A murine Staphylococcus aureus fracture-related infection model characterised by fracture non-union, staphylococcal abscess communities and myeloid-derived suppressor cells.

A fracture-related infection (FRI) is a serious complication that can occur after surgical fixation of bone fractures. Affected patients may encounter delayed healing and functional limitations. Although it is well established that Staphylococcus aureus (S. aureus) is the main causative pathogen of an FRI, the pathophysiology of an S. aureus-induced FRI is not well characterised over time. Therefore, an experimental study in mice comparing S. aureus-inoculated and non-inoculated groups was performed that particularly focused on staphylococcal abscess communities (SACs) and host cellular response. C57Bl/6N female mice received a double osteotomy of the femur, which was stabilised using a titanium 6-hole MouseFix locking plate and four screws. Animals were either S. aureus-inoculated or non-inoculated and euthanised between 1 and 28 d post-surgery. Histopathological evaluation showed normal bone healing for non-inoculated mice, whereas inoculated mice had no fracture consolidation and severe osteolysis. Within the bone marrow of inoculated mice, SACs were observed from 7 d, which increased in size and number over time. A fibrin pseudocapsule enclosed the SACs, which were surrounded by many Ly6G+ neutrophils with some Ly6C+ monocytes and F4/80+ macrophages, the majority of which were viable. The abscesses were encapsulated by fibrin(ogen), collagen and myofibroblasts, with regulatory T cells and M2 macrophages at the periphery. Only bone marrow monocytes and neutrophils of inoculated mice displayed functional suppression of T cells, indicative of myeloid-derived suppressor cells. The present study revealed that an FRI in mice is persistent over time and associated with osteolysis, SAC formation and an immunosuppressive environment.

Case report: Fever- pneumonia- lymphadenectasis- osteolytic- subcutaneous nodule: Disseminated chromoblastomycosis caused by phialophora.

Chromoblastomycosis (CBM) is a chronic cutaneous and subcutaneous fungal infection caused by certain dematiaceous fungi (usually Fonsecaea, Phialophora, or Cladophialophora). Histologically, CBM is characterized by the presence of medlar bodies. However, the diagnosis is difficult because of the rarity of these pathognomonic presentations and the wide variety of presentations. Treatment of these infections is challenging as it lacks standardization. Herein, we report a case of chromoblastomycosis caused by Phialophora, in a 42-year-old immunocompetent male agriculturist from the humid and subtropical region of southern China. He had a 3-month history of pneumonia with intermittent fever, coughing, and expectoration. The infection subsequently spread to the bone and lymph nodes forming deep lesions and eventually resulting in osteolysis and lymphadenectasis. These subcutaneous nodules were observed after 9 months. Antifungal treatment was administered for 20 months leading to clinical improvement before the patient was lost to follow-up. This case is unique because such deep lesions are rare in immunocompetent individuals and because the initial onset was associated with pneumonia.

Disseminated Infection of Encephalitozoon cuniculi Associated With Osteolysis of Hip Periprosthetic Tissue.

Background: Among patients with hip joint endoprosthesis, periprosthetic osteolysis is the most common complication following primary arthroplasty, and subsequent implant loosening is the leading cause of arthroplasty revision. Causes of stability loss, though not always evident, can be mechanical, allergic, or infectious (bacterial and fungal agents) in nature. Microsporidia, widespread opportunistic fungal pathogens that infect most human tissues, are a potential infectious cause of stability loss. Infections caused by Encephalitozoon species-one of the most common microsporidial pathogens in humans-primarily localize to intestinal and respiratory tracts, but can disseminate to tissues throughout the body. Methods: We examined 53 immunocompetent patients, 23 after revision and 30 after primary hip arthroplasty, for infection by Encephalitozoon species. Periprosthetic tissue, urine sediments, and stool samples were tested by microscopic examination and genus-specific nested polymerase chain reaction followed by genotyping. Results: Ten patients had Encephalitozoon-positive periprosthetic tissues, 9 (39%) after revision and 1 (3.3%) after primary hip arthroplasty. Among the tissue-positive postrevision patients, 7 had a positive urine sample and 1 had a positive stool sample. Encephalitozoon cuniculi genotype II was identified in 88.8% (16/18) of samples. Two urine samples were positive for a novel Encephalitozoon species. Conclusions: Encephalitozoon cuniculi should be considered as a cause of osteolysis in hip periprosthetic tissue, leading to a loss of implant stability.

