Id |
Subject |
Object |
Predicate |
Lexical cue |
T1 |
0-160 |
Epistemic_statement |
denotes |
Polymorphisms in the mannose binding lectin-2 gene and acute respiratory distress syndrome * NIH Public Access NIH-PA Author Manuscript NIH-PA Author Manuscript |
T2 |
171-326 |
Epistemic_statement |
denotes |
Objective-The variant alleles in the mannose binding lectin-2 (MBL-2) gene have been associated with MBL deficiency and increased susceptibility to sepsis. |
T3 |
327-481 |
Epistemic_statement |
denotes |
We postulate that the variant MBL-2 genotypes are associated with increased susceptibility to and mortality in acute respiratory distress syndrome (ARDS). |
T4 |
680-1032 |
Epistemic_statement |
denotes |
Measurements and Main Results-Patients homozygous for the variant codon 54B allele (54BB) had worse severity of illness on admission (p = .007), greater likelihood of septic shock (p = .04), and increased odds of ARDS (adjusted odds ratio, 6.7; 95% confidence interval, 1.5-31) when compared with heterozygotes and homozygotes for the wild-type allele. |
T5 |
1033-1184 |
Epistemic_statement |
denotes |
This association with ARDS was especially strong among the 311 patients with septic shock (adjusted odds ratio, 12.0; 95% confidence interval, 1.9-74). |
T6 |
1185-1374 |
Epistemic_statement |
denotes |
Among the patients with ARDS, the 54BB genotype was associated with more daily organ dysfunction (p = .01) and higher mortality (adjusted hazard rate, 4.0; 95% confidence interval, 1.6-10). |
T7 |
1375-1577 |
Epistemic_statement |
denotes |
Development of ARDS and outcomes in ARDS did not vary significantly with variant alleles of codon -221, 52, and 57, but the power to detect an effect was limited secondary to the low allele frequencies. |
T8 |
1578-1672 |
Epistemic_statement |
denotes |
Conclusions-The MBL-2 codon 54BB genotype may be important in ARDS susceptibility and outcome. |
T9 |
1673-1750 |
Epistemic_statement |
denotes |
Additional studies are needed to confirm these findings in other populations. |
T10 |
1752-1926 |
Epistemic_statement |
denotes |
Although clinical predictors for the development to acute respiratory distress syndrome (ARDS) are well recognized, a minority of patients with these risks develop ARDS (1) . |
T11 |
1927-2061 |
Epistemic_statement |
denotes |
Genetic susceptibility to acute lung injury may explain the observed interindividual differences in risk and in outcomes (2) (3) (4) . |
T12 |
2753-2954 |
Epistemic_statement |
denotes |
The variant alleles in exon 1 and the X allele in the MBLXY polymorphism have been found to be associated with serum MBL deficiency especially in individuals homozygous for the variant alleles (8, 9) . |
T13 |
2955-3222 |
Epistemic_statement |
denotes |
In clinical studies, variant MBL-2 alleles have been associated with increased susceptibility to meningococcemia (10) , invasive pneumococcal infection (11) , hepatitis B (12, 13) , severe acute respiratory syndrome (14) , and other infections (8, 9, (15) (16) (17) . |
T14 |
3223-3506 |
Epistemic_statement |
denotes |
In critical illnesses, two small studies have found an association between the variant MBL-2 alleles and increased incidence of systemic inflammatory syndrome from both infectious and noninfectious causes, increased severity of sepsis, and/or increased mortality in sepsis (18, 19) . |
T15 |
3507-3680 |
Epistemic_statement |
denotes |
In both studies, the variant alleles were associated with serum MBL deficiency with the lowest levels found among those patients who were homozygous for the variant alleles. |
T16 |
3681-3807 |
Epistemic_statement |
denotes |
Genes that are important in sepsis are likely to be relevant in ARDS because of the many common links between sepsis and ARDS. |
T17 |
4038-4260 |
Epistemic_statement |
denotes |
