Beta2-adrenergic receptor polymorphisms in African American children with status asthmaticus

BACKGROUND

The beta2-adrenergic receptor plays a central role in the bronchodilator response to beta2-agonists in patients with asthma. Genetic polymorphisms within the gene coding for this receptor influence responsiveness of the receptor. A number of these polymorphisms differ in frequency in the African American and white populations.

OBJECTIVE

To determine the frequency of specific beta2-adrenergic receptor polymorphisms in African American children with status asthmaticus and to examine whether a specific genotype is associated with the clinical response to therapy.

DESIGN

Cohort of African American children diagnosed with status asthmaticus.

SETTING

Tertiary care children's hospital.

PATIENTS

A total of 31 African American children with status asthmaticus.

INTERVENTION

Blood samples were obtained from children at admission. Genotypes were determined by polymerase chain reaction amplification and restriction enzyme digestion.

MAIN OUTCOME MEASURES

The requirement for admission to the pediatric intensive care unit, need for mechanical ventilation, institution of various therapies, and length of stay.

RESULTS

The genotypes of the polymorphic sites at amino acid positions 16 and 27 in the beta2-adrenergic receptor were determined. There were no significant differences between the various genotypes in the percentage of children requiring pediatric intensive care unit admission, mechanical ventilation, terbutaline treatment, or length of stay. However, in children heterozygous for Glu at position 27 of the beta2-adrenergic receptor, the percentage of patients requiring aminophylline treatment, in addition to beta2-agonist therapy, was significantly higher than that seen in patients homozygous for Gln at that position (5/10 [50%] vs. 1/21 [5%], respectively; p = .002).

CONCLUSIONS

African American children with status asthmaticus who have the Gln/Glu genotype at amino acid position 27 of the beta2-adrenergic receptor may benefit from aminophylline treatment in addition to beta2-agonist therapy.

Deletion allele of angiotensin-converting enzyme is associated with increased risk and severity of bronchopulmonary dysplasia

OBJECTIVE

To explore whether the deletion (D) allele of angiotensin-converting enzyme (ACE) is associated with the risk or severity of bronchopulmonary dysplasia (BPD) among very low birth weight (BW) infants.

STUDY DESIGN

Infants with a BW < or = 1250 g were prospectively recruited. The D and I (insertion) alleles of ACE were determined using a polymerase chain reaction followed by restriction fragment length polymorphism analysis.

RESULTS

Infants with DD/DI genotype of ACE had a (mean +/- SD) birth weight (938 +/- 204 g vs 925 +/- 196 g) and gestational age (28 +/- 3 weeks vs 28 +/- 2 weeks), similar to infants with II genotype of ACE (P > .05). Infants with DD/DI genotype of ACE were more likely to have BPD than infants with II genotype (47% vs 22%, P = .025). Among infants with BPD, ACE DD/DI genotype was more common among infants with moderate or severe BPD compared with infants with mild BPD (74% vs 26%, P = .012). The number of D alleles of ACE correlated directly and positively with the severity of BPD (R = 0.23, P = .045).

CONCLUSION

The D allele of ACE is associated with an increased risk and severity of BPD among preterm infants.

Genetic polymorphisms in sepsis

CONTEXT

Wide variability exists in the susceptibility to and outcome from sepsis even within similar intensive care unit populations. Some of this variability in the host may be due to genetic variation in genes coding for components of the innate immune response.

OBJECTIVE

To review the evidence for a genetic influence on the susceptibility to and outcome from sepsis.

DESIGN

Literature review.

PATIENTS

Variety of adult and pediatric patients with various critical illnesses and infections.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Susceptibility to clinical symptoms of sepsis and outcome as measured by severity of disease and mortality.

RESULTS

Polymorphisms in genes coding for proteins involved in the recognition of bacterial pathogens (Toll-like receptor 4, CD14, Fc(gamma)RIIa, and mannose-binding lectin) and the response to bacterial pathogens (tumor necrosis factor-alpha, interleukin (IL)-1alpha, IL-1beta, IL-1 receptor agonist, IL-6, IL-10, heat shock proteins, angiotensin I converting enzyme, plasminogen activator inhibitor-1) can influence the amount or function of the protein produced in response to bacterial stimuli. Evidence is discussed suggesting that some of these genetic polymorphisms influence the susceptibility to and outcome from sepsis.

