Immune reconstitution inflammatory syndrome manifesting as development of multiple autoimmune disorders and skin cancer progression.

We report the case of a 56-year-old man with the rare autoimmune pathologies of alternating hypothyroidism and hyperthyroidism due to thyroid-stimulating hormone receptor antibodies, and rheumatoid arthritis as manifestations of a human immunodeficiency virus-related immune reconstitution inflammatory syndrome. The patient also developed overt progression of a pre-existing skin malignancy that may also be related. This case highlights immune reconstitution syndrome as an important differential diagnosis following antiretroviral therapy commencement, and that a high index of suspicion should be maintained for this rare but important cluster of conditions. Furthermore, the patient's genetic predisposition to autoimmunity provides helpful insights into the pathogenesis of these disorders.

Coupling of the TCR to integrin activation by Slap-130/Fyb.

SLAP-130/Fyb (SLP-76-associated phosphoprotein or Fyn-binding protein; also known as Fyb/Slap) is a hematopoietic-specific adapter, which associates with and modulates function of SH2-containing leukocyte phosphoprotein of 76 kilodaltons (SLP-76). T cells from mice lacking SLAP-130/Fyb show markedly impaired proliferation following CD3 engagement. In addition, the T cell receptor (TCR) in SLAP-130/Fyb mutant cells fails to enhance integrin-dependent adhesion. Although TCR-induced actin polymerization is normal, TCR-stimulated clustering of the integrin LFA-1 is defective in SLAP-130/Fyb-deficient cells. These data indicate that SLAP-130/Fyb is important for coupling TCR-mediated actin cytoskeletal rearrangement with activation of integrin function, and for T cells to respond fully to activating signals.

Increased incidence of Chlamydia species within the coronary arteries of patients with symptomatic atherosclerotic versus other forms of cardiovascular disease.

OBJECTIVES: The objectives of this study were to test prospectively for an association between Chlamydia and atherosclerosis by comparing the incidence of the pathogen found within atherosclerotic plaques in patients undergoing directional coronary atherectomy with a variety of control specimens and comparing the clinical features between the groups. BACKGROUND: Previous work has suggested an association between Chlamydia pneumoniae infection and coronary atherosclerosis, based on the demonstration of increased serologic titers and the detection of bacteria within atherosclerotic tissue, but this association has not yet been regarded as established. METHODS: Coronary specimens from 90 symptomatic patients undergoing coronary atherectomy were tested for the presence of Chlamydia species using direct immunofluorescence. Control specimens from 24 subjects without atherosclerosis (12 normal coronary specimens and 12 coronary specimens from cardiac transplant recipients with subsequent transplant-induced coronary disease) were also examined. RESULTS: Coronary atherectomy specimens were definitely positive in 66 (73%) and equivocally positive in 5 (6%), resulting in 79% of specimens showing evidence for the presence of Chlamydia species within the atherosclerotic tissue. In contrast, only 1 (4%) of 24 nonatherosclerotic coronary specimens showed any evidence of Chlamydia. The statistical significance of this difference is a p value < 0.001. Transmission electron microscopy was used to confirm the presence of appropriate organisms in three of five positive specimens. No clinical factors except the presence of a primary nonrestenotic lesion (odds ratio 3.0, p = 0.057) predicted the presence of Chlamydia. CONCLUSIONS: This high incidence of Chlamydia only in coronary arteries diseased by atherosclerosis suggests an etiologic role for Chlamydia infection in the development of coronary atherosclerosis that should be further studied.

Signaling networks regulating beta1 integrin-mediated adhesion of T lymphocytes to extracellular matrix.

T-cell recognition of foreign antigen and migration to specific anatomic sites in vivo involves transient adhesive contacts between beta1 integrins expressed on T cells and cell surface proteins or extracellular-matrix components. Engagement of the CD3-T-cell receptor (CD3-TCR) complex initiates a complex signaling cascade involving coordinated regulation and recruitment of tyrosine and lipid kinases to specific regions or microdomains in the plasma membrane. Although considerable attention has been focused on the signaling events by which the CD3-TCR complex regulates transcriptional events in the nucleus, CD3-TCR signaling also rapidly enhances integrin-mediated adhesion without increasing surface expression of integrins. Recent studies suggest that CD3-TCR signaling to beta1 integrins involves coordinated recruitment and activation of the Tec family tyrosine kinase Itk by src family tyrosine kinases and phosphatidylinositol 3-kinase. These signaling events that regulate integrin-mediated T-cell adhesion share both common and distinct features with the signaling pathways regulating interleukin-2 gene transcription.

HIV combination therapy: partial immune restitution unmasking latent cryptococcal infection.

