Tumor necrosis factor-alpha, interleukin-6, and interleukin-8 secretion and the acute-phase response in patients with bacterial and tuberculous osteomyelitis

Establishment of a mandible defect model in rabbits infected with multiple bacteria and bioinformatics analysis

Objective: A model of chronic infectious mandibular defect (IMD) caused by mixed infection with Staphylococcus aureus and Pseudomonas aeruginosa was established to explore the occurrence and development of IMD and identify key genes by transcriptome sequencing and bioinformatics analysis. Methods: S. aureus and P. aeruginosa were diluted to 3 × 108 CFU/mL, and 6 × 3 × 3 mm defects lateral to the Mandibular Symphysis were induced in 28 New Zealand rabbits. Sodium Morrhuate (0.5%) and 50 μL bacterial solution were injected in turn. The modeling was completed after the bone wax closed; the effects were evaluated through postoperative observations, imaging and histological analyses. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein‒protein interaction (PPI) network analyses were performed to investigate the function of the differentially expressed genes (DEGs). Results: All rabbits showed characteristics of infection. The bacterial cultures were positive, and polymerase chain reaction (PCR) was used to identify S. aureus and P. aeruginosa. Cone beam CT and histological analyses showed inflammatory cell infiltration, pus formation in the medullary cavity, increased osteoclast activity in the defect area, and blurring at the edge of the bone defect. Bioinformatics analysis showed 1,804 DEGs, 743 were upregulated and 1,061 were downregulated. GO and KEGG analyses showed that the DEGs were enriched in immunity and osteogenesis inhibition, and the core genes identified by the PPI network were enriched in the Hedgehog pathway, which plays a role in inflammation and tissue repair; the MEF2 transcription factor family was predicted by IRegulon. Conclusion: By direct injection of bacterial solution into the rabbit mandible defect area, the rabbit chronic IMD model was successfully established. Based on the bioinformatics analysis, we speculate that the Hedgehog pathway and the MEF2 transcription factor family may be potential intervention targets for repairing IMD.

The osteoblast secretome in Staphylococcus aureus osteomyelitis

Osteomyelitis (OM) is an infectious disease of the bone predominantly caused by the opportunistic bacterium Staphylococcus aureus (S. aureus). Typically established upon hematogenous spread of the pathogen to the musculoskeletal system or contamination of the bone after fracture or surgery, osteomyelitis has a complex pathogenesis with a critical involvement of both osteal and immune components. Colonization of the bone by S. aureus is traditionally proposed to induce functional inhibition and/or apoptosis of osteoblasts, alteration of the RANKL/OPG ratio in the bone microenvironment and activation of osteoclasts; all together, these events locally subvert tissue homeostasis causing pathological bone loss. However, this paradigm has been challenged in recent years, in fact osteoblasts are emerging as active players in the induction and orientation of the immune reaction that mounts in the bone during an infection. The interaction with immune cells has been mostly ascribed to osteoblast-derived soluble mediators that add on and synergize with those contributed by professional immune cells. In this respect, several preclinical and clinical observations indicate that osteomyelitis is accompanied by alterations in the local and (sometimes) systemic levels of both pro-inflammatory (e.g., IL-6, IL-1α, TNF-α, IL-1β) and anti-inflammatory (e.g., TGF-β1) cytokines. Here we revisit the role of osteoblasts in bacterial OM, with a focus on their secretome and its crosstalk with cellular and molecular components of the bone microenvironment and immune system.

Osteomyelitis, Oxidative Stress and Related Biomarkers

Bone is a very dynamic tissue, subject to continuous renewal to maintain homeostasis through bone remodeling, a process promoted by two cell types: osteoblasts, of mesenchymal derivation, are responsible for the deposition of new material, and osteoclasts, which are hematopoietic cells, responsible for bone resorption. Osteomyelitis (OM) is an invasive infectious process, with several etiological agents, the most common being Staphylococcus aureus, affecting bone or bone marrow, and severely impairing bone homeostasis, resulting in osteolysis. One of the characteristic features of OM is a strong state of oxidative stress (OS) with severe consequences on the delicate balance between osteoblastogenesis and osteoclastogenesis. Here we describe this, analyzing the effects of OS in bone remodeling and discussing the need for new, easy-to-measure and widely available OS biomarkers that will provide valid support in the management of the disease.

Histological Identification of Sequestered Parasitized Red Cells

The performance of complete post-mortem examinations of children with severe malaria has helped to explain the cause of death in cerebral malaria as well as show the global phenomenon of sequestration in tissues throughout the body, beyond the brain and eye. The pathology of the brain and other organs has been well described and shows a systemic disease with the most catastrophic features found in the brain (i.e., fatal cerebral edema).This chapter describes the materials and methods needed to study the pathological features of tissues outside of the eye, including the brain and other organs. The bulk of these techniques are standard to pathology including gross examination, histology, special stains, and immunohistochemistry.

Markers for the involvement of endothelial cells and the coagulation system in chronic urticaria: A systematic review

Chronic urticaria (CU) is a chronic inflammatory mast cell-driven disorder. Endothelial cells (ECs) contribute importantly to key features of CU. Several markers of EC (dys)function in CU have been reported, but have not yet been systematically reviewed. In this study, we systematically reviewed and categorized all published markers of EC functions in CU through a comprehensive search in Pubmed, The Cochrane Library, Web of Science, and SCOPUS using the following Mesh terms: CU AND pathogenesis AND (vasculopathy OR microangiopathy OR ECs OR marker). In total, 79 articles were selected and the identified biomarkers were categorized according to EC (dys)function in CU. The most frequent and consistently reported upregulated biomarkers in CU skin were adhesion molecules, TF, and P-selectin. The most frequently reported upregulated and reliable biomarkers in sera of CU patients were F1+2 for coagulation cascade involvement, D-dimers for fibrinolysis, and MMP-9 for vascular permeability. Emerging biomarkers described in the selected articles were endostatin, heat shock proteins, cleaved high molecular weight kininogen, and adipokines. This systematic review contributes to the pool of growing evidence for vascular involvement in CU where EC dysfunction is present in different aspects of cell survival, maintenance of vascular structure, and coagulation/fibrinolysis balance.

