Relationship of HLA-DQA1 alleles and humoral antibody following measles vaccination

Cellular and Molecular Determinants of Biologic Drugs Resistance and Therapeutic Failure in Inflammatory Bowel Disease

The advent of biologic drugs has revolutionized the treatment of Inflammatory Bowel Disease, increasing rates of response and mucosal healing in comparison to conventional therapies by allowing the treatment of corticosteroid-refractory cases and reducing corticosteroid-related side effects. However, biologic therapies (anti-TNFα inhibitors, anti-α4β7 integrin and anti-IL12/23) are still burdened by rates of response that hover around 40% (in biologic-naïve patients) or lower (for biologic-experienced patients). Moreover, knowledge of the mechanisms underlying drug resistance or loss of response is still scarce. Several cellular and molecular determinants are implied in therapeutic failure; genetic predispositions, in the form of single nucleotide polymorphisms in the sequence of cytokines or Human Leukocyte Antigen, or an altered expression of cytokines and other molecules involved in the inflammation cascade, play the most important role. Accessory mechanisms include gut microbiota dysregulation. In this narrative review of the current and most recent literature, we shed light on the mentioned determinants of therapeutic failure in order to pave the way for a more personalized approach that could help avoid unnecessary treatments and toxicities.

Vaccinomics: A scoping review

BACKGROUND

This scoping review summarizes a key aspect of vaccinomics by collating known associations between heterogeneity in human genetics and vaccine immunogenicity and safety.

METHODS

We searched PubMed for articles in English using terms covering vaccines routinely recommended to the general US population, their effects, and genetics/genomics. Included studies were controlled and demonstrated statistically significant associations with vaccine immunogenicity or safety. Studies of Pandemrix®, an influenza vaccine previously used in Europe, were also included, due to its widely publicized genetically mediated association with narcolepsy.

FINDINGS

Of the 2,300 articles manually screened, 214 were included for data extraction. Six included articles examined genetic influences on vaccine safety; the rest examined vaccine immunogenicity. Hepatitis B vaccine immunogenicity was reported in 92 articles and associated with 277 genetic determinants across 117 genes. Thirty-three articles identified 291 genetic determinants across 118 genes associated with measles vaccine immunogenicity, 22 articles identified 311 genetic determinants across 110 genes associated with rubella vaccine immunogenicity, and 25 articles identified 48 genetic determinants across 34 genes associated with influenza vaccine immunogenicity. Other vaccines had fewer than 10 studies each identifying genetic determinants of their immunogenicity. Genetic associations were reported with 4 adverse events following influenza vaccination (narcolepsy, GBS, GCA/PMR, high temperature) and 2 adverse events following measles vaccination (fever, febrile seizure).

CONCLUSION

This scoping review identified numerous genetic associations with vaccine immunogenicity and several genetic associations with vaccine safety. Most associations were only reported in one study. This illustrates both the potential of and need for investment in vaccinomics. Current research in this field is focused on systems and genetic-based studies designed to identify risk signatures for serious vaccine reactions or diminished vaccine immunogenicity. Such research could bolster our ability to develop safer and more effective vaccines.

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.

Pharmacogenomics and Personalized Medicine for Infectious Diseases

Humans have been plagued by the scourge of invasion by pathogens leading to infectious diseases from the time in memoriam and are still the cause of morbidity and mortality among millions of individuals. Trying to understand the disease mechanisms and finding the remedial measures have been the quest of humankind. The susceptibility to disease of an individual in a given population is determined by ones genetic buildup. Response to treatment and the disease prognosis also depends upon individual’s genetic predisposition. The environmental stress induces mutations and is leading to the emergence of ever-increasing more dreaded infectious pathogens, and now we are in the era of increasing antibiotic resistance that has thrown up a challenge to find new treatment regimes. Discoveries in the science of high-throughput sequencing and array technologies have shown new hope and are bringing a revolution in human health. The information gained from sequencing of both human and pathogen genomes is a way forward in deciphering host-pathogen interactions. Deciphering the pathogen virulence factors, host susceptibility genes, and the molecular programs involved in the pathogenesis of disease has paved the way for discovery of new molecular targets for drugs, diagnostic markers, and vaccines. The genomic diversity in the human population leads to differences in host responses to drugs and vaccines and is the cause of poor response to treatment as well as adverse reactions. The study of pharmacogenomics of infectious diseases is still at an early stage of development, and many intricacies of the host-pathogen interaction are yet to be understood in full measure. However, progress has been made over the decades of research in some of the important infectious diseases revealing how the host genetic polymorphisms of drug-metabolizing enzymes and transporters affect the bioavailability of the drugs which further determine the efficacy and toxicology of the drugs used for treatment. Further, the field of structural biology and chemistry has intertwined to give rise to medical structural genomics leading the way to the discovery of new drug targets against infectious diseases. This chapter explores how the advent of “omics” technologies is making a beginning in bringing about a change in the prevention, diagnosis, and treatments of the infectious diseases and hence paving way for personalized medicine.

