Considerations for radiotherapy in Bloom Syndrome: A case series

Bloom Syndrome (BS) is a genetic DNA repair disorder, caused by mutations in the BLM gene. The clinical phenotype includes growth retardation, immunodeficiency and a strong predisposition to different types of malignancies. Treatment of malignancies in BS patients with radiotherapy or chemotherapy is believed to be associated with increased toxicity, but clinical and laboratory data are lacking. We collected clinical data of two Dutch BS patients with solid tumors. Both were treated with radiotherapy before the diagnosis BS was made and tolerated this treatment well. In addition, we collected fibroblasts from BS patients to perform in vitro clonogenic survival assays to determine radiosensitivity. BS fibroblasts showed less radiosensitivity than the severely radiosensitive Artemis fibroblasts. Moreover, studies of double strand break kinetics by counting 53BP1 foci after irradiation showed similar patterns compared to healthy controls. In combination, the clinical cases and laboratory experiments are valuable information in the discussion whether radiotherapy is absolutely contraindicated in BS, which is the Case in other DNA repair syndromes like Ataxia Telangiectasia and Artemis.

Single nucleotide polymorphism (SNP) rs3751143 in P2RX7 is associated with therapy failure in chronic Q fever while rs7125062 in MMP1 is associated with fewer complications

OBJECTIVES

Chronic Q fever is a persistent infection with the intracellular bacterium Coxiella burnetii. Development of chronic Q fever is associated with single nucleotide polymorphisms (SNPs) in genes encoding for pattern recognition receptors, for phagolysosomal pathway components and for matrix metalloproteinases (MMPs). We evaluated the association of SNPs in these innate-immunity and MMP genes with clinical outcomes.

METHODS

SNPs were selected from previous association studies and analysed in a cohort of patients with chronic Q fever. The primary outcome was all-cause mortality; secondary outcomes were therapy failure and chronic Q fever-related complications. Subdistribution hazard ratios (SHR) were calculated.

RESULTS

Nineteen SNPs were analysed in 134 patients with proven and 29 with probable chronic Q fever. In multivariable analysis, none of the selected SNPs was associated with all-cause mortality. However, SNP rs3751143 located in P2RX7 appeared to be associated with therapy failure (SHR 2.42; 95% confidence interval, 1.16-5.05; p 0.02), which is in line with other reports, showing that a loss of function of the P2X7 receptor leads to inefficient killing of intracellular organisms. In addition, SNP rs7125062 located in MMP1, involved in the cleavage of extracellular matrix, was associated with fewer chronic Q fever-related complications such as acute aneurysms (SHR 0.49; 95% confidence interval, 0.29-0.83; p 0.008).

CONCLUSIONS

A polymorphism in P2RX7, known to lead to loss of function of the receptor and inefficient killing of intracellular organisms, and a polymorphism in MMP1 were respectively associated with more therapy failures and fewer complications such as acute aneurysms in patients with chronic Q fever.

Involvement of matrix metalloproteinases in chronic Q fever

OBJECTIVES

Chronic Q fever is a persistent infection with the intracellular Gram-negative bacterium Coxiella burnetii, which can lead to complications of infected aneurysms. Matrix metalloproteinases (MMPs) cleave extracellular matrix and are involved in infections as well as aneurysms. We aimed to study the role of MMPs in the pathogenesis of chronic Q fever.

METHODS

We investigated gene expression of MMPs through microarray analysis and MMP production with ELISA in C. burnetii-stimulated peripheral blood mononuclear cells (PBMCs) of patients with chronic Q fever and healthy controls. Twenty single nucleotide polymorphisms (SNPs) of MMP and tissue inhibitor of MMP genes were genotyped in 139 patients with chronic Q fever and 220 controls with similar cardiovascular co-morbidity. Additionally, circulating MMPs levels in patients with chronic Q fever were compared with those in cardiovascular controls with and without a history of past Q fever.

RESULTS

In healthy controls, the MMP pathway involving four genes (MMP1, MMP7, MMP10, MMP19) was significantly up-regulated in C. burnetii-stimulated but not in Escherichia coli lipopolysaccharide -stimulated PBMCs. Coxiella burnetii induced MMP-1 and MMP-9 production in PBMCs of healthy individuals (both p<0.001), individuals with past Q fever (p<0.05, p<0.01, respectively) and of patients with chronic Q fever (both p<0.001). SNPs in MMP7 (rs11568810) (p<0.05) and MMP9 (rs17576) (p<0.05) were more common in patients with chronic Q fever. Circulating MMP-7 serum levels were higher in patients with chronic Q fever (median 33.5 ng/mL, interquartile range 22.3-45.7 ng/mL) than controls (20.6 ng/mL, 15.9-33.8 ng/mL).