Different Modulatory Effects of Four Methicillin-Resistant Staphylococcus aureus Clones on MG-63 Osteoblast-Like Cells

Staphylococcus aureus is a Gram-positive bacterium responsible for a variety of mild to life-threatening infections including bone infections such as osteomyelitis. This bacterium is able to invade and persist within non-professional phagocytic cells such as osteoblasts. In the present study, four different S. aureus strains, namely, 2SA-ST239-III (ST239), 5SA-ST5-II (ST5), 10SA-ST228-I (ST228), and 14SA-ST22-IVh (ST22), were tested for their ability to modulate cell viability in MG-63 osteoblast-like cells following successful invasion and persistence. Methicillin-sensitive S. aureus (MSSA) ATCC-12598-ST30 (ST30) was used as control strain. Despite being proven that ST30, ST239, and ST22 have a similar ability to internalize and persist in MG-63 osteoblast-like cells under our experimental conditions, we demonstrated that the observed decrease in cell viability was due to the different behavior of the considered strains, rather than the number of intracellular bacteria. We focused our attention on different biochemical cell functions related to inflammation, cell metabolism, and oxidative stress during osteoblast infections. We were able to show the following: (1) ST30 and ST239 were the only two clones able to persist and maintain their number in the hostile environment of the cell during the entire period of infection; (2) ST239 was the only clone able to significantly increase gene expression (3 and 24 h post-infection (p.i.)) and protein secretion (24 h p.i.) of both interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in MG-63 osteoblast-like cells; (3) the same clone determined a significant up-regulation of the transforming growth factorbeta 1 (TGF-β1) and of the metabolic marker glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNAs at 24 h p.i.; and (4) neither the MSSA nor the four methicillin-resistant S. aureus (MRSA) strains induced oxidative stress phenomena in MG-63 cells, although a high degree of variability was observed for the different clones with regard to the expression pattern of nuclear factor E2-related factor 2 (Nrf2) and its downstream gene heme oxygenase 1 (HO-1) activation. Our results may pave the way for an approach to S. aureus-induced damage, moving towards individualized therapeutic strategies that take into account the differences between MSSA and MRSA as well as the distinctive features of the different clones. This approach is based on a change of paradigm in antibiotic therapy involving a case-based use of molecules able to counteract pro-inflammatory cytokines activity such as selective cytokine signaling inhibitors (IL-6, TNF-α).

The inflammatory response to bone infection - a review based on animal models and human patients

Bone infections are difficult to diagnose and treat, especially when a prosthetic joint replacement or implant is involved. Bone loss is a major complication of osteomyelitis, but the mechanism behind has mainly been investigated in cell cultures and has not been confirmed in human settings. Inflammation is important in initiating an appropriate immune response to invading pathogens. However, many of the signaling molecules used by the immune system can also modulate bone remodeling and contribute to bone resorption during osteomyelitis. Our current knowledge of the inflammatory response relies heavily on animal models as research based on human samples is scarce. Staphylococcus aureus is one of the most common causes of bone infections and is the pathogen of choice in animal models. The regulation of inflammatory genes during prosthetic joint infections and implant-associated osteomyelitis has only been studied in rodent models. It is important to consider the validity of an animal model when results are extrapolated to humans, and both bone composition and the immune system of pigs has been shown to be more similar to humans, than to rodents. Here in vivo studies on the inflammatory response to prosthetic joint infections and implant-associated osteomyelitis are reviewed.

Osteoarthritic process modifies expression response to NiTi alloy presence

Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications - helium and hydrogen) on gene expression profile of selected interleukins (IL-1β, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2^-ΔΔCt method. An increased gene expression of IL-1β in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.

Staphylococcus aureus-dependent septic arthritis in murine knee joints: local immune response and beneficial effects of vaccination

Staphylococcus aureus is the major cause of human septic arthritis and osteomyelitis, which deserve special attention due to their rapid evolution and resistance to treatment. The progression of the disease depends on both bacterial presence in situ and uncontrolled disruptive immune response, which is responsible for chronic disease. Articular and bone infections are often the result of blood bacteremia, with the knees and hips being the most frequently infected joints showing the worst clinical outcome. We report the development of a hematogenous model of septic arthritis in murine knees, which progresses from an acute to a chronic phase, similarly to what occurs in humans. Characterization of the local and systemic inflammatory and immune responses following bacterial infection brought to light specific signatures of disease. Immunization of mice with the vaccine formulation we have recently described (4C-Staph), induced a strong antibody response and specific CD4+ effector memory T cells, and resulted in reduced bacterial load in the knee joints, a milder general inflammatory state and protection against bacterial-mediated cellular toxicity. Possible correlates of protection are finally proposed, which might contribute to the development of an effective vaccine for human use.

Serum Immune Proteins in Moderate and Severe Chronic Fatigue Syndrome/Myalgic Encephalomyelitis Patients

Immunological dysregulation is present in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), with recent studies also highlighting the importance of examining symptom severity. This research addressed this relationship between CFS/ME severity subgroups, assessing serum immunoglobulins and serum cytokines in severe and moderate CFS/ME patients. Participants included healthy controls (n= 22), moderately (n = 22) and severely (n=19) affected CFS/ME patients. The 1994 Fukuda Criteria defined CFS/ME and severity scales confirmed mobile and housebound CFS/ME patients as moderate and severe respectively. IL-1β was significantly reduced in severe compared with moderate CFS/ME patients. IL-6 was significantly decreased in moderate CFS/ME patients compared with healthy controls and severe CFS/ME patients. RANTES was significantly increased in moderate CFS/ME patients compared to severe CFS/ME patients. Serum IL-7 and IL-8 were significantly higher in the severe CFS/ME group compared with healthy controls and moderate CFS/ME patients. IFN-γ was significantly increased in severe CFS/ME patients compared with moderately affected patients. This was the first study to show cytokine variation in moderate and severe CFS/ME patients, with significant differences shown between CFS/ME symptom severity groups. This research suggests that distinguishing severity subgroups in CFS/ME research settings may allow for a more stringent analysis of the heterogeneous and otherwise inconsistent illness.

