize generating free radicals which have been suggested to delay proliferation, to modify mobility, to influence platelet-derived growth factor and other secretory protein production in a variety of cell systems. Platelet-derived growth factor, in turn, may induce proliferation and migration of vascular smooth muscle cells and thus play a role in atherogenesis. In the present study the effects of antioxidants on the high glucose-dependent oxidative cell damage and increased platelet-derived growth factor secretion have been investigated using cultured human endothelial cells. Our findings show that rising the glucose concentration in the culture medium from 5 mM to 20 mM, increased the production of free radicals cell damage markers, such as malondialdehyde and conjugated dienes, as well as the production of platelet-derived growth factor. The addition of superoxide dismutase or glutathione prevents both such effects. These results suggest that antioxidants may be a helpful therapeutic adjuvant to reduce the vascular complications of diabetes.

The defence against free radicals protects endothelial cells from hyperglycaemia-induced plasminogen activator inhibitor 1 over-production.

It has been shown that hyperglycaemia may stimulate plasminogen activator inhibitor 1 (PAI-1) over-production in human endothelial cells in culture. At the same time, it has been shown that glucose may enolize, producing free radicals. In this study, the possibility that hyperglycaemia stimulates PAI-1 over-production in human endothelial cells in culture by generating free radicals has been evaluated. For this purpose two experimental models were used: human endothelial cells transfected to express high glutathione peroxidase levels cultured in hyperglycaemic media, and human endothelial cells cultured in hyperglycaemic media with the antioxidant GSH. Cells grown in 20 mM glucose produced higher values of PAI-1 with respect to controls. The production of PAI-1 was not influenced by hyperglycaemia in transfected cells. GSH in the medium reduced hyperglycaemia-induced PAI-1 over-production, but also reduces the basal production of PAI-1 in the cells grown in normal glucose concentration. These data show that antioxidant defences may reduce hyperglycaemia-induced PAI-1 over-production in human endothelial cells in culture. The hypothesis that oxidative stress may play an important role in the pathogenesis of diabetic complications is then supported by this study.