CONCLUSION

Host genetic variability in the regulatory and coding regions of genes for components of the innate immune system may influence the susceptibility to and/or outcome from sepsis. The disparate results observed in many studies of polymorphisms in sepsis emphasize the need for future studies to be larger, to include the analysis of multiple polymorphisms, and to be better designed with respect to control populations to identify the degree of influence that genetic variability has on sepsis.

Severe systemic reaction to Loxosceles reclusa spider bites in a pediatric population

OBJECTIVE

To report 6 children who had severe systemic reaction after spider bites requiring pediatric intensive care unit admission and to describe their clinical presentation, hospital course, and outcome.

METHODS

A retrospective analysis was done to identify patients presenting with brown recluse spider bites. Charts of children admitted to the intensive care unit were reviewed.

RESULTS

Six previously healthy African-American children, aged 3 to 15 years, with brown recluse spider bites were admitted to the pediatric intensive care unit. All had fever, jaundice, and evidence of hemolytic anemia. Four of 6 children had hypotension. One child developed mental status changes, acute renal failure secondary to rhabdomyolysis, and hyperkalemia and required emergent hemodialysis. All children fully recovered.

CONCLUSION

Although most cases of brown recluse spider bites are benign requiring no intervention, severe systemic reactions may occur in the pediatric population resulting in admission to the pediatric intensive care unit. These systemic reactions may include hemolytic anemia, hypotension, and renal failure.

Polymorphism of tumor necrosis factor-alpha and risk and severity of bronchopulmonary dysplasia among very low birth weight infants

BACKGROUND

Preterm infants with bronchopulmonary dysplasia (BPD) exhibit prolonged elevation of inflammatory indices in their tracheal aspirates. Tumor necrosis factor-alpha (TNF-alpha) is a central mediator of the inflammatory response. The adenine-containing alleles of TNF-alpha-308 and lymphotoxin-alpha+250 have been associated with increased levels of TNF-alpha, whereas the adenine allele of TNF-alpha-238 produces lower levels of TNF-alpha after stimulation. High levels of TNF-alpha may promote chronic inflammation by overwhelming counter-regulatory mechanisms and may lead to the development of BPD. Low levels of TNF-alpha may decrease the risk and/or severity of BPD.

OBJECTIVE

To determine whether alleles of TNF-alpha play a role in the susceptibility and/or severity of BPD among very low birth weight infants.

METHODS

Infants with birth weights of < or =1250 g were included. Genotypic analyses (polymerase chain reaction-restriction fragment length polymorphism assays) were performed with DNA extracted from whole-blood samples.

RESULTS

Infants who developed BPD (fraction of inspired oxygen at postconceptional age of 36 weeks of >0.21, n = 51) had a younger gestational age (mean +/- SD: 27 +/- 4 vs 29 +/- 2 weeks) and lower birth weight (853 +/- 184 vs 997 +/- 193 g) than did infants without BPD (n = 69). The genotypic distributions of lymphotoxin-alpha+250 and TNF-alpha-308 were comparable among the groups of infants. However, the AA and GA TNF-alpha-238 genotypes were much less likely to occur among infants with BPD than among infants without BPD. The adenine allele of TNF-alpha-238 was absent among infants with severe BPD and occurred significantly less often among infants with moderate or severe BPD, compared with infants with mild BPD. The number of adenine alleles of TNF-alpha-238 was correlated inversely with the severity of BPD (r = -.341).

CONCLUSION

The adenine allele of TNF-alpha-238 may reduce the risk and severity of BPD.

Tumor necrosis factor-alpha allele lymphotoxin-alpha+250 is associated with the presence and severity of placental inflammation among preterm births