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.

Human leukocyte antigen type and progression from onset of symptoms to development of asthma

This study investigated the influence of human leukocyte antigen (HLA) genes on the progression of asthma, from the initial onset of symptoms to when criteria for asthma are met. Study subjects were a subsample (n = 340) of 838 healthy children, aged 5-12 years, who participated in a previous study, and who had HLA data and asthma status. The duration in time from the initial onset of asthma symptoms documented in each subject's medical records to the index date when the subject first met criteria for asthma was determined. The time duration was compared between carriers and noncarriers of HLA genes of interest of the 340 original subjects with HLA data available, 114 children (33.5%) met criteria for asthma before 18 years of age. The median ages at onset of asthma symptoms and at the index date of asthma were 4.4 years and 7.2 years, respectively. The median time intervals between onset of symptoms and index date for HLA DRB1*11 carriers and noncarriers were 552 versus 61 days, respectively (p = 0.004). The same time intervals for HLA DQB1*0301 carriers and noncarriers were 420 versus 59 days, respectively (p = 0.012). However, HLA DQB1*0302 or DRB1*03 carriers had shorter median intervals, when compared with noncarriers (119 versus 266 days, respectively, p = 0.20; and 86 versus 258 days, respectively, p = 0.38) but they did not reach statistical significance. HLA type appears to influence the progression of asthma from initial symptoms to disease. Thus, genetic factors may affect the natural history of asthma.

Does length-based resuscitation tape accurately place pediatric patients into appropriate color-coded zones?

OBJECTIVE

To determine relationship between length-based resuscitation tape (LBT)-based color-coded zones and actual weight-based color-coded zones.

METHODS

Data were retrospectively abstracted from 839 patients in Rochester, Minnesota, at birth, 4 to 6, and 10 to 12 years. Height was plotted on LBT to determine estimated weight and corresponding color zone. Patient's weight-based color zone was obtained by plotting measured weight on LBT. Degrees of discrepancy between length-based and actual weight-based color zones were assessed.

RESULTS

Total of 544, 520, and 143 subjects were analyzed at birth, 4 to 6, and 10 to 12 years, respectively, with a subset of 103 subjects measured longitudinally at more than 1 age strata. Among infants, all LBT color zones were the same as actual weight-based color zones. In children aged 4 to 6 years, 70% (n = 361) of LBT-estimated color zones were the same as actual weight-based color zones; LBT underestimated 19% (n = 99) by 1 color zone, 0.5% (n = 3) were underestimated by 2 color zones, 0.5% (n = 3) exceeded weight limit on LBT, and 10% (n = 54) were overestimated by 1 color zone. In adolescents aged 10 to 12 years, 40.6% (n = 58) of LBT-estimated color zones were the same as actual weight-based color zones; LBT underestimated 3.5% (n = 5) by 1 color zone, 44.1% (n = 63) exceeded weight limit on LBT, 11.2% (n = 16) were overestimated by 1 color zone, and 0.6% (n = 1) were overestimated by 2 color zones.

CONCLUSIONS

Overall, LBT reasonably estimates appropriate color zones for drug dosing. However, LBT tends to underestimate color zones among younger obese children and adolescents. Potential implications of the rising trend of overweight children on resuscitation practice and drug administration must be considered.

Severity of childhood asthma and human leukocyte antigens type

We sought to learn if Class II HLA genes are associated with the severity of asthma in children. We examined a previously recruited cohort of 340 healthy children who had Class II HLA allele data available. We conducted a comprehensive review of their medical records to determine asthma status and, when present, its severity. We found that Class II HLA alleles, which were previously reported to have an association with asthma incidence, appear to have an association as well with asthma severity. These data support our hypothesis that both the incidence and severity of asthma are heritable and that HLA may play an important role in both development and severity of asthma. Because of limited statistical power, our study findings are subject to further investigation.