CONCLUSION

Coxiella burnetii-induced MMP production may contribute to the development of chronic Q fever.

Intact interferon-γ response against Coxiella burnetii by peripheral blood mononuclear cells in chronic Q fever

OBJECTIVES

Q fever is caused by Coxiella burnetii, an intracellular bacterium that infects phagocytes. The aim of the present study was to investigate whether the C. burnetii-induced IFN-γ response is defective in chronic Q fever patients.

METHODS

IFN-γ was measured in supernatants of C. burnetii-stimulated peripheral blood mononuclear cells (PBMCs) of 17 chronic Q fever patients and 17 healthy individuals. To assess IFN-γ responses, expression profiles of IFN-γ-induced genes in C. burnetii-stimulated PBMCs were studied in six patients and four healthy individuals. Neopterin was measured in PBMC supernatants (of eight patients and four healthy individuals) and in sera (of 21 patients and 11 healthy individuals). In a genetic association study, polymorphisms in genes involved in the Th1-cytokine response were analysed in a cohort of 139 chronic Q fever patients and a cohort of 220 control individuals with previous exposition to C. burnetii.

RESULTS

IFN-γ production by C. burnetii-stimulated PBMCs from chronic Q fever patients was significantly higher than in healthy controls. Many IFN-γ response genes were strongly upregulated in PBMCs of patients. Neopterin levels were significantly higher in PBMC supernatants and sera of patients. The IL12B polymorphisms rs3212227 and rs2853694 were associated with chronic Q fever.

CONCLUSIONS

IFN-γ production, as well as the response to IFN-γ, is intact in chronic Q fever patients, and even higher than in healthy individuals. Polymorphisms in the IL-12p40 gene are associated with chronic Q fever. Thus, a deficiency in IFN-γ responses does not explain the failure to clear the infection. The genetic data suggest, however, that the IL-12/IFN-γ pathway does play a role.

Alpha-fetoprotein, a fascinating protein and biomarker in neurology

Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 μg/l. After birth, AFP gene expression is turned down with a subsequent fall of the serum concentrations of this albumin-like protein to 'adult values' of circa 0.5-15 μg/l from the age of 2 years onwards. Irrespective of its assumed important functions, individuals with AFP deficiency appear fully healthy. The other way around, the presence of AFP in the circulation after the first years of life doesn't seem to harm, since individuals with 'hereditary persistence of AFP' are also without clinical abnormalities. During pregnancy, AFP (in maternal serum) has long been recognized as a marker for congenital anomalies of the fetus. Equally well known is AFP as biomarker for hepatocellular carcinoma and some other malignancies. There are at least four neurodegenerative disorders, all inherited as autosomal recessive traits and characterized by the presence of cerebellar ataxia, abnormal ocular movements, and neuropathy, for which an elevated concentration of serum AFP is an important diagnostic biomarker. The availability of a reliable biomarker is not only important during screening or diagnostic processes, but is also relevant for objective follow-up during (future) therapeutic interventions.

Pulmonary infection, and not systemic inflammation, accounts for increased concentrations of exhaled nitric oxide in patients with septic shock

Nitric oxide (NO) is a key mediator in the pathophysiology of septic shock that can be measured in exhaled breath. To assess whether a pulmonary infection itself or systemic inflammation is responsible for NO production, we determined exhaled NO in ventilated patients with respiratory and non-respiratory septic shock and compared it with the concentration in ventilated intensive care patients without systemic inflammation. In addition, the change of NO production over time and correlations with haemodynamic instability were evaluated. The controls without systemic inflammation, as witnessed by the absence of systemic inflammatory response syndrome criteria and low levels of interleukin-6, had similar concentrations of NO as the patients with non-respiratory septic shock. The respiratory sepsis patients exhaled more NO than the non-respiratory sepsis patients (p = 0.05), and a time dependent decline in time in both groups (p = 0.04). Exhaled NO did not correlate with markers of disease severity, systemic inflammation and haemodynamic instability. These data indicate that the infected lungs are the source of exhaled NO.

Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: reflection of inappropriate immune regulation?