The Lyme Disease Pathogen Borrelia burgdorferi Infects Murine Bone and Induces Trabecular Bone Loss.

Lyme disease is caused by members of the Borrelia burgdorferi sensu lato species complex. Arthritis is a well-known late-stage pathology of Lyme disease, but the effects of B. burgdorferi infection on bone at sites other than articular surfaces are largely unknown. In this study, we investigated whether B. burgdorferi infection affects bone health in mice. In mice inoculated with B. burgdorferi or vehicle (mock infection), we measured the presence of B. burgdorferi DNA in bones, bone mineral density (BMD), bone formation rates, biomechanical properties, cellular composition, and two- and three-dimensional features of bone microarchitecture. B. burgdorferi DNA was detected in bone. In the long bones, increasing B. burgdorferi DNA copy number correlated with reductions in areal and trabecular volumetric BMDs. Trabecular regions of femora exhibited significant, copy number-correlated microarchitectural disruption, but BMD, microarchitectural, and biomechanical properties of cortical bone were not affected. Bone loss in tibiae was not due to increased osteoclast numbers or bone-resorbing surface area, but it was associated with reduced osteoblast numbers, implying that bone loss in long bones was due to impaired bone building. Osteoid-producing and mineralization activities of existing osteoblasts were unaffected by infection. Therefore, deterioration of trabecular bone was not dependent on inhibition of osteoblast function but was more likely caused by blockade of osteoblastogenesis, reduced osteoblast survival, and/or induction of osteoblast death. Together, these data represent the first evidence that B. burgdorferi infection induces bone loss in mice and suggest that this phenotype results from inhibition of bone building rather than increased bone resorption.

Influence of fracture stability on Staphylococcus epidermidis and Staphylococcus aureus infection in a murine femoral fracture model.

Fracture-related infection (FRI) is a major complication in surgically fixed fractures. Instability of the fracture after fixation is considered a risk factor for infection; however, few experimental data are available confirming this belief. To study whether stable fractures led to higher infection clearance, mouse femoral osteotomies were fixed with either stable or unstable fixation and the surgical site was contaminated with either Staphylococcus epidermidis (S. epidermidis)or Staphylococcus aureus (S. aureus)clinical isolates. Infection progression was assessed at different time points by quantitative bacteriology, total cell counts in spleen and lymph node and histological analysis. Operated, non-inoculated mice were used as controls. Two inbred mouse strains (C57BL/6 and BALB/c) were included in the study to determine the influence of different host background in the outcome. Stable fixation allowed a higher proportion of C57BL/6 mice to clear S. epidermidis inoculation in comparison to unstable fixation. No difference associated with fixation type was observed for BALB/c mice. Inoculation with S. aureus resulted in a more severe infection for both stable and unstable fractures in both mouse strains; however, significant osteolysis around the screws rendered the stable group functionally unstable. Our results suggested that fracture stability could have an influence on S. epidermidis infection, although host factors also played a role. No differences were observed when using S. aureus, due to a more severe infection, leading to osteolysis and loss of stability in both groups. Further studies are required in order to address the biological features underlying the differences observed.

Case of disseminated histoplasmosis in a HIV-infected patient revealed by nasal involvement with maxillary osteolysis.

BACKGROUND: Disseminated Histoplasmosis (DH) is a rare manifestation of Acquired Immune Deficiency Syndrome (AIDS) in European countries. Naso-maxillar osteolysis due to Histoplasma capsulatum var. capsulatum (Hcc) is unusual in endemic countries and has never been reported in European countries. Differential diagnoses such as malignant tumors, cocaine use, granulomatosis, vasculitis and infections are more frequently observed and could delay and/or bias the final diagnosis. CASE PRESENTATION: We report the case of an immunocompromised patient infected by Human Immunodeficiency Virus (HIV) with naso-maxillar histoplasmosis in a non-endemic country. Our aim is to describe the clinical presentation, the diagnostic and therapeutic issues. A 53-year-old woman, originated from Haiti, was admitted in 2016 for nasal deformation with alteration of general condition evolving for at least 6 months. HIV infection was diagnosed in 2006 and classified at AIDS stage in 2008 due to cytomegalovirus infection associated with pulmonary histoplasmosis. At admission, CD4 cell count was 9/mm3. Surgical biopsies were performed and ruled out differential or associated diagnoses. Mycological cultures identified Hcc and Blood Polymerase Chain Reaction (PCR) for Hcc was positive. The patient was given daily Amphothericin B liposomal infusion during 1 month. Hcc PCR became negative in the blood under treatment, and then oral switch by itraconazole was introduced. Antiretroviral treatment was reintroduced after a 3-week histoplasmosis treatment. Normalization of naso-maxillar mucosa enabled a palatal prosthesis. CONCLUSION: Naso-maxillar histoplasmosis is extremely rare; this is the first case ever reported in a non-endemic country. Differential diagnoses must be ruled out by conducting microbiologic tools and histological examinations on surgical biopsies. Early antifungal treatment should be initiated in order to prevent DH severe outcomes.

