The effect of rifamycin SV on neutrophil functions in patients with rheumatoid arthritis

Application of NGS Technology in Understanding the Pathology of Autoimmune Diseases

NGS technologies have transformed clinical diagnostics and broadly used from neonatal emergencies to adult conditions where the diagnosis cannot be made based on clinical symptoms. Autoimmune diseases reveal complicate molecular background and traditional methods could not fully capture them. Certainly, NGS technologies meet the needs of modern exploratory research, diagnostic and pharmacotherapy. Therefore, the main purpose of this review was to briefly present the application of NGS technology used in recent years in the understanding of autoimmune diseases paying particular attention to autoimmune connective tissue diseases. The main issues are presented in four parts: (a) panels, whole-genome and -exome sequencing (WGS and WES) in diagnostic, (b) Human leukocyte antigens (HLA) as a diagnostic tool, (c) RNAseq, (d) microRNA and (f) microbiome. Although all these areas of research are extensive, it seems that epigenetic impact on the development of systemic autoimmune diseases will set trends for future studies on this area.

Interaction of rifalazil with oxidant-generating systems of human polymorphonuclear neutrophils

It is well acknowledged that ansamycins display immunosuppressive and anti-inflammatory properties in vitro and in vivo. Rifalazil, a new ansamycin derivative, has not been studied in the context of inflammation. In particular, there are no data on the possible interference of rifalazil with oxidant production by phagocytes. We have compared the antioxidant properties of rifalazil to those of rifampin, a drug well known in this context, by using cellular and acellular oxidant-generating systems. Oxidant production by polymorphonuclear neutrophils was measured in terms of cytochrome c reduction, lucigenin-amplified chemiluminescence (Lu-ACL), and the 2',7'-dichlorofluorescin diacetate H2 (DCFDA-H2) technique (intracellular oxidant production). Rifalazil impaired O2- production in a concentration-dependent manner, with 50% inhibitory concentrations (IC50) (concentrations which inhibit 50% of the response) of 5.4 (30 and 60 min of incubation) and 6.4 (30 min) mg/liter, respectively, for phorbol myristate acetate (PMA) and formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation. In agreement with the published fMLP-like activity of rifampin, the inhibitory effect of rifampin was significantly greater for fMLP (IC50 of 5.6 mg/liter) than for PMA (IC50 of 58 mg/liter) stimulation. Alteration of intracellular oxidant production was also observed with IC50 values similar to those obtained by the cytochrome assay. In addition, rifalazil and rifampin (> or = 25 mg/liter) scavenged O2-, as demonstrated by the acellular (hypoxanthine-xanthine oxidase) system. Interference with light detection systems was evidenced for both drugs by Lu-ACL. The clinical relevance of the antioxidant effect of rifalazil demonstrated in vitro, in particular its potential anti-inflammatory activity, requires further investigation.

Reverse transcriptase-PCR analysis of bacterial rRNA for detection and characterization of bacterial species in arthritis synovial tissue

Onset of rheumatoid arthritis (RA) is widely believed to be preceded by exposure to some environmental trigger such as bacterial infectious agents. The influence of bacteria on RA disease onset or pathology has to date been controversial, due to inconsistencies between groups in the report of bacterial species isolated from RA disease tissue. Using a modified technique of reverse transcriptase-PCR amplification, we have detected bacterial rRNA in the synovial tissue of late-stage RA and non-RA arthritis controls. This may be suggestive of the presence of live bacteria. Sequencing of cloned complementary rDNA (crDNA) products revealed a number of bacterial sequences in joint tissue from each patient, and from these analyses a comprehensive profile of the organisms present was compiled. This revealed a number of different organisms in each patient, some of which are common to both RA and non-RA controls and are probably opportunistic colonizers of previously diseased tissue and others which are unique species. These latter organisms may be candidates for a specific role in disease pathology and require further investigation to exclude them as causative agents in the complex bacterial millieu. In addition, many of the detected bacterial species have not been identified previously from synovial tissue or fluid from arthritis patients. These may not be easily cultivable, since they were not revealed in previous studies using conventional in vitro bacterial culture methods. In situ hybridization analyses have revealed the joint-associated bacterial rRNA to be both intra- and extracellular. The role of viable bacteria or their nucleic acids as triggers in disease onset or pathology in either RA or non-RA arthritis controls is unclear and requires further investigation.