BACKGROUND

Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T).

OBJECTIVE

To find a common immunological denominator in these cutaneous granulomas.

METHODS

The dermatological and immunological features of 4 patients with A-T and cutaneous granulomas were described. The literature on skin granulomas in A-T and in other PIDs is reviewed.

RESULTS

All 4 A-T patients had progressive granulomas on their limbs and showed decreased IgG and IgA concentrations with normal IgM levels. They had a marked decrease in B cells and naïve T cells coinciding with the appearance of the cutaneous granulomas. Similar B- and T-cell abnormalities were described in patients with other PIDs with skin granulomas.

CONCLUSIONS

We hypothesize that the pathogenesis of these skin granulomas is related to immune dysregulation of macrophages due to the absence of naïve T cells with an appropriate T-cell receptor repertoire and the unopposed activity of γδ T cells and/or natural killer cells.

Endotoxin tolerance does not limit mild ischemia-reperfusion injury in humans in vivo

Animal studies have shown that previous exposure to lipopolysaccharide (LPS) can limit ischemia-reperfusion injury. We tested whether pretreatment with LPS also protects against ischemia-reperfusion injury in humans in vivo. Fourteen volunteers received bolus injections of incremental dosages of LPS on 5 consecutive days (LPS group). Before the first and 1 day after the last LPS administration, the forearm circulation of the non-dominant arm was occluded for 10 min, with concomitant intermittent handgripping to induce transient ischemia. After reperfusion, 0.1 mg of ( 99m)Tc-labeled annexin A5 (400 MBq) was injected intravenously to detect phosphatidylserine expression as an early marker of ischemia-reperfusion injury. Similarly, the control group (n = 10) underwent the ischemic exercise twice, but without pretreatment with LPS. Annexin A5 targeting was expressed as the percentage difference in radioactivity in the thenar muscle between both hands. Endotoxin tolerance developed during 5 consecutive days of LPS administration. Annexin A5 targeting was 12.1 +/- 2.2% and 10.4 +/- 2.1% before LPS treatment at 1 h and 4 h after reperfusion, compared to 12.2 +/- 2.4% and 8.9 +/- 2.1% at 1 h and 4 h after reperfusion on day 5 (P = 1.0 and 0.6, respectively). Also, no significant changes in annexin A5 targeting were found in the control group. So, in this model, LPS-tolerance does not protect against ischemia-reperfusion injury in humans in vivo.

von Willebrand factor activation, granzyme-B and thrombocytopenia in meningococcal disease

SUMMARY BACKGROUND

During invasive meningococcal disease, severe thrombocytopenia is strongly associated with a poor outcome.

OBJECTIVES

In order to elucidate the pathophysiological mechanism behind the development of thrombocytopenia, we studied the role of von Willebrand factor (VWF) in meningococcal disease.

PATIENTS/METHODS

Thirty-two children with severe meningococcal disease admitted to our university hospital were included in this study. VWF and related parameters were measured and results were correlated with the development of shock and thrombocytopenia.

RESULTS

At admission, all patients had increased levels of (active) VWF and VWF propeptide. The highest VWF propeptide levels were observed in patients with shock, indicating acute endothelial activation. Although VWF propeptide levels in patients with shock, with or without thrombocytopenia, were similar, increased active VWF was significantly lower in patients with thrombocytopenia as compared with patients without thrombocytopenia. ADAMTS13 was moderately decreased. However, the VWF multimeric pattern was minimally increased. We assume that these findings are explained by VWF consumption and perhaps by granzyme B (GrB). In vitro experiments showed that GrB is able to cleave VWF multimers in plasma, whereas GrB was high in patients with shock, who developed thrombocytopenia.

CONCLUSIONS

Our results demonstrate that consumption of VWF, derived from endothelial cells, could be a key feature of meningococcal disease and primary to the development of thrombocytopenia during shock.

Clinical spectrum of ataxia-telangiectasia in adulthood

OBJECTIVE

To describe the phenotype of adult patients with variant and classic ataxia-telangiectasia (A-T), to raise the degree of clinical suspicion for the diagnosis variant A-T, and to assess a genotype-phenotype relationship for mutations in the ATM gene.

METHODS

Retrospective analysis of the clinical characteristics and course of disease in 13 adult patients with variant A-T of 9 families and 6 unrelated adults with classic A-T and mutation analysis of the ATM gene and measurements of ATM protein expression and kinase activity.