Contribution of Reduced Interleukin-10 Levels to the Pathogenesis of Osteomyelitis in Children with Sickle Cell Disease

Osteomyelitis is a significant complication of sickle cell disease (SCD), and several factors contribute to its pathogenesis, including altered expression of proinflammatory and anti-inflammatory cytokines. In view of the role of interleukin-10 (IL-10) as an anti-inflammatory cytokine, we tested the notion that SCD osteomyelitis is associated with a reduction in IL-10 secretion and, hence, precipitation of a proinflammatory state. Study subjects comprised 52 SCD patients with confirmed diagnosis of osteomyelitis and 165 age- and gender-matched SCD patients with negative histories of osteomyelitis. Results obtained showed that IL-10 serum levels in SCD osteomyelitis patients were significantly lower than those of control SCD patients. Receiver operating characteristic (ROC) analysis demonstrated that altered IL-10 serum levels predicted the development of osteomyelitis, and the mean area under ROC curves of IL-10 was 0.810 among SCD patients with osteomyelitis. A systematic shift in IL-10 serum levels toward lower values was seen in osteomyelitis cases, with an increased osteomyelitis risk associated with decreased IL-10 levels. Multivariate logistic regression analyses confirmed the independent association of reduced IL-10 with osteomyelitis after controlling for sickle hemoglobin (HbS), fetal hemoglobin (HbF), platelet count, and white blood cell (WBC) count. These data support the strong association of decreased IL-10 levels with osteomyelitis, thereby supporting a role for IL-10 in osteomyelitis follow-up.

Free radicals and antioxidant status in chronic osteomyelitis patients: a case control study

INTRODUCTION

Osteomyelitis (OM) is a local or generalized infection of the bone and bone marrow which may be multifactorial in its causation. Chronic infection is characterised by sequestrum and involucrum formation.

AIM

The present study has been carried out for assessing the oxidative stress in chronic OM by measurement of serum oxidants {such as malondialdehyde (MDA), protein carbonyl (PC), nitrite} and the serum antioxidants {such as ascorbic acid, superoxide dismutase (SOD), ceruloplasmin (Cp), blood glutathione} by spectrophotometric method.

MATERIALS AND METHODS

This was a case control study. About 5 ml of venous blood was collected for the estimation of biochemical parameters. This study comprised of 50 OM patients diagnosed at SSLH Hospital, Varanasi and 50 healthy ages (15-35 y) and sex matched individuals.

RESULTS

Significantly increased (p<0.0001) levels of serum oxidants and significantly decreased (p<0.0001) levels of all serum antioxidants except ceruloplasmin indicated significantly increased (p<0.0001) levels in response to infections in chronic OM patients as compared to the healthy controls.

CONCLUSION

These results suggest that there occurs an imbalance between oxidants and antioxidants, especially an increase in oxidative stress, as measured by the levels of the parameters: serum MDA, serum protein carbonyl and serum nitrite.

Potential regulatory molecules in the human trabecular meshwork of patients with glaucoma: immunohistochemical profile of a number of inflammatory cytokines

Glaucoma occurs when there are imbalances between the production and the drainage of the eye liquid. The vast majority of the aqueous humor leaves the eye through the trabecular meshwork (TM). The cause of hypertonicity may be due to an alteration in the thickness of the TM. In the majority of cases the molecular changes that determine primary open‑angle glaucoma (POAG) are unclear. However, it has been hypothesized that the significant increase in the extracellular matrix (ECM) of the fibrillary bands in the TM is associated with possible inflammatory conditions. In this study the tissue distribution of interleukin (IL)‑6, IL‑1β, transforming growth factor-β1 (TGF‑β1), vascular endothelial growth factor (VEGF) and tumor necrosis factor α (TNF‑α) was analyzed in TM samples from patients with POAG by immunohistochemistry. Seven specimens from patients with POAG and three control tissues were analyzed by immunohistochemistry using specific antibodies against these cytokines. Morphological changes in the TM, such as increased cell content, macrophages, fibrosis and accumulation of neutrophils, were observed by transmission electron microscopy. In human TM tissues, an evident immunoreactivity for IL‑6, IL‑1β and TNF‑α was observed in patients with POAG when compared with the control subjects, indicating that these cytokines may be correlated with disease activity. TM endothelial cells secrete a number of factors and cytokines that modulate the functions of the cells and the ECM of the conventional outflow pathway. In the TM in glaucoma, macrophages produce cytokines, including IL‑6, IL‑1β and TNF‑α, leading to an acute inflammatory response and recruitment of other immune cells, including T lymphocytes. In addition, TGF‑β1 regulates and induces the expression of IL‑6 in TM that indirectly induces angiogenesis by stimulating VEGF expression. The present results support previous evidence that suggests that growth factors and cytokines can induce ECM remodelling and alter cytoskeletal interactions in the TM.

Polymorphisms of interleukin 6 and interleukin 10 in Egyptian people with Behcet's disease

Cytokines play critical roles in the pathogenesis of Behçet's disease (BD). They mediated many of the effectors and regulatory functions of immune and inflammatory responses. Many studies have linked Interleukin-6 (IL-6) and Interleukin-10 (IL-10) pathologically to BD. Thus, this study aimed to investigate the associations between IL-6 and IL-10 promoter single-nucleotide polymorphisms (SNPs) and the susceptibility to BD and their implication on plasma levels. We genotyped IL-6 -174 G/C (rs1800795) using Mutagenically Separated Polymerase Chain Reaction PCR (MS-PCR) and IL-10 -1082 G/A (rs1800896) and -819 C/T (rs1800871) using Sequence Specific Primer PCR (SSP-PCR) in 87 Egyptian patients and 97 controls. The plasma levels of IL-6 and IL-10 were measured using Enzyme-linked Immunosorbent Assay (ELISA). Significant increase in the frequency of -1082 GG genotype (P<0.05, OR=2.25, 95%CI=1.03-4.91) and significant decrease in the frequency of -1082 GA genotype (P<0.05, OR=0.53, 95%CI=0.29-0.96) was demonstrated in BD patients compare to controls. Patients with genital ulcer had significantly lower frequency of -1082 GG (P<0.05, OR 0.2, 95% CI=0.04-0.99) and G allele (P<0.05, OR=0.28, 95%CI=0.08-0.93), while patients with ocular manifestations had significantly higher frequency of -1082 G allele (P<0.01, OR=2.28, 95%CI=1.19-4.36). BD patients had significantly higher level of IL-6 (P<0.001) and significantly lower level of IL-10 (P<0.001) compared to controls. The changes in the level of cytokines were independent of any genotype of IL-6 or any genotype/haplotype of IL-10. Patients with active disease state had significantly higher level of IL-6 compared to patients in remission (P<0.05). In conclusion, our preliminary study indicates that the polymorphism at IL-10 -1082 G/A may play a role in BD susceptibility. The significant increase in IL-6 level and the significant decrease in IL-10 level in BD patients were independent of any particular genotype in IL-6 or any particular genotype/haplotype in IL-10.

