Chlamydial infection increases gonococcal colonization in a novel murine coinfection model.

Genital tract infections caused by Neisseria gonorrhoeae and Chlamydia trachomatis serovars D to K occur at high incidence in many areas of the world. Despite high rates of coinfection with these pathogens, investigations of host-parasite interactions have focused on each pathogen individually. We describe here a coinfection model in which female BALB/c mice were first infected with the mouse Chlamydia species C. muridarum and then inoculated with N. gonorrhoeae following treatment with water-soluble 17ß-estradiol to promote long-term gonococcal infection. Viable gonococci and chlamydiae were recovered for an average of 8 to 10 days, and diplococci and chlamydial inclusions were observed in lower genital tract tissue by immunohistochemical staining. Estradiol treatment reduced proinflammatory cytokine and chemokine levels in chlamydia-infected mice; however, coinfected mice had a higher percentage of vaginal neutrophils compared to mice infected with either pathogen alone. We detected no difference in pathogen-specific antibody levels due to coinfection. Interestingly, significantly more gonococci were recovered from coinfected mice compared to mice infected with N. gonorrhoeae alone. We found no evidence that C. muridarum increases gonococcal adherence to, or invasion of, immortalized murine epithelial cells. However, increased vaginal concentrations of inflammatory mediators macrophage inflammatory protein 2 and tumor necrosis factor alpha were detected in C. muridarum-infected mice prior to inoculation with N. gonorrhoeae concurrently with the downregulation of cathelicidin-related antimicrobial peptide and secretory leukocyte peptidase inhibitor genes. We conclude that female mice can be successfully infected with both C. muridarum and N. gonorrhoeae and that chlamydia-induced alterations in host innate responses may enhance gonococcal infection.

Mouse strain-dependent chemokine regulation of the genital tract T helper cell type 1 immune response.

Vaginal infection with the mouse pneumonitis agent of Chlamydia trachomatis (MoPn) produces shorter courses of infection in C57BL/6 and BALB/c mice than in C3H/HeN mice, while C57BL/6 mice are more resistant to oviduct pathology. A robust Th1 response is extremely important in host defense against chlamydia. In this study we examined gamma interferon (IFN-gamma), interleukin 10 (IL-10), and the T-cell-regulatory chemokines macrophage inflammatory protein-1alpha (MIP-1alpha) and monocyte chemoattractant protein-1 (MCP-1) to determine if differences in these responses were associated with the differential courses of infection seen in these three strains of mice. Increased and prolonged IFN-gamma responses and lower IL-10 responses were observed in the C57BL/6 strain compared to BALB/c and C3H. Examination of genital tract chemokines revealed a marked predominance of MIP-1alpha over MCP-1 only in the C57 strain. Thus, a pattern of high MIP-1alpha and low MCP-1 levels during the first week of infection is associated with an increased Th1 response and a shorter, more benign chlamydial infection. Inhibition of the MCP-1 response in C3H mice increased their later T-cell production of IFN-gamma but decreased their early IFN-gamma response and had no effect on the course or outcome of infection. Inhibition of MCP-1 is not beneficial in chlamydial infection because of its pleiotropic effects.

Elevation of serum interleukin 8 levels in acetaminophen overdose in children and adolescents.

