Mapping of IgE and IgG4 antibody-binding epitopes in Cyn d 1, the major allergen of Bermuda grass pollen.

BACKGROUND: Bermuda grass pollen (BGP) is an important seasonal aeroallergen worldwide which induces allergic disorders such as allergic rhinitis, conjunctivitis and asthma. Cyn d 1 is the major allergen of BGP. This study is aimed to map human IgE and IgG(4) antibody-binding sequential epitopes on Cyn d 1 by dot immunoblotting. METHODS: Synthetic peptides (10-mers; 5 overlapping residues) spanning the full length of Cyn d 1 were used for dot immunoblotting to map human IgE and IgG(1-4) antibody-binding regions with sera from BGP-allergic patients. Synthetic peptides with more overlapping residues were used for further mapping. Essential amino acids in each epitope were examined by single amino acid substitution with alanine. Peptides with sequence polymorphism of epitopes of Cyn d 1 were also synthesized to extrapolate their differences in binding capability. RESULTS: Four major IgE-binding epitopes (peptides 15(-1), 21, 33(-2) and 35(+1), corresponding to amino acids 70-79, 101-110, 159-167 and 172-181) and 5 major IgG(4)-binding epitopes (peptides 15(-1), 30(-2), 33(-2), 35(+1) and 39, corresponding to amino acids 70-79, 144-153, 159-167, 172-181 and 192-200) were identified. They are all located on the surface of the simulated Cyn d 1 molecule, and three of them are major epitopes for both IgE and IgG(4). Their critical amino acids were all characterized. Major epitopes for human IgG(1) to IgG(4) are almost identical. CONCLUSIONS: This is the first study to map the sequential epitopes for human IgE and IgG(4) subclasses in Cyn d 1. It will be helpful for future development in immunotherapy and diagnosis.

Comparison of clinical features of childhood norovirus and rotavirus gastroenteritis in Taiwan.

BACKGROUND: Viral gastroenteritis is a common acute infectious disease in infants and young children. This study compared the incidence and clinical features of childhood norovirus (NV) and rotavirus (RV) gastroenteritis in Taiwan. METHODS: Stool specimens were collected from children with acute gastroenteritis aged 6 months to 14 years who were treated at the Children's Medical Center of Taipei Veterans General Hospital between January 2004 and March 2005. The incidence, clinical manifestations, and laboratory findings of childhood NV gastroenteritis were analyzed and compared with those of patients with RV gastroenteritis. Patients with underlying diseases associated with diarrhea or those diagnosed with bacterial gastroenteritis were excluded. Stool specimens were tested for NV and RV using enzyme immunoassay (EIA). NV genogroups were determined by reverse-transcriptase polymerase chain reaction. RESULTS: Among the 201 patients included in this study, NV was detected in 44 (21.9%) by 1 or more tests (22 by EIA). Five of these isolates were genogroup I (11.3%), and 39 were genogroup II (88.7%). Fifty-two (25.9%) specimens had a positive EIA result for RV. Compared with NV, patients with RV gastroenteritis had a significantly higher percentage of diarrhea (94 vs. 69%, p < 0.001), fever (82 vs. 26.2%, p < 0.001), and longer hospital stay (3.81 vs. 2.93 days, p = 0.048). Laboratory studies showed significantly higher liver enzymes and C-reactive protein levels in patients with RV infection. In contrast, white blood cell counts were significantly higher in patients with NV infection. CONCLUSION: Norovirus is one of the leading agents of acute gastroenteritis in children in Taiwan, and genogroup II is the predominant type.

Characteristics of Chlamydia trachomatis infection in hospitalized infants with lower respiratory tract infection.

BACKGROUND AND PURPOSE: To study the epidemiology, presentation and laboratory findings of Chlamydia trachomatis pneumonia in hospitalized infants younger than 6 months. METHODS: Between January 2001 and December 2005, infants younger than 6 months admitted to the children's medical center of Taipei Veterans General Hospital with the diagnosis of acute bronchiolitis, bronchopneumonia or pneumonia were prospectively studied. Chest radiograph findings were reviewed in all patients. Basic laboratory examinations performed included white blood cell count and eosinophil count. C. trachomatis was detected via enzyme-linked immunosorbent assay antigen test and the titers of immunoglobulin G and immunoglobulin M by indirect immunoperoxidase assay. RESULTS: A total of 60 infants, 32 males and 28 females, were included. C. trachomatis infection was detected in 30% of patients (18/60). The median age was 2.5 months (range, birth to 6 months). Fever was not detected in 72% of patients (13/18). Only 22% (4/18) of these patients had the characteristic staccato cough. The mean duration of symptoms before admission was 8 days (range, 1 day to 2 months). Rhinorrhea was a prodromal symptom in 67% (12/18) of patients, with a mean pre-onset duration of 7 days (range, 1 to 14 days). Eighty three percent (15/18) of the patients had tachypnea, with a mean duration of 3.2 days (range, 1 to 7 days). Conjunctivitis was noted before admission in 6 patients (33%). Only peripheral eosinophils showed statistically significant difference between Chlamydia-positive and -negative disease (p=0.046), and may be clinically useful in cases of suspected C. trachomatis infection. Mixed infection with other pathogens including adenovirus, respiratory syncytial virus, Mycoplasma pneumoniae, cytomegalovirus and Streptococcus pneumoniae was found in 27% (5/18) of patients. CONCLUSIONS: C. trachomatis is not infrequent and plays an important role in infants younger than 6 months old hospitalized due to lower respiratory tract infection.