Histologic inflammation of placenta has been associated with increased risk for bronchopulmonary dysplasia and periventricular leukomalacia among preterm infants. Tumor necrosis factor-alpha (TNF-alpha) plays a central role in the regulation of inflammation. Some alleles of TNF (LT-alpha+250, TNF-alpha-308, and TNF-alpha-238) have been associated with susceptibility and/or severity of many diseases characterized by inflammation and/or involving the immune system. To determine whether alleles of TNF-alpha affect the risk and/or the severity of chorioamnionitis, we examined the placentas of 101 preterm births (birth weight <or=1250 g) for the presence of inflammation. Maternal and fetal chorioamnionitis (MCA and FCA, respectively) were graded for severity and staged for location of inflammatory infiltrate. Analysis for TNF-alpha alleles was done using PCR-restriction fragment length polymorphism technique on DNA extracted from infants' whole blood. MCA and FCA were seen in 45 and 38 placentas, respectively (p = 0.64). Genotypes of TNF-alpha-308 did not affect the development or the severity of placental inflammation. However, the AA genotype of LT-alpha+250 occurred more often when MCA and FCA were present compared with placentas without inflammation (p = 0.016 and p = 0.007, respectively). The GA genotype of TNF-alpha-238 was more common in placentas with severe MCA than with mild MCA (p = 0.015). The number of A alleles of LT-alpha+250 (GG = 0, GA = 1, AA = 2) correlated directly and significantly with grades and stages of MCA and FCA (p < 0.05). The AA genotype of LT-alpha+250 is associated with the development of chorioamnionitis among preterm births. The A allele of LT-alpha+250 seems to worsen the degree of placental inflammation.

Association between surfactant protein B + 1580 polymorphism and the risk of respiratory failure in adults with community-acquired pneumonia

OBJECTIVE

Pulmonary surfactant protein (SP)-B plays a vital role in the formation and function of surfactant in the lung. A genetic polymorphism (SP-B + 1580) is postulated to result in diminished activity of SP-B. The objective was to determine whether the SP-B + 1580 CC genotype is associated with an increased risk of respiratory failure and ARDS in adults with community-acquired pneumonia.

DESIGN

Prospective cohort of adults diagnosed with community-acquired pneumonia.

SETTING

Hospital system.

PATIENTS

We enrolled 402 adults > or = 18 yrs of age with community-acquired pneumonia; 158 were white, 243 were African American, and one was Asian.

INTERVENTIONS

Genotypic analysis was performed on DNA isolated from whole blood using polymerase chain reaction amplification and DdeI restriction enzyme digestion.

MEASUREMENTS AND MAIN RESULTS

We recorded the requirement for mechanical ventilation, the presence of acute respiratory distress syndrome (ARDS) or septic shock, and mortality. Sixty-three patients required mechanical ventilation, 12 patients developed ARDS, and 35 patients developed septic shock. Genotypic frequencies at the SP-B + 1580 site were T/T 183 of 402 (0.45), T/C 160 of 402 (0.40), and C/C 59 of 402 (0.15). Of the 59 patients who were C/C at the SP-B + 1580 site, 21 (0.356) required mechanical ventilation, compared with 26 of 160 patients (0.163) who were T/C and 16 of 183 (0.087) patients who were T/T (p < .001). ARDS developed in five of 59 (0.085) patients with the C/C genotype, compared with six of 160 (.038) patients with T/C and one of 183 patients with T/T (0.005, p < .009). Septic shock occurred in 12 of 59 (0.203) patients with the C/C genotype, compared with 13 of 160 (0.081) patients with T/C and ten of 183 (0.055) patients with T/T (p < .001). Mortality rate was not different between the three genotypes.

CONCLUSION

Carriage of the C allele at the SP-B + 1580 site is associated with ARDS, septic shock, and the need for mechanical ventilation in adults with community-acquired pneumonia.

Clinical relevance of angiotensin-converting enzyme gene polymorphisms to predict risk of mechanical ventilation after coronary artery bypass graft surgery

OBJECTIVE

Prolonged mechanical ventilation is a significant complication after coronary artery bypass graft surgery. Angiotensin-converting enzyme mediates ischemia-reperfusion injury, which is an important mechanism of postcoronary artery bypass graft complications. An insertion/deletion polymorphism within the angiotensin-converting enzyme gene is associated with variable concentrations of angiotensin-converting enzyme. Whether this polymorphism is associated with prolonged mechanical ventilation is not known. The primary objective was to determine whether the insertion/deletion angiotensin-converting enzyme gene polymorphism is associated with prolonged mechanical ventilation. The release of inflammatory mediators and risk of prolonged mechanical ventilation are higher after conventional coronary artery bypass graft compared with off-pump coronary artery bypass graft. Therefore, we examined the risk of prolonged mechanical ventilation for angiotensin-converting enzyme genotypes in patients undergoing conventional coronary artery bypass graft and off-pump coronary artery bypass graft separately. Tumor necrosis factor down-regulates angiotensin-converting enzyme concentrations, and functional polymorphisms within the tumor necrosis factor gene have been associated previously with prolonged mechanical ventilation. Therefore, we examined interactions between these polymorphisms.

