Infection of infants with human herpesvirus type 6 may be associated with reduced allergic sensitization and T-helper type 2 development.

BACKGROUND: Epidemiological studies point to an inverse relationship between microbial exposure and the prevalence of allergic diseases. The underlying mechanism for this observation remains largely unknown, as well as the nature of the microbes involved. OBJECTIVE: To investigate the effects of early infection with human herpesviruses (HHVs) on IgE formation and T-helper type 2 (Th2) development in infants. METHODS: Serum was collected from children aged 18 months and assessed for IgE to common allergens and IgG to five common herpesviruses. Cord blood plasmacytoid dendritic cells (pDC) were exposed to HHV type 6 in vitro and mixed with allogeneic cord blood CD4(+) T cells. Cytokine levels were determined by ELISA and by flow cytometry. RESULTS: We found that children seropositive at 18 months of age to HHV type 6 were significantly less often IgE sensitized than seronegative children [odds ratio (OR): 0.08, 95% confidence interval (CI): 0.009-0.68]. HHV type 6 also decreased the production of the Th2-associated cytokines IL-5 and IL-13 by CD4(+) T cells when co-cultured with allogeneic cord blood pDC. This was associated with an increased production of IFN-alpha by pDC exposed to HHV type 6. CONCLUSION: These data indicate that an early childhood infection with HHV type 6 could down-regulate Th2 responses and reduce IgE formation to common allergens in a young child.

Effective control measures limited measles outbreak after extensive nosocomial exposures in January-February 2008 in Gothenburg, Sweden.

In January-February 2008, one imported case of measles initiated a series of exposures with around 380 nosocomial secondary contacts. Susceptible individuals were traced early and control measures were initiated that managed to limit the consequences considerably. Only four secondary cases were identified by the end of March. This minor outbreak illustrates the importance and efficiency of early control measures as well as the fact that the risk of measles outbreaks still exists in a country that has high measles, mumps, rubella vaccination coverage among children.

Prevalence of serum antibodies to human papilloma virus in patients with genital ulcer disease in an urban population of Tanzania.

BACKGROUND: The epidemiology of human papillomavirus (HPV) in Tanzania is largely unknown both in risk groups and in the general population. OBJECTIVE: To determine the cumulative seroprevalence of selected HPV types in order to evaluate exposure to HPV in urban Tanzania. METHOD: In a cross-sectional study, sera of 200 patients of both sexes with genital ulcer disease (GUD) and sera of 60 male blood donors and 60 pregnant women were tested for antibodies to the oncogenic HPV types 16, 18, 31, 33, 35, 51 and 52 using an ELISA based on virus-like particles (VLP). RESULTS: The overall seroprevalence of HPV types for all patients with GUD was 83% and 77% for women and men, respectively. For pregnant women and male blood donors, the corresponding percentages were 55% and 15%, respectively. The most common HPV types were 16, 18 and 52. Infection with multiple types was more than 10 and 5 times more frequent than infection with a single type 16 in patients with GUD and in pregnant women, respectively. The seroprevalence to HPV types 16, 18, 51 and 52 was considerably higher in HIV-positive patients with GUD than in HIV-negative patients. CONCLUSIONS: Infections with the oncogenic HPV types 16, 18 and 52 are common among patients with GUD and pregnant women in urban Tanzania, emphasising the need for control, treatment and implementation of appropriate HPV vaccine programmes.

Male serum Chlamydia trachomatis IgA and IgG, but not heat shock protein 60 IgG, correlates with negatively affected semen characteristics and lower pregnancy rates in the infertile couple.

