Neonatal infection in premature infants and use of human immunoglobulin

Effectiveness of Immunoglobulins for the Prevention of Systemic Infections : A Meta-Analysis of 8 Clinical Studies in Premature Infants

The prophylactic administration of immunoglobulins to preterm neonates has a controversial effectiveness in reducing the incidence of nosocomial infections. Since the clinical trials conducted so far have given conflicting results, a metaanalysis was carried out to summarise the overall information presently available on this issue. Eight randomised clinical trials were identified by our literature search that met the inclusion criteria of our meta-analysis. In each study, the effectiveness of intravenous immunoglobulins was compared with that of no treatment or placebo. The overall number of patients included in our metaanalysis was 3739. The end-point was the incidence of proven infections. The results of our meta-analysis demonstrate that prophylactic immunoglobulins significantly reduced the incidence of proven infections (pooled odds ratio = 0.79, 95% CI: 0.69 to 0.91; p = 0.0014; reduction in the incidence of infection from 23.2 to 19.3%). There was, however, a significant intertriai heterogeneity. A cost-effectiveness analysis indicated that the prophylactic administration of immunoglobulins implies a cost of approximately $US8000 to prevent each case of infection in premature infants. This cost seems to be at least equal to the cost of treating an episode of sepsis in an infant.

The role of intravenous immunoglobulin for the prevention and treatment of neonatal sepsis

The use of intravenous immunoglobulin (IVIG) for the prevention and treatment of sepsis in neonates is appealing because of the relative immunodeficiency of the neonate and the desire to improve the relatively poor outcome even with optimal antimicrobial treatment. The effectiveness of IVIG for these uses has been studied in numerous prospective as well as retrospective small and large trials that have had discordant conclusions. Meta-analysis demonstrates the marginal but significant benefit of prophylactic IVIG administered shortly after birth in preventing early onset sepsis in premature low birth weight newborns (P = .0193, two-sided). The expense of prophylactic use of IVIG administration for the relatively large premature newborn population given the minimal benefit as demonstrated by original studies and by meta-analysis is not justified. In contrast, meta-analysis of studies of IVIG for the treatment of neonates with sepsis shows a significant and unequivocal sixfold decrease in the mortality rate (P = .007, two-sided) when IVIG is administered in addition to standard therapies. The additional benefit of decreasing the risk for acute mortality indicates that the inclusion of IVIG should be considered a part of the routine therapy of neonatal sepsis.

Meta-analyses of the effectiveness of intravenous immune globulin for prevention and treatment of neonatal sepsis

OBJECTIVE

To determine the effectiveness of intravenous immune globulin (IVIG) in the prevention and treatment of neonatal sepsis.

DESIGN

All published studies of IVIG for the prevention or treatment of neonatal sepsis were reviewed. Peer-reviewed, prospective, randomized trials with high merit were analyzed by two meta-analyses. The effect of prophylactic IVIG was evaluated by comparison of the numbers of cases of sepsis (bacteremia in the presence of systemic manifestations of sepsis), and of therapeutic IVIG by comparison of the numbers of deaths resulting from early-onset sepsis.

RESULTS

Meta-analysis of 4933 evaluable newborns in 12 studies of IVIG prophylaxis showed a statistically significant negative association with the incidence of sepsis in premature low birth weight newborns given IVIG shortly after birth (P = .0193, two-sided). The heterogeneity across these studies precluded estimation of a common odds ratio. Meta-analysis of 110 evaluable cases of neonatal sepsis in three studies of IVIG treatment of neonatal sepsis showed a significant decrease in the mortality rate for neonates with sepsis given IVIG (P = .007, two-sided). The common odds ratio was .173 (95% confidence interval = .031 to .735).

CONCLUSIONS

Using conservative and objective outcome rating criteria, the addition of IVIG to standard therapies is of minimal but demonstrable benefit in preventing sepsis when administered prophylactically to premature low birth weight newborns, and of unequivocal benefit in preventing death when administered therapeutically for early-onset neonatal sepsis. The likelihood of newborns with sepsis living past the neonatal period was improved nearly sixfold when IVIG was administered in addition to standard therapies.

Comparison of two types of intravenous immunoglobulins in the treatment of neonatal sepsis

In a prospective double-blind study, standard intravenous immunoglobulin (IVIG) was compared with an IgM-enriched IVIG in the treatment of neonatal sepsis. The two treatment groups were also compared with matched controls. One hundred and thirty babies (65 in each group) ranging from 0 to 24 days old, 480 to 4200 g in weight and born between 24 and 42 weeks of gestation who had, or were suspected of having, sepsis were given either standard IVIG or IgM-enriched IVIG (250 mg/kg per day) for 4 days in addition to supportive and antibiotic therapy. A further 65 babies who received similar supportive, antibiotic and fluids but not IVIG were used as matched controls. Mortality from infection in 'culture proven sepsis' was 3/44 (6.8%) in the IgM-enriched IVIG group, 6/42 (14.2%) in the standard IVIG group, and 11/43 (25.5%) in the control group (P = 0.017, IgM versus control, P = 0.19 standard IVIG versus control). There was no statistical difference in the outcome between the two immunoglobulin therapy groups (P = 0.25). The study indicates that IVIG improves outcome in neonatal sepsis when used as an adjunct to supportive and antibiotic therapy, but larger studies are required to confirm this.

A controlled trial of intravenous immune globulin to reduce nosocomial infections in very-low-birth-weight infants. National Institute of Child Health and Human Development Neonatal Research Network

BACKGROUND

Nosocomial infections are a major cause of morbidity and mortality in premature infants. As a rule, their low serum gamma globulin levels at birth subsequently decline to hypogammaglobulinemic values; hence, prophylactic administration of intravenous immune globulin may reduce the rate of hospital-acquired infections.

