Kwang Ha Yoo

Assessment of humoral and cell-mediated immune response to measles-mumps-rubella vaccine viruses among patients with asthma.

Little is known about the influence of asthma status on humoral and cell-mediated immune responses to measles-mumps-rubella (MMR) vaccine viruses. We compared the virus-specific IgG levels and lymphoproliferative response of peripheral blood mononuclear cells to MMR vaccine viruses between asthmatic and nonasthmatic patients. The study subjects included 342 healthy children aged 12-18 years who had received two doses of the MMR vaccine. We ascertained asthma status by applying predetermined criteria. Of the 342 subjects, 230 were available for this study of whom 25 were definite asthmatic patients (10.9%) and the rest of subjects were nonasthmatic patients. The mean of the log-transformed lymphoproliferative responses between definite asthma and nonasthma who had a family history of asthma were for measles, 0.92 ± 0.31 versus 1.54 ± 0.17 (p = 0.125); for mumps, 0.98 ± 0.64 versus 2.20 ± 0.21 (p = 0.035); and for rubella, 0.12 ± 0.37 versus 0.97 ± 0.16 (p = 0.008), respectively, adjusting for the duration between the first MMR vaccination and determination of the immune responses. There were no such differences among children without a family history of asthma. MMR virus-specific IgG levels were not different between study subjects with or without asthma. The study findings suggest asthmatic patients may have a suboptimal cell-mediated immune response to MMR vaccine viruses and a family history of asthma modifies this effect.

The Impact of Electronic Medical Records on Timeliness of Diagnosis of Asthma

We assessed timeliness of diagnosis of asthma before and after the inception of electronic medical record (EMR). The proportions of children with a delay in diagnosis of asthma before and after the inception of EMR were 67.8% and 56.8%, respectively (p = 0.088). A significant proportion of children have delayed diagnosis of asthma, and availability of EMR plays a minimal role in reducing delays in diagnosis of asthma. However, considering the limited statistical power and a potential trend of EMR toward the positive impact on timely diagnosis of asthma, the study results need to be revisited in a larger study.

Characteristics of Children with Asthma Who Achieved Remission of Asthma

Objective. To characterize two groups of asthmatics who had achieved remission and those who had not achieved remission of asthma. Methods. The study was a retrospective cohort study based on 117 asthmatic children who participated in a previous study. We categorized the children into two groups: asthmatics with remission versus asthmatics without remission. We defined remission of asthma as lack of symptoms/signs of asthma or asthma-related medications or health care services for at least three consecutive years. Long-term remission was defined by no relapse of asthma after achieving remission. We characterized these groups. Results. Of the 117 subjects, 70 (60%) were male, 91 (78%) were Caucasians, and the mean age at index date of asthma was 8.1 years. A total of 59 asthmatic children (50%) achieved remission and 28 asthmatics (24%) achieved long-term remission. Asthmatics with remission were more likely to be Caucasian (87%) compared to those without (69%) (p = .039) There were no differences in the frequency of visits for viral (0.3 vs. 0.4 per person-years, p = .29) or bacterial infections (0.7 vs. 0.5 per person-years, p = .49) between asthmatics with and without remission. Gender, socioeconomic status, smoking exposure, family history of asthma or atopy, breastfeeding history, peak flow meter availability, asthma action plan, and influenza vaccinations were not associated with remission. Conclusions. Only half of asthmatic children accomplished remission of asthma ever and 24% of asthmatic children had long-term remission. Ethnicity may affect remission of asthma but microbial infections may not influence the likelihood of remission of asthma and vice versa.

Asthma Status and Waning of Measles Antibody Concentrations after Measles Immunization

Background: Asthmatics have increased risks of common and serious microbial infections including vaccine preventable diseases. Little is known about whether asthma influences waning of humoral immunity. We assessed whether asthma status influences waning of anti-measles virus antibody concentrations over time. Methods: The study used a cross-sectional study cohort of healthy children who had been immunized with 1 dose of MMR-II at age approximately 15 months. Between 5 and 12 years of age, measles vaccine virus-specific antibody (IgG) values were measured by enzyme immunoassay and considered seropositive if the enzyme immunoassay index unit was ≥ 1. The medical records were reviewed to determine asthma status during the first 18 years of life by applying predetermined criteria for asthma. A least squares regression model was used to evaluate the effect of asthma status on the relationship between measles antibody titer and time elapsed between the initial measles vaccination and measurement of measles antibody concentrations. Results: Of the 838 eligible children, 281 (34%) met criteria for asthma. Measles antibody waned over time (r = −0.19, P < 0.001), specifically more rapidly in asthmatics (r = −0.30, P < 0.001, a decrease of −0.114 unit per year) than non-asthmatics (r = −0.13, P = 0.002, a decrease of −0.046 unit per year; P value for interaction = 0.010). This differential waning rate resulted in a lower mean (SD) measles antibody concentration [1.42 (0.67) vs. 1.67 (0.69), P = 0.008] and lower seropositivity rate (73% vs. 84%, P = 0.038) in asthmatics than non-asthmatics starting around 9.3 years after the initial measles vaccination. Conclusion: Asthma status is associated with waning kinetics of measles antibody among children.