BACKGROUND: The objective of this study was to evaluate whether serum Chlamydia trachomatis immunoglobulin-A (IgA), IgM and C. trachomatis heat shock protein 60 (CHSP60) IgG are of additional value to C. trachomatis IgG regarding the impact on fecundity in infertile couples, and to relate C. trachomatis serum antibodies to semen characteristics, diagnoses and pregnancy outcome. METHODS: A total of 226 infertile couples, previously tested for C. trachomatis IgG, were tested for C. trachomatis IgA, IgM and CHSP60 IgG, and semen samples from all men were analysed. RESULTS: Chlamydia trachomatis serum IgA in men (but not in women) correlated with reduced chances of achieving pregnancy [p = 0.021, relative risk (RR) =0.65, 95% confidence interval (CI) 0.42-1.005] and in combination with C. trachomatis IgG the chance was further reduced (p =0.001, RR = 0.35, 95% CI 0.15-0.84). Chlamydia trachomatis serum IgA was also significantly correlated with reduced motility of the spermatozoa (-8.7%, p = 0.023), increased number of dead spermatozoa (+10.5%, p = 0.014) and higher prevalence of leucocytes in semen (+122%, p = 0.005), and in combination with C. trachomatis IgG positivity, there was also a decrease in sperm concentration (-35%, p = 0.033), the number of progressive spermatozoa (-14.8%, p = 0.029) and a rise in the teratozoospermia index (+4.4%, p = 0.010). CHSP60 IgG correlated with reduced motility (-5.6%, p = 0.033), and in the women to tubal factor infertility (p = 0.033), but no correlations of C. trachomatis serum IgM or CHSP60 IgG with pregnancy rates were found. CONCLUSIONS: Chlamydia trachomatis serum IgA in the male partner of the infertile couple has an additive value to IgG in predicting pregnancy chances, and serum IgA and IgG are associated with subtle negative changes in semen characteristics.

Characterization of T-cell reactive epitopes in glycoprotein G of herpes simplex virus type 2 using synthetic peptides.

We have previously shown that the CD4+ T-cell response to herpes simplex virus type 2 glycoprotein G-2 is type-specific and can thus be used to evaluate herpes simplex virus type 2-specific T-cell responses in individuals with a concomitant herpes simplex virus type 1 infection. In this study we have followed the glycoprotein G-2-specific T-cell responses over time, and also tried to identify T-cell epitopes in the membrane bound portion and the secreted portion of glycoprotein G-2 using synthetic peptides spanning the whole amino acid sequence of glycoprotein G-2. We found that the magnitude of the glycoprotein G-2-specific response varied considerably in infected individuals over time, even though all patients responded to at least one of the two glycoproteins at all time-points examined. We could also document strong T-cell responses to synthetic peptides from the secreted glycoprotein G-2 but only low responses to synthetic peptides corresponding to sequences from the heavily glycosylated membrane-bound glycoprotein G-2. We were able to map an immunogenic region (amino acid 31-125) within the secreted glycoprotein G-2. This region of the glycoprotein induced proliferative responses in 47% of the herpes simplex virus type 2-infected individuals. However, we were not able to identify any universal T-cell epitope.

Conservation of type-specific B-cell epitopes of glycoprotein G in clinical herpes simplex virus type 2 isolates.

Glycoprotein G (gG-2) of herpes simplex virus type 2 (HSV-2) is cleaved to a secreted amino-terminal portion and to a cell-associated, heavily O-glycosylated carboxy-terminal portion that constitutes the mature gG-2 (mgG-2). The mgG-2 protein is commonly used as a type-specific antigen in the serodiagnosis of HSV-2 infection. As the amino acid sequence variability of mgG-2 in clinical isolates may affect the performance of such assays, the gG-2 gene was sequenced from 15 clinical HSV-2 isolates. Few mutations were identified, and these were mostly localized outside the epitope regions described earlier. Five isolates were identical to different laboratory strains, indicating that the gG-2 gene is highly conserved over time. In the search for HSV-2 isolates harboring mutations within the immunodominant region of mgG-2, a pool of 2,400 clinical HSV-2 isolates was tested for reactivity with two anti-mgG-2 monoclonal antibodies (MAbs). Ten MAb escape HSV-2 mutants, which all harbored structurally restricted single- or dual-point mutations within the respective epitopes explaining the loss of binding, were identified. Sera from corresponding patients were reactive to mgG-2, as well as to a peptide representing the immunodominant region, suggesting that the point mutations detected did not diminish seroreactivity to mgG-2. The conservation of the gG-2 gene reported here further supports the use of mgG-2 as a type-specific antigen in the diagnosis of HSV-2 infections.

