|Year : 2018 | Volume
| Issue : 3 | Page : 987-993
Serum mannose-binding lectin as a biomarker in neonatal sepsis
Fady M El-Gendy1, Seham A Khodeer2, Hanan M Elsayed1, Sabrin A Elsayed1
1 Department of Pediatrics, Faculty of Medicine, El-Menoufiya University, Shebeen El-Koame City, El-Menoufiya Governorate, Egypt
2 Department of b Clinical Pathology, Faculty of Medicine, El-Menoufiya University, Shebeen El-Koame City, El-Menoufiya Governorate, Egypt
|Date of Submission||12-Feb-2017|
|Date of Acceptance||18-Apr-2017|
|Date of Web Publication||31-Dec-2018|
Sabrin A Elsayed
Berket Elsaba City, El-Menoufiya
Source of Support: None, Conflict of Interest: None
The aim of thi s study was to evaluate the levels of mannose-binding lectin (MBL) in neonates to determine the relation between MBL deficiency and the development of sepsis.
The MBL is a member of the collection family that is produced by the liver as an acute-phase protein. MBL activates macrophages, enhances phagocytosis, and contributes toward complement activation. Low serum MBL levels increase the risk of infections, especially if associated with other conditions such as immune deficiencies of various origins. Neonates are considered to be immunocompromised because their adaptive immunity has not yet been developed.
Patients and methods
This case–control study was carried out on 86 neonates classified into two groups: 45 neonates diagnosed with sepsis and 41 healthy neonates with no clinical signs or laboratory evidence of sepsis who were enrolled as a control group. Assessment of history, clinical examination, and investigations (complete blood count, C-reactive protein, blood culture, MBL levels) were performed for all neonates.
The mean MBL serum level was found to be lower in the septic group (0.49 ± 0.1) than the control group (1.4 ± 0.3) with high statistical significance.
Low MBL serum levels are related to the development of sepsis.
Keywords: biomarker, mannose-binding lectin, neonatal sepsis
|How to cite this article:|
El-Gendy FM, Khodeer SA, Elsayed HM, Elsayed SA. Serum mannose-binding lectin as a biomarker in neonatal sepsis. Menoufia Med J 2018;31:987-93
|How to cite this URL:|
El-Gendy FM, Khodeer SA, Elsayed HM, Elsayed SA. Serum mannose-binding lectin as a biomarker in neonatal sepsis. Menoufia Med J [serial online] 2018 [cited 2019 Jan 22];31:987-93. Available from: http://www.mmj.eg.net/text.asp?2018/31/3/987/248757
| Introduction|| |
Neonatal sepsis represents a major complication of the neonatal period. Its beginning may be slow and characterized by subtle, late, and unspecific symptoms in some cases, but fulminant sepsis with quick deterioration in neonates' clinical status may also occur. Under both circumstances, an increased risk of neonatal death is reported among preterm and term neonates.
As the early detection of neonates at risk of sepsis could increase the therapeutic window and improve neonatal outcomes, several markers of sepsis have been investigated over the last few years as possible tools to enable an early identification.
The use of noninvasive laboratory biomarkers has become a key element in clinical practice throughout the last decades. The research of new biological markers enables an early identification of neonates at risk of neonatal diseases, allowing close monitoring of the disease and providing information on prognosis.
The WHO, together with the United Nations and the International Labor Organization, defined a biomarker as ‘any substance, structure, or process that can be measured in the body or its products and influences or predicts the incidence of outcome or disease’.
The MBL is a member of the collection family, which is produced by the liver as an acute-phase protein. MBL binds to a wide range of pathogens including bacteria, viruses, and fungi.
MBL activates macrophages, enhances phagocytosis, and contributes toward complement activation.
Low serum MBL levels increase the risk of infections, especially if associated with other conditions such as immune deficiencies of various origins. Low serum MBL concentrations have also been reported among neonates with sepsis, suggesting a possible role of MBL as a biomarker for the early identification of neonates at risk of infection.