A new murine model to study musculoskeletal tuberculosis (short communication)

Musculoskeletal tuberculosis (TB) is a severe extrapulmonary manifestation of chronic Mycobacterium (M.) tuberculosis infection. Considering increasing incidence, multi-drug resistance and associated treatment difficulties, more preclinical research is needed. In this study we developed a murine model for musculoskeletal TB. Mice, intranasally infected with M. tuberculosis, were sacrificed after ten months. Mycobacterial growth was detected in lung and femur homogenates. Ziehl-Neelsen staining of paraffin-embedded femurs showed acid-fast rods in the myelum and Magnetic Resonance Imaging demonstrated osteomyelitis and macronodular tuberculomas. This new murine model of musculoskeletal TB might be of value to further investigate immunologic and radiologic responses.

Implant-associated localized osteitis in murine femur fracture by biofilm forming Staphylococcus aureus: a novel experimental model

Staphylococcus aureus (SA) is the most common causative agent for implant-associated osteitis. The present study characterizes a novel model of a low grade acute SA osteitis with bone defect in the femur which is stabilized by a titanium locking plate. Wild-type Balb/c mice were osteotomized, fixed by a locking plate and infected with SA. Mice underwent debridement 7 and 14 days later and were sacrificed at Day 28. At Days 7, 14, and 28 after inoculation local and systemic cell populations and IL-6 were analyzed. Fracture healing was quantified by radiography. The control group underwent the same procedure without infection. The bacterial load of implant-associated osteitis with biofilm formation was quantified by counting CFU and real-time PCR. Fracture healing determined by radiography was delayed in infected compared to non-infected mice. Throughout the investigation period CFU and leukocyte counts, as well as IL-6 levels were found to be significantly elevated in infected mice at the infection site but not systemically. Our murine model allows the detailed investigation of implant associated localized osteitis with biofilm producing SA and its influence on fracture healing. The model provides a tool to analyze therapeutic or prophylactic approaches to the problem of biofilm-associated osteitis.

Comparison of platelet count in tuberculosis spine to other spine pathology

PURPOSE

Haematological markers currently used to investigate TB spine vary from WCC, Anaemia, ESR and CRP. Platelet count in TB spine as a marker has been inadequately investigated.

METHOD

In this retrospective review, Platelet count in TB spondylitis on admission was compared to patients undergoing other elective spinal surgery (control) preoperatively. Comparisons of the platelets with ESR and the effect of HIV on platelet count in TB spine were also evaluated.

RESULTS

160 TB spine patients showed statistically significant higher platelet count when compared to 210 patients in the control group (p < 0.001). 52.5 % patients had a raised platelet count in the TB spondylitis group. Raised Platelet count had a sensitivity and specificity of 52.5 % and 86.2 %, respectively in TB spondylitis. ESR and platelet count had a Pearson correlation r = 0.31 (p < 0.001). HIV however did not statistically show any difference in the platelet count (p = 0.12).

CONCLUSION

A raised platelet count in spinal pathology may be used as an inflammatory marker of TB spondylitis.

Association of serum albumin concentration with mortality, morbidity, CD4 T-cell reconstitution among tanzanians initiating antiretroviral therapy

BACKGROUND

Prospective studies of serum albumin concentration measurement as a low-cost predictor of human immunodeficiency virus (HIV) disease progression are needed for individuals initiating antiretroviral therapy (ART) in resource-limited settings.

METHODS

Serum albumin concentration was measured at ART initiation for 2145 adults in Tanzania who were enrolled in a trial examining the effect of multivitamins on HIV disease progression. Participants were prospectively followed for mortality, morbidity, and anthropometric outcomes at monthly visits (median follow-up duration, 21.2 months). Proportional hazard models were used to analyze mortality, morbidity, and nutritional outcomes, while generalized estimating equations were used to analyze CD4(+) T-cell counts.

RESULTS

Individuals with hypoalbuminemia (defined as a serum albumin concentration of <35 g/L) at ART initiation had a hazard of death that was 4.52 times (95% confidence interval, 3.37-6.07; P < .001) that of individuals with serum albumin concentrations of ≥ 35 g/L, after multivariate adjustment. Hypoalbuminemia was also independently associated with the incidence of pulmonary tuberculosis (P < .001), severe anemia (P < .001), wasting (P = .002), and >10% weight loss (P = .012). Secondary analyses suggested that serum albumin concentrations of <38 g/L were associated with increased mortality and incident pulmonary tuberculosis. There was no association between serum albumin concentration and changes in CD4(+) T-cell counts (P = .121).

CONCLUSIONS

Serum albumin concentrations can identify adults initiating ART who are at high risk for mortality and selected morbidities. Future research is needed to identify and manage conditions that reduce the serum albumin concentration.

Distinct cytokine profiles of circulating mononuclear cells stimulated with Staphylococcus aureus enterotoxin A in vitro during early and late episodes of chronic osteomyelitis

We investigated the cytokine profile of peripheral mononuclear cells from chronic osteomyelitis (OST) patients following in vitro stimulation with staphylococcal enterotoxin A (SEA). We demonstrate that stimulation with SEA induced prominent lymphocyte proliferation and high levels of tumour necrosis factor (TNF)-α, interleukin (IL)-4 and IL-10 secretion in both OST and non-infected individuals (NI). Even though stimulation with SEA had no impact on IL-6 production in either patient group, the baseline level of IL-6 production by cells from OST patients was always significantly less than that produced by cells from NI. After classifying the osteomyelitic episodes based on the time after the last reactivation event as "early" (1-4 months) or "late" osteomyelitis (5-12 months), we found that increased levels of TNF-α and IL-4 in combination with decreased levels of IL-6 were observed in the early episodes. By contrast, increased levels of IL-10, IL-2 and IL-6 were hallmarks of late episodes. Our data demonstrate that early osteomyelitic episodes are accompanied by an increased frequency of "high producers" of TNF-α and IL-4, whereas late events are characterised by increased frequencies of "high producers" of IL-10, IL-6 and IL-2. These findings demonstrate the distinct cytokine profiles in chronic osteomyelitis, with a distinct regulation of IL-6 production during early and late episodes.