Microbial osteolysis in an Early Pleistocene hominin (Paranthropus robustus) from Swartkrans, South Africa.

Microbiological degradation is one of the most important factors responsible for the destruction of bone in archaeological contexts. Microscopic focal destruction (MFD) is the most prevalent form of microbial tunneling and is encountered very commonly in human bones from archaeological sites, whereas animal bones from these same sites show significantly better preservation if they were deposited in a fragmentary (e.g., butchered) state. Similarly, most fossils show either no evidence or only minor traces of bacterial osteolysis. These observations and experimental evidence point to an endogenous origin for osteolytic bacteria, suggesting that bone bioerosion could potentially aid in reconstructing early taphonomic events. We here report extensive MFD in the mandibular corpus of a small (presumptive female) individual of the hominin Paranthropus robustus from the Early Pleistocene site of Swartkrans, South Africa. The specimen (SKX 5013) derives in situ from the Member 2 deposit, which is dated to ca. 1.5-1.0 Ma. Examination of sections from the corpus by backscattered electron microscopy reveals numerous small linear longitudinal and budded tunneling cavities, which tend to be concentrated around Haversian canals and are more abundant closer to the endosteal aspect of the section. The taphonomy of Swartkrans has been the subject of intense investigation, and given the possibility that different agents of accumulation may have been responsible for the faunal and hominin fossils in the different members at the site, the observation that a specimen of P. robustus from Member 2 displays significant microbial osteolysis is of potential interest. A study of the prevalence of this process in adequately large samples of the animal bones from these units may yield novel insights and provide refinement of our understanding of their taphonomic histories. Such observations might well reveal differences among the various members that could provide another valuable source of osteoarchaeological information for the site.

Retrospective analysis of 14 cases of disseminated Penicillium marneffei infection with osteolytic lesions.

BACKGROUND: Penicillium marneffei disseminates hematogenously and can infect most organs, though infection leading to osteolysis is extremely rare. We describe the clinical and laboratory features, management, and outcomes of patients with penicilliosis marneffei (PSM) with osteolytic lesions. METHODS: This retrospective study was conducted between January 1, 2003 and May 1, 2014 at the First Affiliated Hospital of Guangxi Medical University. Patients who presented with culture and/or histopathologic proof of disseminated PSM within osteolytic lesions were included. RESULTS: P. marneffei infection was diagnosed in 100 patients (65 HIV-infected and 35 HIV-negative). Fourteen patients, all HIV-negative, (14/35, 40%) had osteolytic lesions. The most common comorbidity was diabetes mellitus, though previous glucocorticoid therapy, ß-thalassemia, breast cancer, and Langerhans cell histiocytosis also occurred. Five patients had no comorbidity. Fever, malaise, ostealgia, weight loss, and anemia were the most common symptoms, followed by cutaneous lesions, lymphadenopathy, hepatosplenomegaly, cough, sputum, and stethalgia. Ostealgia, joint pain, and joint disorders were also recorded. White blood cell and neutrophil counts were increased (mean 22.3 ± 7.4 × 10(9) cells/L; mean 18.84 ± 4.5 × 10(9) cells/L, respectively). The most common sites were the vertebrae, skull and femur, ribs and ilium, though the clavicle, scapula, humerus, and tibia were also involved. Radiography and computed tomography (CT) showed multiple radiolucencies with moth-eaten bone destruction, periosteal proliferation, bone fracture, and surrounding soft-tissue swelling. Emission CT showed significantly increased uptake in many skeletal regions. Positron emission tomography/CT showed generalized lymphadenopathy, bone metabolic activity, and bone destruction. The (18) F-FDG standard uptake value was increased in the entire skeleton (mean 6.16). Twelve patients received antifungal therapy, four of whom died during treatment, and eight recovered, though four of these eight relapsed within 3-24 months. Two patients discontinued treatment because of severe multiple organ failure and died. CONCLUSIONS: Osteolysis is often overlooked in HIV-negative individuals with disseminated P. marneffei infection. However, P. marneffei involving the bone and leading to osteolysis may indicate severe systemic disturbance, and is characterized by a poor prognosis, high recurrence rate, and the need for prolonged antifungal treatment.