Twenty years of experience with intra-articular rifamycin for chronic arthritides

Rheumatoid arthritis is a chronic progressive disease causing substantial morbidity and mortality for which current treatments are largely unsatisfactory. Over the past 20 years we have developed a novel therapeutic approach based on the intra-articular administration of rifamycin. The published studies on rifamycin therapy of rheumatoid arthritis and other chronic arthritic disorders, mainly from our group, are reviewed. Our results indicate that intra-articular rifamycin is effective against active synovitis and can profitably be combined with any basic therapy with slow-acting antirheumatic drugs. There is good evidence that the development of new erosions can be prevented or delayed by this treatment and that the balance between side-effects (mainly local pain) and antiarthritic activity is very favourable in the long term. Our observations have led us to hypothesize a possible systemic effect of rifamycin injected multilocally in peripheral joints; we believe that the available data deserve further investigation by independent researchers.

Rifamycins inhibit human neutrophil functions: new derivatives with potential antiinflammatory activity

In our study we investigated the effect of rifamycin SV, rifamycin B, rifampicin and five semisynthetic derivatives on human neutrophil functions such as locomotion, superoxide production and degranulation stimulated by specific agonists. All compounds were tested at concentrations ranging from 10(-9) to 10(-5) M. Among the newly synthesized compounds the most active we found to be the derivatives carrying an acidic substituent at C3: these significantly lowered the superoxide generation induced by PMA throughout the entire concentration range, whereas rifamycin SV, rifamycin B and rifampicin were effective only at the highest concentrations. Moreover, chemotactic movement was significantly attenuated by derivative R4, rifamycin B and rifamycin SV at high doses; granule enzyme release was unaffected by all compounds.

Clinical improvement in ankylosing spondylitis with rifamycin SV infiltrations of peripheral joints

In an open study, a new treatment modality was evaluated in 22 patients with active ankylosing spondylitis and compared with oral treatment. Patients were given a 10-week course of rifamycin SV infiltrations to all large peripheral joints, whether or not affected, and were followed for up to 12 months after the end of treatment. Clinical improvements observed at the end of the 10-week treatment cycle persisted for 12 months: morning stiffness (P less than 0.02); subjective pain (P less than 0.0001); Schober's test (P less than 0.006); hand-ground distance (P less than 0.001); erythrocyte sedimentation rate (P less than 0.001); and C-reactive protein (P less than 0.04). The number of painful joints became significantly lower at 6 (P less than 0.01) and 12 months (P less than 0.02) of the follow-up period. Oral administration of rifampin at three times the intra-articular dosage was devoid of any therapeutic activity. It is not known how treatment of peripheral joints influenced the inflammatory process at the level of the axial skeleton. These results must be considered preliminary due to the small number of patients and the short follow-up period, and because it was an open study.

Multiple intra-articular treatment of rheumatoid arthritis: a randomized prospective study comparing rifamycin SV with pefloxacin

In a randomized, prospective study the efficacy and tolerability of extensive multiple intra-articular administrations of two antibiotics, rifamycin SV and pefloxacin, were evaluated in 40 patients with classical or definite rheumatoid arthritis. Total weekly doses of 525 mg rifamycin or 560 mg pefloxacin were given for 10 weeks, and 12 months after treatment all clinical indices, erythrocyte sedimentation rate and C-reactive protein improved significantly in the rifamycin group. Some of the treatment indices (morning stiffness, severity of pain by visual analogue scale, grip strength and Ritchie's index) were already improved when the treatment ended, whereas others (erythrocyte sedimentation rate, C-reactive protein, number of painful and swollen joints) improved progressively during the follow-up. In the pefloxacin treatment group all indices except C-reactive protein and severity of pain determined using a visual analogue scale were significantly improved 12 months after treatment. Comparison of the two treatments showed a significant difference in erythrocyte sedimentation rate (P less than 0.047), Ritchie's index (P less than 0.036) and C-reactive protein (P less than 0.028) in favour of rifamycin.

Deficiency of neutrophil membrane antigen detected by monoclonal antibody in rheumatoid arthritis

Monoclonal antibodies (mAbs) against cell surface antigens and receptors are instrumental in defining specific membrane markers. mAbs GF 26.7.3 and MF 25.1 against human neutrophils modulated the activation mechanism of superoxide anion production induced by formyl-peptide and PMA in all subject. However, treatment with mAb MF 25.1 of neutrophils from patients with rheumatoid arthritis did not have any effect. This may suggest that the antigen which MF 25.1 binds is absent in rheumatoid conditions. This confirms our previous data showing that defective expression of membrane components is associated with neutrophil dysfunction.

