Predictive factors and prognosis of macrophage activation syndrome associated with adult-onset Still's disease.

OBJECTIVES: To summarise the clinical data of adult-onset Still's disease (AOSD) patients and analyse their clinical manifestations, predictors for the formation and prognosis of macrophage activation syndrome (MAS). METHODS: A retrospective analysis was performed on the clinical data of 182 AOSD hospitalised patients from the Department of Rheumatology of the First Affiliated Hospital of Zhengzhou University, China from January 2012 to August 2018, including 11 patients with pathogenesis of MAS. RESULTS: Compared with the patients without MAS, the patients with MAS had a higher incidence of splenomegaly and pericarditis at the initial diagnosis of AOSD. The number of platelets (PLT) and the concentration of fibrinogen (FIB), D-Dimer and ferritin were significantly higher in AOSD-MAS patients. Multivariate regression analysis showed that splenomegaly (OR: 5.748, 95% CI: 1.378-23.984, p=0.016), pericarditis (OR: 6.492, 95% CI: 1.43-29.461, p=0.015), and ferritin >2000 µg/L (OR: 4.715, 95% CI: 1.12-19.86, p=0.035) were risk factors for MAS. Survival analysis indicated that the mortality of AOSD-MAS patients was significantly higher than patients without MAS. CONCLUSIONS: Splenomegaly, pericarditis and elevated ferritin concentration are risk factors for MAS formation in AOSD patients. MAS resulted in a significant decrease in the survival rate of the AOSD patients.

EGFR transactivation contributes to neuroinflammation in Streptococcus suis meningitis.

BACKGROUND: Streptococcus suis serotype 2 (SS2) is an important zoonotic bacterial pathogen in both humans and animals, which can cause high morbidity and mortality. Meningitis is one of the major clinical manifestations of SS2 infection. However, the specific process of SS2 meningitis and its molecular mechanisms remain unclear. Epidermal growth factor receptor (EGFR) has been reported to initiate transduction of intracellular signals and regulate host inflammatory responses. Whether and how EGFR contributes to the development of S. suis meningitis are currently unknown. METHODS: The tyrosine phosphorylation of cellular proteins, the transactivation of EGFR, as well as its dimerization, and the associated signal transduction pathways were investigated by immunoprecipitation and western blotting. Real-time quantitative PCR was used to investigate the transcriptional level of the ErbB family members, EGFR-related ligands, cytokines, and chemokines. The secretion of cytokines and chemokines in the serum and brain were detected by Q-Plex™ Chemiluminescent ELISA. RESULTS: We found an important role of EGFR in SS2 strain SC19-induced meningitis. SC19 increasingly adhered to human brain microvascular endothelial cells (hBMEC) and caused inflammatory lesions in the brain tissues, with significant induction and secretion of proinflammatory cytokines and chemokines in the serum and brains. SC19 infection of hBMEC induced tyrosine phosphorylation of cellular EGFR in a ligand-dependent manner involving the EGF-like ligand HB-EGF, amphiregulin (AREG), and epiregulin (EREG) and led to heterodimerization of EGFR/ErbB3. The EGFR transactivation did not participate in SS2 strain SC19 adhesion of hBMEC, as well as in bacterial colonization in vivo. However, its transactivation contributed to the bacterial-induced neuroinflammation, via triggering the MAPK-ERK1/2 and NF-κB signaling pathways in hBMEC that promote the production of proinflammatory cytokines and chemokines. CONCLUSIONS: We investigated for the first time the tyrosine phosphorylation of cellular proteins in response to SS2 strain SC19 infection of hBMEC and demonstrated the contribution of EGFR to SS2-induced neuroinflammation. These observations propose a novel mechanism involving EGFR in SS2-mediated inflammatory responses in the brain, and therefore, EGFR might be an important host target for further investigation and prevention of neuroinflammation caused by SS2 strains.