OBJECTIVE: To describe two cases of cryptococcal meningitis and one re-exacerbation of Cryptococcus-associated meningitis occurring in temporal association with commencement of highly active antiretroviral therapy (HAART) in patients with advanced HIV infection (CD4 cells < 50 x 10(6)/l), which suggests that partial immune restitution can facilitate development of clinically apparent meningitis in response to Cryptococcus or its antigen. DESIGN: All HIV-infected patients with culture-proven cryptococcal meningitis diagnosed at a tertiary referral centre specialist infectious diseases unit from 1 January 1996 to 31 December 1996 were reviewed to examine the clinical and immunological parameters prior to and after commencing antiretroviral therapy. RESULTS: Three patients were diagnosed with clinically apparent meningitis within 7-39 days of changing or altering antiretroviral combination therapy consisting of zidovudine or stavudine, in combination with lamivudine and saquinavir. All patients had CD4 cell counts below 50 x 10(6)/l at initiation of therapy. Following institution of HAART, evidence of immune restitution was suggested by the following: (i) significant increases (3.7-14-fold) in numbers of CD4 cells (all three patients), (ii) significantly reduced (> 2-4 log10 reduction) HIV viral loads (two out of three patients), and (iii) prominent inflammatory changes in cerebrospinal fluid (white blood cells > 10 x 10(6)/l) at diagnosis (two out of three patients). CONCLUSIONS: Our report suggests that in patients with advanced HIV infection, partial immune restitution induced by HAART can precipitate onset of clinically apparent meningitis in those patients with latent cryptococcal central nervous system infection or with residual cryptococcal antigen present in the cerebrospinal fluid.

Extrinsic factors that put patients at risk of acquiring central nervous system infections.

Although many host defenses, including physical barriers, phagocytic cells, and humoral elements, normally protect the central nervous system from microbial pathogens, a variety of extrinsic factors may compromise these defenses and put patients at risk of acquiring central nervous system infection. These risk factors include: (1) communication of the cerebrospinal fluid space with integumentary surfaces; (2) communication of the cerebrospinal fluid space with other body spaces through shunts; (3) suppurative foci contiguous to the central nervous system; (4) hematogenous spread of infectious agents; (5) new acquisition of infectious agents with a propensity for causing central nervous system infection; and (6) administration of certain antimicrobial or immunosuppressive drugs. Recognition that these factors are present and therefore that the patient is at risk allows monitoring for and prompt response to signs and symptoms of central nervous system infection.

Detection of individual hypoxic cells in multicellular spheroids by flow cytometry using the 2-nitroimidazole, EF5, and monoclonal antibodies.

PURPOSE: The purpose of this work was to evaluate EF5, a 2-nitroimidazole compound, and anti-EF5 antibodies as a method to quantify radiobiologically hypoxic cells. METHODS AND MATERIALS: Multicellular spheroids of EMT6 mammary sarcoma cells were used as a model to identify hypoxic cells that were resistant to radiation damage. This was accomplished by incubating the spheroids with the 2-nitroimidazole (EF5), which forms hypoxia-dependent adducts with cellular macromolecules that are detected by fluorescent monoclonal antibodies. RESULTS: Cells from spheroids grown for 2 days in sealed flasks had an increased surviving fraction following radiation as compared to fully reoxygenated spheroids, indicating the presence of radiobiological hypoxia. Treatment of the spheroids with EF5 and subsequent immunohistochemical staining of cryosections with an anti-EF5 fluorochrome conjugated monoclonal antibody allowed for the identification of EF5-adduct containing cells. Spheroids grown under hypoxic conditions in the presence of EF5 showed limited staining of the peripheral cell layers, intense staining of the interior, and an absence of staining within the necrotic center. In contrast, there was minimal staining in reoxygenated spheroids and no staining in control spheroids incubated in the absence of EF5. Flow cytometric analysis of single cells dissociated from spheroids allowed for the calculation of the percentage of stained cells, as well as the intensity of staining. A comparison of the intensity of staining of EF5 treated hypoxic spheroids with the intensity of staining of single cells incubated with EF5 under controlled oxygen concentrations was used to estimate the oxygen concentration range within spheroids. Selective dissociation of spheroids provided a direct demonstration that the cells containing the highest level of EF5 binding were also the cells with increased radiation resistance. CONCLUSION: This technique provides an excellent means of detecting and quantifying hypoxia, which should be directly applicable in tumors.

Molecular mechanisms of pathogenicity of gonococcal salpingitis.

