Efficacy of local conjunctival immunotherapy in allergic conjunctivitis.

Background: Allergic conjunctivitis was a chronic inflammatory disease, usually associated with rhinitis. Several modalities of treatment were available, but few studies mentioned of immunotherapy which might had benefits in chronic and severe cases. Objective: To evaluate efficacy and safety of local conjunctival immunotherapy (LCIT) using a mixed Dermatophagoides extracts for treatment of allergic conjunctivitis (AC) Methods: A prospective, double-blind and randomized controlled trial (RCT) was performed on eighteen patients with positive skin prick test (SPT) reactions to house dust mites. They were randomized into 2 groups: 1) treated with LCIT and 2) treated with balanced salt solution (BSS) as a control for a 6-month period. Allergen extracts were prepared in eyedrops and given once daily in LCIT group. Efficacy was assessed by clinical scores and conjunctival provocation test (CPT). Results: At 6 months, the CPT scores for the LCIT group reached statistical significance compared to the control group (p = 0.038), but there were no statistically significant differences in signs (p = 0.591), symptoms (p =0.885) and medication scores (p = 0.338) between both groups. Patients in LCIT group were able to tolerate the allergen without developing any serious adverse events. Conclusion: LCIT treatment significantly reduced CPT scores which indicated that the patients were able to tolerate the antigen better than their counterparts. However, LCIT alone at short period did not alleviate symptoms and signs of allergic conjunctivitis from multiple allergens.

Cow's milk allergy in Thai children.

Cow's milk allergy (CMA) is nowadays a common problem in Thai children. We reviewed medical records of patients with CMA from the Department of Pediatrics at King Chulalongkom Memorial Hospital of the past 10 years, from 1998 to 2007. The criteria for the diagnosis of CMA included: elimination of cow's milk formula resulting in improvement of symptoms, and: recurrence of symptoms after reintroduction of cow's milk by oral challenge or by accidental ingestion. Of the 382 children with a diagnosis of CMA, 168 were girls and 214 were boys. The average age at the time of diagnosis was 14.8 months (7 days-13 years). The average duration of symptoms before diagnosis was 9.2 months. A family history of atopic diseases was found in 64.2% of the patients. All of the mothers reported an increased consumption of cow's milk during their pregnancy. The most common symptoms were respiratory (43.2%) followed by gastrointestinal (GI) (22.5%) and skin manifestations (20.1%). Less common symptoms included failure to thrive (10.9%), anemia (2.8%), delayed speech due to chronic serous otitis media (0.2%) and anaphylactic shock (0.2%). A prick skin test with cow milk extract was positive in 61.4%. Exclusively breast-fed was found in 13.2% of the patients. Successful treatment included elimination of cow's milk and milk products and substitution with soy formula in 42.5%, partial hydrolysate formula (pHF) in 35.7%, extensive hydrolysate formula (eHF) in 14.2%, and amino acid formula in 1.7%. Continued breast feeding was successful in 5.9% (with maternal restriction of cow's milk and milk products). Our study demonstrates the variety of clinical manifestations of CMA in Thai children especially respiratory symptoms which are usually overlooked.

Nonsense mutations of the CYBB gene in two Thai families with X-linked chronic granulomatous disease.

X-linked chronic granulomatous disease (X-CGD) is an immunodeficiency disorder characterized by defective intracellular killing of microorganisms due to the neutrophils' inability to generate superoxide ions. Although it is always caused by mutations in the CYBB gene, clinical and molecular characteristics vary in different ethnic backgrounds. Two unrelated Thai boys presented with severe persistent pulmonary infections at the age of two months. Their abnormal dihydrorhodamine (DHR) flow cytometry assays supported the diagnosis of X-CGD. Mutation analysis was performed by polymerase chain reaction (PCR) amplification and sequencing of the entire coding regions of CYBB. Mutations identified were confirmed by restriction enzyme analyses. PCR-sequencing of the entire coding regions of CYBB identified nonsense mutations, 271C>T (R91X) in exon 4 and 456T>A (Y152X) in exon 5, in probands of each family. Both of the patients' mothers were found to be carriers. This observation supports that CYBB is the gene responsible for X-CGD across different populations and nonsense mutations are associated with severe phenotypes.

Seroprevalence of tetanus antibody in the Thai population: a national survey.

