Association of cystic fibrosis transmembrane conductance regulator gene variants with acute lung injury in African American children with pneumonia*.

OBJECTIVES: The cystic fibrosis transmembrane conductance regulator regulates fluid balance in alveolar epithelial cells and appears to modulate the inflammatory response. To determine whether more severe lung injury in children who develop community-acquired pneumonia is associated with variations known to affect function in the gene coding for cystic fibrosis transmembrane conductance regulator. DESIGN: A prospective cohort genetic association study of lung injury in children with community-acquired pneumonia. SETTING: Three major tertiary care children's hospitals. SUBJECTS: Caucasian and African American children with community-acquired pneumonia either evaluated in the emergency department or admitted to the hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Caucasian and African American children with pneumonia were genotyped for the most common variants reported to affect cystic fibrosis transmembrane conductance regulator function, the p.508del mutation, the (TG)mTn variable repeat region, and the M470V polymorphism in the cystic fibrosis transmembrane conductance regulator gene. Genotypes and haplotypes were determined, and the association of high-risk alleles or high-risk haplotypes (defined as the presence of at least one variant known to decrease the level of functional cystic fibrosis transmembrane conductance regulator) with the need for mechanical ventilation or the development of acute lung injury was evaluated. Forty-two children in the Caucasian cohort (n = 304) required mechanical ventilation; 32 developed acute lung injury. Forty-three children in the African American cohort (n = 474) required mechanical ventilation; 29 developed acute lung injury. In African American children, high-risk (TG)mTn alleles known to result in decreased levels of functional cystic fibrosis transmembrane conductance regulator were associated with the need for mechanical ventilation (p = .0013) and the development of acute lung injury (p = .0061). Multivariable analysis demonstrated that high-risk (TG)mTn alleles were independently associated with mechanical ventilation (odds ratios = 3.19; 95% confidence interval, 1.63-6.26) and acute lung injury (odds ratios = 3.36; 95% confidence interval, 1.50-7.53) in African American children. CONCLUSION: Genetic variation in cystic fibrosis transmembrane conductance regulator is associated with acute lung injury in African American children with community-acquired pneumonia.

Determination of neutrophil antigen HNA-3a and HNA-3b genotype frequencies in six racial groups by high-throughput 5' exonuclease assay.

BACKGROUND: People with the human neutrophil antigen (HNA)-3b/3b type can make HNA-3a antibodies, which have been reported to cause immune neutropenia disorders and are especially prone to cause severe cases of transfusion-related acute lung injury. However, knowledge of HNA-3 allele frequencies outside Caucasian populations is limited. We developed a high-throughput genotyping assay and determined the HNA-3a/3b genotype frequencies in six different racial and ethnic groups. STUDY DESIGN AND METHODS: Genotyping utilized TaqMan 5' exonuclease chemistry and real-time polymerase chain reaction. A total of 742 DNA samples from six different racial and ethnic groups were genotyped for HNA-3a and HNA-3b. RESULTS: The genotyping assay showed 100% sensitivity and specificity compared to sequencing and phenotyping and had high throughput. A significant percentage of Caucasians (6.5%), Han Chinese (16%), and Asian Indians (6%) typed HNA-3b/3b, but only a small percentage of Hispanics (1%) and no African or Native Americans. CONCLUSIONS: The HNA-3 genotyping assay had high sensitivity, specificity, and sample throughput. HNA-3b/b genotype results determined for 742 individuals representing six different racial and ethnic groups showed that there could be a significant risk of producing anti-HNA-3a in Chinese, as well as in Caucasian and Asian Indian blood donor populations, but a very low risk in Hispanic, African, or Native American populations.

Type 2 deiodinase and host responses of sepsis and acute lung injury.