METHODS

In this prospective, multicenter, two-phase controlled trial, 2416 infants were stratified according to birth weight (501 to 1000 g and 1001 to 1500 g) and randomly assigned to an intravenous immune globulin group (n = 1204) or a control group (n = 1212). Control infants were given placebo infusions during phase 1 of the study (n = 623) but were not given any infusions during phase 2 (n = 589). Infants weighing 501 to 1000 g at birth were given 900 mg of immune globulin per kilogram of body weight, and infants weighing 1001 to 1500 g at birth were given a dose of 700 mg per kilogram. The immune globulin infusions were repeated every 14 days until the infants weighed 1800 g, were transferred to another center, died, or were sent home from the hospital.

RESULTS

Nosocomial infections of the blood, meninges, or urinary tract occurred in 439 of the 2416 infants (18.2 percent): 208 (17.3 percent) in the immune globulin group and 231 (19.1 percent) in the control group (relative risk, 0.91; 95 percent confidence interval, 0.77 to 1.08). Septicemia occurred in 15.5 percent of the immune globulin recipients and 17.2 percent of the controls. During phase 1 the rate of nosocomial infections was 13.4 percent in the immune globulin group and 17.8 percent in the control group; the respective rates during phase 2 were 21.0 percent and 20.4 percent. The predominant organisms included gram-positive cocci (53.0 percent), gram-negative bacilli (22.4 percent), and candida species (16.0 percent). Adverse reactions were rarely observed during the infusions. Immune globulin therapy had no effect on respiratory distress syndrome, bronchopulmonary dysplasia, intracranial hemorrhage, the duration of hospitalization, or mortality. The incidence of necrotizing enterocolitis was 12.0 percent in the immune globulin group and 9.5 percent in the control group.

CONCLUSIONS

Prophylactic use of intravenous immune globulin failed to reduce the incidence of hospital-acquired infections in very-low-birth-weight infants.

Serum IgG at birth in preterm appropriate- and small-for-gestational age newborns

Serum IgG at birth was estimated in 31 preterm and 33 full term newborns, grouped according to their weight-for-gestational age. Preterm small-for-gestational age neonates were found to have significantly reduced IgG levels as compared to preterm appropriate-for-gestational age and full term small-for-gestational age newborns. It is suggested that preterms with intra-uterine growth retardation are most suitable for exogenous IgG supplementation to reduce neonatal and postneonatal susceptibility to infections.

Prophylactic intravenous immunoglobulin in pre-term infants: a controlled trial

Sixty-six pre-term infants of less than 30 weeks gestation consecutively admitted to either of two neonatal intensive care units were randomized to receive routine intensive care only or prophylactic intravenous immunoglobulin, 200 mg/kg body weight at 3-weekly intervals in addition to routine intensive care. Eleven babies, 6 in the control group and 5 in the treatment group, were withdrawn from the trial due to early death from extreme prematurity (7 babies), early return to the referring hospital (3 babies), and elective treatment with intravenous immunoglobulin for severe congenital septicaemia (1 baby). Of the 55 who remained in the trial, significantly fewer babies in the treatment group had infection, 8 compared to 17 (p = 0.01). This difference was not significant when blood-culture-proven septicaemia only was considered, 8 compared to 14 (p = 0.09). Twenty-seven (84%) of 32 blood-culture-positive episodes of infection were caused by coagulase-negative staphylococci. Serum IgG was significantly higher with treatment and achieved levels comparable to those of normal full-term babies at the same post-natal age.

Pharmacokinetics of intravenous immunoglobulin in neonates

Intravenous immunoglobulin (IVIG) may be a therapeutic adjunct to antibiotic treatment of neonatal infections. We examined the pharmacokinetics and safety of IVIG in human neonates. Thirty neonates with suspected sepsis were randomly assigned either to a treatment (receiving either 250, 500, or 1,000 mg/kg of IVIG plus antibiotics) or control (antibiotics alone) group. The 500 mg/kg dose produced a rise in total IgG for greater than 8 and in group B streptococcus (GBS) type-specific IgG for greater than 4-14 days. The type-specific antibody elevation varied with the amount of pathogen-specific antibody and dose of IVIG. Pharmacokinetic analysis suggests a Vdss of 42 ml/kg, Cl of 3.0 ml/kg/day, a biphasic elimination curve, and a terminal elimination half-life of 24.2 days. No toxicity was observed. These data may be valuable in determining optimal dosing schedules for IVIG in treating or preventing neonatal infections.

Septicaemia with coagulase negative staphylococci in a neonatal intensive care unit. Risk factors for infection, and antimicrobial susceptibility of the bacterial strains

Septicaemia caused by coagulase negative staphylococci is a problem in the neonatal intensive care units (NICU). The very low birthweight (VLBW) infants are at a special high risk because of their immature host defense. In this study the potential risk factors were compared between the VLBW septicaemia patients and the VLBW infants who had not contracted septicaemia in the NICU. The factor most clearly related with septicaemia was the use of umbilical artery catheters. The strategy against neonatal septicaemia includes restriction of the use of intravascular catheters. Also enhancement of the host defense by immunoglobulin therapy is considered. The coagulase negative staphylococci were multiresistant to antibiotics. The combination of netilmicin and benzylpenicillin covered the bacteria found in septicaemia cases in the NICU, and is now the standard treatment in suspected cases. Coagulase negative staphylococci are treated with vancomycin or netilmicin.