DESIGN

Prospective observational cohort study.

SETTING

Tertiary care center.

SUBJECTS

Patients who underwent coronary artery bypass graft (with or without valve replacement surgery).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured angiotensin-converting enzyme genotype and time to extubate. Patients with the DD and DI genotypes were at higher risk of prolonged mechanical ventilation compared with those with the II genotypes (hazard ratio = 2.2 and 1.6, respectively, p =.0005). Interactions were seen between the angiotensin-converting enzyme genotypes with surgical technique and with tumor necrosis factor-308/lymphotoxin + 250 GG haplotype for prolonged mechanical ventilation (p =.078 and.0003, respectively). The association was stronger for those undergoing conventional coronary artery bypass graft, whereas neither angiotensin-converting enzyme genotype conferred higher risk to those undergoing off-pump coronary artery bypass graft.

CONCLUSIONS

Angiotensin-converting enzyme gene polymorphisms are associated with respiratory complications postcardiopulmonary bypass. The increased risk associated with genotype may be amenable to alternative surgical technique or pharmacologic manipulation.

Extubation failure in pediatric intensive care: A multiple-center study of risk factors and outcomes

OBJECTIVE

To determine a contemporary failed extubation rate, risk factors, and consequences of extubation failure in pediatric intensive care units (PICUs). Three hypotheses were investigated: a) Extubation failure is in part disease specific; b) preexisting respiratory conditions predispose to extubation failure; and c) admission acuity scoring does not affect extubation failure.

DESIGN

Twelve-month prospective, observational, clinical study.

SETTING

Sixteen diverse PICUs in the United States.

PATIENTS

Patients were 2,794 patients from the newborn period to 18 yrs of age experiencing a planned extubation trial.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A descriptive statistical analysis was performed, and outcome differences of the failed extubation population were determined. The extubation failure rate was 6.2% (174 of 2,794; 95% confidence interval, 5.3-7.1). Patient features associated with extubation failure (p <.05) included age < or =24 months; dysgenetic condition; syndromic condition; chronic respiratory disorder; chronic neurologic condition; medical or surgical airway condition; chronic noninvasive positive pressure ventilation; the need to replace the endotracheal tube on admission to the PICU; and the use of racemic epinephrine, steroids, helium-oxygen therapy (heliox), or noninvasive positive pressure ventilation within 24 hrs of extubation. Patients failing extubation had longer pre-extubation intubation time (failed, 148.7 hrs, SD +/- 207.8 vs. success, 107.9 hrs, SD +/- 171.3; p <.001), longer PICU length of stay (17.5 days, SD +/- 15.6 vs. 7.6 days, SD +/- 11.1; p <.001), and a higher mortality rate than patients not failing extubation (4.0% vs. 0.8%; p <.001). Failure was found to be in part disease specific, and preexisting respiratory conditions were found to predispose to failure whereas admission acuity did not.

CONCLUSION

A variety of patient features are associated with an increase in extubation failure rate, and serious outcome consequences characterize the extubation failure population in PICUs.

A region of the third intracellular loop of the short form of the D2 dopamine receptor dictates Gi coupling specificity

The D2 dopamine receptor has two isoforms, the short form (D2s receptor) and the long form (D2l receptor), which differ by the presence of a 29-amino acid insert in the third cytoplasmic loop. Both the D2s and D2l receptors have been shown to couple to members of the G alpha(i) family of G proteins, but whether each isoform couples to specific G alpha(i) protein(s) remains controversial. In previous studies using G alpha(i) mutants resistant to modification by pertussis toxin (G alpha(i)PT), we demonstrated that the D2s receptor couples selectively to G alpha(i2)PT and that the D2l receptor couples selectively to G alpha(i3)PT (Senogles, S. E. (1994) J. Biol. Chem. 269, 23120-23127). In this study, two point mutations of the D2s receptor were created by random mutagenesis (R233G and A234T). The two mutant D2s receptors demonstrated pharmacological characteristics comparable with those of the wild-type D2s receptor, with similar agonist and antagonist binding affinities. We used human embryonic kidney 293 cells stably transfected with G alpha(i1)PT, G alpha(i2)PT, or G alpha(i3)PT to measure agonist-mediated inhibition of forskolin-stimulated cAMP accumulation before and after pertussis toxin treatment. The two mutant D2s receptors demonstrated a change in G(i) coupling specificity compared with the wild-type D2s receptor. Whereas the wild-type D2s receptor coupled predominantly to G alpha(i2)PT, mutant R233G coupled preferentially to G alpha(i3)PT, and mutant A234T coupled preferentially to G alpha(i1)PT. These results suggest that this region of the third cytoplasmic loop is crucial for determining G(i) protein coupling specificity.