[Pathophysiology of implant-associated infections: From biofilm to osteolysis and septic loosening]. / Pathophysiologie der implantatassoziierten Infektion : Vom Biofilm zur Osteolyse und septischen Lockerung.

Biofilm formation is the key factor in the pathogenesis of implant-associated infections. The most common pathogens isolated are Staphylococcus species, opportunists belonging to the physiological flora of the skin. Biofilm formation starts with the adhesion of bacteria and colonisation preferentially occurs on the surfaces of the foreign body material. As an interactive symbiotic "city of microbes," biofilm formation represents an efficient survival strategy for bacteria. In clinically apparent infections the biofilm induces a local host response with infiltration of phagocytic immune cells. The proinflammatory microenvironment results in a stimulation of osteoclastogenesis, with local osteolysis, and finally septic loosening of the implant. According to the biofilm theory, retaining the implant in primary revision surgery is only recommended in early-stage infections with a stable implant; in late-stage infections, or when loosening occurs, the implant should be removed. Results of previous anti-biofilm therapies have not been satisfactory; therefore, current research is focused on prevention strategies, especially the modification of implant surfaces. Basic knowledge of the underlying pathophysiology is a prerequisite for the development of innovative interdisciplinary therapy and prevention strategies; in this context, essential aspects of biofilm formation, its consequences, and its relevance to diagnosis and therapy are described and discussed.

Sinus fungal balls: characteristics and management in patients with host factors for invasive infection.

BACKGROUND: The characteristics of sinus fungal ball (SFB), classically considered being a non-invasive form of fungal infection, in patients with host factors for invasive fungal infection (IFI) are unknown. OBJECTIVE: To characterize SFB and their management in patients with host factors for IFI. METHODOLOGY: Retrospective single-centre study of the clinical, radiology, histology and mycology records of patients treated for SFB between 1997 and 2007. Patients with and without host factors for IFI were compared. RESULTS: One hundred eighty one patients were classified into two groups: 19 (group 1) with and 162 (group 2) without host fac- tors for IFI. In group 1, SFB were asymptomatic in 26.3% of the cases, ethmoido-sphenoidal sinuses were more frequently involved than in group 2 and fungal culture was positive in 37.5% of the cases. The main species was Aspergillus sp. in both groups. Four cases of complicated SFB were observed, only in patients of group 1. Cure without recurrence was obtained in both groups by endonasal surgery, combined with triazole therapy in complicated forms with osteolysis. CONCLUSION: In patients with host factors for IFI, SFB more frequently involves deep sinuses and can be complicated by clinical signs suggestive of invasion and radiological signs of osteolysis, with no histological evidence of fungal invasion.

Relationship between the degree of osteolysis and cultures obtained by sonication of the prostheses in patients with aseptic loosening of a hip or knee arthroplasty.

INTRODUCTION: The pathogenesis of prosthesis loosening is not well understood. The aim of our study was to sonicate components of joint prostheses removed due to aseptic loosening, culture the sonicate fluid, and to correlate these results with the degree of radiological osteolysis. METHODS: From January 2008 to June 2009 all consecutive patients who underwent a revision of hip or knee prosthesis due to aseptic loosening were included in the study. Aseptic loosening was established when the patient had radiological signs of loosening without symptoms or signs of infection. The diagnosis was confirmed when histology was negative, and ≥ 5 out of 6 standard cultures of periprosthetic tissue were negative. Bone lysis was measured according to the Paprosky or Engh classifications without knowing the result of sonication cultures. Removed components were placed in sterile bags and immediately transported to the microbiology laboratory and sonicated. Sonicate fluid was cultured and the results were correlated with the degree of bone lysis. The proportion of components with positive sonication culture according to the bone lysis classification was compared using χ(2) test. RESULTS: A total of 52 patients were included and 123 components were sonicated. In 30 patients at least 1 sonicated component was positive (57.7%) and 44 out of 123 (35.8%) components were positive. The proportion of positive sonication cultures was significantly higher in the group of components with a higher degree of bone lysis of 3 (76.5%) than in those with lower degrees (33.9% for 1 and 24% for 2) (χ(2) test, p = 0.0004). CONCLUSIONS: Sonication cultures were positive in 57% of patients who underwent revision arthroplasty for aseptic loosening. The percentage of positive sonication cultures was significantly higher in patients with severe osteolysis. LEVEL OF EVIDENCE: level I of Prognostic Studies-Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