Childhood asthma and human leukocyte antigen type

Little is known about the relationship between human leukocyte antigen (HLA) class II genes and family history of asthma or atopy in relation to the incidence of childhood asthma. The objective of the study was to determine whether specific HLA class II genes (e.g., DRB1*03) are associated with asthma and whether such association explains the influences of family history of asthma or atopy on asthma incidence. A stratified random sample of 340 children who had HLA data available from the Rochester Family Measles Study cohort (n= 876) and a convenience sample of healthy children aged 5-12 years were the participants. We conducted comprehensive medical record reviews to determine asthma status of these children. The associations between the presence of specific HLA alleles and development of asthma and the role of family history of asthma or atopy in the association were evaluated by fitting Cox models. The cumulative incidence of asthma by 12 years of age among children who carry HLA DRB1*03 was 33%, compared to 24.2% among those who did not carry this allele. Adjusting for family history of asthma or atopy, gender, low birth weight, season of birth, HLA DRB1*04, and HLA DQB1*0302, the hazards ratio for HLA DRB1*03 carriers was 1.8 (95% confidence interval: 1.1-2.9, P= 0.020). We concluded that the HLA DRB1*03 allele is associated with asthma. However, the HLA class II gene does not explain the influences of family history of asthma or atopy on development of asthma. The mechanism underlying the association between asthma and HLA genes needs to be elucidated.

Human leukocyte antigen polymorphisms: variable humoral immune responses to viral vaccines

Antibody formation in response to antigen stimulation remains the basis for measuring an individual's response and protection for most viral vaccines. A significant proportion of the variation in individual humoral immune response to vaccination appears to be genetic. The collection of genes found on chromosome 6 forming the human leukocyte antigen system provides one of the greatest sources of genetic variation in individuals with respect to their immunological responses. Recent research has demonstrated significant associations between vaccine response and human leukocyte antigen alleles. These associations not only explain why vaccine-induced humoral immune responses vary among individuals and between populations, but these variations may also hold the key to the development of future generations of vaccines.

Hypertrophic osteodystrophy in the Weimaraner dog: lack of association between DQA1 alleles of the canine MHC and hypertrophic osteodystrophy

Hypertrophic osteodystrophy (HOD) is a canine bone disease that affects mainly large breed dogs, including the Weimaraner, and studies have shown a link between recent vaccination with a modified live virus and the onset of HOD in this breed. In humans, it has been suggested that human leukocyte antigen (HLA) alleles can influence antibody response to vaccination. The aim of this study was to investigate whether there is an association between the development of HOD in Weimaraners and MHC alleles at the DLA-DQA1 locus in a group of 33 unrelated dogs. The DQA1 allele and genotype frequencies were determined by sequence-based typing. Although clinical signs developed within six weeks of vaccination in all 12 dogs for which information was available, no association was found between DQA1 alleles and HOD in this population of Weimaraner dogs. A role for other immune-response genes in the pathogenesis of HOD should not however be ruled out. Whereas recent vaccination may be a trigger for the disease, it was concluded that there is no specific vaccine that is most responsible for the expression of the disease.

Association of chronic fatigue syndrome with human leucocyte antigen class II alleles

BACKGROUND

A genetic component to the development of chronic fatigue syndrome (CFS) has been proposed, and a possible association between human leucocyte antigen (HLA) class II antigens and chronic fatigue immune dysfunction has been shown in some, but not all, studies.

AIMS

To investigate the role of HLA class II antigens in CFS.

METHODS

Forty nine patients with CFS were genotyped for the HLA-DRB1, HLA-DQA1, and HLA-DQB1 alleles and the frequency of these alleles was compared with a control group comprising 102 normal individuals from the UK. All patients and controls were from the same region of England and, apart from two patients, were white.

RESULTS

Analysis by 2 x 2 contingency tables revealed an increased frequency of HLA-DQA1*01 alleles in patients with CFS (51.0% v 35%; odds ratio (OR), 1.93; p = 0.008). HLA-DQB1*06 was also increased in the patients with CFS (30.2% v 20.0%; OR, 1.73, p = 0.052). Only the association between HLA-DQA1*01 and CFS was significant in logistic regression models containing HLA-DQA1*01 and HLA-DRQB1*06, and this was independent of HLA-DRB1 alleles. There was a decreased expression of HLA-DRB1*11 in CFS, although this association disappeared after correction for multiple comparisons.