Herpes simplex virus types 1 and 2 differ in their interaction with heparan sulfate.

Cell surface heparan sulfate (HS) serves as an initial receptor for many different viruses, including herpes simplex virus types 1 and 2 (HSV-1 and 2, respectively). Glycoproteins C and B (gC and gB) are the major components of the viral envelope that mediate binding to HS. In this study, purified gB and gC homologous proteins as well as purified HSV-1 and HSV-2 virions were compared for the ability to bind isolated HS receptor molecules. HSV-1 gC and HSV-2 gC bound comparable amounts of HS. Similarly, HSV-1 gB and its HSV-2 counterpart showed no difference in the HS-binding capabilities. Despite the similar HS-binding potentials of gB and gC homologs, HSV-1 virions bound more HS than HSV-2 particles. Purified gC and gB proteins differed with respect to sensitivity of their interaction with HS to increased concentrations of sodium chloride in the order gB-2 > gB-1 > gC-1 > gC-2. The corresponding pattern for binding of whole HSV virions to cells in the presence of increased ionic strength of the medium was HSV-2 gC-neg1 > HSV-1 gC(-)39 > HSV-1 KOS 321 > HSV-2 333. These results relate the HS-binding activities of individual glycoproteins with the cell-binding abilities of whole virus particles. In addition, these data suggest a greater contribution of electrostatic forces for binding of gB proteins and gC-negative mutants compared with binding of gC homologs and wild-type HSV strains. Binding of wild-type HSV-2 virions was the least sensitive to increased ionic strength of the medium, suggesting that the less extensive binding of HS molecules by HSV-2 than by HSV-1 can be compensated for by a relatively weak contribution of electrostatic forces to the binding. Furthermore, gB and gC homologs exhibited different patterns of sensitivity of binding to cells to inhibition with selectively N-, 2-O-, and 6-O-desulfated heparin compounds. The O-sulfate groups of heparin were found to be more important for interaction with gB-1 than gB-2. These results indicate that HSV-1 and HSV-2 differ in their interaction with HS.

Glycoprotein G of herpes simplex virus type 1: identification of type-specific epitopes by human antibodies.

Serological diagnosis of herpes simplex virus (HSV) infections requires assays based on antigens that expose type-specific determinants. This study was designed to outline the B-cell epitopes of the type-specific glycoprotein G-1 (gG-1) of HSV type 1 (HSV-1), by investigating the reactivity of human anti-gG-1 antibodies, purified from 21 HSV-1-isolation-proven patient sera, to cellulose-bound synthetic peptides spanning the entire gG-1 sequence. The epitope mapping demonstrated that these antibodies bound preferentially to antigenic determinants that localized to regions with a high degree of amino acid similarity to the corresponding glycoprotein in HSV-2, gG-2. In spite of this, the purified anti-gG-1 antibodies were found to be non-reactive to native gG-2 antigen, as well as to overlapping gG-2 peptides, thus supporting the role of gG-1 as a prototype HSV-1 type-specific antigen. One immunodominant region, delimited by amino acids 112-127, reacted with all purified anti-gG-1 antibodies and may be of interest for the further development of a peptide-based HSV-1 type-specific seroassay.

Variability of the glycoprotein G gene in clinical isolates of herpes simplex virus type 1.