Decreasing beta-lactam resistance in Pneumococci from the Memphis region: analysis of 2,152 isolates From 1996 to 2001

STUDY OBJECTIVES

The Memphis region historically has had high pneumococcal antibiotic resistance rates. In recent years, we have seen a significant shift in antibiotic use away from beta-lactams toward the newer quinolones and macrolides. We hypothesized that these changes would cause a shift in pneumococcal antibiotic resistance patterns.

DESIGN

Retrospective cohort study.

SETTING

A large private hospital system.

PATIENTS AND METHODS

We analyzed the antibiotic susceptibility patterns of 2,152 pneumococcal isolates obtained in the Memphis area from 1996 to 2001. Isolates were categorized as invasive or noninvasive and antibiotic resistance was classified according to the 2000 guidelines of the National Committee for Clinical Laboratory Standards.

RESULTS

Over the study period, the proportion of penicillin-susceptible noninvasive pneumococcal isolates taken from children increased from 22 to 44% (p = 0.0004 [for trend across the 6-year period]). In noninvasive isolates taken from adults, penicillin susceptibility increased from 22 to 55% (p = 0.002), with a trend toward increasing sensitivity to cefotaxime (p = 0.02) in noninvasive isolates over the same period. The proportion of isolates with high-level penicillin resistance (ie, minimum inhibitory concentration, > or = 4 microg/mL) also decreased between 1996 and 2001 (p = 0.003). Clindamycin resistance in adult noninvasive isolates also declined (p = 0.002). The only adverse trend observed over this period was an increase in erythromycin resistance in noninvasive isolates from adults (p = 0.01). Resistance rates were significantly higher in children than in adults and were higher in noninvasive isolates than in invasive isolates.

CONCLUSIONS

The stabilization of beta-lactam resistance rates in our region suggests that a continuous increase in pneumococcal resistance to antibiotics is not inevitable and may be avoidable.

Heat shock protein 70-2+1267 AA homozygotes have an increased risk of septic shock in adults with community-acquired pneumonia

OBJECTIVE

Heat shock protein (HSP)70-2 is an important immunomodulatory protein induced in response to inflammatory stimuli. We assessed whether HSP70-2+1267 genotype influenced the risk of septic shock in a prospective cohort study of community-acquired pneumonia and whether HSP70-2+1267 genotype is a better predictor of septic shock than the genotype at lymphotoxin-alpha +250.

DESIGN

Prospective cohort study.

SETTING

A large, nonprofit, private hospital system in Memphis, TN.

PATIENTS

Adults admitted with community-acquired pneumonia between 1998 and 2001. Septic shock was defined according to consensus criteria (American College of Chest Physicians/Society of Critical Care Medicine, 1992).

INTERVENTIONS

Blood sampling.

MEASUREMENTS AND MAIN RESULTS

A total of 343 subjects were enrolled; 30 had septic shock. HSP70-2+1267 and lymphotoxin-alpha +250 genotype was determined using polymerase chain reaction and restriction enzyme digestion. HSP70-2+1267 AA genotype was the strongest predictor of septic shock (p =.0005; relative risk, 3.5). Lymphotoxin-alpha +250 AA genotype was also associated with an increased risk of septic shock (p =.002; relative risk, 2.7). Logistic regression analysis found only age (p =.04) and HSP70-2+1267 genotype (p =.006) were predictors of septic shock. The greatest risk of septic shock was associated with carriage of the HSP70-2+1267 A/lymphotoxin-alpha +250 A haplotype (p <.0001).