A prospective observational study was carried out at our institution, including 365 critically ill neonates, and it was found that the median MBL serum concentrations were significantly lower among infected neonates than among uninfected neonates. Moreover, low MBL levels on admission increased the risk of infection, independent of gestational age and invasive procedures. Nevertheless, MBL levels on admission and the peak levels during infection were not associated with death.
It should be underlined that a significant interindividual variability in serum MBL concentrations has been reported. More specifically, particularly low MBL levels have been detected among preterm neonates.
The aim of this study was to evaluate the levels of mannose-binding lectin (MBL) in neonates to determine the relation between MBL deficiency and the development of sepsis
On the basis of a past review of the literature, Wahab and Saeed, sample size has been calculated at 80% power and 95% confidence interval. This required 45 participants for every single group. Among the controls, four cases dropped out, resulting in a total of 45 patients and 41 controls.
| Patients and Methods|| |
This prospective case–control study was carried out on 86 neonates enrolled from the neonatal ICUs of Obstetrics and Gynecology Department at Benha Teaching Hospital during the period from November 2015 to March 2016. An informed consent was obtained from the parents before the enrollment of the neonates in the study.
Neonates were divided into two groups
The case group
This group included 45 neonates diagnosed with sepsis (16 males and 29 females) according to clinical findings and laboratory investigations.
The control group
This group included 41 healthy neonates (20 males and 21 females) with no clinical signs or laboratory evidence of sepsis.
Neonates were excluded from the study if they had neonatal asphyxia, metabolic diseases, congenital malformations, and dysmorphic features and were born to diabetic mothers.
Careful assessment of history was performed including maternal, obstetric, and perinatal history. In addition, birth weight measurement and assessment of gestational age were performed. Newborns were examined for any clinical features of sepsis such as lethargy, hypotonia, fever, tachycardia, abdominal distention, retractions, grunting, hypotension, delayed capillary refill, hypoglycemia, pallor, hepatomegaly, apnea, abnormal skin color, bradycardia, sclerema, shock, and features of disseminated intravascular coagulation, and from these data, the clinical sepsis score was determined.
Blood samples were withdrawn from all neonates by venipuncture under aseptic conditions within the first 24 h of admission.
Two ml venous blood was collected in a plain tube and was allowed to clot for 30 min. Samples were then centrifuged for 15 min at ~3000 rpm. The sera were separated and stored at −20°C until the time of the assay to estimate the MBL serum level using an enzyme-linked immuno-sorbent assay technique (Bay Bio Human MBL ELIZA Kit; The Protein Array Pioneer Company, Baltimore, USA).
Complete blood count at the time of diagnosis was performed on Coulter Counter Gen (Coulter Electronics Corporation, Hielach, Florida, USA). Differential leukocytic count was performed on Leishman-stained peripheral blood smears and from these data, the hematological sepsis score was determined.
Blood samples were obtained at the time of presentation of sepsis. Aerobic and anaerobic cultures were performed on blood agar plates at 10% CO2 and on MacConkey agar plates. True bacteremia was considered when the blood culture was positive within 72 h. If no growth was detected, the samples were incubated up to 10 days with further subcultures every other day on solid media. If no growth appeared after 10 days of incubation, blood culture was considered negative. An antibiotic sensitivity test was performed using the Kirby Baur technique.
The C-reactive protein (CRP) serum level was assessed using the slide latex agglutination test (1268 N, kit provided by Teco diagnosis, Lakeview Ave Anaheim, California, USA). It was considered positive when the titer was more than 6 mg/l.