Glycoprotein G (gG) of herpes simplex virus type 1 (HSV-1) has been used as a prototype antigen for HSV-1 type-specific serodiagnosis, but data on the sequence variability of the gene coding for this protein in wild-type strains are lacking. In this study, direct DNA sequencing of the gG-1 genes from PCR products was performed with clinical HSV-1 isolates from 11 subjects as well as with strains Syn 17(+), F, and KOS 321. The reference strains Syn 17(+) and F showed a high degree of conservation, while KOS 321 carried 13 missense mutations and, in addition, 12 silent mutations. Three clinical isolates showed mutations leading to amino acid alterations: one had a mutation of K(122) to N, which is a gG-1-to-gG-2 alteration; another contained all mutations which were observed in KOS 321 except two silent mutations; and the third isolate carried five missense mutations. Two clinical isolates as well as strain KOS 321 showed a mutation (F(111)-->V) within the epitope of a gG-1-reactive monoclonal antibody (MAb). When all viruses were tested for reactivity with the anti-gG-1 MAb, the three strains with the F(111)-->V mutation were found to be unreactive. Furthermore, gG-1 antibodies purified from sera from the two patients carrying strains mutated in this epitope were less reactive when they were tested by an HSV-1-infected-cell assay. Therefore, our finding that the sequence variability of the gG-1 gene also affects B-cell epitope regions of this protein in clinical isolates may have consequences for the use of this protein as a type-specific antigen for serodiagnosis.

Herpes simplex virus type 2 glycoprotein G-negative clinical isolates are generated by single frameshift mutations.

Herpes simplex virus (HSV) codes for several envelope glycoproteins, including glycoprotein G-2 (gG-2) of HSV type 2 (HSV-2), which are dispensable for replication in cell culture. However, clinical isolates which are deficient in such proteins occur rarely. We describe here five clinical HSV-2 isolates which were found to be unreactive to a panel of anti-gG-2 monoclonal antibodies and therefore considered phenotypically gG-2 negative. These isolates were further examined for expression of the secreted amino-terminal and cell-associated carboxy-terminal portions of gG-2 by immunoblotting and radioimmunoprecipitation. The gG-2 gene was completely inactivated in four isolates, with no expression of the two protein products. For one isolate a normally produced secreted portion and a truncated carboxy-terminal portion of gG-2 were detected in virus-infected cell medium. Sequencing of the complete gG-2 gene identified a single insertion or deletion of guanine or cytosine nucleotides in all five strains, resulting in a premature termination codon. The frameshift mutations were localized within runs of five or more guanine or cytosine nucleotides and were dispersed throughout the gene. For the isolate for which a partially inactivated gG-2 gene was detected, the frameshift mutation was localized upstream of but adjacent to the nucleotides coding for the transmembranous region. Thus, this study demonstrates the existence of clinical HSV-2 isolates which do not express an envelope glycoprotein and identifies the underlying molecular mechanism to be a single frameshift mutation.

Typing of clinical herpes simplex virus type 1 and type 2 isolates with monoclonal antibodies.

The purpose of this study was to evaluate the performance of a herpes simplex virus (HSV) type 1-specific anti-glycoprotein C-1 monoclonal antibody (MAb) and a type 2-specific anti-glycoprotein G-2 MAb for typing of 2,400 clinical HSV-1 isolates and 2,400 clinical HSV-2 isolates, respectively, using an enzyme immunoassay. The anti-HSV-1 MAb showed sensitivity and specificity of 100%, and the anti-HSV-2 MAb showed a sensitivity of 99.46% and 100% specificity, indicating that these MAbs are suitable for typing of clinical HSV isolates.

Localization of type-specific epitopes of herpes simplex virus type 2 glycoprotein G recognized by human and mouse antibodies.