CONCLUSIONS

CFS may be associated with HLA-DQA1*01, although a role for other genes in linkage disequilibrium cannot be ruled out.

Frequency and distribution of alleles of canine MHC-II DLA-DQB1, DLA-DQA1 and DLA-DRB1 in 25 representative American Kennel Club breeds

The frequency and distribution of dog leucocyte antigens (DLA) class II -DQA1, -DQB1 and -DRB1 alleles were determined for 25 American Kennel Club (AKC) registered dog breeds, representing 360 dogs from each of the seven major performance categories. Six to twenty-eight (average n=11) dogs were studied per group, with the exception of the Akita dog (n=94). All dogs were unrelated with no common grandparents based on AKC pedigree records (F-value <0.125). DLA class II allelic diversity was broad across breeds; 31/61 published DLA-DRB1 alleles, 11/18 published DLA-DQA1 alleles and 31/47 published DLA-DQB1 alleles were found among the 25 breeds. However, allelic diversity was severely limited within a breed. Seventeen of the DLA-DRB1 alleles were each found in only a single breed, and only seven alleles were shared by seven or more breeds. DLA-DRB1*00101 and DLA-DRB1*01501 were shared by 16 and 19 breeds, respectively. DLA-DQA1*00101 and DLA-DQA1*00601 alleles were shared by many breeds. The Rough Collie (DLA-DQA1*00901), English Setter (DLA-DQA1*00101) and Scottish Terrier (DLA-DQA1*00101) were monoallelic for DLA-DQA1. Eleven DLA-DQB1 alleles were each found only in a single breed and only seven alleles were shared by six or more breeds. DLA-DQB1*00201 and DLA-DQB1*02301 were shared by 17 and 18 breeds, respectively. Forty per cent of dogs typed were homozygous at DLA-DRB1, 52% at DLA-DQA1 and 44% at DLA-DQB1. Nine new DLA class II alleles were identified; three for DRB1 and six for DQB1. Comparison of our study of North American purebred dogs to previous European DLA surveys showed a similar use of common alleles consistent with known founder effects. However, more alleles were detected in European breeds, compared to their North American descendents, indicating that additional DLA class II diversity was lost when European breeds were established in North America.

Associations between human leukocyte antigen (HLA) alleles and very high levels of measles antibody following vaccination

Associations between human leukocyte antigen (HLA) genes and very high levels of antibodies (or hyperseroresponsiveness) to measles antigens in a genetically heterogeneous human population are poorly understood. We studied the association between antibody levels after measles vaccination and HLA class I and II alleles among 170 US schoolchildren who received one dose of measles-mumps-rubella II vaccine. Vaccine recipients were divided into two groups: 93 recipients who were seropositive and 77 recipients who were hyperseropositive (the upper 10th percentile of antibody levels of all subjects). Out of all the alleles analyzed, HLA-B(*)7 (odds ratio (OR) 1.9; P = 0.05), DQA1(*)0104 (OR 4.6; P = 0.02) and DPA1(*)0202 (OR 4.8; P = 0.04) alleles were positively associated with hyperseropositivity, whereas HLA-B(*)44 (OR 0.4; P = 0.02), DRB1(*)01 (OR 0.6; P = 0.09), DRB1(*)08 (OR 0.3; P = 0.04), DQB1(*)0301 (OR 0.5; P = 0.04), and DPB1(*)0401 (OR 0.6; P = 0.03) alleles were negatively associated with hyperseropositivity. The alleles B(*)44, DRB1(*)01, DRB1(*)08 and DQA1(*)0104 remained statistically significant after accounting for the effects of other alleles. The results suggest that HLA alleles have important associations with measles antibody hyperseropositivity. These data increase our understanding of measles vaccine-induced immune response and will be useful for future mechanistic work on measles virus antigen processing and presentation in seronegative and hyperseropositive individuals.

