A rapid method for detecting Junin virus viremia in the guinea pig.

A method for detecting Junin virus viremia in guinea pigs is described. The method consists of infecting BHK-21 cells with blood samples from infected guinea pigs; 48 h later, Junin virus antigens are detected in the cells by indirect immunofluorescence. Application of this technique to patients with Argentine hemorrhagic fever may lead to the quickest method for the virologic diagnosis of this disease.     

Immunofluorescent anti-Junin virus antibodies in Argentine hemorrhagic fever.

Immunofluorescent anti-Junin virus antibodies were detected in 15 nonfatal cases of Argentine hemorrhagic fever between the 2nd and 3rd week after onset of symptoms. In most cases, antibodies appeared by the day of clinical improvement, or between 2 and 4 days later. It was interesting to note that in 5 of 11 cases studied, the first positive serum sample presented anti-Junin virus immunofluorescent antibodies in IgA. In 2 of these 5 cases, IgA was the only immunoglobulin with antibody activity in the early positive serum sample.     

TNFRp55 modulates IL-6 and nitric oxide responses following Yersinia lipopolysaccharide stimulation in peritoneal macrophages

While cytokines are major regulators of macrophage activation following host-pathogen interactions, they also act to limit inflammation to avoid tissue damage. In previous studies we reported the development of progressive Yersinia enterocolitica-induced reactive arthritis (ReA) in mice lacking the tumor necrosis factor receptor p55 (TNFRp55). In this work, we analyzed the response of TNFRp55^−/− macrophages to Y. enterocolitica antigens. We found higher concentration of nitric oxide (NO) in TNFRp55^−/− compared to wild-type macrophages in response to heat-killed Yersinia (HKY) and Yersinia outer membranes (OM). Moreover, Toll-like receptor (TLR)4 expression was increased in OM-stimulated TNFRp55^−/− versus wild-type (WT) macrophages. Accordingly, NO production was inhibited in TLR4-deficient macrophages following stimulation with OM, suggesting that LPS may function as a major OM component implicated in these responses. Thus, augmented NO production together with enhanced expression of inducible nitric oxide synthase (iNOS) and higher IL-6 production, may provide a pro-inflammatory setting in Yersinia LPS-stimulated TNFRp55^−/− macrophages. Augmented synthesis of NO and IL-6 was prevented by treatment with Polymyxin B, or by exposure to a specific NF-κB p65 oligonucleotide antisense, indicating the involvement of TLR4-mediated NF-κB activation in the unleashed pro-inflammatory response triggered by TNFRp55 deficiency. Thus, TNFRp55 modulates macrophage functions in response to Yersinia LPS stimulation through mechanisms involving NO, IL-6 and NF-κB pathways, suggesting an essential regulatory role of TNF via TNFRp55 signaling.     

Expanding the Universe of Cytokines and Pattern Recognition Receptors: Galectins and Glycans in Innate Immunity

Effective immunity relies on the recognition of pathogens and tumors by innate immune cells through diverse pattern recognition receptors (PRRs) that lead to initiation of signaling processes and secretion of pro- and anti-inflammatory cytokines. Galectins, a family of endogenous lectins widely expressed in infected and neoplastic tissues have emerged as part of the portfolio of soluble mediators and pattern recognition receptors responsible for eliciting and controlling innate immunity. These highly conserved glycan-binding proteins can control immune cell processes through binding to specific glycan structures on pathogens and tumors or by acting intracellularly via modulation of selective signaling pathways. Recent findings demonstrate that various galectin family members influence the fate and physiology of different innate immune cells including polymorphonuclear neutrophils, mast cells, macrophages, and dendritic cells. Moreover, several pathogens may actually utilize galectins as a mechanism of host invasion. In this review, we aim to highlight and integrate recent discoveries that have led to our current understanding of the role of galectins in host–pathogen interactions and innate immunity. Challenges for the future will embrace the rational manipulation of galectin–glycan interactions to instruct and shape innate immunity during microbial infections, inflammation, and cancer.     

Common FMF alleles may predispose to development of Behcet's disease with increased risk for venous thrombosis

BACKGROUND: Behcet's disease (BD) is an inflammatory disorder of unknown cause, associated with vasculitis. Arterial or venous thrombosis occurs in about 25% of BD patients. Familial Mediterranean fever (FMF) is another inflammatory disorder, which stems from mutations in the FMF gene (MEFV) and shares a number of features with BD. OBJECTIVE: MEFV analysis in patients with BD suggests that mutated MEFV may act as a susceptibility gene in BD. We studied the rate and the clinical correlates of MEFV mutations in Israeli BD patients. METHODS: Included were 54 BD patients who satisfied the International Study Group criteria for BD. All BD patients were genotyped using polymerase chain reaction (PCR) and restriction enzyme analysis for the three most common MEFV mutations (M694V, V726A, and E148Q). The association between BD manifestations and MEFV alleles was analysed. RESULTS: Twenty-one BD patients were found to carry a single MEFV mutation and three additional patients were compound heterozygotes, a frequency significantly higher than that expected for ethnically matched healthy individuals. There were no statistically significant differences between carriers and non-carriers with respect to gender, frequency of HLA B5 antigen, cutaneous lesions, joint disease, and severity score. However, carriers did experience thrombosis more often [54% vs. 17%, p<0.005, odds ratio (OR) = 6.9, 95% confidence interval (CI) 1.75-26.9] and uveitis less often (20% vs. 40%, p<0.05, OR = 0.2, 95% CI 0.04-0.92). CONCLUSIONS: MEFV appears to be a susceptibility and modifier gene in BD.     

Health status of patients with juvenile rheumatoid arthritis at 1 and 5 years after diagnosis

OBJECTIVE: To describe the health and functional status of children with juvenile rheumatoid arthritis (JRA) diagnosed in the early 1990s. METHODS: Patients were obtained from the Pediatric Rheumatology Disease Registry, a database of patients seen in pediatric rheumatology centers across the United States. Questionnaires designed to be filled out after retrospective chart review were sent to pediatric rheumatologists caring for children diagnosed with JRA between 1992 and 1997. RESULTS: We studied 703 patients -- 376 with pauciarticular onset (pauci), 232 with polyarticular onset (poly), and 95 with systemic onset JRA (systemic). At 1 year after diagnosis, half of the pauci and systemic patients no longer required medication, compared to 78% of the poly patients; 98% of the patients functioned in Steinbrocker classes I and II. Six percent of pauci, 27% of poly, and 11% of systemic patients had limitations in school function. Nearly 1/3 of poly patients already had joint space narrowing on radiograph. By 5 years after diagnosis, all pauci, 88% of poly, and 70% of systemic patients were in Steinbrocker classes I and II; but 6% of pauci, 28% of poly, and 44% of systemic patients had limitations in school function. Nearly 2/3 of poly and systemic patients had joint space narrowing. CONCLUSION: In these children treated prior to the era of biologic therapy, at 5 years after onset, > 25% of poly and nearly half of systemic patients had functional limitations that required modifications in their school schedule. Radiographically evident joint space damage was seen within a year of onset in poly patients, and by 5 years 2/3 of poly and systemic patients had damage.