Implementation of a pediatric asthma management program in rural primary care clinics

OBJECTIVE

Rural communities experience a significant asthma burden. We pilot tested the implementation of Easy Breathing, a decision support program for improving primary care provider adherence to asthma guidelines in a rural community, and characterized asthma risk factors for enrollees.

METHODS

We implemented Easy Breathing in two rural primary care practices for two years. Patient demographics, exposure histories, asthma severity, asthma medications, and treatment plans were collected. Providers' adherence to guidelines included the frequency of children with persistent asthma who were prescribed guidelines-based therapy and the frequency of children with a written asthma treatment plan on file. Clinicians provided feedback on the feasibility and acceptability of Easy Breathing using a validated survey tool and through semi-structured interviews.

RESULTS

Two providers implemented the program. Enrollment included 518 children, of whom 135 (26%) had physician-confirmed asthma. After enrollment into Easy Breathing, 75% of children with asthma received a written asthma treatment plan All children with persistent asthma were prescribed an anti-inflammatory drug as part of their treatment plan. Providers (n = 2) rated Easy breathing as highly acceptable (M = 4.5), feasible (M = 4.5), and appropriate (M = 4.5). Qualitative feedback was positive, with suggestions to integrate the paper-based program into the electronic health record system for broader uptake. Enrollees with asthma were more likely to have a family history of asthma and endorse exposure to tobacco smoke and cockroaches.

CONCLUSIONS

Easy Breathing shows promise as a decision support system that can be implemented in rural, medically underserved communities via primary care.

16(th) IHIW: extending the number of resources and bioinformatics analysis for the investigation of HLA rare alleles

Continuing a project presented at the 15th International HLA and Immunogenetics Workshop (IHIWS) on the rarity of HLA alleles, we sought to expand the number of data sources and bioinformatics tools available in the Allele Frequencies Net Database website (AFND, www.allelefrequencies.net). In this 16th IHIWS Rare Alleles project, HLA alleles described in the latest IMGT/HLA Database (release 3.8.0) were queried against different sources including data from registries (stem cell) and from 74 different laboratories around the world. We demonstrated that approximately 40% of the alleles officially named in the IMGT/HLA Database have been reported only once across all different sources. To facilitate the large-scale analysis of rare alleles, we have produced an online tool called the Rare Allele Detector that simplifies the detection of alleles that are considered to be 'very rare', 'rare' or 'frequent'. Tools and associated data can be accessed via the www.allelefrequencies.net website.

Association of HLA alleles with Plasmodium falciparum severity in Malian children

Pre-erythrocytic immunity to Plasmodium falciparum malaria is likely to be mediated by T-cell recognition of malaria epitopes presented on infected host cells via class I and II major histocompatibility complex (MHC) antigens. To test for associations of human leukocyte antigen (HLA) alleles with disease severity, we performed high-resolution typing of HLA class I and II loci and compared the distributions of alleles of HLA-A, -B, -C and -DRB1 loci in 359 Malian children of Dogon ethnicity with uncomplicated or severe malaria. We observed that alleles A*30:01 and A*33:01 had higher frequency in the group of patients with cerebral disease compared to patients with uncomplicated disease [A*30:01: gf = 0.2031 vs gf = 0.1064, odds ratio (OR) = 3.17, P = 0.004, confidence interval (CI) (1.94-5.19)] and [A*33:01: gf = 0.0781 vs gf = 0.0266, 4.21, P = 0.005, CI (1.89-9.84)], respectively. The A*30:01 and A*33:01 alleles share some sequence motifs and A*30:01 appears to have a unique peptide binding repertoire compared to other A*30 group alleles. Computer algorithms predicted malaria peptides with strong binding affinity for HLA-A*30:01 and HLA-A*33:01 but not to closely related alleles. In conclusion, we identified A*30:01 and A*33:01 as potential susceptibility factors for cerebral malaria, providing further evidence that polymorphism of MHC genes results in altered malaria susceptibility.

HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1, DPB1) alleles and haplotypes in the Han from southern China

In this study, polymerase chain reaction-sequence-specific oligonucleotide prode (SSOP) typing results for the human leukocyte antigen (HLA) class I (A, B, and C) and class II (DRB1, DQA1, DQB1, and DPB1) loci in 264 individuals of the Han ethnic group from the Canton region of southern China are presented. The data are examined at the allele, genotype, and haplotype level. Common alleles at each of the loci are in keeping with those observed in similar populations, while the high-resolution typing methods used give additional details about allele frequency distributions not shown in previous studies. Twenty distinct alleles are seen at HLA-A in this population. The locus is dominated by the A*1101 allele, which is found here at a frequency of 0.266. The next three most common alleles, A*2402, A*3303, and A*0203, are each seen at frequencies of greater than 10%, and together, these four alleles account for roughly two-thirds of the total for HLA-A in this population. Fifty alleles are observed for HLA-B, 21 of which are singleton copies. The most common HLA-B alleles are B*4001 (f= 0.144), B*4601 (f= 0.119), B*5801 (f= 0.089), B*1301 (f= 0.068), B*1502 (f= 0.073), and B*3802 (f= 0.070). At the HLA-C locus, there are a total of 20 alleles. Four alleles (Cw*0702, Cw*0102, Cw*0801, and Cw*0304) are found at frequencies of greater than 10%, and together, these alleles comprise over 60% of the total. Overall, the class II loci are somewhat less diverse than class I. Twenty-eight distinct alleles are seen at DRB1, and the most common three, DRB1*0901, *1202, and *1501, are each seen at frequencies of greater than 10%. The DR4 lineage also shows extensive expansion in this population, with seven subtypes, representing one quarter of the diversity at this locus. Eight alleles are observed at DQA1; DQA1*0301 and 0102 are the most common alleles, with frequencies over 20%. The DQB1 locus is dominated by four alleles of the 03 lineage, which make up nearly half of the total. The two most common DQB1 alleles in this population are DQB1*0301 (f= 0.242) and DQB1*0303 (f= 0.15). Eighteen alleles are observed at DPB1; DPB1*0501 is the most common allele, with a frequency of 37%. The class I allele frequency distributions, expressed in terms of Watterson's (homozygosity) F-statistic, are all within expectations under neutrality, while there is evidence for balancing selection at DRB1, DQA1, and DQB1. Departures from Hardy-Weinberg expectations are observed for HLA-C and DRB1 in this population. Strong individual haplotypic associations are seen for all pairs of loci, and many of these occur at frequencies greater than 5%. In the class I region, several examples of HLA-B and -C loci in complete or near complete linkage disequilibrium (LD) are present, and the two most common, B*4601-Cw*0102 and B*5801-Cw*0302 account for more than 20% of the B-C haplotypes. Similarly, at class II, nearly all of the most common DR-DQ haplotypes are in nearly complete LD. The most common DRB1-DQB1 haplotypes are DRB1*0901-DQB1*0303 (f= 0.144) and DRB1*1202-DQB1*0301 (f= 0.131). The most common four locus class I and class II combined haplotypes are A*3303-B*5801-DRB1*0301-DPB1*0401 (f= 0.028) and A*0207-B*4601-DRB1*0901-DPB1*0501 (f= 0.026). The presentation of complete DNA typing for the class I loci and haplotype analysis in a large sample such as this can provide insights into the population history of the region and give useful data for HLA matching in transplantation and disease association studies in the Chinese population.