The role of thyroid hormone metabolism in clinical outcomes of the critically ill remains unclear. Using preclinical models of acute lung injury (ALI), we assessed the gene and protein expression of type 2 deiodinase (DIO2), a key driver for synthesis of biologically active triiodothyronine, and addressed potential association of DIO2 genetic variants with ALI in a multiethnic cohort. DIO2 gene and protein expression levels in murine lung were validated by microarrays and immunoblotting. Lung injury was assessed by levels of bronchoalveolar lavage protein and leukocytes. Single-nucleotide polymorphisms were genotyped and ALI susceptibility association assessed. Significant increases in both DIO2 gene and D2 protein expression were observed in lung tissues from murine ALI models (LPS- and ventilator-induced lung injury), with expression directly increasing with the extent of lung injury. Mice with reduced levels of DIO2 expression (by silencing RNA) demonstrated reduced thyroxine levels in plasma and increased lung injury (increased bronchoalveolar lavage protein and leukocytes), suggesting a protective role for DIO2 in ALI. The G (Ala) allele of the Thr92Ala coding single-nucleotide polymorphism (rs225014) was protective in severe sepsis and severe sepsis-associated ALI after adjustments for age, sex, and genetic ancestry in a logistic regression model in European Americans. Our studies indicate that DIO2 is a novel ALI candidate gene, the nonsynonymous Thr92Ala coding variant of which confers ALI protection. Increased DIO2 expression may dampen the ALI inflammatory response, thereby strengthening the premise that thyroid hormone metabolism is intimately linked to the integrated response to inflammatory injury in critically ill patients.

The influence of genetic variation in surfactant protein B on severe lung injury in African American children.

OBJECTIVE: To determine whether genetic variations in the gene coding for surfactant protein B are associated with lung injury in African American children with community-acquired pneumonia. DESIGN: A prospective cohort genetic association study of lung injury in children with community-acquired pneumonia. SETTING: Two major tertiary care children's hospitals. SUBJECTS: African American children with community-acquired pneumonia (n = 395) either evaluated in the emergency department or admitted to the hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Three hundred ninety-five African American children (14 days to 18 yrs of age) with community-acquired pneumonia were enrolled. Thirty-seven patients required mechanical ventilation and 26 of these were diagnosed with acute lung injury or acute respiratory distress syndrome. Genotyping was performed on seven linkage disequilibrium-tag single nucleotide polymorphisms in the surfactant protein B gene. Univariate analysis demonstrated two linkage disequilibrium-tag single nucleotide polymorphisms, rs1130866 (also known as SP-B + 1580 C/T) and rs3024793, were associated with the need for mechanical ventilation in African American children (p = .016 and p = .030, respectively). Multivariable analysis indicated that both of these single nucleotide polymorphisms are independently associated with need for mechanical ventilation (p = .040 and p = .012, respectively) as was rs7316 when its interaction with age was considered (p = .015). Multivariable analysis examining acute lung injury demonstrated a significant association of rs7316 with acute lung injury (p = .031). Haplotype analysis was also performed. Two haplotypes, GTGCGCG and ATATAAG, were associated with need for mechanical ventilation using either univariate (p = .041 and p = .043, respectively) or multivariable analysis (odds ratios of 2.62, p = .048, and 3.12, p = .033, respectively). CONCLUSIONS: Genetic variations in the gene coding for surfactant protein B are associated with more severe lung injury as indicated by the association of specific single nucleotide polymorphism genotypes and haplotypes with the need for mechanical ventilation in African American children with community-acquired pneumonia.

Ethnic and age-specific acute lung injury/acute respiratory distress syndrome risk associated with angiotensin-converting enzyme insertion/deletion polymorphisms, implications for COVID-19: A meta-analysis.

BACKGROUND: The reported association between an insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene and the risk for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) remains controversial despite the publication of four meta-analyses on this topic. Here, we updated the meta-analysis with more studies and additional assessments that include adults and children within the context of the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Sixteen articles (22 studies) were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using three genetic models (allele, recessive and dominant), in which ARDS patients were compared with non-ARDS patients (A1) and healthy controls (A2). Mortality outcomes were also assessed (A3). The influence of covariates was examined by meta-regression. Bonferroni correction was performed for multiple pooled associations. Subgroup analyses based on ethnicity (Asians, Caucasians) and life stage (adults, children) were conducted. Heterogeneity was addressed with outlier treatment. RESULTS: This meta-analysis generated 68 comparisons, 21 of which were significant. Of the 21, four A1 and three A3 highly significant (Pa = 0.00001-0.0008) outcomes withstood Bonferroni correction. For A1, allele and recessive associations were found in overall (OR 0.49, 95% CI 0.39-0.61), Caucasians (OR 0.46, 95% CI 0.35-0.61) and children (ORs 0.49-0.66, 95% CI 0.33-0.84) analyses. For A3, associations were found in overall (dominant: OR 0.45, 95% CI 0.29-0.68) and Asian subgroup (allele/ dominant: ORs 0.31-0.39, 95% CIs 0.18-0.63) analyses. These outcomes were either robust, or statistically powered or both and uninfluenced by covariates. CONCLUSIONS: Significant associations of the ACE I/D polymorphism with the risk of ALI/ARDS were indicated in Caucasians and children as well as in Asians in mortality analysis. These findings were underpinned by high significance, high statistical power and robustness. ACE genotypes may be useful for ALI/ARDS therapy for patients with COVID-19.