Humanized Mice Exhibit Exacerbated Abscess Formation and Osteolysis During the Establishment of Implant-Associated Staphylococcus aureus Osteomyelitis.

Staphylococcus aureus is the predominant pathogen causing osteomyelitis. Unfortunately, no immunotherapy exists to treat these very challenging and costly infections despite decades of research, and numerous vaccine failures in clinical trials. This lack of success can partially be attributed to an overreliance on murine models where the immune correlates of protection often diverge from that of humans. Moreover, S. aureus secretes numerous immunotoxins with unique tropism to human leukocytes, which compromises the targeting of immune cells in murine models. To study the response of human immune cells during chronic S. aureus bone infections, we engrafted non-obese diabetic (NOD)-scid IL2Rγnull (NSG) mice with human hematopoietic stem cells (huNSG) and analyzed protection in an established model of implant-associated osteomyelitis. The results showed that huNSG mice have increases in weight loss, osteolysis, bacterial dissemination to internal organs, and numbers of Staphylococcal abscess communities (SACs), during the establishment of implant-associated MRSA osteomyelitis compared to NSG controls (p < 0.05). Flow cytometry and immunohistochemistry demonstrated greater human T cell numbers in infected versus uninfected huNSG mice (p < 0.05), and that T-bet+ human T cells clustered around the SACs, suggesting S. aureus-mediated activation and proliferation of human T cells in the infected bone. Collectively, these proof-of-concept studies underscore the utility of huNSG mice for studying an aggressive form of S. aureus osteomyelitis, which is more akin to that seen in humans. We have also established an experimental system to investigate the contribution of specific human T cells in controlling S. aureus infection and dissemination.

Activation of the acquired immune response reduces coupled bone formation in response to a periodontal pathogen.

Osteoimmunolgy involves the interaction of the immune system with skeletal elements. This interaction can lead to the formation of osseous lesions. To investigate how the acquired immune response could contribute to osteolytic lesions, we injected the periodontal pathogen Porphyromonas gingivalis adjacent to calvarial bone with or without prior immunization against the bacterium. Activation of the acquired immune response increased osteoclastogenesis and decreased coupled bone formation. The latter was accompanied by an increase in nuclear translocation of the transcription factor FOXO1 in vivo, increased apoptosis of bone-lining cells measured by the TUNEL assay and number of activated caspase-3 positive cells and a decrease in bone lining cell density. Further studies were conducted with MC3T3 osteoblastic cells. Apoptosis and increased FOXO1 DNA binding activity were induced when a combination of cytokines was tested, IL-beta, TNF-alpha, and IFN-gamma. Knockdown of FOXO1 by small interfering RNA significantly reduced cytokine stimulated apoptosis, cleaved caspase-3/7 activity and decreased mRNA levels of the proapoptotic genes, TNF-alpha, FADD, and caspase-3, -8, and -9. These results indicate that activation of the acquired immunity by a periodontal pathogen reduces the coupling of bone formation and resorption. This may occur by enhancing bone lining cell apoptosis through a mechanism that involves increased FOXO1 activation. These studies give insight into inflammatory bone diseases such as periodontal disease and arthritis were the formation of lytic lesions occurs in conjunction with deficient bone formation and activation of an acquired immune response.

Characterization and regulation of osteoclast precursors following chronic Porphyromonas gingivalis infection.