BACKGROUND: Elevations of inflammatory cytokines have been reported in animal models of acetaminophen (INN, paracetamol) toxicity. In addition, interleukin 8, a chemokine, has been found to be elevated in toxin-associated hepatic disease (ie, acute alcoholic hepatitis). The purpose of this study was to measure serum cytokine levels in children and adolescents with acetaminophen overdose and to evaluate relationships between cytokine elevation and hepatotoxicity. METHODS: Serum levels of tumor necrosis factor alpha, interleukin 1beta, interleukin 6, interleukin 8, and interleukin 10 were measured by ELISA in children and adolescents (n = 35) with acetaminophen overdose. Peak cytokine levels were examined relative to biochemical evidence of hepatocellular injury, nomogram risk assessment, and prothrombin time. RESULTS: Five patients had aspartate aminotransferase or alanine aminotransferase levels >1000 IU/L, and 4 patients had aspartate aminotransferase or alanine aminotransferase levels > or =100 IU/L and < or =1000 IU/L. No elevations of tumor necrosis factor alpha or interleukin 1beta were detected. Peak interleukin 8, but not interleukin 6 or interleukin 10, correlated with hepatotoxicity (Mann-Whitney exact test, P <.001). The peak interleukin 8 level was greater in patients at high risk by the nomogram combined with those presenting at >15 hours, as compared with other patients (Mann-Whitney U test, P <.01). The interleukin 8 level peaked before aspartate aminotransferase or alanine aminotransferase in 5 of the 9 patients with hepatotoxicity. In addition, interleukin 8 concentrations of >20 pg/mL were associated with peak prothrombin time values (Mann-Whitney exact test, P <.015). CONCLUSIONS: Interleukin 8 elevation in patients with acetaminophen hepatotoxicity corresponds with other common clinical measures that are predictive of hepatocellular injury. Further study is warranted to evaluate possible mechanistic relationships between inflammatory cytokines and acetaminophen hepatotoxicity in children and adults.

Early local cytokine profiles in strains of mice with different outcomes from chlamydial genital tract infection.

In this study, we expand on the examination of genetically determined differences in host responses that correlate with clearance of Chlamydia trachomatis from the genital tract. We infected C57BL/6, BALB/c, and C3H/HeN mice with the mouse pneumonitis agent of C. trachomatis (MoPn). C57BL/6 mice had the shortest course of infection (22 days) and the lowest incidence of severe hydrosalpinx. BALB/c mice also had a short course of infection (25 days), but all developed hydrosalpinx. C3H/HeN mice had the longest course of infection (38 days), and all developed severe hydrosalpinx. Determination of local cytokine responses by enzyme-linked immunosorbent assay (ELISA) of genital tract secretions revealed that the levels of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were significantly increased in the C57BL/6 and BALB/c strains compared to those in the C3H/HeN strain whereas the level of IL-6 was not different. The level of the neutrophil chemokine macrophage inflammatory protein 2 (MIP-2) was increased during the first week of infection in all three strains but was significantly higher in the BALB/c strain, the strain with the most rapid influx of neutrophils into the genital tract. Prolonged detection of MIP-2 in C3H/HeN mice was associated with a protracted presence of neutrophils in the genital tract. Early increases in the levels of the proinflammatory cytokines TNF-alpha and IL-1beta are associated with earlier eradication of infection in the C57BL/6 and BALB/c strains than in the C3H/HeN strain. Increased levels of MIP-2 and neutrophils in BALB/c and C3H/HeN mice relative to C57BL/6 mice suggest that these responses may contribute to pathology.

Does inhibition of tumor necrosis factor alpha affect chlamydial genital tract infection in mice and guinea pigs?

The role of tumor necrosis factor alpha (TNF-alpha) in host defense against chlamydial infection remains unclear. In order to further evaluate the relevance of TNF-alpha to host resistance in chlamydial genital tract infection, we examined the effect of local inhibition of the TNF-alpha response in normal C57 mice and in interferon gamma gene-deficient C57 mice infected intravaginally with the mouse pneumonitis agent of Chlamydia trachomatis. Since the guinea pig model of female genital tract infection more closely approximates the human in terms of ascending infection and development of pathology, we also examined the effect of local inhibition of the TNF-alpha response in guinea pigs infected intravaginally with the guinea pig strain of Chlamydia psittaci. We successfully blocked the early TNF-alpha response in the respective animal models. This blockade had no effect on the numbers of organisms isolated from the genital tract during the time of TNF-alpha inhibition in mice or guinea pigs. Analysis of interleukin-1beta, macrophage inflammatory protein-2, and granulocyte macrophage-colony stimulating factor in the mouse model revealed that blockade of the TNF-alpha response did not alter the release of these proinflammatory proteins. Yet, in TNF-alpha-depleted mice, increased numbers of neutrophils were detected in the genital tract, and, in TNF-alpha-depleted guinea pigs, increased numbers of neutrophils as well as infiltrating lymphocytes were seen in the endocervix. Blockade of TNF-alpha does not affect the level of infection in mice or guinea pigs, but it may decrease TNF-alpha-induced apoptosis of infiltrating inflammatory cells.