The genetic basis for measles vaccine failure

The US measles epidemics of 1989-1991 included a series of outbreaks resulting from vaccine failure. A series of studies was launched aimed at elucidating the mechanisms of this vaccine failure. A meta-analysis of the literature examining epidemics in vaccinated populations was conducted, which showed that the secondary vaccine failure rate (development of the disease despite an initial or primary vaccine success) is no more than 0.2%. The overwhelming proportion of measles vaccine failure was due to primary vaccine failure (failure to ever generate antibody from antigenic stimulation). This comparison of two geographically distinct communities revealed that 10% of children previously vaccinated against measles lacked antibody on follow-up and that these vaccine failures clustered in families. A study of monozygotic and dizygotic twins revealed a high degree of heritability of measles vaccine antibody level. Subsequent studies found associations with both class I and class II alleles in these population-based studies. In the future, detection of the specific peptides that interact with human leukocyte antigen (HLA) molecules may serve as the basis for improved vaccines and address vaccine failure that results from cold-chain problems, immaturity of the immune system, malnutrition and maternal immunity.

Associations between measles antibody levels and the protein structure of class II human leukocyte antigens

In this study, we describe associations between variation in human leukocyte antigen (HLA) DP and DQ amino acid sequences and low measles antibody levels after measles immunization. We tested serum samples from 242 children for measles immunoglobulin G antibodies. We performed class II HLA typing and examined associations between DQ and DP exon 2 amino acid sequences and antibody levels. No DP amino acid variants were associated with seronegativity. However, 11 DQA and 6 DQB amino acid variants were associated with seronegativity (p<0.005). These amino acid variants were highly correlated, and the significant DQA amino acids were only found in alleles *0201, *0301, *0401, *0501, and *0601. Two of the amino acids associated with measles seronegativity were located in predicted binding pockets of the DQ molecule; one was present in the leader sequence. Among the DQB alleles, all of the amino acid variants associated with seronegativity were present only in the DQB*0201 allele. Two of the amino acids associated with seronegativity were located in predicted binding pockets of the DQ molecule; two were located in the leader sequence. Our data suggest that specific DQA and DQB amino acid variations are associated with measles seronegativity after vaccination.

Lack of association between transporter associated with antigen processing (TAP) and HLA-DM gene polymorphisms and antibody levels following measles vaccination

The transporter associated with antigen processing (TAP) and human leukocyte antigen-DM (HLA-DM) genes are involved in the antigen-processing pathway of both HLA class I and class II-restricted antigen presentation. We hypothesized that polymorphisms within the TAP and DM genes may influence antibody levels following measles vaccination. We examined TAP and DM polymorphisms in 242 school children from Olmsted County, Minnesota, USA who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months. Based on the level of serum measles-specific immunoglobulin G (IgG) antibodies, subjects were classified as seronegatives (n = 72) or seropositives (n = 170). We determined TAP1 and TAP2 allele types by polymerase chain reaction (PCR) amplification of specific alleles (PASA) and determined DM allele type by PCR amplification followed by direct sequencing of the polymorphic sites. We analysed the data for any TAP or DM allelic association with antibody levels post measles vaccination using the chi-square test and univariate linear regression analysis. We found no trend in the overall distribution of TAP and DM genotype frequencies between seronegative and seropositive subjects, suggesting that TAP and DM polymorphism and antibody levels following measles vaccination are not directly associated. In addition, we did not find an association between TAP (TAP1, P = 0.71; TAP2, P = 0.87) or DM (DMA, P = 0.42; DMB, P = 0.71) homozygosity and seronegativity to measles vaccine in this study group. Our study suggests that TAP and DM gene polymorphisms do not influence antibody levels post measles vaccination.

High-dose hepatitis B vaccine in patients waiting for lung transplantation

STUDY OBJECTIVE

To increase the response rate to hepatitis B vaccine in patients awaiting lung transplantation.

DESIGN

Historically controlled, open-label study.

SETTING

Lung transplant clinic at a university hospital.

SUBJECTS

Twenty-seven consecutive individuals with end-stage pulmonary disease who were enrolled to accrue 15 subjects who would complete the vaccine series before transplantation; and 27 lung transplant recipients who were immunized with the conventional dose before the study and served as historical controls.

INTERVENTION

Intramuscular injection of high-dose hepatitis B vaccine 40 microgram at 0, 1, and 6 months.

MEASUREMENTS AND MAIN RESULTS

Hepatitis B surface antibody (anti-HBs) concentrations were measured 1-2 months after completing the high-dose series. Individuals with undetectable anti-HBs received additional vaccine to a maximum of six doses. The response rate to the series was compared with that in the control group. Seventeen individuals in the high-dose group and 14 controls met the study criterion of complete vaccine series before transplantation. The former had a much higher response rate than the latter (9 [53%] vs 1 [7%], p<0.01). Four of six patients who received additional doses of vaccine seroconverted. Two of them underwent transplantation shortly after completing the three-dose series.