Glycoprotein G is a major target for the humoral immune response against herpes simplex virus (HSV) and a prototype antigen for type-specific serodiagnosis discriminating HSV-1 and HSV-2 infections. The mature part of HSV-2 glycoprotein G-2 (gG-2) contains a unique stretch suspected to mediate type specificity, and in addition a region homologous to HSV-1 glycoprotein G-1 (gG-1). Antigenic determinants of the mature gG-2 were mapped by testing the reactivity of mouse anti-gG-2 monoclonal antibodies (MAbs) and purified human anti-gG-2 antibodies with synthetic peptides coupled to cellulose membranes. The anti-gG-2 MAbs bound to four epitopes localized in a narrow cluster within a gG-2 segment delimited by amino acids (aa) 552 and 611. This cluster was located between the predicted O-glycan-rich region and the transmembrane anchor sequence. The epitopes of the human anti-gG-2 antibodies were localized within three stretches of amino acids, two of which were overlapping with those recognized by anti-gG-2 MAbs. One of these stretches, delimited by aa 552 and 574, showed reactivity to all human HSV-2 sera tested, but not to HSV-1 sera or to purified anti-gG-1 antibodies. Neither the anti-gG-2 MAbs nor the purified human anti-gG-2 antibodies were cross-reactive to gG-1 peptides or HSV-1 antigen, although most of the epitopes were localized within the part of gG-2 which was homologous to gG-1. The findings concerning HSV-2 type-specific human antibody response to a defined stretch within gG-2 may be of importance for the further development of type-discriminating serodiagnosis.

Emergency room prediction of mortality and severe complications in patients with suspected acute myocardial infarction.

This study aims at describing the in-hospital prognosis of patients admitted with suspected acute myocardial infarction, focusing on the possibility of emergency room prediction of the risk for death and severe complications. From 7157 consecutive patients with chest pain or other symptoms suggestive of acute myocardial infarction in the emergency room, 4690 were hospitalized. Of these, 246 (5%) died in hospital, with a mortality rate among the 921 patients who developed myocardial infarction of 14%, and among those without infarction of 3%. From the clinical history, examination and electrocardiogram in the emergency room, independent predictors of death and death or any severe complication were determined by logistic regression analysis. These included age, initial degree of suspicion of infarction, electrocardiographic pattern, history of diabetes mellitus, history of congestive heart failure and on admission arrhythmias, loss of consciousness, acute congestive heart failure, or unspecific symptoms. From these analyses the probability of death or death or any severe complication can be calculated. Thus, 18% of patients hospitalized due to suspected acute myocardial infarction suffered a severe complication or died in hospital. From a statistical model it is possible to predict the in-hospital prognosis of every such patient.

Localization of a functional autoimmune epitope on the muscarinic acetylcholine receptor-2 in patients with idiopathic dilated cardiomyopathy.

A peptide corresponding to the sequence 169-193 of the second extracellular loop of the human muscarinic acetylcholine receptor-2 was used as an antigen to screen sera from patients with idiopathic dilated cardiomyopathy (DCM, n = 36) and healthy blood donors (HBD, n = 40). The sera from 14 patients with DCM (38.8%) and 3 HBD (7.5%) recognized the muscarinic receptor peptide at dilutions varying from 1:20 to 1:160 in ELISA. A highly significant correlation (P = 0.006) was found between the presence of antimuscarinic receptor-2 autoantibodies and anti-beta-adrenoceptor-1 autoantibodies in the patients' sera. Affinity-purified autoantibodies from positive sera of patients with DCM recognized on the electrotransferred protein of rat ventricular membrane a major band of about 80 kD. Incubation of autoantibodies with membrane resulted not only in a decrease in the maximal binding sites (Bmax) but also in an increase in Kd of radioligand binding in a concentration-dependent manner. This suggests a mixed-type of inhibition. Moreover, preincubation with atropine abolished the inhibitory effect of autoantibodies on the receptor binding whereas carbachol appeared to have no effect on the activity of the autoantibodies. These data define a subgroup of patients with idiopathic DCM who have in their sera functionally active autoantibodies against muscarinic receptor-2.

Occurrence of angina pectoris prior to acute myocardial infarction and its relation to prognosis.