Staphylococcus aureus protein A plays a critical role in mediating bone destruction and bone loss in osteomyelitis

Staphylococcus aureus is the most frequent causative organism of osteomyelitis. It is characterised by widespread bone loss and bone destruction. Previously we demonstrated that S. aureus protein A (SpA) is capable of binding to tumour necrosis factor receptor-1 expressed on pre-osteoblastic cells, which results in signal generation that leads to cell apoptosis resulting in bone loss. In the current report we demonstrate that upon S. aureus binding to osteoblasts it also inhibits de novo bone formation by preventing expression of key markers of osteoblast growth and division such as alkaline phosphatase, collagen type I, osteocalcin, osteopontin and osteocalcin. In addition, S. aureus induces secretion of soluble RANKL from osteoblasts which in turn recruits and activates the bone resorbing cells, osteoclasts. A strain of S. aureus defective in SpA failed to affect osteoblast growth or proliferation and most importantly failed to recruit or activate osteoclasts. These results suggest that S. aureus SpA binding to osteoblasts provides multiple coordinated signals that accounts for bone loss and bone destruction seen in osteomyelitis cases. A better understanding of the mechanisms through which S. aureus leads to bone infection may improve treatment or lead to the development of better therapeutic agents to treat this notoriously difficult disease.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

Interaction of staphylococci with bone

Staphylococci, in particular Staphylococcus aureus, are the predominant cause of bone infections worldwide. These infections are painful, debilitating and with the rise in antibiotic-resistant forms, increasingly difficult to treat. The growth in the number of prosthetic joint replacement procedures also provides new opportunities for these infections to take hold. Comprehending the mechanisms by which staphylococci interact with and damage bone is critical to the development of new approaches to meet this challenge. This review summarises current understanding of the mechanisms by which staphylococci infect and damage bone. We address the role of the inflammatory response to staphylococcal infection in disrupting the homeostatic balance of bone matrix deposition and resorption and thereby mediating bone destruction. A number of virulence factors that have been shown to contribute to bone infection and pathology are discussed, however no single factor has been defined as being specific to bone infections. Although traditionally considered an extracellular pathogen, there is increasing evidence that staphylococci are able to invade host cells, and that an intracellular lifestyle may facilitate long-term persistence in bone tissue, enabling evasion of antimicrobials and host immune responses. ‘Small colony variant’ strains, with mutations disabling the electron transport pathway appear particularly adept at invading and persisting within host cells, and exhibit enhanced antimicrobial resistance, and may represent a further complication in the treatment and management of staphylococcal bone disease.

Current trends in the management of ocular symptoms in Adamantiades-Behçet's disease

Adamantiades-Behçet’s disease (ABD) is a multisystemic vasculitic disease. It is most prevalent in the Eastern Mediterranean countries and the Eastern region of Asia. Its effect on the eye can range from mild to debilitating, resulting in total blindness. A necrotizing and obliterative vasculitis affects both arteries and veins of organs. Recurrent attacks of uveitis, oral aphthous ulcers, skin lesions, and genital ulcers are common. Topical and systemic corticosteroids have been the mainstay in the treatment of ocular inflammation for many years; however, due to the several known side effects of corticosteroids and thanks to scientific advances, more novel approaches to ABD treatment have been emerging. Antimetabolites such as methotrexate and azathioprine have been utilized with the latter showing positive results. Chlorambucil has been utilized effectively for ocular manifestations of ABD. Interferon alpha has shown encouraging results in the management of refractory ocular inflammation associated with ABD, either alone or in combination with other immunosuppressive agents. Surgical interventions to deal with complications from ABD can be safely done if adequate control of inflammation is achieved peri-operatively. Early detection and aggressive treatment, when needed, have proven to be essential in the management of this relentlessly explosive disease.

Diet, tuberculosis, and the paleopathological record

Osseous manifestation of infectious disease is of paramount importance to paleopathologists seeking to interpret ancient health, but the relationships among infectious agent exposure, development of disease, and skeletal involvement are complex. The outcome of an exposure strongly depends on multiple factors, including ecology, diet, nutrition, immune function, and the genetics of pathogen and host. Mycobacterial diseases are often studied in ancient remains but also are especially influenced by these factors; individual and population differences in severity and course are apparent following onset of active disease. The osteological record for these diseases represents the complex interplay of host and pathogen characteristics influencing within- and among-individual skeletal lesion prevalence and distribution. However, many of these characteristics may be assessed independently through the archaeological record. Here, we explore the contributions of dietary protein and iron to immune function, particularly the course and outcome of infection with Mycobacterium tuberculosis. We emphasize how nutrition may influence the dissemination of bacilli to the skeleton and subsequent formation of diagnostic lesions. We then generate models and hypotheses informed by this interplay and apply them to four prehistoric New World areas. Finally, discrepancies between our expectations and the observed record are explored as a basis for new hypotheses.

Influence of interleukin 1alpha (IL-1alpha), IL-4, and IL-6 polymorphisms on genetic susceptibility to chronic osteomyelitis

The association between cytokine gene polymorphisms and chronic osteomyelitis was investigated in order to determine whether genetic variability in cytokine genes predisposes to osteomyelitis susceptibility. Significant genotypic and allelic associations were observed between interleukin 1alpha (IL-1alpha) -889-C/T, IL-4 -1098-G/T and -590-C/T, and IL-6 -174-G/C polymorphisms and osteomyelitis in the Greek population, pointing towards their potential involvement in osteomyelitis pathogenesis.