RESULTS

Patients with variant A-T were only correctly diagnosed in adulthood. They often presented with extrapyramidal symptoms in childhood, whereas cerebellar ataxia appeared later. Four patients with variant A-T developed a malignancy. Patients with classic and variant A-T had elevated serum alpha-fetoprotein levels and chromosome 7/14 rearrangements. The mildest variant A-T phenotype was associated with missense mutations in the ATM gene that resulted in expression of some residual ATM protein with kinase activity. Two splicing mutations, c.331 + 5G>A and c.496 + 5G>A, caused a more severe variant A-T phenotype. The splicing mutation c.331 + 5G>A resulted in less ATM protein and kinase activity than the missense mutations.

CONCLUSIONS

Ataxia-telangiectasia (A-T) should be considered in patients with unexplained extrapyramidal symptoms. Early diagnosis is important given the increased risk of malignancies and the higher risk for side effects of subsequent cancer treatment. Measurement of serum alpha-fetoprotein and chromosomal instability precipitates the correct diagnosis. There is a clear genotype-phenotype relation for A-T, since the severity of the phenotype depends on the amount of residual kinase activity as determined by the genotype.

Serum bactericidal activity against Helicobacter pylori in patients with hypogammaglobulinaemia

The two major primary antibody deficiency disorders are X-linked hypogammaglobulinaemia (XLA) and common variable immunodeficiency (CVID). CVID patients have an elevated risk for gastric cancer and extra-nodal marginal zone lymphoma. Both diseases are associated with Helicobacter pylori infection. We investigated whether antibody deficiency leads to defective serum bactericidal activity against H. pylori. We also investigated the correlation with immunoglobulin (Ig)M levels and observed the terminal complement complex (TCC) activity. Sera of 13 CVID patients (four H. pylori positive), one patient with hyper-IgM syndrome, one patient with Good syndrome (both H. pylori positive), five XLA patients, four H. pylori seropositive controls, four H. pylori seronegative controls and a sample of pooled human serum (PHS) were incubated in vitro with bacterial suspensions of H. pylori for 30 min. After 72 h of culture, colony-forming units were counted. TCC formation was measured by enzyme-linked immunosorbent assay. We found that normal human serum is bactericidal for H. pylori, whereas heat-inactivated serum shows hardly any killing of H. pylori. Serum (1%) of hypogammaglobulinaemia patients has a decreased bactericidal activity against H. pylori. Helicobacter pylori-positive (HP(+)) normal individuals show more than 90% killing of H. pylori, whereas CVID patients show 35% killing (P = 0.007) and XLA patients only 19% (P = 0.003). Serum (1%) of HP(+) volunteers showed significantly better killing compared with serum of H. pylori-negative (HP(-)) volunteers (P = 0.034). No correlation between (substituted) IgG levels and serum bactericidal activity was found, but a weak correlation between total serum IgM and serum bactericidal activity was found. In conclusion, serum bactericidal activity against H. pylori is decreased in patients with hypogammaglobulinaemia. Heat treatment of the serum abolished the bactericidal capacity, indicating that complement activity is essential for the bactericidal effect.

Pre-admission clinical course of meningococcal disease and opportunities for the earlier start of appropriate intervention: a prospective epidemiological study on 752 patients in the Netherlands, 2003-2005

To improve the timeliness of health care delivery to patients with meningococcal disease, the early disease evolution and clinical manifestation at admission were studied in all 752 patients with invasive meningococcal disease in the Netherlands in 2003-2005. Eighty-eight percent (88%) had serogroup B disease. The case fatality rate (CFR) was 6.7% overall, but reached 16% among adults over 50 years of age. The CFR was similar for serogroups B (6.3%) and C (5.2%). Admission followed 17 h (median) after the onset of symptoms. The CFR in patients admitted within 12 h, 12-18 h, 18-36 h or >36 h after the first symptoms was 10.2, 7.8, 3.5 and 2.2%, respectively. Only 60% of patients had skin lesions, and admission followed 2 h (median) later. Earlier recognition can be achieved when non-petechial clues are included in the diagnosis. A short duration of disease before admission is a simple tool in the recognition of patients with severe disease.

Clinical spectrum of immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome)

BACKGROUND

Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients.

OBJECTIVE

To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients.

METHODS

Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors.

RESULTS AND CONCLUSIONS

45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.