We hypothesized that the X allele of the MBLXY polymorphism and the variant D, B, and C alleles of the codon 52, 54, and 57 in the MBL-2 gene are associated with increased susceptibility to and increased mortality in ARDS. |
T18 |
4599-4836 |
Epistemic_statement |
denotes |
Exclusion criteria included age <18, diffuse alveolar hemorrhage, chronic lung diseases, directive to withhold intubation, immunosuppression except if secondary to corticosteroid, and treatment with granulocyte colony-stimulating factor. |
T19 |
4947-5485 |
Epistemic_statement |
denotes |
Enrolled patients were screened daily for the primary outcome of ARDS as defined by respiratory failure requiring intubation and fulfillment of American-European Consensus Conference criteria for ARDS as follows (23, 24) : a) presence of hypoxemia as evidenced by PaO 2 /FIO 2 ≤200 mm Hg; b) presence of bilateral infiltrates on chest radiographs; and c) absence of left atrial hypertension as evidenced by pulmonary arterial occlusion pressure ≤18 mm Hg or lack of notation for congestive heart failure as a problem in the progress note. |
T20 |
7487-7762 |
Epistemic_statement |
denotes |
Haplotypes were generated from the genotype results using the Partition Ligation-Expectation Maximization (PL-EM) version 1.0 (26), as in other association studies (27) that reconstruct individual probabilities for individual phasing accuracy based on unphased genotype data. |
T21 |
8522-8596 |
Epistemic_statement |
denotes |
Backward selection algorithms were used to determine possible confounders. |
T22 |
9614-9781 |
Epistemic_statement |
denotes |
To evaluate whether the MODS score varied significantly by genotype during the course of ARDS, an interaction term between genotype and time was included in the model. |
T23 |
10233-10562 |
Epistemic_statement |
denotes |
Assuming an α-error of .05, 80% power, and genotype frequencies of 24% for the MBLXY X allele and 12%, 26%, and 3% for variant 52D, 54B, and 57C, respectively (9,31), a study with 212 cases and 442 controls would have a minimum detectable odds ratios of 1.6 for MBLXY and 1.9, 1.7, and 2.9 for codon 52, 54, and 57, respectively. |
T24 |
11948-12053 |
Epistemic_statement |
denotes |
However, this was not statistically significant (p = .4), given the smaller number of patients with ARDS. |
T25 |
12184-12280 |
Epistemic_statement |
denotes |
This is unlikely to be due to genotyping error as there was no discrepancy on repeat genotyping. |
T26 |
12281-12522 |
Epistemic_statement |
denotes |
However, controls in this study were not healthy, and patients homozygous for the codon 54B genotype were more likely to have septic shock on ICU admission as a predisposing injury for ARDS (eight of ten [80%] vs. 303 of 643 [47%]; p = .04). |
T27 |
12523-12675 |
Epistemic_statement |
denotes |
An association between the codon 54B genotype and the underlying condition among the controls may explain the deviation from Hardy Weinberg equilibrium. |
T28 |
13260-13551 |
Epistemic_statement |
denotes |
On multivariate analyses after adjustment for age, gender, APACHE III, septic shock, trauma, direct pulmonary injury, hematologic and hepatic failure, and transfusion, the codon 54B genotype was still significantly associated with development of ARDS (OR adj , 6.7; 95% CI, 1.5-31; p = .01). |
T29 |
13552-13756 |
Epistemic_statement |
denotes |
When the analysis was restricted to the 311 patients admitted to the ICU with septic shock, the association between the 54BB genotype and ARDS was even stronger (OR adj , 12.0; 95% CI, 1.9 -74; p = .008). |
T30 |
14053-14262 |
Epistemic_statement |
denotes |
However, the frequency of the variant alleles of MBL XY, codon 52, or codon 57 on the MBL-2 gene did not vary significantly with ARDS ( The four polymorphisms are in complete linkage disequilibrium (D' = 1.0). |
T31 |
14509-14588 |
Epistemic_statement |
denotes |
Only the ABAY haplotype was associated with the development of ARDS (Table 5) . |
T32 |
14928-15075 |
Epistemic_statement |
denotes |