Bax gene G(-248)A promoter polymorphism is associated with increased lifespan of the neutrophils of patients with osteomyelitis

BACKGROUND

Patients with osteomyelitis have a decreased rate of spontaneous apoptosis of their peripheral blood neutrophils. The G(-248)A polymorphism in the promoter region of the bax gene is associated with prolonged peripheral blood neutrophil survival in leukemic patients and may play some role in osteomyelitis.

METHODS

Bax G(-248)A promoter polymorphism was detected by DNA amplification using polymerase chain reaction, followed by restriction fragment length polymorphism analysis. Spontaneous apoptosis of peripheral blood neutrophils was measured by propidium iodide, annexin V, and flow cytometry, and Bax was quantified by Western blotting.

RESULTS

The bax promoter polymorphism A allele was significantly more frequent in 80 patients with osteomyelitis than in 220 healthy donors (18.1% vs. 10.6%, chi=4.84, odds ratio=1.81, 95% confidence interval=1.06-3.07, P=.028). Carriers of the A allele had a lower apoptotic rate of their peripheral blood neutrophils compared with noncarriers (33.3+/-16.7 vs. 43.1+/-3.1, P=.036). Patients with the AA genotype showed a lower expression of the Bax protein compared with carriers of other genotypes (P=.038).

CONCLUSIONS

Substitution of a nucleotide G-->A at position -248 in the bax gene was more frequent in patients with osteomyelitis and was associated with a longer lifespan of their peripheral blood neutrophils and lower Bax protein expression. These findings may play a role in the pathogenesis of osteomyelitis.

The NOS3 (27-bp repeat, intron 4) polymorphism is associated with susceptibility to osteomyelitis

Cytokines generate nitric oxide (NO) in osteoblasts and neutrophils through the induction of NO synthase isoforms, endothelial (NOS3) and inducible (NOS2), thereby producing bone loss. In osteomyelitis (OM), a chronic infection of the bone, homozygosity for the NOS3 (27-bp repeat, intron 4 polymorphism) 4 allele was significantly more frequent among the 80 patients than in 300 healthy controls (p=0.044). No significant differences were found for other polymorphisms of the NOS genes such as NOS3, the promoter (-786T/C), and the missense change (E298D) in exon 7, and for NOS2, the G/A substitution at position 37498 in exon 22, the (CCTTT)(n), and (TAAA)(n) micro-satellites and the -954G/C in the promoter. Serum NO levels were significantly higher only in the OM patients homozygous for the NOS3 (27-bp repeat, intron 4 polymorphism) 4 allele, compared to controls. In the presence of bacteria or bacterial products, the neutrophils of these patients produced more NO. However, immunolabelling of osteoblasts for NOS3 in biopsy tissues did not correlate with the carriage of a determined NOS polymorphism but with the presence of bone inflammation. This is the first report of an association between a NOS3 polymorphism and the risk of developing OM.

The ever-expanding association between rheumatologic diseases and tuberculosis

We summarized most of the rheumatologic manifestations of tuberculosis (TB) and the occurrence of Mycobacterium tuberculosis disease associated with rheumatologic diseases. We established 4 different categories: (1) direct musculoskeletal involvement of M. tuberculosis, including spondylitis, osteomyelitis, septic arthritis, and tenosynovitis; (2) M. tuberculosis as an infectious pathogen in rheumatologic diseases, particularly with the use of newer agents such as tumor necrosis factor-alpha inhibitors; (3) antimycobacterial drug-induced rheumatologic syndromes, including tendinopathy, drug-induced lupus, and others; and (4) reactive immunologic phenomena caused by TB, such as reactive arthritis, erythema nodosum, and others. In addition, Bacille-Calmette-Guérin vaccination used for the prevention of TB or as a chemotherapeutic agent for bladder carcinoma also may be associated with musculoskeletal adverse events. We conclude that M. tuberculosis can directly or indirectly affect the musculoskeletal system.

Potential role of interleukin 6 in reactive thrombocytosis and acute phase response in pulmonary tuberculosis

OBJECTIVE

Reactive thrombocytosis is found in a number of clinical situations including infectious diseases such as pulmonary tuberculosis (PTB). To examine the possible role of interleukin (IL6) in reactive thrombocytosis and acute phase response in PTB this study measured serum IL6, C reactive protein (CRP), erythrocyte sedimentation rate (ESR), albumin concentrations in 62 PTB patients and 20 healthy volunteers.

METHOD

PTB patients were divided into two groups based on thrombocyte counts. Twenty seven PTB patients with normal thrombocyte counts constituted group 1, 35 PTB patients with thrombocytosis constituted group 2, and 20 healthy volunteers constituted group 3.

RESULTS

The median IL6 concentration of group 1 was 12.8 pg/ml (95% CI: 12.1 to 56.9 pg/ml) and group 2 was 40.6 pg/ml (95% CI: 67.1 to 168.7 pg/ml). The comparison of IL6 concentrations in the three groups was significant (p = 0.0001). Patients in group 1 had a higher concentration of CRP (p = 0.0001) and lower concentration of albumin (p = 0.002) than group 3 whereas group 2 had higher concentration of CRP (p = 0.003) and lower concentration of albumin (p = 0.002) than group 1. Serum IL6 concentrations were significantly correlated with thrombocyte counts (p = 0.004, r = 0.36), CRP (p = 0.007, r = 0.34), and albumin concentrations (p = 0.005, r = -0.34). IL6 concentrations were significantly correlated with the number of involved zones (p = 0.005, r = 0.35) and acid fast bacilli positivity (p = 0.03, r = 0.27). Patients in group 2 had weight loss (p = 0.004), fever (p = 0.038), and night sweats (p = 0.007) more frequently than group 1. Also, group 2 had more extensive radiological findings (involved zones p = 0.001, bilateral disease p = 0.0001, presence of cavity p = 0.02) than group 1.

CONCLUSIONS

IL6 might play a contributory part in reactive thrombocytosis and acute phase response in PTB.