Reversible hypogammaglobulinaemia

In this report we present four patients with reversible hypogammaglobulinaemia who required immunoglobulin substitution for several years. One patient had documented systemic lupus erythematosus (SLE), the other three patients had primary hypogammaglobulinaemia without known cause. Whereas the cessation of azathioprine therapy may have contributed to the recovery in the patient with SLE, the restoration of the immunoglobulin production in the other three patients occurred spontaneously. All four patients were IgA deficient when the hypogammaglobulinaemia was first detected and remained so after IgM and IgG production had recovered. Two of the three patients who also had anti-IgA antibodies started to produce anti-IgA again after stopping the immunoglobulin substitution. We conclude that recovery of hypogammaglobulinaemia is possible but rare. When recovery is suspected, we recommend that immunoglobulin substitution is stopped and the antibody response to vaccination is tested.

[Walking in the sun: heat stroke and heat exhaustion during the Four-Day March in Nijmegen, in 2006]

The annual Four-Day March in Nijmegen, The Netherlands, in July 2006 was cancelled after the first day because two participants had died, men aged 65 and 57 years, and many had become unwell while walking in unusually high ambient temperatures. However, the cause of death of the two who died turned out to be cardiovascular and not heat-related. The case of two of the people that became unwell, men aged 58 and 59 years, respectively, shows that heat stroke and heat exhaustion were important causative conditions. Heat-related illnesses are relatively uncommon in the Netherlands due to its temperate climate. Heat stroke is the most severe of these and associated with a high mortality rate if not recognised and treated promptly. The primary cause is accumulation of heat due either to diminished loss or increased endogenous heat production, such as by physical exertion. Heat exhaustion is caused by salt or water depletion.

Neuromuscular abnormalities in ataxia telangiectasia: a clinical, electrophysiological and muscle ultrasound study

Thirteen classical ataxia telangiectasia (A-T) patients, varying in age from 1 to 25 years, were studied clinically, electrophysiologically as well as by muscle ultrasound to chart the development and spectrum of neuromuscular abnormalities in A-T. The most prominent finding was a progressive axonal sensorimotor polyneuropathy, apparent by electromyography and muscle ultrasound from the age of 8 years and becoming clinically discernible around 12 years of age. Before the age of 8 years decreased tendon reflexes and slightly slowed sensory nerve conduction velocities could already be observed. With routine electrophysiological techniques the severe polyneuropathy precludes conclusions about the presence of anterior horn cell loss in older patients.

The absent and vanishing spleen: congenital asplenia and hyposplenism--two case reports

Two unrelated patients are reported: one with isolated familial asplenia diagnosed postmortem, the other with isolated hyposplenism diagnosed after recurring invasive bacterial infections. Because both children died of fulminant septic shock, the importance of early diagnosis of splenic dysfunction is evident. Clues for an early diagnosis of congenital asplenia are recurrent invasive bacterial infections, Howell-Jolly bodies in the blood smear or a relative with congenital isolated asplenia. Although the guidelines for infection prevention in asplenism--patient education, antibiotic prophylaxis and vaccination--are well defined, controversy remains as to how to differentiate hyposplenism from functional asplenism.

CONCLUSION

Based on the present observations, we define a patient as functionally asplenic--and therefore at risk for life-threatening infections-when Howell-Jolly bodies are present in the blood smear, a very small spleen is found by ultrasound, or splenic blood flow is compromised.

Association between familial deficiency of mannose-binding lectin and mutations in the corresponding gene and promoter region

In a recent report, our group presented clinical research data supporting the role of mannose-binding lectin (MBL) deficiency in susceptibility to meningococcal disease (W. A. Bax, O. J. J. Cluysenaer, A. K. M. Bartelink, P. C. Aerts, R. A. B. Ezekowitz, and H. van Dijk, Lancet 354:1094-1095, 1999). This association was reported earlier by Hibberd et al. (M. L. Hibberd, M. Sumiya, J. A. Summerfield, R. Booy, M. Levin, and the Meningococcal Research Group, Lancet 353:1049-1053, 1999) but was not based on family data. Our study included three members of one family who had acquired meningococcal meningitis in early adulthood. The objective of the present study was to investigate whether the genotypes of the MBL gene in this family, analyzed by PCR, correlate with MBL concentrations. We found that genotype variants in the MBL gene and promoter region match the low functional MBL levels (<0.25 microg of equivalents/ml) in the sera of the three patients in this family and that a significant correlation between genotype MBL deficiency and meningococcal disease existed.

