Association of Immunoglobulin G at Birth with Late-Onset Sepsis and Related Mortality in Very Low Birth Weight Infants

PURPOSE: We aimed to evaluate the association between immunoglobulin G (IgG) at birth and late-onset sepsis (LoS) in preterm infants. METHODS: Medical records of very-low-birth-weight infants, born at gestational age <28 weeks, between 2013 and 2016, were retrospectively reviewed. Subjects were divided into two groups based on the occurrence of LoS (LoS vs. non-LoS), and IgG levels at 1 day, and at 2 weeks and 4 weeks after birth were investigated. IgG levels, other perinatal factors, and clinical factors were compared in the two groups. The relationship between IgG levels and mortality among infants in the LoS group was also analyzed. RESULTS: A total of 105 infants were analyzed after exclusion of cases with early onset sepsis or death at < 72 hours of life. Gestational age in the LoS group was lower than in the non-LoS group (25.0±1.8 vs. 26.3±1.4 weeks, P=0.004). IgG levels at birth were similar between the two groups (236.4±96.4 vs. 282.0±104.7 mg/dL, P=0.078). Multivariate analysis showed that IgG at birth was not an independent risk factor for LoS. In the LoS group, IgG levels at birth were comparable between survivors and cases involving mortality. CONCLUSION: IgG levels at birth were not associated with the occurrence of LoS in extremely preterm infants.

Clinical Manifestations and Treatment in Korean Patients with X-Linked Agammaglobulinemia

PURPOSE: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in the Bruton's tyrosine kinase (Btk) gene. The aim of this study was to investigate the clinical manifestations, molecular features, and treatment status of XLA in Korean patients at Seoul National University Children's Hospital. METHODS: Fourteen Korean boys with XLA showing serum agammaglobulinemia, non-detectable to less than 2% of peripheral B-cells, and mutation of the Btk gene were enrolled. We observed the clinical features, laboratory findings, status of treatment, and complications in these XLA patients. RESULTS: All XLA patients had a history of recurrent bacterial infections before diagnosis, and 20% of them had a neutropenia. Of the XLA patients 35.7% had a family history of XLA and 75% of their mothers were carriers. Btk gene analysis showed variable gene mutations in Xq22 including 9 amino acid substitutions, 3 frameshifts, 1 premature stop codon, and 1 splice defect. After intravenous immunoglobulin replacement therapy, infection episodes decreased, but complications such as bronchiectasis and chronic sinusitis remained. CONCLUSIONS: In patients less than 4 years of age with recurrent infection, analysis of serum gamma globulin levels and the Btk gene are recommended for the early diagnosis of XLA and for the appropriate prevention of recurrent infection.

Clinical Manifestations and Treatment in Korean Patients with X-Linked Agammaglobulinemia

PURPOSE: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in the Bruton's tyrosine kinase (Btk) gene. The aim of this study was to investigate the clinical manifestations, molecular features, and treatment status of XLA in Korean patients at Seoul National University Children's Hospital. METHODS: Fourteen Korean boys with XLA showing serum agammaglobulinemia, non-detectable to less than 2% of peripheral B-cells, and mutation of the Btk gene were enrolled. We observed the clinical features, laboratory findings, status of treatment, and complications in these XLA patients. RESULTS: All XLA patients had a history of recurrent bacterial infections before diagnosis, and 20% of them had a neutropenia. Of the XLA patients 35.7% had a family history of XLA and 75% of their mothers were carriers. Btk gene analysis showed variable gene mutations in Xq22 including 9 amino acid substitutions, 3 frameshifts, 1 premature stop codon, and 1 splice defect. After intravenous immunoglobulin replacement therapy, infection episodes decreased, but complications such as bronchiectasis and chronic sinusitis remained. CONCLUSIONS: In patients less than 4 years of age with recurrent infection, analysis of serum gamma globulin levels and the Btk gene are recommended for the early diagnosis of XLA and for the appropriate prevention of recurrent infection.

Decreased Incidence of Necrotizing Enterocolitis after Introduction of Exclusive Breast Milk Feeding in a Single Neonatal Intensive Care Center

PURPOSE: To evaluate the effects of exclusive breast milk feeding (BMF) on the incidence of necrotizing enterocolitis (NEC) in preterm infants. METHODS: All newborn infants, born at <32 weeks of gestation and weighing <1,500 g, admitted to the neonatal intensive care center at Seoul National University Bundang Hospital during the study period, were included. The study was divided into period I: pre-exclusive BMF (January 2010–March 2014) and period II: exclusive BMF (April 2014–December 2016). RESULTS: A total of 374 infants were enrolled in this study, with 174 in period I and 174 in period II. The incidence of NEC was 11.5% in period I and 3.4% in period II. As the mean gestational age and birth weight were significantly greater in infants in period II, the difference in the incidence of NEC between the two periods was adjusted by gestational age. After adjustment, the incidence of NEC in period II was significantly lower than in period I (P=0.024). CONCLUSION: Exclusive BMF significantly reduced the incidence of NEC in a single neonatal intensive care center.