Serum interleukin 18 and tumour necrosis factor-alpha levels are increased in Behcet's disease

Inflammation in Behcet's disease is thought to be mediated by cytokines derived from T-helper type 1 (Th1) lymphocytes. In this study, we tried to determine serum interleukin (IL)-18 and tumour necrosis factor (TNF)-alpha levels of patients with Behcet's disease. Twenty-seven patients with active Behcet's disease, and 20 healthy control subjects were included in this study. Differences between mean serum IL-18 and TNF-alpha level of patients with Behcet's disease were significantly increased when compared with the control group. A significant correlation was found between serum IL-18 and TNF-alpha levels of Behcet patients (rs = 0.627, P < 0.0001). IL-18 and TNF-alpha levels may be related to disease pathogenesis. Increased levels of IL-18 also support Th1 predominance in Behcet's disease.

IL-1 alpha (-889) promoter polymorphism is a risk factor for osteomyelitis

As osteomyelitis (OM) induces the synthesis of inflammatory cytokines and IL-1 mediates bone resorption by osteoclasts we determined if there is an association between certain common polymorphisms of the genes encoding proinflammatory cytokines (IL-1 alpha and beta, IL-6, TNF-alpha) and OM in adults. The IL-1 alpha (-889) TT genotype was significantly more frequent among 52 OM patients than in 109 healthy controls (13/52, [25.0%] vs. 9/109, [8.3%], P = 0.0081, chi(2) = 7.01, OR = 3.7, 95% CI, 1.35-10.34). Patients who were homozygous for the T allele were younger than the rest of the OM patients (mean age 35.7 +/- 11.5 vs. 58.1 +/- 18.6 years, P = 0.001). IL-1 beta TT (+3953) polymorphism was also more frequent in OM patients (P = 0.014, chi(2) = 5.12, OR = 5.1, 95% CI, 1.21-52.14), but IL-1 beta is in linkage disequilibrium with the IL-1 alpha *T (P < 0.001). Route of infection, chronicity of the infection, type of microorganism isolated, and frequency of relapses were similar in patients with and without the IL-1 alpha TT genotype. There were no associations between OM and polymorphisms of other cytokines genes. IL-1 alpha serum levels were significantly increased in all the OM patients independently of their IL-1 genotype compared to the controls (P = 0.021). Although IL-1 alpha serum levels were not significantly higher in patients with the IL-1 alpha (-889) polymorphism, this does not exclude a difference in production of IL-1 alpha by osteoclasts or other inflammatory cells at the site of infection.

Differential regulation of chemokine secretion in tuberculous and staphylococcal osteomyelitis

Bone infection or osteomyelitis is characterized by uncontrolled inflammation and destructive bone loss although little is known about immunopathogenesis of infection. We investigated control of chemokine secretion from osteoblasts infected with either Mycobacterium tuberculosis, which normally elicits a granulomatous host response, or Staphylococcus aureus, which drives a host response dominated by neutrophil influx. We show that M. tuberculosis infection of cultured and primary osteoblasts induces extensive secretion of the chemokines interleukin (IL)-8, inducible protein (IP) 10, RANTES, and monocyte chemoattractant protein (MCP) 1 within 72 h (1630 +/- 280 pg/ml per 4 x 10(5) cells, 74,130 +/- 8480 pg/ml per 4 x 10(5) cells, 18,330 +/- 3040 pg/ml per 4 x 10(5) cells, and 138,670 +/- 13,340 pg/ml per 4 x 10(5) cells, respectively, for MG-63 osteoblasts). S. aureus infection also results in secretion of these chemokines but secretion is delayed and of lesser magnitude (210 +/- 10 pg/ml per 4 x 10(5) cells, 11,570 +/- 1240 pg/ml per 4 x 10(5) cells, 930 +/- 34 pg/ml per 4 x 10(5) cells, and 13,770 +/- 720 pg/ml per 4 x 10(5) cells for IL-8, IP-10, RANTES, and MCP-1, respectively). The minimal up-regulation of secretion of the neutrophil attractant IL-8 in staphylococcal infection is both striking and unexpected. In both infections, chemokine secretion was dependent on the presence of live organisms. Differences in kinetics and magnitude of chemokine secretion are associated with distinct patterns of mRNA expression, as assessed by ribonuclease protection assay (RPA) and reverse-transcription polymerase chain reaction (RT-PCR). In addition, nuclear localization of the transcription factor activator protein (AP) 1 in M. tuberculosis-infected osteoblasts also is distinct as compared with S. aureus-infected cells. In summary, this study shows that osteoblasts have an important pathogen-specific role in control of chemokine gene expression and secretion during the human immune response to osteomyelitis.

Serum levels of TNF-alpha, sIL-2R, IL-6, and IL-8 are increased and associated with elevated lipid peroxidation in patients with Behçet's disease

AIM

Behçet's disease (BD) is asystemic immunoinflammatory disorder and the aetiopathogenesis is to be specified. Cytokines play a role in immune response and in many inflammatory diseases. The aim of this case-control study is to investigate serum pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha, interleukin-1beta (IL-1beta), soluble IL-2 receptor (sIL-2R), IL-6, and chemokine IL-8 levels in patients with BD. We also determined the end product of lipid peroxidation (malondialdehyde (MDA)) in BD patients as an index for oxidative stress.

METHODS

A total of 37 patients (19 men, 18 women) with BD (active, n = 17; inactive, n = 20) and 20 age-matched and sex-matched healthy control subjects (11 men, nine women) included in this cross-sectional, blinded study. Serum TNF-alpha, IL-1beta, sIL-2R, IL-6 and IL-8 levels were determined by a spectrophotometer technique using the immulite chemiluminescent immunometric assay. Lipid peroxidation was evaluated by Wasowicz et aL The levels of cytokines and lipid peroxidation in the active period were compared with the inactive period of the disease. Results are expressed as mean +/- standard error.

RESULTS

IL-1beta levels were below the detection limits of the assay (< 5 pg/ml) in all samples. Mean levels of MDA (8.1+/-0.7 micromol/l), sIL-2R (800+/-38 U/ml), IL-6 (12.6+/-1.1 pg/ml), IL-8 (7.2+/-0.4 pg/ml), and TNF-alpha (7.9+/-0.5 pg/ml) in active BD patients were significantly higher than those in inactive patients (4.3+/-0.5 micromol/l, p < 0.01; 447+/-16 U/ml, p < 0.001; 8.3+/-0.6 pg/ml, p = 0.006; 5.3+/-0.1 pg/ml, p < 0.001; and 5.1 0.2 pg/ml, p < 0.001; respectively) or control subjects (2.1+/-0.2 micromol/l, p < 0.001; 446+/-20 U/ml, p < 0.001; 6.4+/-0.2 pg/ml, p < 0.001; 5.4+/-0.1 pg/ml, p < 0.001; and 4.7+/-0.1 pg/ml, p < 0.001, respectively). On the contrary, only the mean IL-6 level was significantly different between inactive BD and control subjects (p = 0.02). All acute phase reactants were significantly higher in active BD than in inactive period (for each, p < 0.01).