However, non-survivors had significantly fewer ventilator-free days than survivors (median 0 days [25-75% 0-0] vs. 7 days [25-75% 2-14]; p < .001). |
T33 |
15436-15706 |
Epistemic_statement |
denotes |
Among controls, the codon 54BB genotype was not significantly associated with ICU mortality (HR adj , 7.4; 95% CI, 0.90-61.3), although the power to determine an association was limited given that there were only three patients with the BB genotype who did develop ARDS. |
T34 |
15707-16000 |
Epistemic_statement |
denotes |
ARDS patients homozygous for the variant codon 54B allele had a nonsignificant trend to greater severity of illness on admission (p = .08) and significantly greater daily multiple organ dysfunction score after development of ARDS even after adjustment for potentially important variables (Fig. |
T35 |
16006-16217 |
Epistemic_statement |
denotes |
On multivariate analysis, the codon 54BB genotype remained associated with increased mortality compared with ARDS patients who were homozygous for the wild-type A allele (HR adj , 4.0; 95% CI, 1.6-10; p = .003). |
T36 |
16430-16780 |
Epistemic_statement |
denotes |
In a study of prospectively enrolled ICU patients with clearly defined ARDS risk factors, we found significant associations between the BB genotype of the MBL-2 codon 54 polymorphism and increased severity of illness on admission, increased development of ARDS, more multiple organ failures after development of ARDS, and increased mortality in ARDS. |
T37 |
17032-17169 |
Epistemic_statement |
denotes |
Using critically ill controls who have the opportunity to develop the outcome is more clinically relevant than using healthy individuals. |
T38 |
17170-17370 |
Epistemic_statement |
denotes |
Although this may bias the study toward the null, using at-risk controls also reduces the confounding from any possible association between the gene and the risk condition such as sepsis or pneumonia. |
T39 |
17371-17688 |
Epistemic_statement |
denotes |
Several other studies have found the variant O allele (codon 52D, codon 54B, or codon 57C allele) to be associated with infections, systemic inflammatory responses, or other disease states in a codominant (AO and OO vs. AA genotype) (8, 15, 18, 34, 35) or recessive model (OO vs. AO and AA genotype) (11, 10, 9, 36) . |
T40 |
17689-17801 |
Epistemic_statement |
denotes |
We did not find any associations between ARDS and the MBLXY X allele or the variant alleles for codon 52 and 57. |
T41 |
17802-17952 |
Epistemic_statement |
denotes |
However, it is important to note that, given the low variant allele frequency, our power to detect an association for the codon 52 and 57 was limited. |
T42 |
17953-18018 |
Epistemic_statement |
denotes |
Nevertheless, codon 54 may be very significant in the MBL-2 gene. |
T43 |
18365-18513 |
Epistemic_statement |
denotes |
Of the four polymorphisms, codon 54B has been independently found to be associated with increased susceptibility to infection (12, 14, 16, 17, 38) . |
T44 |
18514-18644 |
Epistemic_statement |
denotes |
It is not clear why patients with the codon 54 BB genotype may be at increased risk of developing and dying of ARDS in this study. |
T45 |
18645-18744 |
Epistemic_statement |
denotes |
Homozygotes for the variant MBL-2 alleles have been associated with a low circulating MBL (9, 18) . |
T46 |
18745-18863 |
Epistemic_statement |
denotes |
It is possible that patients with low MBL may be more susceptible to multilobar pneumonia or more severe septic shock. |
T47 |
18864-18992 |
Epistemic_statement |
denotes |
Alternatively, it is possible that MBL may influence the inflammatory response to the initial injury in critical illnesses (7) . |
T48 |
18993-19196 |
Epistemic_statement |
denotes |
MBL has been shown to decrease tumor necrosis factor release (39) and stimulate the production of anti-inflammatory cytokines such as interleukin-10 (40), but MBL modulation of TNF may be dose dependent. |