Tetanus is a disease with high mortality and the most important measure for effective prevention is vaccination. Tetanus immunization has been introduced to Thailand's national immunization program for 30 years. Yet, the coverage and seroprevalence of tetanus antibody in vast parts of the population has not been assessed. This study has been performed on 1,277 subjects aged between 6 months and 60 years or above from four geographically distinct provinces of Thailand. Tetanus antibody levels were measured using a commercially available ELISA kit. Most of the Thai population had immunity against tetanus. The level of antibodies to tetanus, as demonstrated by the geometric mean titer of antibody (GMT) (and 95% confidence interval) was 2.62 (2.34-2.91) IU/ml. The highest and lowest GMT was found in subjects aged between 5 and 9 years, and above 60 years of age with GMT (and 95% confidence intervals) of 3.64 (3.34-3.96) and 1.24 (0.67-2.29) IU/ml respectively. The minimum protective level of antitoxin (>0.01 IU/ml) was detected in 99.7 % of subjects. More than 90% of subjects displayed durable antibody protection levels (DAPL) (> or = 1.0 IU/ml), except for subjects above the age of 60 years (82%). According to this study, the majority of the population expresses tetanus antibody levels that can confer long term protection. Yet, considering the lowest GMT and the highest incidence of tetanus cases found in subjects aged above 60 years, re-immunization should be targeted at this age group especially if they had sustained any tetanus-prone injury.

Food induced urticaria in children.

We conducted a prospective study at King Chulalongkorn Memorial Hospital, from June 2001 to November 2003, to identify the contribution of food allergy to urticaria in children. During the study period, 100 children with urticaria were enrolled, 36 of whom had a history suspicious of food allergy. Fifteen of 100 patients had fever (9 from upper respiratory tract infections, 4 from diarrhea and 2 from skin infections). A skin prick test (SPT) was positive in 15 of the 36 children who were suspected of having food allergy; 5 patients out of the positive SPT group had anaphylaxis due to food (2 from cow milk, 2 from wheat and 1 from egg). Six patients in the positive SPT group had a negative food challenge test (4 from open challenges and 2 from double-blind placebo-controlled food challenges [DBPCFC]). The other 4 patients of the positive SPT group refused the food challenge test. The parents of a patient who had urticaria from egg refused the skin prick test; an oral challenge test confirmed the diagnosis of egg allergy. One of the 21 patients that had a negative SPT had shrimp allergy proven by DBPCFC. Of the 64 patients who had no history related to food, SPT was done in 27 patients and revealed a positive result in 7 patients, all of whom had a negative food challenge test (4 with open challenge and 3 with DBPCFC). Urticaria from food was found in 7% and was suspected in another 4% of the patients. Severe reactions to food like anaphylaxis may occur. SPT alone is not adequate in making the diagnosis of food allergy; it must be confirmed by a food challenge test. Thirty percent of patients that did not have a history related to food had false positive SPT. Without a history suspicious of food allergy, SPT yields only minimal benefit.

Peak inspiratory flow rate and the ability to use the Turbuhaler in Thai children aged 3-7 years.

A Turbuhaler is a dry powder inhaler device commonly used by asthmatic patients. Its superiority over a metered-dose inhaler device includes easy technique, convenience in handling and absence of chloro fluoro carbon (CFC). However, the use of this device has some limitations in young children who may not be able to generate the inspiratory flow rate high enough to assure adequate medication delivery. Even though the Turbuhaler has been used in Thailand for many years, the study of inspiratory flow rate and the ability to use this device in Thai preschool children is lacking. In the present study, the authors aimed to evaluate the ability to use the Turbuhaler in Thai preschool children by measuring the peak inspiratory flow rate, peak inspiratory flow rate through the Turbuhaler as well as positive test of the Turbutester. Subjects included 468 Thai preschool children, aged 3-7 years old. They were assigned to perform the test with In-Check Dial, Mini-Wright Peak Flow Meter and Turbutester. The authors found that the ability to use the device correlated directly with age and children with age of 5 years or more could perform significantly better. Children weight of 20 kilograms or more, or a height of 113 centimeters or more were also able to generate adequate inspiratory flow rate for medication delivery. The authors concluded that children from the age of five years, or with a weight from 20 kilograms or a height from 113 centimeters were able to generate adequate inspiratory flow rate for effective medication delivery by the Turbuhaler.

Declining hepatitis A seroprevalence among medical students in Bangkok, Thailand, 1981-2001.

The severity of clinical symptoms following hepatitis A virus (HAV) infection is age dependent. Hepatitis A in children is mostly an asymptomatic disease while adolescents and adults usually show symptoms of clinical hepatitis. Improved personal hygiene and environmental sanitation has led to a decline in natural immunity acquired in childhood, creating a population of susceptible adults. In the past decade, the incidence and prevalence of hepatitis A disease in Thailand have decreased significantly. In this study, we used enzyme-linked immunosorbent assay to determine the prevalence of anti-HAV antibodies among medical students at two different time points in 1996 and 2001. We then compared these results with data from previous studies in 1981 and 1992. The seroprevalence was 73.01%, 30.23%, 16.67% and 6.67% in 1981, 1992, 1996 and 2001, respectively. A significant decline has happened over the past two decades (p < 0.001). Considering the decreasing immunity to HAV in the younger generations, more cases of symptomatic HAV infection could be anticipated. Further seroprevalence studies in other adolescence groups from different socioeconomic status are needed to elucidate the current situation of HAV infection in the young generation more comprehensively and to develop an appropriate prevention program.