CONCLUSION

The high-dose hepatitis B vaccine series produced a protective immune response in lung transplant recipients; however, the response was suboptimal, and alternative immunization strategies should be studied.

The association of class I HLA alleles and antibody levels after a single dose of measles vaccine

Despite the success of the current measles vaccine in controlling disease in industrialized countries, the importance of vaccine failure has become increasingly apparent. Our objective was to determine if associations exist between seronegativity after measles vaccination and class I human leukocyte antigen (HLA) alleles. We undertook a cross-sectional observational study in Rochester, Minnesota, with 242 school-age children previously recruited from a communitywide seroprevalence study. We studied two groups of subjects: 72 were seronegative (EIA < or =0.8 after a single dose of measles vaccine) and 170 were seropositive (enzyme immunoassy [EIA] > or =1.0 after one dose). We used the resources of Mayo Clinic's tissue typing laboratory for serotyping class I HLA-A and HLA-B alleles via microlymphocytotoxicity assays. We found no statistically significant associations with class I HLA-A but did find associations with class I HLA-B, which includes alleles associated with seronegativity (B8, B13, and B44) and those associated with seropositivity (B7 and B51). Elucidation of the specific peptide-HLA complex interactions that lead to varying or failed immune responses may provide fertile groundwork for improved vaccines that can overcome limitations of the current live, attenuated measles vaccine.

Immune responses to measles and measles vaccine: challenges for measles control

Most strategies for reducing global measles morbidity and mortality and eliminating measles are based on the ability to enhance immune responses to measles virus. Challenges to measles elimination and eradication are based in part on the need to sustain high levels of population immunity to interrupt transmission of measles virus. We review aspects of the immunology of measles and measles vaccination with the aim of demonstrating how knowledge of the immune responses is essential to furthering the goals of reducing measles morbidity and mortality and the elimination of measles. Better understanding of the mechanisms of immune suppression after measles, the potential for alternative vaccination strategies to induce immunity in young infants, and the immunologic basis of atypical measles, increased mortality after high-titer measles vaccine, and waning immunity will lead to improved strategies for measles control and elimination.

Association of parental vaccination reports with measles, mumps, and rubella protective antibody levels: comparison of Somali immigrant, Hispanic migrant, and US children in Rochester, Minn

OBJECTIVES

To compare measles, mumps, and rubella antibody levels in Somali immigrant, Hispanic migrant, and US children in Rochester, Minn, and to determine whether parental vaccination reports predict seropositivity.

SUBJECTS AND METHODS

From 1995 to 1997, we conducted a cross-sectional analysis using measles, mumps, and rubella antibody levels obtained from a sample of Somali, Hispanic, and Rochester children. Volunteers provided blood samples, vaccination histories, and demographic information. We assessed differences in measles, mumps, and rubella antibody levels among the 3 groups of children and calculated positive and negative predictive values to determine whether parental report of vaccination predicted seropositivity.

RESULTS

Study participants included 79 Hispanic migrant, 69 Somali immigrant, and 730 Rochester children. Somali children reported vaccination at significantly older ages compared with Hispanic or Rochester children (P<.001). Most children were seropositive for all 3 antibodies. Parental reports of vaccination had high positive predictive values (71%-100%) but low negative predictive values (0%-50%).

CONCLUSION

Somali and Hispanic children were as likely as Rochester children to be seropositive for measles, mumps, and rubella antibodies despite poor documentation of vaccination. Somali children, however, tended to receive vaccinations at significantly older ages than Hispanic and Rochester children.

Identification of an association between HLA class II alleles and low antibody levels after measles immunization

This is the first large cohort study to report a genetic association between humoral antibody level after measles vaccine and the HLA class II genes. The WHO goal to eradicate measles world-wide magnifies the importance of data relating to the influence of immunogenetics on measles vaccine-induced antibody responses. We present here the analysis of 242 individuals who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months and were genotyped for HLA class II alleles. These subjects fit into one of three categories; 72 were classified as seronegative, 93 were seropositive and 77 were serohyperpositive. HLA-DRB1*03 (odds ratio (OR), 2.22) and HLA-DPA1*0201 (OR, 1.71) were significantly associated with measles vaccine seronegativity, while additional alleles provided suggestive evidence of association with seronegativity: DQA1*0201, DQB1*0201, and DQA1*0501. The alleles DRB1*03 and DQA1*0201 remained statistically significant after accounting for the effects of other alleles. These findings are crucial in designing both measles eradication by the use of vaccine, and future vaccines to be used in genetically heterozygous populations.