Despite the availability of effective antimicrobial agents and aggressive public health programmes, gonococcal infections, including salpingitis, remain a major worldwide problem resulting in significant rates of morbidity and infertility. Using an experimental model of gonococcal-infected human fallopian tubes in organ culture which are examined by light microscopy and scanning and transmission electron microscopy, basic pathogenic interactions between the gonococcus and the fallopian tube have been elucidated. The major steps in the pathogenic process include attachment, damage and invasion. Attachment appears to result from interaction of gonococcal pili with the tips of microvilli of non-ciliated cells of the fallopian tube mucosa. After gonococcal attachment occurs, fallopian tube damage is evident with loss of ciliary activity and sloughing of ciliated cells. The 2 compounds most likely to be mediators of this damage appear to be gonococcal lipopolysaccharide, which is released from the surface of the organism in the form of outer membrane blebs, as well as monomeric units of peptidoglycan, which are elaborated by the organism. Gonococcal attachment and perhaps elaboration of some molecule appear to initiate phagocytosis by non-ciliated epithelial cells. Gonococci are transported to the base of the non-ciliated cells and are released into the subepithelial space. This may lead to local disease (salpingitis) or disseminated disease (dermatitis-arthritis). Understanding the molecular mechanisms by which gonococci attach to, damage or invade the fallopian tube mucosa may result in identification of ways of preventing gonococcal infections and their sequelae.

DHEAS as an effective vaccine adjuvant in elderly humans. Proof-of-principle studies.

We have demonstrated that in aged mice, the titer of serum antibody induced against tetanus toxoid correlates with resistance to local paralysis caused by injection of tetanus toxin. Only mice immunized shortly after oral dosing with DHEAS demonstrated high serum antibody titers and complete protection from paralysis. These results became the basis for initiating proof-of-principle studies in human volunteers above age 65 using a licensed influenza vaccine and tetanus toxoid in two independent studies. The use of an oral delivery form of DHEAS before influenza vaccination was associated with a demonstrable increase in the number of individuals with a fourfold increase in HAI titers following vaccination. The overall mean increase in HAI titers was highest in the DHEAS-treated group. The use of DHEAS in the immunization of elderly subjects against tetanus toxoid, while unable to enhance the responses, was not a detriment to antibody response. We conclude that further studies will justify the use of DHEAS as an adjuvant for antigens that represent primary responses in the elderly.

Necrotizing group A streptococcal infections associated with streptococcal toxic shock syndrome.

BACKGROUND: Group A streptococci (GAS) cause a variety of life-threatening infectious complications, including necrotizing fasciitis (NF), purpura fulminans (PF), and streptococcal toxic shock syndrome (strepTSS), in which bacteremia is associated with shock and organ failure. METHODS: We reviewed our experience in the management of patients with necrotizing GAS infections from 1991 to 1995. RESULTS: Eight adult patients (6 NF, 2 PF) were identified. Patients presented with fever, leukocytosis, and severe pain, and rapidly developed shock and organ dysfunction. The diagnosis of strepTSS was confirmed in 6 cases. A total of 54 surgical procedures were required, including widespread debridements and amputations. Two patients died (25%). CONCLUSIONS: Recognition of the need for aggressive diagnosis and surgical treatment of this most rapidly progressive surgical infection is necessary for successful management.

Chlamydia species infect human vascular endothelial cells and induce procoagulant activity.

BACKGROUND: Chlamydia pneumoniae infections have been linked with myocardial infarction, stroke, and the development of atherosclerosis by epidemiologic studies, immunohistochemical studies, and electron microscopic studies. The mechanisms underlying this association are unknown. METHODS: Using cultured human venous endothelial cells, we investigated whether C pneumoniae, C trachomatis (types H and L2/434/BU) could infect these cells. The ability of infected cells to express procoagulant (tissue factor) activity was also measured using clotting and chromogenic substrate assays. Adhesion of platelets to chlamydia-infected cells was also quantitated. RESULTS: We found that C pneumoniae, C trachomatis type H, and C trachomatis L2/434/BU could infect cultured human umbilical vein endothelial cells and stimulate a 4-fold increase in expression of tissue factor, which reached a peak 18 hours postinfection. Tissue factor expression was enhanced even in the presence of tetracycline, suggesting that the chlamydial factor responsible for stimulating synthesis of endothelial cell tissue factor was preformed. Platelet adhesion was significantly enhanced when endothelial cells were infected by chlamydia species. CONCLUSIONS: These in vitro studies suggest possible pathogenic mechanisms that may explain the association of thrombotic events with C pneumoniae infection, including pathologically enhanced production of tissue factor by human endothelial cells and enhanced focal platelet deposition.

Investigation of an outbreak of vancomycin-resistant Enterococcus faecium in a low prevalence university hospital.