Analysis of the frequencies of HLA-A, B, and C alleles and haplotypes in the five major ethnic groups of the United States reveals high levels of diversity in these loci and contrasting distribution patterns in these populations

The HLA system is the most polymorphic of all human genetic systems. The frequency of HLA class I alleles and their linkage disequilibrium patterns differ significantly among human populations as shown in studies using serologic methods. Many DNA-defined alleles with identical serotypes may have variable frequencies in different populations. We typed HLA-A, B, and C loci at the allele level by PCR-based methods in 1,296 unrelated subjects from five major outbred groups living in the U.S.A (African, AFAM; Caucasians, CAU; Asian, ORI; Hispanic, HIS, and North American Natives, NAI). We detected 46, 100 and 32 HLA-A, B, and C alleles, respectively. ORI and HIS presented more alleles at each of these loci. There was lack of correlation between the levels of heterozygosity and the number of alleles detected in each population. In AFAM, heterozygosity (>90%) is maximized at all class I loci. HLA-A had the lowest heterozygosity in all populations but CAU. Tight LD was observed between HLA-B and C alleles. AFAM had weaker or nonexistent associations between alleles of HLA-A and B than other populations. Analysis of the genetic distances between these and other populations showed a close relationship between specific US populations and a population from their original continents. ORI exhibited the largest genetic distance with all the other U.S. groups and were closer to NAI. Evidence of admixture with CAU was observed for AFAM and HIS. HIS also had significant frequencies of AFAM and Mexican Indian alleles. Differences in both LD and heterozygosity levels suggest distinct evolutionary histories of the HLA loci in the geographical regions from where the U.S. populations originated.

Genetic variability and linkage disequilibrium within the HLA-DP region: analysis of 15 different populations

In order to understand the forces governing the evolution of the genetic diversity in the HLA-DP molecule, polymerase chain reaction (PCR)-based methods were used to characterize genetic variation at the DPA1 and DPB1 loci encoding this heterodimer on 2,807 chromosomes from 15 different populations including individuals of African, Asian, Amerindian, Indian and European origin. These ethnically diverse samples represent a variety of population substructures and include small, isolated populations as well as larger, presumably admixed populations. Ten DPA1 and 39 DPB1 alleles were identified and observed on 87 distinct DP haplotypes, 34 of which were found to be in significant positive linkage disequilibrium in at least one population. Some haplotypes were found in all ethnic groups while others were confined to a single ethnic group or population. Strong positive global linkage disequilibrium (Wn) between DPA1 and DPB1 was present in all 15 populations. The African populations displayed the lowest values of Wn whereas the Amerindian populations displayed near absolute disequilibrium. Analysis of the distribution of haplotypes using the normalized deviate of the Ewens-Watterson homozygosity statistic, F, suggests that DP haplotypes encoding the functional heterodimer are subject to much lower degrees of balancing selection than other loci within the HLA region. Finally, neighbor joining tree analyses demonstrate the power of haplotype diversity for inferring the relationships between the different populations.

Natural course of the human bite wound: incidence of infection and complications in 434 bites and 803 lacerations in the same group of patients

Human bites and common lacerations are frequent in certain residential groups in institutions for the care of developmentally disabled individuals. We screened the records of such an institution and studied the course and outcome of 434 human bite wounds and 803 lacerations in the same group of clients. Infection developed in 13.4% of the lacerations, and 17.7% of the bite wounds (chi 2 = 3.474; p greater than 0.06). Prophylactic antibiotics were administered after 14.0% of the bite wounds, and 3.2% of the lacerations. Infection supervened after prophylactic antibiotics in 29.5% of the bites and 34.6% of the lacerations. No patient with a bite wound required debridement, initial or subsequent surgical intervention other than wound closure, admission to hospital, or intravenous antibiotics. There is no recorded instance of a bite wound complication other than immediate loss of tissue. These data substantiate a higher incidence of infection in human bite wounds, but they are scant support for admonition that such wounds are indication for routine antimicrobial prophylaxis or aggressive surgical intervention.