Bone destruction in inflammatory osteolytic diseases including periodontitis is related to excessive activity of osteoclasts (OC), which originate from precursor cells of the myeloid lineage, termed osteoclast precursors (OCP). In contrast to ample knowledge that we currently have on mature OC, little is known about OCP and their regulation during bacterial infection. Therefore, this study aimed to identify and characterize OCP following chronic infection with a periodontal bacteria Porphyromonas gingivalis (Pg). We used a micro-osmotic pump to continually release Pg subcutaneously in a murine model. Two weeks after Pg infection, the frequency of CD11b+c-fms+Ly6Chi population is significantly elevated within the bone marrow, spleen and peripheral blood. In vitro and in vivo studies identified these cells as the OCP-containing population and Pg infection significantly enhanced the osteoclastogenic activity of these cells. Furthermore, mRNA sequencing analysis indicated a unique gene and pathway profile in CD11b+c-fms+Ly6Chi population following Pg infection, with changes in genes and pathways related to OC differentiation, cell proliferation and apoptosis, inflammatory response, phagocytosis and immunity, as well as antigen processing and presentation. Moreover, using IL-6 knockout mice, we found that IL-6 is important for Pg-induced accumulation of CD11b+c-fms+Ly6Chi population from the bone marrow and periphery. Our results provide new insights into the characterization and regulation of OCP following a chronic bacterial infection. This knowledge is relevant to the understanding of the pathogenesis of bacteria-induced bone loss, and to the identification of potential therapeutic targets of bone loss diseases.

Bacillus cereus isolated from a positive bone tissue culture in a patient with osteolysis and high-titer anti-interferon-γ autoantibodies: A case report.

RATIONALE: Bacillus cereus (B cereus) is an aerobic or facultative anaerobic gram-positive, spore-forming bacterium. It can cause fatal disease and generally manifests as 3 distinct syndromes: food intoxication, localized infection, and systemic infection. It is a rare infection that can occur in immunocompetent persons with osteolytic and high-titer anti-IFN-γ autoantibodies. PATIENT CONCERNS: We reported a case of an HIV-negative 24-year old man with an interrupted fever and a 20-day history of progressive ache in the right thigh and high-titer anti-IFN-γ autoantibodies. Magnetic resonance imaging, X-radiography, high-resolution computed tomography, and 3-dimensional reconstruction of the bone showed multiple lucent defects with moth-eaten destruction of the bone and cortical substance of bone in the right femur. Emission CT showed significantly increased uptake in the femur. DIAGNOSIS AND INTERVENTIONS: The patient was originally misdiagnosed with osteosarcoma; acute osteomyelitis was also considered. He received intravenous piperacillin, sulbactam, and levofloxacin during hospitalization; however, he did not respond to the 3-week antibiotic course and his condition worsened. After cultures from incisional biopsy specimens were obtained from the femoral cavity, B cereus-induced osteomyelitis was diagnosed. He received intravenous injections of moxifloxacin 400 mg qd for 4 weeks and oral moxifloxacin 400 mg qd for 8 weeks. OUTCOMES: The patient's symptoms and signs improved. His X-radiography, HRCT, MRI, and 3-dimensional reconstruction of the bone showed absolute absorption in the right femur. However, the anti-IFN-γ autoantibody titer was still high. No recurrence was observed after 24 months of follow-up. He is still undergoing follow-up at this time. LESSONS: This is the first case involving a patient with B cereus infection showing a high titer of anti-IFN-γ autoantibodies. B cereus infection can involve the bone, leading to osteolysis in HIV-negative individuals. Although this patient was HIV-negative and had no other comorbidities, the presence of high titer anti-IFN-γ autoantibodies may be the primary reason for B cereus infection. Clinicians should pay more attention to the identification of osteolytic destruction caused by tumor and infection.

Fine needle aspiration in aspergilloma of frontal sinus: a case report.

BACKGROUND: The increased incidence of fungal diseases in humans is most likely due to indiscriminate use of broad-spectrum antibiotics and increased numbers of immunocompromised patients. Although Aspergillus species are ubiquitous and normally nonpathogenic, they can be opportunistic pathogens in immunocompromised individuals. CASE: A 22-year-old immunocompetent man presented with a gradually increasing subcutaneous swelling near the root of his nose for previous 6 months. The mass was soft to firm, solid, nontender and immobile. There was no superficial skin ulceration and no local signs of inflammation. Proptosis of the left eye was present without any visual impairment. An osteolytic lesion that was contiguous with the subcutaneous mass, with the opacities of both the fontal sinuses was observed radiographically. Fine needle aspiration cytology (FNAC) demonstrated presence of branching hyphae in the cytoplasm of multinucleated giant cells along with mixed inflammatory cells. The species was identified by culture in Sabouraud's agar with chloramphenicol and wet mount with lactophenol cotton blue stain. CONCLUSION: Aspergillosis can remain dormant over a long period. Although uncommon, it can occur in immunocompetent patients. FNA is a very useful tool in establishing the diagnosis

RANKL Triggers Treg-Mediated Immunoregulation in Inflammatory Osteolysis.