CONCLUSIONS

High levels of sIL-2R, IL-6, IL-8 and TNF-alpha indicate the activation of immune system in BD. Serum sIL-2R, IL-6, IL-8 and TNF-alpha seem to be related to disease activity. Increased lipid peroxidation suggests oxidative stress in BD and therefore tissue damage in such patients. Amelioration of clinical manifestations would be envisaged by targeting these cytokines, chemokines and lipid peroxidation with pharmacological agents.

Intrapleural administration of tumour necrosis factor-alpha (TNFalpha) in patients with mesothelioma: cytokine patterns and acute-phase protein response

BACKGROUND

Tumour necrosis factor-alpha (TNFalpha) has been found to be very effective in the isolated limb perfusion setting for advanced extremity tumours. In a phase I study of intrapleural administration of TNFalpha 5 patients were followed for inflammatory response patterns.

PATIENTS AND METHODS

Malignant mesothelioma patients were treated with repeated intrapleural administration of 0. 1-0.2 mg recombinant TNFalpha. Samples of serum and pleural fluid were taken at different time-points before and after TNFalpha-administration. Levels of TNFalpha, interleukin-6 (IL-6), interleukin-8 (IL-8), C-reactive protein (CRP) and secretory phospholipase A2 (sPLA2) were measured using enzyme-linked immunosorbent assays (ELISAs). Alpha 1-acid glycoprotein (alpha1-AG) was measured by nephelometry.

RESULTS

In pleural fluid TNFalpha and IL-8 reached peak levels, up to 50-700 ng mL-1 and 6-60 ng mL-1, respectively, 24 h after administration of TNFalpha. IL-6 (peak levels up to 250 ng mL-1) and sPLA2 peaked after 48 h. A slower and less dramatic pattern was observed for the levels of CRP and alpha1-AG. In serum no detectable levels of TNFalpha and no IL-8 were observed, whereas serum levels of IL-6, sPLA2 and CRP showed a clear increase after intrapleural administration of TNFalpha. Cytokines and acute-phase proteins showed the same pattern during subsequent cycles even up to 12 cycles. Tumour regression was not observed.

CONCLUSIONS

In the setting of a phase I study of repetitive intrapleural administration of TNFalpha in mesothelioma patients, we studied the characteristics of the inflammatory response. Intrapleural administration was followed by a clear inflammatory response locoregionally. In spite of TNFalpha peak levels as high as 700 ng mL-1 systemic levels were never detectable. The secondary cytokine response led to very high intrapleural IL-6 and IL-8 levels. Systemically IL-8 levels were never detectable whereas high IL-6 levels were induced systemically initially, with a decreased response to each intrapleural TNFalpha administration over time. The acute-phase response in contrast remained remarkably constant throughout the course of repeated intrapleural administrations of TNFalpha. Intrapleural administration of TNFalpha is well tolerated but associated with inconsistent and rather moderate impact on production of pleural fluid. This can be achieved by other simpler and cheaper treatment, thus we see no justification for further studies.

Local and systemic concentrations of tumour necrosis factor-alpha, interleukin-6 and interleukin-8 in bacterial osteomyelitis

Osteomyelitis is a major cause of morbidity worldwide but there are few data investigating pathogenesis of infection and no investigations into local secretion of proinflammatory cytokines in patients. Tumour necrosis factor-alpha (TNF), interleukin (IL)-6 and IL-8 concentrations were measured in pus of infected bone from 30 Zambian patients with chronic osteomyelitis (principally caused by Staphylococcus aureus), in plasma, and after lipopolysaccharide stimulation of whole-blood leucocytes. Patients had reduced body mass index compared to controls (P = 0.025) and an acute-phase response. Elevated concentrations of proinflammatory cytokines were detected in bone compared to plasma (all P < 0.0002). Bone IL-8 concentrations were greater than IL-8 levels after lipopolysaccharide stimulation of whole blood (P < 0.01). In contrast, systemic and ex-vivo-stimulated concentrations of proinflammatory cytokine were similar in patients and controls, despite differences in body mass index and an acute-phase response. In summary, we observed marked local TNF, IL-6 and IL-8 secretion in established bacterial osteomyelitis without systemic cytokine release.

Use of car headlamps

Polymorphonuclear neutrophils are critical for resolution of bacterial infections. In tissues, most of the neutrophils quickly die through apoptosis. Using propidium iodide DNA staining and DNA gel electrophoresis, we found that spontaneous apoptosis of neutrophils from patients suffering osteomyelitis (n = 52) was significantly decreased in relation to control neutrophils (n = 20) (40.2% +/- 25.2% versus 54.5% +/- 23.5%; P < 0.03). Incubation of neutrophils from normal volunteers with sera from patients with osteomyelitis reduced apoptosis from 79.1% +/- 14.8% in control sera to 62.2% +/- 18.7% in osteomyelitis sera. A significant increase of serum interleukin-6 (IL-6) and IL-1alpha was found in osteomyelitis (IL-6, 8.8 +/- 11.9 pg/ml versus 1.8 +/- 1.2 pg/ml in controls [P < 0.004]; IL-1alpha, 3.8 +/- 6.4 pg/ml versus 1.0 +/- 2.2 pg/ml in controls [P < 0.02]). No differences in the levels of other cytokines, such as tumor necrosis factor alpha, were found. There was an inverse correlation between IL-6 levels and neutrophil apoptosis (r = -0.855; P < 0.007), but this was not the case for other cytokines. The antiapoptotic effect of the osteomyelitis sera was reversed with anti-IL-6 antibodies (P < 0.03) and was reproduced with recombinant human IL-6 (P < 0.001). The longer life span of neutrophils in osteomyelitis induced by IL-6 could contribute to the tissue damage that occurs in these chronic bone infections.