In 917 patients with acute myocardial infarction (AMI) we evaluated the impact of previous angina pectoris on the prognosis. Thirty-four percent of the patients had chronic angina prior to AMI, and 22% had angina pectoris of short duration. Patients with chronic angina pectoris differed from the remaining patients having a more frequent previous history of AMI, diabetes mellitus, hypertension, and congestive heart failure. They less frequently developed a Q-wave AMI, and had smaller infarcts according to maximum serum-enzyme activity as compared with the remaining patients. They had a higher one-year mortality rate (36%) as compared with those having angina pectoris of short duration (22%), and those with no angina pectoris (26%). Their reinfarction rate was also higher (26%) as compared with that in the other two groups (15% and 9% respectively). In a multivariate analysis considering age, sex, clinical history, initial symptoms, initial electrocardiogram and estimated infarct size, previous chronic angina pectoris was not an independent risk factor for death, but was independently associated with the risk of reinfarction (P < 0.001). Among patients with a history of angina pectoris the outcome was related to medication prior to onset of AMI and at discharge from hospital. Patients in whom beta-blockers were prescribed at discharge had a one-year mortality of 13% as compared with 30% in the remaining patients (P < 0.001).

Failure to demonstrate enterovirus aetiology in Swedish patients with dilated cardiomyopathy.

Attempts were made to establish a possible relationship between enterovirus infection and dilated cardiomyopathy (DCM) by use of serology, virus isolation from faecal samples, and detection of enteroviral RNA in endomyocardial biopsies (EMB) by the polymerase chain reaction (PCR). Sera from 63 patients with DCM and matched controls were examined for enterovirus infection by mu-capture IgM and indirect IgG ELISA. Thirty-six patients were further tested for the presence of enterovirus group-specific antigen (VP1) in an immunoassay system. The results were consistently negative. Faecal samples from 35 of these patients were negative by enterovirus isolation both when samples were cultured directly and after acid treatment. EMB from 35 patients were examined for enteroviral RNA by PCR; none of the samples was reactive. In conclusion, the results fail to indicate involvement of enteroviruses in the aetiology of DCM.

Early identification of acute myocardial infarction and prognosis in relation to mode of transport to hospital.

Of 2,840 consecutive patients who were admitted to the emergency department of a Swedish university hospital due to suspected acute myocardial infarction (AMI), only 25% were reached by the mobile coronary care unit (MCCU), and only 4% simultaneously fulfilled traditional criteria for prehospital thrombolysis (ie, had ST-segment elevation on admission electrocardiogram and a delay time of less than 6 hours). In the subset of patients who fulfilled criteria for a confirmed AMI, 31% were reached by an MCCU and 11% fulfilled criteria for prehospital thrombolysis. Among patients with confirmed AMI, the hospital mortality rate was highest in patients transported by standard ambulance (19%) versus 15% in those transported by an MCCU and 8% in those transported by other means. The authors conclude that AMI patients transported by ambulance are high-risk patients for early death. Prehospital thrombolysis might reduce their rate of mortality. However, according to the authors' experience only a minor fraction of patients are available for prehospital thrombolysis.

Torsade de pointes tachycardias induced by overdosage of zimeldine.

Torsade de pointes tachycardias may occur in connection with overdoses, and more rarely with therapeutic doses, of tricyclic antidepressant agents and antiarrhythmic drugs, especially in the presence of hypokalemia. Zimeldine is a selective serotonin reuptake blocker, which according to studies in humans and animals, has no serious cardiovascular side effects in therapeutic doses. We report a patient who was admitted with repeated syncopal attacks resulting from prolonged QT intervals and torsade de pointes tachycardias. She also had hypokalemia, although she had had no treatment known to affect the potassium level. Correction of the potassium level rapidly prevented further tachycardias and led to normalization of the QT interval. Repeated blood samples verified high levels of zimeldine and its metabolites. We conclude that whenever torsade de pointes tachycardias occur, treatment with antidepressant or antiarrhythmic agents should be immediately suspected and verified. In addition, prompt initiation of potassium infusion may dramatically resolve the arrhythmias, even if the serum potassium level is within the lower normal range, and may also potentiate the effect of class I antiarrhythmic drugs such as lidocaine.