CONCLUSIONS

HSP70-2+1267 genotype is a stronger predictor of septic shock in patients with community-acquired pneumonia than lymphotoxin-alpha +250 genotype.

Association of tumor necrosis factor gene polymorphisms and prolonged mechanical ventilation after coronary artery bypass surgery

OBJECTIVE

Prolonged mechanical ventilation is a common complication after coronary artery bypass graft surgery. Tumor necrosis factor alpha is an important proinflammatory mediator in the post-coronary artery bypass graft inflammatory cascade. We attempted to study the effect of polymorphisms at the -308 site in the promoter region of the tumor necrosis factor gene (TNF-308) and the +250 site within the lymphotoxin-alpha gene (LT alpha+250) on the risk of prolonged mechanical ventilation after coronary artery bypass grafting.

DESIGN

Prospective observational study.

SETTING

Tertiary care center.

PATIENTS

A total of 400 patients undergoing coronary artery bypass grafting were enrolled.

MEASUREMENTS

The primary end point was time to extubate. Secondary end points were the percentages of patients extubated at 8, 24, and 48 hrs; the length of intensive care unit and hospital stay; the need for a rehabilitation facility; and 30-day mortality. Precollected blood was used for gene analysis. Genotyping was performed by polymerase chain reaction and restriction enzyme digestion.

MAIN RESULTS

Patients with an AA genotype at the LT alpha+250 site and those without the LT alpha+250G/-308TNFG haplotype had a shorter duration of mechanical ventilation (11.5 vs. 27.8 hrs and 11.2 vs. 29.4 hrs; =.039 and.01, respectively). The risk of prolonged mechanical ventilation at 8, 24, and 48 hrs was higher for patients with a GA or GG genotype at the LT alpha+250 site and the LT alpha+250G/TNF-308G haplotype. This association between genotype and duration of mechanical ventilation was more dramatic in patients undergoing conventional coronary artery bypass grafting than in those undergoing off-pump coronary artery bypass grafting. With Bayesian analysis, clinical criteria and genotype can be used sequentially to predict the risk of prolonged mechanical ventilation.

CONCLUSIONS

The LT alpha+250 and LT alpha+250G/TNF-308G haplotypes are associated with prolonged mechanical ventilation after coronary artery bypass graft. Preoperative genetic screening may guide intraoperative management to reduce postoperative complications.

Association between the A/A genotype at the lymphotoxin-alpha+250 site and increased mortality in children with positive blood cultures

INTRODUCTION

Tumor necrosis factor-alpha has been implicated in the hemodynamic manifestations of sepsis. Genetic polymorphisms located in the first intron of the lymphotoxin-alpha gene have been associated with increased secretion of tumor necrosis factor-alpha. We hypothesized that bacteremic children with the high secretor genotype, AA, have higher levels of tumor necrosis factor-alpha and a worse outcome.

METHODS

Genotypic analysis was performed in children with bacteremia using polymerase chain reaction amplification and restriction enzyme digestion. The serum tumor necrosis factor-alpha levels were measured by enzyme-linked immunosorbent assay technique.

RESULTS

Genotypic frequencies at the lymphotoxin-alpha+250 site were 11 of 34 (0.32) AA, 16 of 34 (0.47) GA, and 7 of 34 (0.21) GG. Serum tumor necrosis factor-alpha levels were 324 +/- 124 pg/mL in bacteremic children with the AA genotype at the lymphotoxin-alpha+250 site compared with 92 +/- 59 pg/mL in bacteremic children with the AG genotype (p < .001) and 92 +/- 21 pg/mL in bacteremic children with the GG genotype (p < .001). Eight of 11 bacteremic children with the AA genotype died compared with 3 of 16 bacteremic children with the GA genotype (p < .001) and zero of seven bacteremic children with the GG genotype (p < .001).

CONCLUSION

The AA genotype at the lymphotoxin-alpha+250 site is associated with higher serum tumor necrosis factor-alpha levels and a higher mortality in children with bacteremia.