All data were collected, tabulated, and statistically analyzed using SPSS 19.0 for windows (SPSS Inc., Chicago, Illinois, USA) and MedCalc 13 for windows (MedCalc Software BVBA, Ostend, Belgium).
| Results|| |
The characteristics of the neonates studied are listed in [Table 1]. The case group included 45 neonates diagnosed with sepsis, with a mean gestational age of 36.47 ± 2.138 weeks and a mean birth weight of 2.81 ± 0.8 kg. The control group included 41 healthy neonates with a mean gestational age of 37.15 ± 1.47 weeks and a mean birth weight of 2.8 ± 0.5 kg. There was no significant difference in gestational age, birth weight, sex, and mode of delivery between both groups. There was a significant decrease in the Apgar score at 1 min and a highly significant decrease in the Apgar score at 5 min in the case group.
|Table 1: Comparison between cases and controls in terms of their characteristics|
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Details of the clinical manifestations suggestive of sepsis in the case group are shown in [Table 2]. The most common presenting symptom was as follows: 100% of cases had O2 requirements, 95.6% developed respiratory distress, 93.3% had petechiae, 77.8% had mottling, 55.6% of cases had poor suckling reflex, 46.7% developed hypotonia, 28.9% were lethargic, 13.3% had jaundice, 8.9% had cyanosis, 11.1% had abdominal distention, 13.3% had hepatosplenomegaly, and 8.9% had temperature instability. CRP was positive in 39 (86.7%) neonates in the case group, with a highly significant difference between the two groups, P = 0.001.
There were significant differences between the case group and the control group in platelet count, immature polymorph nuclear leukocytes, immature/total neutrophil ratio, immature/mature neutrophil ratio, degenerative changes in neutrophils, blood culture, and CRP [Table 3].
|Table 3: Comparison of the case and control groups in terms of their laboratory data|
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There were significant differences between the case group and the control group in hematological and clinical sepsis scores, P = 0.001 [Table 4].
|Table 4: Comparison of the case and control groups in hematological and clinical sepsis scores|
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The mean value of MBL levels in the case group was 0.49 μg/ml and that in the control group was 1.4 μg/ml. MBL levels in the case group had a median value of 0.5 μg/ml, SD of 0.1 μg/ml, whereas the control group had a median value of 1.4 μg/ml, SD of 0.39 μg/ml and range 1.5 μg/ml. Statistical results of both groups showed a highly significant difference, with P = 0.001 [Table 5] and [Figure 1].
|Table 5: Comparison of the case and control groups in serum mannose-binding lectin levels|
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|Figure 1: Comparison between the case and control groups in terms of mannose-binding lectin (MBL) levels.|
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Comparisons between the mean values of serum MBL in cases with positive and negative blood cultures in the case group are shown in [Table 6] and [Figure 2] and [Figure 3].
|Table 6: Comparison between serum mannose-binding lectin in cases with positive and negative blood cultures in the case group|
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|Figure 2: Comparison between serum mannose-binding lectin (MBL) in cases with positive and negative blood cultures in the case group.|
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|Figure 3: Receiver operating characteristic (ROC) curve for detection the best cutoff point of serum mannose-binding lectin in the studied group.|
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| Discussion|| |
MBL is a plasma protein that plays an important role in the innate immune defense. MBL activates the lectin pathway of the complement system by binding to various microorganisms. This leads to opsonization and enhanced phagocytosis.
Circulating MBL plasma levels are determined genetically and may vary between 0 and 10 μg/ml.
Low MBL levels were found at birth in neonates with nosocomial sepsis.
In the present study, the MBL level was found to be lower in the septic group (mean: 0.49 μg/ml, median: 0.5 μg/ml, SD: 0.1 μg/ml, and range; 0.47 μg/ml) compared with the control group (mean: 1.4 μg/ml, median: 1.4 μg/ml, SD: 0.39 μg/ml, and range: 1.5 μg/ml). Statistical test results between both groups showed a significant difference, with P = 0.001. This result is similar to a study carried out by Özkan et al., who obtained a median value of MBL levels in infants with neonatal sepsis that was significantly lower than those without sepsis, with P less than 0.05. A study by Frakking et al. found that early-onset neonatal sepsis (EONS) in infants with low MBL levels is more frequent than that in the EONS infants with normal MBL levels.