Characteristics and outcome of septic arthritis in children.

BACKGROUND AND PURPOSE: To assess the etiologic agents, presentation, laboratory findings, treatment, clinical outcome and prognostic factors of pyogenic arthritis in pediatric patients. METHODS: We reviewed the medical records of patients under 18 years of age with a diagnosis of septic arthritis from January 1971 to July 2004. Information collected included clinical characteristics, laboratory data, response to therapy and outcome. An unsatisfactory clinical outcome was defined as the development of sequelae including ambulatory disability, limb-length discrepancy, chronic osteomyelitis, and abnormalities of bone growth. RESULTS: A total of 60 children who met the criteria for diagnosis of septic arthritis were included. The etiologic agent was identified in 71.7% of the patients. Staphylococcus aureus was the most common etiologic agent in all age groups (59.0%). The erythrocyte sedimentation rate was higher than 20 mm/h in 89% of patients and soft tissue swelling was the most common radiographic finding (16.7%). Lower extremity involvement was found in 90.8% of patients and the knee joint was most commonly involved. The clinical outcome was unsatisfactory in 28.3% of patients. The duration of symptoms before the initiation of treatment was significantly longer in patients with sequelae (4.2 vs 13.1 days, p<0.01), and the neutrophil percentage in peripheral blood was also significantly higher in this group (81.5% vs 65.7%, p=0.027). CONCLUSIONS: Delayed treatment and increased neutrophil ratio in peripheral blood were significantly associated with an increased risk of sequelae.

Epidemiology of respiratory syncytial virus in children with lower respiratory tract infection.

Respiratory syncytial virus (RSV) is the most frequent pathogen found in hospitalized young children with lower respiratory tract infection, and the virus is distributed worldwide. Respiratory distress and respiratory failure are caused by RSV in some severe cases. Its appearance always varies every year and depends on differences of latitudes, altitudes and climates. The purpose of this study was to investigate the epidemiology of hospitalized children from a hospital located in northern Taiwan with RSV induced lower respiratory tract infection. This study was conducted from January 2001 to December 2003, and the selected patients were children aged under five and diagnosed with lower respiratory tract infection. The means adopted in this study were analyses of clinical presentations and laboratory tests (including viral identification with either virus culture or RSV antigen rapid test from the nasopharyngeal aspirate). The results showed that 153 children were positive with RSV identification. These cases were diagnosed in clinical practice all year round, and its peak was in spring, especially in March and April. Thirteen percent of all RSV-infected children in this study presented as severe form with respiratory distress and a need of respiratory support. However, none of these cases died from this disease, and all cases recovered without long-term respiratory complication. We concluded that RSV infection was still a common pathogen for young children in northern Taiwan; in addition, March and April were regarded as peak months of epidemic. Patients aged under 12 months or suffered from underlying cardiopulmonary disease were at high risk of getting severe forms of RSV infection.

Hepatopulmonary syndrome in a child.

We report a case of congenital biliary atresia and liver cirrhosis who developed hepatopulmonary syndrome thirteen years after Kasai operation. This 15-yea-old girl suffered from hyperbilirubinemia and acholic stool since birth. Congenital biliary atresia was diagnosed at 6 weeks of age and she received Kasai operation when liver cirrhosis was also found during the surgery. Dyspnea and cyanosis insidiously occurred since the age of 13 and she had been admitted to our hospital due to episodes of esophageal varices bleeding where esophageal varices ligation was performed. Serial examinations showed PaO2: 71 mmHg despite of 100% oxygen supplement. Pulmonary catheterization showed multiple arteriovenous shunts and macroaggregated albumin test revealed significant shunting. Contrast-enhanced echocardiogram showed microbubbles in the left heart. Thus, hepatopulmonary syndrome type II was diagnosed. Treatment is a dilemma although liver transplantation with concomitant lung transplantation is a possible choice.

Hyperkalemia during the early postnatal days in premature infants.

Plasma electrolyte concentrations in premature infants are unstable, and hyperkalemia may induce significant, even life-threatening, symptoms in tiny infants. The medical records of 95 premature infants were retrospectively reviewed. Patients with a major congenital anomaly or mortality within 24 h after birth were excluded. Plasma electrolytes, blood urea nitrogen, creatinine, blood pH, urine output, and related clinical conditions during first 96 h of life were analyzed. Plasma potassium concentrations had significant negative correlations with gestational age and birth weight (p < 0.05). Infants with a gestational age of less than 29 weeks had significantly higher potassium concentrations (average 5.9 +/- 0.3 mEq/L, peak 7.8 +/- 0.4 mEq/L, p < 0.05) than other gestational age groups, and their plasma potassium levels were significantly higher at 24 and 48 h of age (p < 0.05). Forty-two infants (42/95, 44%) had peak plasma potassium concentrations greater than or equal to 6 mEq/L. With statistical analysis, the hyperkalemic infants comprised of significantly (p < 0.05) fewer males (31% vs. 55%), they had more-severe respiratory distress syndrome (RDS) (grades 2 +/- 0 vs. 1 +/- 0, p < 0.05), and needed more frequent use of inotropics (52% vs. 23%, p < 0.05) compared to normokalemic infants. In conclusion, hyperkalemia during the first 2 days of life is common in extremely premature infants. Small gestational age, very low birth weight, female gender, high RDS grade, need of exogenous surfactant and inotropic agents, delayed feeding, and a high mortality rate were observed in hyperkalemic infants.