Effect of Chlamydia trachomatis infection and subsequent tumor necrosis factor alpha secretion on apoptosis in the murine genital tract.

The pathology observed during Chlamydia infection is due initially to localized tissue damage caused by the infection itself, followed by deleterious host inflammatory responses that lead to permanent scarring. We have recently reported that the infection by Chlamydia in vitro results in apoptosis of epithelial cells and macrophages and that infected monocytes secrete the proinflammatory cytokine interleukin-1beta. At the same time, proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) can also trigger apoptosis of susceptible cells. To study the possible relationship between Chlamydia trachomatis infection and apoptosis in vivo, we used the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling technique to determine whether infection may cause apoptosis in the genital tract of mice and, conversely, whether cytokines produced during the inflammatory response may modulate the level of apoptosis. Our results demonstrate that infected cells in the endocervix at day 2 or 7 after infection are sometimes apoptotic, although there was not a statistically significant change in the number of apoptotic cells in the endocervix. However, large clumps of apoptotic infected cells were observed in the lumen, suggesting that apoptotic cells may be shed from the endocervix. Moreover, there was a large increase in the number of apoptotic cells in the uterine horns and oviducts after 2 or 7 days of infection, which was accompanied by obvious signs of upper tract pathology. Interestingly, depletion of TNF-alpha led to a decrease in the level of apoptosis in the uterine horns and oviducts of animals infected for 7 days, suggesting that the inflammatory cytokines may exert part of their pathological effect via apoptosis in infected tissues.

Chlamydia / Chlamydia

Chlamydia pneumoniae ha sido identificado como una importante causa de enfermedades respiratorias en humanos. Este patógeno es transmitido persona a persona por transmisión aérea mediante secrecciones respiratorias. La infección es rara en niños menores de dos años, incrementándose la incidencia en edades escolares. Se estima que aproximadamente el 40 por ciento-60 por ciento de los adultos tienen anticuerpos contra C. pneumoniae. El diagnóstico se basa en la serología, normalmente microinmunofluorescencia (MIF), pero últimamente han aparecido nuevos métodos nuevos como PCR y cultivos mejorados. En niños, C. pneumoniae puede causar una variedad de enfermedades respiratorias como bronquitis, neumonía, sinusitis y faringitis. En los últimos años, se ha relacionado C. pneumoniae con una larga lista de enfermedades, incluyendo las enfermedades cardiovasculares. La hipótesis de que la infección en edades tempranas pueda dar lugar al desarrollo de arteriosclerosis en adultos está siendo evaluada actualmente. Si se confirma, la asociación reportada entre C. pneumoniae y arteriosclerosis podría llevar a el tratamiento de algunas enfermedades cardiovasculares con antibióticos como los macrólidos o las tetraciclinas, que son comúnmente activos contra la infección por C. pneumoniae (AU)

Morbidity and cost of vaccine-preventable varicella in previously healthy children in Arkansas.

Many physicians have not recognized varicella as a serious disease and are not advocating use of varicella vaccine. This retrospective study describes the morbidity and costs incurred by previously healthy children hospitalized at Arkansas Children's Hospital due to complications of varicella during a time period when an effective vaccine was approved for use. Fifty-five previously healthy children from 19 countries in Arkansas were hospitalized secondary to complications of varicella in the three years following release of varicella vaccine. Total numbers of hospital days for these patients were 192 with a cost totaling $252,084. Increased efforts are needed to vaccinate the children of Arkansas against varicella.

Prevention of perinatal transmission of HIV in Arkansas.