T49 |
19390-19636 |
Epistemic_statement |
denotes |
It is possible that in critically ill patients with the low or defective MBL-producing genotypes, circulating MBL may not be sufficiently high or effective enough to switch from enhancement to suppression of the proinflammatory cytokine response. |
T50 |
19637-19791 |
Epistemic_statement |
denotes |
Unfortunately, the functional significance of the MBL-2 polymorphisms and the inflammatory response of these patients in this study could not be examined. |
T51 |
19792-19932 |
Epistemic_statement |
denotes |
Additional studies are clearly needed to investigate the possible mechanisms by which MBL-2 genotypes may be important in acute lung injury. |
T52 |
20079-20126 |
Epistemic_statement |
denotes |
This is unlikely to be due to genotyping error. |
T53 |
20325-20523 |
Epistemic_statement |
denotes |
It is more likely that deviation from Hardy-Weinberg occurred because of a possible association between the codon 54 polymorphism and the underlying condition requiring ICU admission such as sepsis. |
T54 |
20524-20670 |
Epistemic_statement |
denotes |
Indeed, patients in this study who were homozygous for the variant codon 54B allele were more likely to have septic shock on admission to the ICU. |
T55 |
20671-20836 |
Epistemic_statement |
denotes |
The association found between the codon 54 MBL-2 polymorphism and ARDS cannot be attributed to this association between 54B and septic shock, a risk factor for ARDS. |
T56 |
20837-20984 |
Epistemic_statement |
denotes |
The association between the 54BB genotype and ARDS was actually strengthened when the analyses were restricted to those patients with septic shock. |
T57 |
21156-21232 |
Epistemic_statement |
denotes |
However, the findings in this report are unlikely to be due to type I error. |
T58 |
21233-21375 |
Epistemic_statement |
denotes |
The polymorphism was chosen a priori as a candidate in ARDS based on previous studies supporting its role in infection and critical illnesses. |
T59 |
21376-21473 |
Epistemic_statement |
denotes |
The results are consistent with our hypothesis and with previous reports on infection and sepsis. |
T60 |
21637-21758 |
Epistemic_statement |
denotes |
Nevertheless, as is true of all genetic association studies, our findings will need to be confirmed in other populations. |
T61 |
21759-21808 |
Epistemic_statement |
denotes |
We recognize some other limitations to our study. |
T62 |
21897-22101 |
Epistemic_statement |
denotes |
Because of the study design, the results may not be generalizable to the community setting, to immunocompromised hosts or patients without risk factors for ARDS, or with different clinical risks for ARDS. |
T63 |
22102-22296 |
Epistemic_statement |
denotes |
In addition, the analyses were restricted to Caucasians, which reduces the possibility of confounding from ethnicity (42) but does not permit extrapolation of the results to other ethnic groups. |
T64 |
22297-22421 |
Epistemic_statement |
denotes |
We report an association between the MBL-2 codon 54 genotype and severity of illness, septic shock, and development of ARDS. |
T65 |
22422-22527 |
Epistemic_statement |
denotes |
The MBL-2 codon 54 genotype may also be associated with multiple organ dysfunction and mortality in ARDS. |
T66 |
22528-22629 |
Epistemic_statement |
denotes |
Additional studies are needed to confirm these findings in other populations with other risk factors. |
T67 |
23360-23763 |
Epistemic_statement |
denotes |
Daily Brussels multiple organ dysfunction score for each day after development of acute respiratory distress syndrome (ARDS) for the 212 patients with ARDS after adjustment for potentially important variables such as age, trauma as a risk factor for ARDS, Acute Physiology and Chronic Health Evaluation III scores, history of treatment with corticosteroids, liver failure, transfusion, and septic shock. |