Tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) play a main role in inducing acute phase protein production by hepatocytes. This study describes the serum levels of TNF alpha and IL-6 in relation to serum levels of C-reactive protein (CRP) and alpha 1-acid glycoprotein (alpha 1AG) in three systemic lupus erythematosus (SLE) patients. Disease courses of these patients were divided in a total of 19 clinical periods, according to the clinical symptoms and interleukin profiles. Significantly elevated TNF alpha levels were found in all but three of the defined periods, without being associated with disease activity. In only four of the defined periods elevated TNF alpha were observed combined with elevated IL-6 and CRP levels. Two of these periods coincided with minor symptoms of SLE, one with an exacerbation and the other one with a systemic infection while SLE activity was low. All other periods showed varying combinations of elevated TNF alpha and/or IL-6 levels being followed or not by elevated CRP levels. Significantly raised alpha 1AG levels were measured in all clinical periods. In most of the observed periods a dissociation was found between TNF alpha and IL-6 and also between the different cytokine (TNF alpha and IL-6) levels and acute phase protein (CRP and alpha 1AG) levels. These data could not be explained by differences in disease course or influences of medication. We conclude that more factors other than TNF alpha and IL-6 must play a role in the regulatory pathway of the acute phase response in SLE.(ABSTRACT TRUNCATED AT 250 WORDS)

SummarySystemic lupus erythematosus (SLE) patients are characterized by a low lymphocyte count, which is considered a specific disease marker and is related to disease activity. The membrane bound molecules CD25 and CD27 are expressed and released in a soluble CD25 (sCD25) and soluble CD27 (sCD27) form by activation of predominantly T cells. In previous studies it was claimed that sCD25 as well sCD27 might be used as parameters for activation of the immune system; a correlation between the sCD25 profile with the disease course in SLE patients was also shown. To assess the relationship between lymphocyte count and these T cell activation markers, we performed a cross-sectional and a longitudinal study. In the longitudinal study three SLE patients who were known for a long time at our outpatient clinic were studied. Both T cell markers strongly correlated with each other and formed a reflection of the disease course. In all 7 periods of exacerbation, which we observed in the 3 investigated patients, both levels increased preceding this period; however, no correlation was found with the lymphocyte count. In the cross sectional study of 69 patients with SLE, sCD25 and sCD27 levels were correlated with defined disease manifestations; sCD25 was elevated in all periods of increased disease activity. The same holds true for sCD27, with the exception of patients with nephritis in which the highest levels were observed. Both profiles of sCD25 and sCD27 were strongly correlated during the whole disease course. Our data prove that in the pathogenesis of SLE an active recruitement of unprimed and primed T cells takes place.

As autoantibodies are thought to participate in the pathogenesis of renal inflammation in systemic lupus erythematosis (SLE) we investigated associations between serological markers of disease activity in SLE and the activity of renal histopathological lesions in thirty-five patients with lupus nephritis (LN). We found the following prevalence of serum auto-antibodies in LN: IgG antinuclear antibodies (ANA) 100%, IgM ANA 69%, IgA ANA 60%, IgG anti-dsDNA 60%, IgM anti-dsDNA 71%, IgA anti-dsDNA 60%, anti-RNP 20%, anti-Sm 14%, anti-SSA 31%, anti-SSB 14%, anti-histone 37%, anti-cardiolipin 80% and antibody to ribosomal protein (anti-P) 6%. No correlation was found between serological parameters and the WHO-classification of biopsies. The activity-index of histological lesion, assessed according to the NIH-renal histology scoring system, correlated with IgM ANA and IgM anti-dsDNA titers. Of all the specific features of histological renal inflammation, glomerular proliferation showed the best overall correlation with serological parameters of disease activity. Anticardiolipin antibodies were correlated with overall disease activity, but not with renal histological activity. Thus, serological markers of disease activity did not adequately reflect the amount of renal inflammation in LN and cannot replace renal biopsy as a diagnostic tool.