IL-6 blockade by monoclonal antibodies inhibits apolipoprotein (a) expression and lipoprotein (a) synthesis in humans.

Lipoprotein (a) [Lp(a)] is a highly atherogenic lipid particle. Although earlier reports suggested that Lp(a) levels are mostly determined by genetic factors, several recent studies have revealed that Lp(a) induction is also caused by chronic inflammation. Therefore, we aimed to examine whether cytokine blockade by monoclonal antibodies may inhibit Lp(a) metabolism. We found that interleukin 6 (IL-6) blockade by tocilizumab (TCZ) reduced Lp(a) while TNF-α-inhibition by adalimumab in humans had no effect. The specificity of IL-6 in regulating Lp(a) was further demonstrated by serological measurements of human subjects (n = 1,153) revealing that Lp(a) levels are increased in individuals with elevated serum IL-6. Transcriptomic analysis of human liver biopsies (n = 57) revealed typical IL-6 response genes being correlated with the LPA gene expression in vivo. On a molecular level, we found that TCZ inhibited IL-6-induced LPA mRNA and protein expression in human hepatocytes. Furthermore, examination of IL-6-responsive signal transducer and activator of transcription 3 binding sites within the LPA promoter by reporter gene assays, promoter deletion experiments, and electrophoretic mobility shift assay analysis showed that the Lp(a)-lowering effect of TCZ is specifically mediated via a responsive element at -46 to -40. Therefore, IL-6 blockade might be a potential therapeutic option to treat elevated Lp(a) serum concentrations in humans and might be a noninvasive alternative to lipid apheresis in the future.

Interleukin-6 and tumour necrosis factor-α differentially regulate lincRNA transcripts in cells of the innate immune system in vivo in human subjects with rheumatoid arthritis.

lincRNAs recently have been discovered as evolutionary conserved transcripts of non-coding DNA sequences and have been implicated in the regulation of cellular differentiation. In humans, molecular studies have suggested a functional role for lincRNAs in cancer development. The aim of the present study was to examine whether these novel molecules are specifically regulated by different cytokines in cells of the innate immune system in humans in vivo and whether lincRNAs thereby might be involved in the pathophysiology of rheumatoid arthritis (RA). Therefore, CD14(+) monocytes were isolated from RA patients before and after anti-IL-6R (tocilizumab) or anti-TNF-α (adalimumab) therapy and lincRNA transcription was analysed by a microarray based experiment. As expected, we found lincRNAs to be present in CD14(+) monocytes of RA patients. However, of the total number of 7.419 lincRNAs examined in this study only a very small number was significantly regulated by either IL-6 or TNF-α (85 lincRNAs, corresponding to 1.1%). The numbers of lincRNAs regulated was higher due to TNF-α compared to IL-6. Interestingly, none of the identified lincRNAs was influenced by both, IL-6 and TNF-α, suggesting the regulation of lincRNA transcription to be highly specific for distinct cytokines. Taken together, our results suggest (1) that lincRNAs are novel intracellular molecular effectors of specific cytokines in cells of the innate immune system in humans in vivo and (2) that lincRNAs might be involved in the molecular pathophysiology of RA.

The Schnitzler syndrome: chronic urticaria and monoclonal gammopathy--an autoinflammatory syndrome?

Schnitzler syndrome describes the simultaneous occurrence of monoclonal gammopathy and chronic urticaria with at least two additional minor symptoms (arthralgia, bone pain, fever of uncertain origin, hepato- or splenomegaly, lymphadenopathy, increased erythrocyte sedimentation rate, leukocytosis/thrombocytosis or increased bone density). Schnitzler syndrome is not wellknown and very likely under-recognized. Comprehensive diagnostic examinations are necessary to rule out other diseases, especially those of hematologic origin. Close interdisciplinary collaboration is mandatory. The etiology of Schnitzler syndrome is unclear, but the rapid response to the interleukin-1 receptor inhibitor anakinra underlines the pivotal role which the proinflammatory cytokine interleukin-1 may play in the pathophysiology of this potentially autoinflammatory disorder.

B Lymphocyte Stimulator (BLyS) is expressed in human adipocytes in vivo and is related to obesity but not to insulin resistance.

Inflammation and metabolism have been shown to be evolutionary linked and increasing evidence exists that pro-inflammatory factors are involved in the pathogenesis of obesity and type 2 diabetes. Until now, most data suggest that within adipose tissue these factors are secreted by cells of the innate immune system, e. g. macrophages. In the present study we demonstrate that B lymphocyte stimulator (BLyS) is increased in human obesity. In contrast to several pro-inflammatory factors, we found the source of BLyS in human adipose tissue to be the adipocytes rather than immune cells. In grade 3 obese human subjects, expression of BLyS in vivo in adipose tissue is significantly increased (p<0.001). Furthermore, BLyS serum levels are elevated in grade 3 human obesity (862.5+222.0 pg/ml vs. 543.7+60.7 pg/ml in lean controls, p<0.001) and are positively correlated to the BMI (r = 0.43, p<0.0002). In the present study, bariatric surgery significantly altered serum BLyS concentrations. In contrast, weight loss due to a very-low-calorie-formula-diet (800 kcal/d) had no such effect. To examine metabolic activity of BLyS, in a translational research approach, insulin sensitivity was measured in human subjects in vivo before and after treatment with the human recombinant anti-BLyS antibody belimumab. Since BLyS is known to promote B-cell proliferation and immunoglobulin secretion, the present data suggest that adipocytes of grade 3 obese human subjects are able to activate the adaptive immune system, suggesting that in metabolic inflammation in humans both, innate and adaptive immunity, are of pathophysiological relevance.

Biologics as treatment for systemic lupus: great efforts, sobering results, new challenges.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by specific organ manifestations and the production of autoantibodies to nuclear antigens. SLE can induce severe organ damage and carries the risk of fatal outcome. During recent years, no major progress has been made regarding new treatment options except for the introduction of mycophenolate mofetil. Therefore, the results of several large clinical trials using biological agents for treatment of SLE were hopefully awaited. Yet, the application of abatacept, belimumab and rituximab, respectively, to non-renal or renal lupus patients surprisingly has not been successful. Other studies using different agents have not been completed yet. Nevertheless, the results available so far will have a significant impact on the design of future clinical trials and will stimulate the debate on new targets for treatment of SLE.

C1qRP (CD93) expression on peripheral blood monocytes in patients with systemic lupus erythematosus.

Aim of the study was to compare the expression of monocytes C1qRp (CD93) in patients with systemic lupus erythematosus (SLE) with that of healthy controls and to determine the influence of glucocorticoids and LPS on C1qRp expression. Thirty-six SLE patients and 20 healthy controls were analyzed by flow cytometry. Additionally, monocytes from five patients and five controls were cultured and stimulated with dexamethasone, interferon-gamma and LPS, respectively, before the measurement of C1qRp expression. There was no difference in C1qRp expression between SLE and HC. SLE patients with no or only low dose steroids had a significantly higher C1qRp expression than those with higher doses. However, in vitro dexamethasone did not stimulate or down-regulate C1qRp expression. Upon LPS stimulation, C1qRp was significantly up regulated on monocytes both from patients and from controls. In conclusion, C1qRp expression and regulation was not altered in SLE patients. Possible relations with disease activity and medication need further investigations.