The chronic inflammatory immune response triggered by the infection of the tooth root canal system results in the local upregulation of RANKL, resulting in periapical bone loss. While RANKL has a well-characterized role in the control of bone homeostasis/pathology, it can play important roles in the regulation of the immune system, although its possible immunoregulatory role in infectious inflammatory osteolytic conditions remains largely unknown. Here, we used a mouse model of infectious inflammatory periapical lesions subjected to continuous or transitory anti-RANKL inhibition, followed by the analysis of lesion outcome and multiple host response parameters. Anti-RANKL administration resulted in arrest of bone loss but interfered in the natural immunoregulation of the lesions observed in the untreated group. RANKL inhibition resulted in an unremitting proinflammatory response, persistent high proinflammatory and effector CD4 response, decreased regulatory T-cell (Treg) migration, and lower levels of Treg-related cytokines IL-10 and TGFb. Anti-RANKL blockade impaired the immunoregulatory process only in early disease stages, while the late administration of anti-RANKL did not interfere with the stablished immunoregulation. The impaired immunoregulation due to RANKL inhibition is characterized by increased delayed-type hypersensitivity in vivo and T-cell proliferation in vitro to the infecting bacteria, which mimic the effects of Treg inhibition, reinforcing a possible influence of RANKL on Treg-mediated suppressive response. The adoptive transfer of CD4+FOXp3+ Tregs to mice receiving anti-RANKL therapy restored the immunoregulatory capacity, attenuating the inflammatory response in the lesions, reestablishing normal T-cell response in vivo and in vitro, and preventing lesion relapse upon anti-RANKL therapy cessation. Therefore, while RANKL inhibition efficiently limited the periapical bone loss, it promoted an unremitting host inflammatory response by interfering with Treg activity, suggesting that this classic osteoclastogenic mediator plays a role in immunoregulation.

The role of RANKL/RANK/OPG system in the canine model of hip periprosthetic infection osteolysis.

PURPOSE: We aimed to investigate whether the RANKL/RANK/OPG system is associated with the incidence of periprosthetic osteolysis with septic loosening, and to investigate the differences of RANKL/RANK/OPG system expression in synovial fluid surrounding the normal and septic loosening hip prosthesis in canine models. METHODS: Twelve healthy adult mongrel canines were divided into two groups: experimental and control. Femoral head and stem replacements were conducted on the right side in both groups. The experimental group received the bacteria fluid intra-articular injection and the other group received the same amount of saline in the same day. The synovial fluid samples were gathered at the 1st, 2nd, 4th, 8th, 12th, 16th and 19th week after the bacteria fluid intra-articular injection for enzyme-linked immunosorbent assay (ELISA), the expression of the RANKL/RANK/OPG system. RESULTS: Surgery on all animals was successful. Two dogs were excluded from the analysis of the result because of a surgery infection or death. The ELISA of the synovial fluid revealed that the ratio of RANKL/OPG showed a significant upward trend (p≤0.05) with time in the test group but the ratio of RANKL/OPG in the control group changed slowly over time (p>0.05). The ratio of RANKL/OPG value between the test and control group showed a significant upward trend, but had no statistical difference (p>0.05) over time. CONCLUSIONS: It could be concluded that the RANKL/RANK/OPG system is correlated with the incidence of periprosthetic osteolysis with septic loosening. Consequently, imbalance RANKL/RANK/OPG system was related to periprosthetic osteolysis with septic loosening.

Isolated lytic bone lesion in tuberculosis.

Causes of lytic bone lesions include benign, malignant, and infectious processes. Lytic lesions due to tuberculosis (TB) may closely mimic those due to tumors such as bone cyst, osteoblastoma, osteosarcoma, and metastatic bone disease radiologically. Histopathology and culture help in definitive diagnosis and prompt management. We describe an immunocompetent patient with isolated lytic bone lesion in the distal part of ulna due to TB to make the readers aware of such unusual presentations of TB.