Age-, sex-, and race-based differences among patients enrolled versus not enrolled in acute lung injury clinical trials.

OBJECTIVE: Little is known about the participation of racial/ethnic minorities, women, and the elderly into critical care clinical trials. We sought to characterize the representation of racial and ethnic minorities, women, and older patients in clinical trials of patients with acute lung injury and to determine the reasons for nonenrollment. DESIGN, SETTING, AND PATIENTS: We performed a cross-sectional analysis of pooled screening logs from 44 academic hospitals participating in three multicentered, randomized, controlled trials conducted by the Acute Respiratory Distress Syndrome Network from 1996 to 2005. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We calculated odds ratios of enrollment for age, sex, racial groups, and the odds ratio for the presence of each exclusion criterion by age, sex, and race adjusted for demographics, acute lung injury risk factor, study, and study center. A total of 10.4% of 17,459 screened patients with acute lung injury were enrolled. The median (range) enrollment by center was 15% (2% to 88%). Older patients of both sexes were less likely to be enrolled, but older women were more likely to be enrolled than older men. The adjusted odds ratio (95% confidence interval) for enrollment among men > or =75 yrs of age was 0.59 (0.45 to 0.77) and for women > or =75 yrs of age was 0.45 (0.32 to 0.62) compared with men <35 yrs of age. There were no differences in the likelihood of enrollment among all racial/ethnic groups. Older patients and men were less likely to be enrolled because of medical comorbidity. Among all patients who were not enrolled, black patients and their families refused participation more often than white patients. CONCLUSIONS: Older patients are less likely to be enrolled in acute lung injury clinical trials. There is no evidence that women or racial/ethnic minorities are underrepresented in acute lung injury clinical trials.

Racial and ethnic disparities in mortality from acute lung injury.

OBJECTIVE: Little is known about the influence of race and ethnicity on mortality from acute lung injury (ALI). We sought to determine whether black race or Hispanic ethnicity is independently associated with mortality among patients with ALI. DESIGN: Retrospective cohort study of patients enrolled in the Acute Respiratory Distress Syndrome Network randomized controlled trials. SETTING: Adult intensive care units participating in the Acute Respiratory Distress Syndrome Network trials. PATIENTS: A total of 2362 mechanically ventilated patients (1715 white, 449 black, and 198 Hispanic) with ALI. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 60-day mortality. A secondary outcome was number of ventilator-free days. Crude mortality was 33% for both blacks and Hispanics compared with 27% for whites (p = 0.02). After adjusting for demographic and clinical covariates, the association between race/ethnicity and mortality persisted (odds ratio [OR] = 1.42; 95% confidence interval [CI] 1.10-1.84 for blacks; OR = 1.94; 95% CI, 1.36-2.77 for Hispanics; OR = 1.00 for whites). After adjustment for severity of illness (Acute Physiology Score), black race was no longer significantly associated with mortality (OR = 1.25; 95% CI, 0.95-1.66), whereas the association with Hispanic ethnicity persisted (OR = 2.00; 95% CI, 1.37-2.90). Hispanics had significantly fewer ventilator-free days compared with whites after adjustment for demographic and clinical covariates (mean difference in days = -2.3; 95% CI -3.90 to -0.70). CONCLUSIONS: Black and Hispanic patients with ALI have a significantly higher risk of death compared with white patients. This increased risk seemed to be mediated by increased severity of illness at presentation for blacks, but was unexplained among Hispanics.

Sex, race, and the development of acute lung injury.