In the current study, it was found that lower gestational age was not significantly associated with increased frequency of sepsis. This result is similar to that reported by Frakkling et al., who found no statistically significant difference between preterm and full-term groups in MBL levels. In contrast, some studies such as the study carried out by de Bendetti et al. showed that MBL levels were related to gestational age. Neonates with gestational age above 32 weeks had significantly higher MBL levels than those with gestational age below 32 weeks. Thus, they concluded that low MBL levels in neonates may also be secondary to a maturational defect, possibly involving the liver secretory capacity, that is, prematurity is associated with insufficient MBL production by the liver. In our study, this result may be because of the small sample of the studied group.
In the current study, there was no significant difference between the case and control groups in terms of birth weight. This result is similar to the study of Lau et al. that showed that the MBL level was not affected by birth weight, suggesting that small for gestational age preterm neonates have similar MBL levels to appropriate for gestational age preterm neonates.
In our study, mode of delivery was not significantly associated with increased frequency of sepsis. Mathai et al. and Oncel et al. found the same result. In contrast, our results were not in agreement with those of Stoll et al. and Fanaroff et al., who observed that babies born by vaginal delivery were more likely to have EONS than those delivered by cesarean section. This may be related to good sterilization and intrapartum chemoprophylaxis, which markedly decreased the risk of sepsis in neonates delivered by cesarean section.
In this study, the frequency of sepsis did not differ significantly between males and females. This is in agreement with the study of De Benedetti et al. and also the study of Betty and Inderpreet, who studied 1743 newborns and found that the rates of infection were similar in males and females. In contrast, this study was not in agreement with Gerdes, who found that the frequency of neonatal sepsis was significantly higher in males. The difference in the results may be related to racial or genetic differences between populations.
In the present study, clinical evaluation of neonates with sepsis showed that O2 was required in 100%, respiratory distress was present in 95.6%, petechiae was present in 93.3%, mottling was present in 77.8%, absent suckling reflex was present in 55.6%, lethargy was present in 28.9%, jaundice was present in 13.3%, and absent moro reflex was present in 11.1%; these were the most common clinical presentations. Similar observations were made by Mustafa et al., who found that feeding intolerance (100%), respiratory distress (90%), temperature instability (80%), lethargy (70%), poor perfusion (60%), hypotension (60%), poor reflexes (60%), and jaundice (56%) were the most common clinical presentations.
In terms of the frequency of clinical manifestations in the sepsis group compared with the control group, respiratory distress occurred in 95.6% of cases. This supports the conclusion of Stoll and Weisman, who found that respiratory distress is the most common clinical sign of sepsis, occurring in all septic newborns. This may be explained by many factors, mainly pneumonia, respiratory distress syndrome, or a mere body reaction to septicemia, Jein and Marcy.
In the current study, 86.7% of septic neonates had a positive CRP, with a range from 12 to 192 mg/l. Similar results were obtained in the study of Carrigan, who reported that concentrations of CRP in septic patients ranged from 12 to 159 mg/l. This small difference in the upper limit of CRP is because of differences in the laboratory techniques used.
The results of blood cultures in our study showed that only 36 (80%) of cases with sepsis were culture positive. Similar results were obtained in the study of Betty and Inderpreet, who found that culture-proven sepsis occurred in 41.6% of cases with sepsis. The sensitivity of blood cultures in neonatal sepsis is low and depends on the number and timing of cultures taken, blood volume, culture medium, technique, temperature, and organism density, Kumar et al..
The limitation of this study is that we could not perform follow-up for the neonates with sepsis; thus, we did not have information on the complications and trials of treatment for these neonates. Another limitation of our study was the small sample size.
The strength of this study is that we can carry out this study in many hospitals, which may help in the diagnosis of neonatal sepsis, and thus we can initiate the treatment early and improve the prognosis.
| Conclusion|| |
We conclude that serum MBL levels were significantly lower in septic neonates than in the control group. MBL levels were not related to gestational age and birth weight in the case group.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]