Angiotensin-converting enzyme genotype and outcome in pediatric IgA nephropathy

Angiotensin-converting enzyme (ACE) I/D polymorphism has been implicated as a genetic marker for progression of glomerular disease. Studies of ACE genotypes in adults with IgA nephropathy (IgAN) have yielded conflicting results. We performed ACE genotyping on 79 patients with IgAN diagnosed prior to age 18 years who had either progressed to end-stage renal disease (ESRD) or are now more than 5 years post biopsy. Mean follow-up was 14.8 years for those with normal renal function. Forty-three (54.4%) subjects had normal renal function and a normal urinalysis at last evaluation. Sixteen (20%) progressed to ESRD and 1 has chronic renal insufficiency. Kaplan-Meier survival curves for progression to ESRD did not differ significantly for the ACE DD, ID, and II genotype groups (P=0.095, log-rank test). By univariate analysis, presence of hypertension and degree of proteinuria at diagnosis, and unfavorable histology but not ACE genotype, was significantly associated with progression to ESRD. In the Cox proportional hazards model that included grade of proteinuria, the ACE D allele was a significant independent predictor of outcome with a hazard ratio of 2.37 (P=0.031). Our data, while inconclusive, suggest that the ACE D allele may associate with poor outcome in pediatric IgAN.

Respiratory syncytial virus infections in the pediatric intensive care unit: clinical characteristics and risk factors for adverse outcomes

OBJECTIVES

To describe the clinical characteristics of infants admitted to a pediatric intensive care unit (PICU) with respiratory syncytial virus (RSV) infection, including the prevalence of indications for RSV passive antibody prophylaxis (as currently recommended by the American Academy of Pediatrics), and to identify risk factors that predict adverse outcomes among this population.

DESIGN

Retrospective medical record review.

SETTING

Tertiary care PICU.

PATIENTS

Children <2 yrs of age admitted to PICU for the management of RSV disease during the 1994-95, 1995-96, and 1996-97 RSV seasons.

MEASUREMENTS AND MAIN RESULTS

The medical records of 89 infants were reviewed. Of these, 55% were born before 36-wks gestation, 14% had chronic lung disease that required medical therapy within the previous 6 months, and 30% met at least one indication for RSV passive antibody prophylaxis. Seven infants had congenital heart disease, five had upper airway abnormalities, and six had various noncardiac congenital malformations. Logistic regression was used to determine which characteristics were associated with prolonged durations (>75th percentile) of mechanical ventilation, PICU stay, and hospital stay. Prolonged mechanical ventilation was associated with congenital heart disease (p = 0.014), chronic lung disease (p = 0.007), and noncardiac congenital malformations (p = 0.022). Only congenital heart disease was associated with prolonged PICU stay (p = 0.004) or prolonged hospital stay (p = 0.006). All of the infants with airway abnormalities had prolonged ventilator days, PICU days, and hospital days. Currently recommended indications for RSV passive antibody prophylaxis were not predictive of prolonged ventilation, PICU stay, or hospital stay.

CONCLUSIONS

A minority of infants admitted to our PICU for severe RSV disease meet currently recommended indications for RSV passive antibody prophylaxis. Risk factors that predict prolonged durations of ventilation, PICU stay, or hospital stay among this population include congenital heart disease, chronic lung disease, upper airway abnormalities, and noncardiac congenital malformations.

Increased frequency of the tumor necrosis factor-alpha-308 A allele in adults with human immunodeficiency virus dementia

Genetic polymorphisms in the regulatory regions of various cytokine genes influence the amount of cytokine produced in response to inflammatory stimuli. To determine whether such polymorphisms might play a role in human immunodeficiency virus (HIV) dementia, a disease process in which tumor necrosis factor (TNF)-alpha is believed to play a role, we analyzed HIV-infected adults with and without dementia and control populations for a polymorphic site located in the promoter region of the gene coding for TNF-alpha. The presence of the A allele at the TNF-alpha-308 site was overrepresented among adults with HIV dementia compared to those without dementia (0.28 vs 0.07; OR 5.5; 95% CI 1.8-17.0) and a healthy control population (0.28 vs 0.11). The increased frequency of the A allele in HlV-infected adults with dementia suggests that this locus may play a role in the pathophysiology of dementia and suggests a genetic predisposition for the development of HIV dementia.