Phagocytosis and intracellular killing of Staphylococcus aureus by polymorphonuclear cells from synovial fluid of patients with rheumatoid arthritis

The phagocytosis and intracellular killing by synovial fluid (SF) polymorphonuclear cells (PMN) of 10 patients with rheumatoid arthritis was studied. PMN phagocytosis was assessed by morphologic and microbiologic methods and intracellular killing was measured independently of continuous phagocytosis of Staphylococcus aureus. Phagocytosis of S aureus by SF PMN or peripheral blood (PB) PMN was as effective in the presence of synovial fluid as in the presence of serum. On average, SF PMN ingested S aureus opsonized with synovial fluid and serum more efficiently than patient or donor PB PMN did. Enhanced ingestion of S aureus was associated with increased expression of C3 receptors on the membrane of SF PMN. In the presence of heat-inactivated synovial fluid, the capacity of SF PMN to ingest S aureus was greater than that of patient or donor PB PMN. Under these conditions, phagocytic activity was correlated with Fc receptor expression. SF PMN was found to be as active in killing S aureus as PB PMN from healthy donors.

Uptake, intracellular activity, and influence of rifampin on normal function of polymorphonuclear leukocytes

Quinone and hydroquinone forms of rifampin accumulated in normal polymorphonuclear leukocytes (PMN) (maximal cellular to extracellular concentration ratio [C/Emax] +/- standard error of the mean, 9.36 +/- 0.54 and 8.82 +/- 0.65, respectively, after 5 to 10 min) and chronic granulomatous disease PMN (C/Emax, 13.76 +/- 0.77 and 14.29, respectively). Uptake of rifampin was influenced by incubation temperature and extracellular pH but not by phorbol myristate acetate stimulation or metabolic inhibitors. At extracellular concentrations between 0.06 and 5.0 mg/liter, rifampin significantly reduced the number of staphylococci surviving inside chronic granulomatous disease PMN, thus compensating for the bactericidal defect inherent with this disease. Spontaneous migration and chemotaxis of normal PMN were unaffected by rifampin. However, phagocytosis of yeast particles and oxygen consumption of stimulated PMN were moderately depressed, and O2- production and chemiluminescence were significantly depressed in a dose-dependent manner. The bactericidal activity of normal PMN was not impaired. Inhibition of chemiluminescence and O2- release were also observed in a cell-free system. We conclude that rifampin possesses favorable characteristics for the effective elimination of intracellular microorganisms. Further studies are needed to evaluate the in vivo significance of ion scavenging by rifampin, which could be hazardous to immunocompromised patients.

Phagocytosis and intracellular killing by polymorphonuclear cells from patients with rheumatoid arthritis and Felty's syndrome

The present in vitro study concerned the phagocytosis and intracellular killing by polymorphonuclear cells (PMN) of 5 patients with rheumatoid arthritis (RA) and 12 patients with Felty's syndrome (FS). PMN phagocytosis was assessed by microbiologic and morphologic methods, and intracellular killing was measured independently of continuous phagocytosis of viable bacteria (Staphylococcus aureus). PMN from patients with RA or FS ingested S aureus opsonized with immunoglobulins and complement as effectively as did PMN from healthy donors. However, the capacity of patient PMN to ingest S aureus opsonized with sera lacking complement activity, e.g., heat-inactivated donor serum and the sera of 2 patients with FS, was lower than that of healthy donor PMN. This decreased ingestion is associated with diminished expression of Fc receptors on the membrane of PMN from patients who have RA or FS. As with sera lacking complement activity, decreased capacity to ingest S aureus was observed after preloading donor PMN with immune aggregates, which also decreased the expression of Fc receptors. PMN from patients with RA or FS were found to be as active in killing S aureus as cells from healthy donors.

Effect of antiinflammatory agents on neutrophil superoxide production in rheumatoid arthritis

Granulocyte superoxide production by different stimuli was studied in 14 patients suffering from rheumatoid arthritis, and in four cases defective O(2) generation was shown. The effect of two chemically related drugs, such as indomethacin and oxamethacin, was also evaluated, since we have previously investigated the action of antiinflammatory agents on cell locomotion. Indomethacin did not affect O(2) production, whereas oxamethacin reduced significantly superoxide generation in PMNs from all subjects tested. Moreover, the extent of the effect was dependent on the stimulant used, being larger when the activation of O(2) generating system was induced by opsonized zymosan.