Hypothesis: Normalisation of cytokine dysbalance explains the favourable effects of strict glucose regulation in the critically ill

Recent trials investigating the effects of strict glucose regulation in critically ill patients have shown impressive reductions in morbidity and mortality. Although the literature focuses on the possible toxic effects of high blood glucose levels, the underlying mechanism for this improvement is unclear. We hypothesise that strict glucose regulation results in modulation of cytokine production, leading to a shift towards a more anti-inflammatory pattern. This shift in the cytokine balance accounts for the reduction in morbidity and mortality. To support our hypothesis, effects of glucose and insulin on cytokine release and effects of glucose, insulin, and cytokines on host defence, cardiac function and coagulation will be reviewed.

Circulating concentrations of soluble granzyme A and B increase during natural and experimental Plasmodium falciparum infections

Release of soluble Granzymes (sGranzymes) is considered to reflect activation of cytotoxic T lymphocytes and NK cells. sGranzymes and a number of pro-inflammatory cytokines were measured in plasma of malaria patients with natural or experimentally induced Plasmodium falciparum infections. Concentrations of sGranzyme A and B, IL-10, IL-12p70 and CRP were significantly increased in African children presenting with clinical malaria; IL-10 and CRP concentrations were significantly correlated with disease severity. In nonimmune Dutch volunteers which were experimentally infected by P. falciparum-infected mosquitoes, sGranzyme A increment started 1-2 days prior to clinical symptoms and microscopically detectable parasitaemia. This coincided with increases in IFNgamma, IL-12p40 and IL-8, while sGranzyme B and IL-10 levels increased 24-48 h later. The elevation of sGranzyme A and IFNgamma in nonimmune volunteers suggests that NK cells are activated upon release of parasites by infected liver cells and subsequently during blood stage infection; thus, NK cells are likely involved innate immune human host resistance in the early phase of a malaria infection.

Cytokine induction by non-lipopolysaccharide components of Neisseria meningitidis

Background

Lipopolysaccharide (LPS), or endotoxin, is considered responsible for the pattern of cytokine activation and the subsequent pathophysiological events during Gram-negative septic shock. To determine whether non-LPS components of Neisseria meningitidis are able to induce cytokine activation, the cytokine-inducing capacities of serogroup B wild-type N. meningitidis H44/76, of an LPS-deficient mutant (Plak 33) and of meningococcal LPS in human peripheral blood mononuclear cells were studied.

Methods

2-Keto-3-deoxyoctanate spectrophotometry was used to obtain a molar-based quantitative comparison between LPS and bacteria.

Results

Whole meningococci H44/76 were more potent inducers of cytokine production than isolated LPS; the LPS-deficient meningococci, Plak 33, were also able to induce cytokine production. LPS-deficient meningococci supplemented with an amount of LPS equivalent to that present in the wild-type strain produced the same amount of cytokines as the wild-type meningococcus.

Conclusion

LPS is not the sole toxic element in meningococcal sepsis, because non-LPS components of N. meningitidis are able to induce cytokine activation substantially. Antiendotoxin therapy alone may not be sufficient to inhibit the pattern of cytokine activation and the subsequent pathophysiological events during meningococcal septic shock.

Determination of 2-keto-3-deoxyoctanate: a simple method for the quantitative comparison of cytokine induction by meningococcal lipopolysaccharide and that of other bacteria

Background

Lipopolysaccharide (LPS), or endotoxin, is considered to be the toxic element in Gram-negative septic shock. There is increasing evidence that the pathogenic properties of LPS differ from species to species but, to date, exact comparison between the biological activities of LPS has been difficult.

Methods

With the aim of quantitatively comparing the cytokine-inducing capacities of Neisseria meningitidis LPS and Escherichia coli LPS in human peripheral blood mononuclear cells on a molar basis, 2-keto-3-deoxyoctanate (KDO) spectrophotometry was used.

Results

Since the KDO region of LPS is a preserved part of the LPS molecule, unlike the saccharide tail, and the molecular weight of this region is known, KDO measurement can provide accurate information about the molarity of an LPS suspension. On a molar basis, the cytokine-inducing capacity of meningococcal LPS was at least ten times higher than that of E. coli LPS.