In 1994, the Centers for Disease Control and Prevention (CDC) recommended zidovudine (ZDV) prophylaxis to reduce perinatal transmission of HIV. Caregivers at the University of Arkansas for Medical Sciences (UAMS) instituted a program of universal voluntary HIV testing of pregnant females combined with maternal education regarding ZDV prophylaxis in October 1994. Since that time, 7 of 39 (18%) infants referred to Arkansas Children's Hospital (ACH) for evaluation of perinatal HIV exposure have been infected compared to 21 of 53 (40%) referred prior to October 1994, (p = 0.042). Unfortunately, of the 39 infants referred to ACH after October 1994, 21 were born to HIV-infected mothers who did not comply with prophylaxis. Fifteen of these mothers were not offered intravenous ZDV during delivery; five have children infected with HIV. These data indicate the need for increased efforts by health officials in Arkansas to institute nationally recommended methods of prevention of perinatal HIV.

A role for interleukin-6 in host defense against murine Chlamydia trachomatis infection.

Interleukin-6-deficient (IL-6(-/-)) knockout mice had significantly increased Chlamydia trachomatis levels in lung tissue and increased mortality compared to B6129F2/J controls early after intranasal infection. Gamma interferon production and chlamydia-specific antibody levels were consistent with a decreased but reversible Th1-like response in IL-6(-/-) mice. IL-6 is needed for an optimal early host response to this infection.

Mouse strain-dependent variation in the course and outcome of chlamydial genital tract infection is associated with differences in host response.

Whether there is a pathogenic or protective outcome to chlamydial infection may be defined by the host response. We infected C57BL/6 (C57) and C3H/HeN (C3H) mice with the human biovar of Chlamydia trachomatis, serovar E, and, in select experiments, with the mouse pneumonitis agent of C. trachomatis (MoPn). We compared the courses of infection, histopathology, and host responses that resulted from these infections. The duration of infection with either chlamydial biovar was significantly increased in the C3H strain of mice. The intensity of infection was examined in mice infected with serovar E, and it was significantly increased in the C3H strain. Histopathology revealed the incidence of severe hydrosalpinx to be significantly greater in C3H mice than in C57 mice. In contrast, severe distention of the uterine horns was observed in all infected C57 mice compared to none of the C3H mice infected with serovar E and only 25% of those infected with MoPn. Acute inflammation was significantly increased in the uterine horns of C57 mice compared to that of C3H mice. Examination of antigen-specific responses revealed qualitatively similar responses in the two strains. Determination of gamma interferon- versus interleukin 4- producing cells revealed the predominance of a Th1 response in both strains. Serum enzyme-linked immunosorbent assays for immunoglobulin G1 (IgG1) and IgG2a revealed a predominance of IgG2a antibody in both strains, although the levels of antibody were significantly greater in C3H mice. Lymphocyte proliferation studies revealed increased proliferation in the iliac nodes of both strains at 1 to 3 weeks after infection. Because of the early eradication of infection observed in the C57 strain, we explored the relative production of tumor necrosis factor alpha (TNF-alpha) in the two strains. TNF-alpha levels were significantly increased in the genital tract secretions of C57 mice compared to that of C3H mice during the first week of infection. Increased TNF-alpha may be beneficial to the host by leading to earlier eradication of infection, thereby preventing infection of the oviduct and thus the major disease sequelae associated with chlamydial infection of the genital tract.

Intravenous immunoglobulin inhibits staphylococcal toxin-induced human mononuclear phagocyte tumor necrosis factor alpha production.

