Objective: To investigate the expression of inducible co-stimulator (ICOS) and other immunological molecules on peripheral blood T lymphocyte subsets in patients with systemic lupus erythematosus (SLE) and to find out the relationship with disease-activity, disease-stage and the contents of anti-dsDNA antibody and immunoglobulin in serum so as to pave the way for further studying the possibly immunologically pathological role of ICOS in SLE.
Methods: Peripheral blood samples were collected from 51 patients with SLE, 3 males and 22 females. Three-color flow cytometry was used to detect the levels of ICOS, CD45RO, CD45RA, and HLA-DR expression on the peripheral blood T lymphocytes subsets. The results were analyzed along with the disease-activity, disease-stage, contents of anti-dsDNA antibody and immunoglobulin in serum. Thirty healthy subjects were used as controls.
Results: Compared with the healthy subjects the level of ICOS expression on the peripheral blood CD4+ and CD8+ T cells in the patients with SLE during active- and stable-stages were significantly increased (all P < 0.05), but there was no significant difference between the last two group patients (P > or = 0.05); In the same patients, the level of ICOS expression on the peripheral blood CD4+, CD8+, CD45RO+, CD4+CD45RO+ and CD8+CD45RO+ cells in active-stage were significantly increased compared with those in stable-stage (P <0.05); The level of ICOS expression on the peripheral blood CD45RO+ cells in the untreated primary patients was higher than those with disease-relapse (P <0.05); The levels of ICOS expression on the peripheral blood CD45RO+ and CD4+CD45RO+ cells were significantly increased in the patients with serum anti-dsDNA antibody(+) and the patients with aberrantly high content of immunoglobulin compared with those of the patients with serum anti-dsDNA antibody(-) and the patients with normal content of immunoglobulin, respectively (all P < 0.05).
Conclusion: ICOS is aberrantly highly expressed on certain peripheral blood T lymphocyte subsets in patients with SLE, which is related to disease-activity, disease-stage and the contents of serum anti-dsDNA antibody and immunoglobulin, thus ICOS may play a role in SLE pathogenesis.