Novel and highly sensitive immunoassay for total hepatitis B surface antigen, including that complexed with hepatitis B surface antibody.

BACKGROUND: Hepatitis B surface antigen (HBsAg) is used as a clinical marker of hepatitis B virus (HBV) infection. However, conventional HBsAg assays have so far failed to accurately detect HBsAg in blood because of interference by patient-derived antibodies against HBsAg (HBsAb). METHODS: We developed a novel, fully automated assay system that can detect total HBsAg in blood, including antigens complexed with HBsAb. The immunoassay inactivates HBsAb via a simple pretreatment step to dissociate the HBsAg molecule from HBsAg-HBsAb complexes and thereby estimate total HBsAg. Accordingly, the test has been termed the "immunoassay for total antigen including complex via pretreatment (iTACT)-HBsAg." RESULTS: The recovery rate of HBsAg in the presence of HBsAb was greater than 87 % at a cutoff value set at 5.0 mIU/mL on the basis of data from 545 healthy controls. Analyses using serial serum samples from 25 HBV carriers who became negative for HBsAg during follow-up showed that the iTACT-HBsAg could detect HBsAg over a period of years despite a loss in detection by conventional assays and was able to detect HBsAg in 39 (53 %) of 73 samples with HBsAb. CONCLUSIONS: The new iTACT-HBsAg assay appears to detect total HBsAg with high sensitivity, even in the presence of HBsAb, and may useful in identifying subclinical or occult HBV carriers.

Effects of indomethacin on patent ductus arteriosus in neonates with genetic disorders and/or congenital anomalies.

OBJECTIVES: The study aimed to evaluate the effectiveness of intravenous indomethacin (IND) therapy for patent ductus arteriosus (PDA) in neonates with genetic disorders and/or congenital anomalies soon after birth. STUDY DESIGN: A total of 301 neonates with a genetic disorder and/or congenital anomalies and with a gestational age of ≥ 35 weeks were admitted during the study period. Eighty-five neonates with 56 genetic disorders (30 cases of trisomy 21, 10 cases of trisomy 18, and 16 others) and 29 congenital anomalies, and with clinical symptoms received intravenous IND therapy. The management methods were similar to those used for PDA in low-birth-weight infants. RESULTS: IND therapy had a clinical benefit at a high rate of 79% in these patients (90% and 70% in neonates with trisomies 21 and 18, respectively), including complete closure of the PDA in 52% of the patients. Although oliguria was observed in 43 infants (51%) and slight gastrointestinal bleeding was observed in 12 (14%), no infants had severe complications such as intracranial bleeding. CONCLUSIONS: IND therapy is an effective treatment option before considering surgery for PDA in neonates with genetic disorders and/or congenital anomalies. This therapy may reduce the difficulty of treatment in the acute stage among these neonates.