BACKGROUND: Prior studies suggest that mortality differs by sex and race in patients who develop acute lung injury (ALI). Whether differences in presentation account for these disparities remains unclear. We sought to determine whether sexual and racial differences exist in the rate of ALI development and ALI-related mortality after accounting for differences in clinical presentations. METHODS: This was a multicenter, observational cohort study of 5,201 patients at risk for ALI. Multivariable logistic regression with adjustment for center-level effects was used to adjust for potential covariates. RESULTS: The incidence of ALI development was 5.9%; in-hospital mortality was 5.0% for the entire cohort, and 24.4% for those patients who developed ALI. Men were more likely to develop ALI compared to women (6.9% vs 4.7%, P , .001) and had a nonsignificant increase in mortality when ALI developed (27.6% vs 18.5%, P 5 .08). However, after adjustment for baseline imbalances between sexes these differences were no longer significant. Black patients, compared to white patients, presented more frequently with pneumonia, sepsis, or shock and had higher severity of illness. Black patients were less likely to develop ALI than whites (4.5% vs. 6.5%, P 5 .014), and this association remained statistically significant after adjusting for differences in presentation (OR, 0.66; 95 % CI, 0.45-0.96). CONCLUSIONS: Sex and race differences exist in the clinical presentation of patients at risk of developing ALI. After accounting for differences in presentation, there was no sex difference in ALI development and outcome. Black patients were less likely to develop ALI despite increased severity of illness on presentation.

Angiotensin-converting enzyme polymorphism affects outcome of local Chinese with acute lung injury.

INTRODUCTION: Acute Lung Injury (ALI) with genetic predisposition is fatal. Relationship between angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism and the prognosis of local Chinese patients with ALI was investigated; meanwhile, the mechanisms involved were explored. METHODS: 101 ALI patients, 408 non-ALI patients and 236 healthy blood donors were enrolled. ACE I/D polymorphism was detected by polymerase chain reaction, then ACE genotype (II, ID, DD) and allele (I, D) frequencies were compared. Clinical data of ALI patients was calculated. Also, peripheral blood mononuclear cells (PBMC) were isolated from healthy volunteers with different ACE genotypes. Lipopolysaccharide (LPS)-induced ACE gene mRNA expression and ACE activity was measured. RESULTS: There was no significant difference in the frequencies of the genotypes and alleles. Acute Physiology and Chronic Health Evaluation (APACHE) II score was higher in DD subgroup than in II subgroup (19.7 ± 8.7 and 15.6 ± 6.2; P < 0.05). The 28-day mortality was significantly different (17.4%, 26.8%, and 64.3% for II, ID, and DD; P = 0.013). DD genotype was the independent prognostic factor for 28-day outcome. Furthermore, LPS-induced ACE mRNA expression and ACE activity from PBMC in DD genotype subgroup were both significantly higher than those in the other two subgroups. CONCLUSIONS: ACE I/D polymorphism is a prognostic factor for ALI. Patients with the DD genotype have higher mortality of ALI. Polymorphism influences the expression of ACE gene in LPS-stimulated PBMC, DD genotype leads to higher level of mRNA and enzyme activity. It may be one of the mechanisms involved.

The influence of race on the development of acute lung injury in trauma patients.

BACKGROUND: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are sequelae of severe trauma. It is unknown if certain races are at greater risk of developing ALI/ARDS, and once established, if there are racial differences in the severity of lung injury or mortality. METHODS: Retrospective cohort study of 4,397 trauma patients (1,831 Caucasians, 871 African-Americans, 886 Hispanics, and 809 Asian/Pacific Islanders) requiring intensive care unit (ICU) admission between 1996 and 2007 at an urban Level I trauma center. RESULTS: African-American patients were most likely to present in shock with penetrating trauma and receive a massive transfusion. The incidence of ALI/ARDS was similar by race (P = .99). Among patients who developed ALI/ARDS, there was no evidence to support a difference in partial pressure of oxygen in arterial blood to fraction of inspired oxygen (Pao(2)/Fio(2)) (P = .33), lung injury score (P = .67), or mortality (P = .78) by race. CONCLUSIONS: Despite differences in baseline characteristics, the incidence of ALI/ARDS, severity of lung injury, and mortality were similar by race.