Septic shock and respiratory failure in community-acquired pneumonia have different TNF polymorphism associations

Genetic factors are likely to contribute to the variable presentation of community-acquired pneumonia (CAP). The purpose of this prospective cohort study was to determine whether the LTalpha+250 (TNFbeta+250) and TNFalpha-308 gene polymorphisms are associated with different presentations of CAP. Septic shock (SS) was defined using American College of Chest Physicians/Society of Critical Care Medicine (ACCP-SCCM) criteria. Type I respiratory failure (T1RF) was defined as an O(2) saturation on room air of < 90% with a normal PCO(2). A total of 280 patients were genotyped; 31 had SS, 80 had T1RF. Genotype proportions are given in the order of AA/GA/ GG. The proportion of patients in each genotype developing SS was as follows: LTalpha+250 0.19/0.07/0.09 (p = 0.01 AA versus non-AA); TNFalpha-308 0.16/0.06/0.12 (p = NS). Carrying at least one AA (tumor necrosis factor [TNF] high secretor) genotype had an 18.0% risk of SS versus 6.8% (p = 0.006). GG homozygotes (TNF low secretors) at both loci had only a 2.9% risk of SS. Septic shock was associated with the LTalpha+250:TNFalpha-308 A:G haplotype but not the A:A haplotype, suggesting that LTalpha+250 is a marker, rather than a causative polymorphism. Carriage of the G:G haplotype had a significant protective effect against the development of septic shock (p = 0.011). T1RF was not associated with LTalpha+250 AA genotype. In the absence of septic shock, there was a significant trend to greater T1RF in patients with LTalpha+250 GG (TNFalpha hyposecretor) genotype (p = 0.03). Our finding of different genotype associations for SS and T1RF has important implications for immunotherapy in both CAP and sepsis, as well as for the definition of the systemic inflammatory response syndrome (SIRS).

Increased frequency of alleles associated with elevated tumor necrosis factor-alpha levels in children with Kawasaki disease

Genetic polymorphisms influence the magnitude of the cytokine response after an inflammatory stimulus. To determine whether such polymorphisms might play a role in Kawasaki disease (KD), we analyzed white and Japanese children with KD and control populations for two polymorphic loci in which the A allele is associated with high tumor necrosis factor-alpha secretion. The lymphotoxin-alpha+250 A/A genotype was overrepresented among white children with KD compared with controls (0.59 versus 0.36; p = 0.013). The tumor necrosis factor-alpha-308 A/G genotype was overrepresented among whites with KD who had coronary artery abnormalities compared with those with normal echocardiograms (0.36 versus 0.09; p = 0.044). No significant difference was seen at either locus between Japanese children with KD and Japanese controls. The increased frequency of the high secretor alleles in white children with KD suggests that these loci may be related to susceptibility to KD and to outcome after disease.

Routine chest radiographs in pediatric intensive care units

OBJECTIVES

To determine whether interventions were performed based on portable routine morning chest x-rays (CXRs) in pediatric intensive care unit (PICU) patients and to identify patient subgroups for whom the routine CXR is most useful.

DESIGN

Prospective multiinstitutional study. Setting. PICUs of 15 tertiary care hospitals. Patients. PICU patients who received a routine morning CXR were included in the study.

OUTCOME MEASURES

Recorded data included: weight, diagnosis, presence of active cardiopulmonary problems, length of stay, and number and type of devices. The number and types of interventions based on the interpretation of the CXR were recorded.

RESULTS

Five hundred twelve routine CXRs were evaluated. The majority of the routine chest radiographs were obtained on patients who were admitted for cardiovascular disease (195/512; 38%) or respiratory failure (186/512; 36%), and 465/512 of the routine CXRs (91%) were performed on patients with one or more devices. Two hundred thirty-one of the 512 routine CXRs (45%) resulted in 1 or more interventions. One hundred fifty-five of the 284 routine CXRs (55%) obtained in children </=10 kg resulted in one or more interventions, compared with 61/152 (40%) and 15/76 (20%) of routine CXRs obtained in children 10 to 40 kg and >/=40 kg, respectively. The frequency of interventions increased from 19% in children with no devices to >50% in children with 2 or more devices. One or more interventions were performed in 27% of routine CXRs when no active cardiopulmonary problems were present, compared with 51% of routine CXRs when active cardiopulmonary problems were present. Diagnosis and length of intensive care unit stay at the time the routine CXR was obtained did not affect the percentage of CXRs that resulted in interventions.

CONCLUSIONS

Routine CXRs are more likely to result in interventions in the smaller, critically ill child with one or more devices and if active cardiopulmonary problems are present.