BACKGROUND: Until 1995, there were no cases of vancomycin resistant enterococcus (VRE) identified at our university hospital. From May 1995 to August 1996, we investigated a cluster of 10 cases of phenotypic class Van B Enterococcus faecium. METHODS: Patients were matched with controls who were on the same unit for at least 7 days prior to the case developing VRE. Control patients were age and sex matched if possible, and had duration of hospitalization at least as long as the number of days it took the patient to become VRE positive. We analyzed 16 independent risk factors using Epi-info version 6. Environmental cultures were obtained in the MICU where 5 of the patients were located. All 10 patient isolates and environmental isolates were analyzed by pulsed field gel electrophoresis (PFGE). RESULTS: PFGE confirmed the genetic relatedness of all 10 patient isolates and environmental isolates. The VRE-positive group was more likely to be immunosuppressed and to have exposure to 3 physicians. In the MICU, significant, P < 0.05) risk factors for VRE were higher Apache scores, location adjacent to a VRE case, duration of vancomycin and amino-glycoside use, duration of invasive catheter use, and diarrhea. Among the VRE-positive environmental cultures was a blood pressure cuff wash that was used on several patients. CONCLUSION: We hypothesize that a VRE strain was introduced into our hospital environment and was spread by personnel or contaminated equipment. As a consequence of this study, a hospital-wide VRE policy was implemented.

Lodderomyces elongisporus endocarditis in an intravenous drug user: a new entity in fungal endocarditis.

Lodderomyces elongisporus has been recently identified in the literature as an infrequent human bloodstream isolate, commonly mistaken for a non-albicans Candida. A case of Lodderomyces endocarditis in an intravenous drug user is described. To our knowledge, this report highlights the first documented case of Lodderomyces as a cause of endocarditis and summarizes the susceptibility patterns in the reported literature. All isolates reported so far have fluconazole MICs of ≤0.25 µg ml(-1).

Pertussis: an old disease in a new era.

Pertussis has a worldwide incidence of 51,000,000 cases per year with a 1% case fatality rate and primarily affects young children. Despite the availability of an effective whole-cell pertussis vaccine, pertussis has reemerged as a significant cause of human morbidity in areas where pertussis vaccine programs have ceased because of vaccine safety concerns. The search for new vaccines without side effects has stimulated an intensive study of virulence determinants of Bordetella pertussis. As a result of this research, virulence genes of B pertussis and factors that regulate these genes have been identified and characterized. The molecular characterization of the virulence determinants of B pertussis has helped to elucidate the basis of some of the clinical observations that characterize disease caused by B pertussis. It appears that host factors may potentially determine whether virulence genes are expressed. It is now possible to construct mutants of B pertussis that are deficient in individual virulence determinants. The era of the molecular Koch's postulates is upon us, and the roles of individual virulence factors in disease pathogenesis can be studied. In this article, issues concerning immunity to pertussis, safety of whole-cell vaccine, and virulence factors of B pertussis are considered. The molecular Koch's postulates as they relate to testing prospective virulence factors in pertussis infection model systems will be presented. The mucosal environment as a potential modulator of virulence factors will be addressed.

Continuous and 4 h infusion of amphotericin B: a comparative study involving high-risk haematology patients.

OBJECTIVES: To assess whether a continuous infusion of amphotericin B (CI-AmB) is less nephrotoxic than a 4 h infusion in haematology patients with fever and neutropenia, including bone-marrow transplant recipients. Efficacy was assessed as a secondary end-point. PATIENTS AND METHODS: We conducted a retrospective cohort study over a 2 year period. A total of 1073 haematology admissions were reviewed (98.3% complete) and 81 admissions were eligible for study entry; 39 received CI-AmB and 42 a 4 h infusion of AmB. RESULTS: Renal impairment occurred significantly less frequently with CI-AmB compared with a 4 h infusion of AmB [10% versus 45%, respectively, odds ratio (OR) 0.14; 95% confidence interval (CI) 0.04-0.5, P < 0.001]. The difference was maintained among allogeneic transplant recipients (P = 0.007) and patients receiving concurrent nephrotoxic drugs (P < 0.001). An AmB infusion rate of <0.08 mg/kg/h was associated with a significant reduction in renal impairment (P < 0.001). A difference in survival was observed between the continuous and 4 h infusion of AmB (95% versus 79%, respectively, OR 5.1; 95% CI 1.02-25.1, P = 0.03). CONCLUSIONS: CI-AmB appears to be significantly less nephrotoxic than 4 h infusion AmB in haematology patients with fever and neutropenia--including high-risk bone-marrow transplant recipients--without increasing mortality. An AmB infusion rate of <0.08 mg/kg/h appears to be a safe threshold, associated with reduced renal impairment.