Conclusion

KDO spectrophotometry is a simple method of making a quantitative comparison between the biological effects of different endotoxins. N. meningitidis LPS is a more potent inducer of cytokine production than E. coli LPS. This may, in part, explain the more fulminant course of meningococcal sepsis compared with E. coli sepsis.

Genetic analysis as a valuable key to diagnosis and treatment of periodic Fever

We describe 2 Dutch patients with recurrent fever attacks undiagnosed for more than 40 years. The diagnosis of periodic fever was made when molecular analysis revealed novel mutations in the tumor necrosis factor (TNF) receptor gene (TNFRSF1A), establishing the diagnosis of TNF receptor-associated periodic syndrome. This syndrome is an autosomal dominant disorder characterized by recurring episodes of fever, arthralgia, and skin lesions that is caused by mutations in the 55-kd TNFRSF1A gene. This finding has facilitated treatment for TNF receptor-associated periodic syndrome because blocking of TNF signaling seems to alleviate the symptoms. Use of a short course of recombinant p75TNFR:Fc fusion protein (etanercept) induced prolonged remission in one patient.

[Corticosteroid administration for critically ill patients]

In critically ill patients, the hypothalamic-pituitary-adrenal axis is usually activated, resulting in elevated plasma cortisol levels. This enables the human organism to cope with sepsis, trauma and other forms of stress. During critical illness, total adrenal insufficiency rarely occurs. On the other hand, septic shock can be accompanied by a relative deficit of cortisol. Causes of this relative adrenal insufficiency are a dysfunction of the hypothalamic-pituitary-adrenal axis and/or cortisol resistance. There are no strict biochemical criteria available to diagnose relative adrenal insufficiency; clinical observation is the decisive factor. In randomised trials with patients in septic shock, a more rapid haemodynamic recovery was obtained with physiological doses of hydrocortisone than with a placebo. The observed haemodynamic response following hydrocortisone administration supports the concept of relative adrenal insufficiency.

Contributions of Neisseria meningitidis LPS and non-LPS to proinflammatory cytokine response

To determine the relative contribution of lipopolysaccharide (LPS) and non-LPS components of Neisseria meningitidis to the pathogenesis of meningococcal sepsis, this study quantitatively compared cytokine induction by isolated LPS, wild-type serogroup B meningococci (strain H44/76), and LPS-deficient mutant meningococci (strain H44/76[pLAK33]). Stimulation of human peripheral-blood mononuclear cells with wild-type and LPS-deficient meningococci showed that non-LPS components of meningococci are responsible for a substantial part of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta production and virtually all interferon (IFN)-gamma production. Based on tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of LPS in proteinase K-treated lysates of N. meningitidis H44/76, a quantitative comparison was made between the cytokine-inducing capacity of isolated and purified LPS and LPS-containing meningococci. At concentrations of >10(7) bacteria/mL, intact bacteria were more potent cytokine inductors than equivalent amounts of isolated LPS, and cytokine induction by non-LPS components was additive to that by LPS. Experiments with mice showed that non-LPS components of meningococci were able to induce cytokine production and mortality. The principal conclusion is that non-LPS parts of N. meningitidis may play a role in the pathogenesis of meningococcal sepsis by inducing substantial TNF-alpha, IL-1beta, and IFN-gamma production.

Cytokine measurement in vivo and in vitro

Cytokines play a pivotal role in both defense against meningococcal infection and the pathophysiology of invasive meningococcal disease. These chemical messengers are crucial cogwheels in the machinery of the innate immune system and are also powerful forces in the antigen-specific defense system.

[Acute and chronic Q fever; epidemiology, symptoms, diagnosis and therapy of infection caused by Coxiella burnetii]

Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium. Domestic ungulates and parturient cats are the primary reservoirs of infection. The animals excrete the bacterium in urine, faeces, milk and amniotic fluid. After desiccation the micro-organism spreads via aerosols. After inhalation or ingestion and an incubation period of 2-6 weeks acute Q fever may develop with atypical pneumonia and hepatitis as major clinical symptoms. The infection also may present as a flu-like illness or remain asymptomatic. Generally, the prognosis is favourable. However, endocarditis or another chronic form of Q fever occasionally develops with possibly fatal outcome. Diagnosis relies upon serologic testing with an indirect immunofluorescence method. Doxycycline is the antibiotic of choice in the treatment of Q fever. Endocarditis needs therapy for years with the addition of rifampin or hydroxychloroquine. Q fever is poorly recognised due to the variety of clinical presentations.