Intravenous gamma immunoglobulin (IVIG) is used as therapy in superantigen-mediated disease, yet its mode of action is not clear. Pooled immunoglobulin G contains high concentrations of staphylococcal exotoxin (SE)-specific antibodies which inhibit the in vitro activation of T cells. However, SE and streptococcal exotoxins are potent stimulators of monocytes as well. Monocytes exposed to SE in vitro release large amounts of tumor necrosis factor alpha (TNF-alpha). The purpose of the present study was to determine if SE-specific antibodies in IVIG can inhibit the activation of monocytes by SE. We examined the in vitro effect of IVIG on the ability of staphylococcal exotoxin A (SEA) and staphylococcal exotoxin B (SEB) to stimulate release of TNF-alpha from human mononuclear phagocytes (MO). Pretreatment of SEA with 0.1 mg of IVIG per ml resulted in a slight decrease of SEA-induced TNF-alpha secretion by MO. In contrast, pretreatment of SEB with 0.1 mg of IVIG per ml resulted in significant (greater than 50%) inhibition of SEB-induced TNF-alpha secretion at 24, 48, 72, and 96 h (P < 0.05 for TNF-alpha levels induced by SEB alone versus SEB pretreated with IVIG at all time points). Enzyme-linked immunosorbent assay and Western immunoblotting assays of the IVIG revealed high concentrations of antibodies against SEB and lower concentrations of antibodies to SEA. These data indicate that IVIG can act in a toxin-specific manner to decrease the MO TNF-alpha response to superantigens. Such inhibition may be one mechanism by which IVIG exerts an immunoregulatory role in superantigen-mediated disease.

Blastomycosis in children.

Infections due to Blastomyces dermatitidis are not commonly encountered in children and adolescents. Knowledge of the diagnosis and treatment of this disease is largely based upon experience with adult patients. We recently reviewed our experience with blastomycosis to evaluate the difficulties in diagnosis and treatment of this disease in the pediatric population. Ten patients with blastomycosis were identified during our review, and five had pulmonary disease alone. Of these five patients, four required open-lung biopsy for diagnosis, even though three had previously undergone bronchoalveolar lavage. The response to treatment with the oral azole antifungal agents (ketoconazole, fluconazole, and itraconazole) was limited, and the agent with the greatest success remains amphotericin B. Until more data are available, amphotericin B should be used for complicated and life-threatening cases of blastomycosis. If oral azole agents are used for non-life-threatening cases, patients should be followed closely, and if clinical deterioration occurs or serum levels of medications are not adequate, then amphotericin B should be substituted for the oral azole agent.

Tumor necrosis factor alpha activity in genital tract secretions of guinea pigs infected with chlamydiae.

Previous studies using the guinea pig model of chlamydial genital infection demonstrated that primary infection is associated with a marked acute inflammatory response early on, while chronic inflammation appears later, at a time when the level of infection is reduced. Challenge infections result primarily in a chronic inflammatory response. The stimuli that initiate inflammation and lead to tissue damage have not been defined. We investigated the possibility that tumor necrosis factors (TNFs) play a role in the inflammatory response to chlamydial genital tract infection. Cytotoxicity assays for TNF were performed on genital tract secretions collected from female guinea pigs during infection with the Chlamydia psittaci agent of guinea pig inclusion conjunctivitis. During the early days of primary infection, high levels of TNF-alpha were detected in genital tract secretions from inbred S2 strain and outbred Hartley strain guinea pigs. Significantly lower levels of TNF-alpha were detected in secretions from both strains during challenge infection. In general, the intensity of the TNF-alpha response was proportional to the intensity of infection. High TNF-alpha levels were present during primary infection at a time of marked neutrophil influx. Thus, TNF-alpha may play an important role in the response to primary chlamydial genital tract infection.

Recent advances in pediatric HIV.

Pediatric human immunodeficiency virus (HIV) infection is a disease of mother-to-infant transmission. The World Health Organization estimates there will be ten million HIV-infected children by the end of this century. It is now thought that both intrauterine and intrapartum transmission of HIV occurs. Infants infected in utero develop clinical signs and symptoms at an earlier age than those who are infected at the time of delivery. We describe two cases that demonstrate early-onset and late-onset pediatric HIV disease, respectively. Recently, it was determined that perinatal transmission of HIV can be significantly reduced by the administration of the antiretroviral drug, zidovudine (ZDV), to HIV-positive pregnant women and their newborns, making HIV screening of pregnant women more desirable than ever. A program of universal voluntary HIV testing for pregnant women has been successfully implemented at the University of Arkansas for Medical Sciences. Details of this program are described herein.