Twin studies of immunogenicity--determining the genetic contribution to vaccine failure

CONTEXT

Estimating the magnitude of the genetic contribution to the overall variation of antibody levels among individuals should help clarify the role of genetic association in the biological mechanism of vaccine response and failure. This, in turn, should help guide the design of improved vaccines with enhanced efficacy.

OBJECTIVE

To explore the magnitude of genetic influence on antibody levels following measles, mumps and rubella vaccines.

DESIGN

Cross-sectional survey study.

SETTING

Olmsted County, Minnesota.

PARTICIPANTS

Healthy twin-pairs. Of the 100 twin-pairs enrolled, 45 were monozygotic.

INTERVENTIONS

Determinations of zygosity, vaccine status, and quantitative IgG to measles, mumps, and rubella.

MAIN OUTCOME MEASURE

Heritability (ratio of genetic variance to total variance).

RESULTS

The number of vaccine-doses, the age at initial immunization, and the time between immunization and sampling did not differ between monozygotic and dizygotic twin pairs. The genetic variance - the variance in antibody levels presumably due to genetic effects - was 0.49 for measles, 0.54 for mumps, and 0.13 for rubella. Heritability, the ratio of genetic variance to total variance, was 88.5% for measles, with the lower bound of a one-sided 95% confidence interval equal to 52.4%. The heritability was, for mumps, 38.8% with a lower bound of 1.60%. The heritability for rubella was 45.7% with a lower bound of 4.94%.

CONCLUSION

Our data support the concept that genetic influences play a substantial role in the variation of antibody levels following immunization against measles and, to a lesser extent, mumps and rubella.

High frequency of HLA-A*0103 allele in a Somali population

We report the existence of class I HLA allele A*0103 in an ethnic group (Somali) where this allele has not been reported. This allele was discovered in a study to examine the relationship between HLA alleles and humoral antibody response to measles vaccine among recent immigrants from Somalia to Olmsted County, Minnesota. We initially used polymerase chain reaction-sequence-specific primers (PCR-SSP) to carry out HLA class I typing. Based on PCR-SSP, 55 subjects were assigned the allele HLA-A*0101. Following direct DNA sequencing of the PCR products, 37 of the 55 subjects (67.3%) that were initially assigned the A*0101 allele were found to actually be A*0103. Our data are significant because it demonstrates that many of the previously typed A*0101 individuals are actually A*0103 as the SSP or sequence-specific oligonucleotide probes method cannot distinguish between the two alleles. Lastly, this is the first identification of this allele in the homozygous state.

Correlations between measles, mumps, and rubella serum antibody levels in Olmsted County school children

We examined correlations between serum antibody levels to determine whether individuals with low levels of antibody to one component of the measles, mumps, and rubella (MMR) vaccine were also likely to have low antibody levels to the other MMR vaccine components. Our results indicate that children who had a low antibody level to one component of the MMR vaccine had a modest probability of having a low antibody level to either of the other MMR vaccine components. Overall, we found small, but statistically significant, correlations between antibody levels that were largely unaffected by race, sex, age at immunization, and time since immunization. While the correlations we observed were modest, approximately 25% of our population was seronegative for at least one component of the MMR vaccine. Therefore, our results support the current policy of continuing to administer the trivalent MMR vaccine even when only a single low antibody titer is observed.

Response to different measles vaccine strains given by aerosol and subcutaneous routes to schoolchildren: a randomised trial

BACKGROUND

More than one dose of measles vaccine is necessary for the sustained control of measles. The aerosol route is thought to be more immunogenic for booster doses than traditional subcutaneous injections, so we did a randomised comparative trial of aerosol and subcutaneous measles vaccines in South African schoolchildren.

METHODS

4327 schoolchildren (aged 5-14 years), assigned by block randomisation of classrooms, received standard titre doses of either Schwarz or Edmonston-Zagreb measles vaccines subcutaneously or by aerosol. Blood samples for antibody assay were collected before vaccination, at 1 month, and 1 year after vaccination. The main endpoints (antibody titres at 1 month and 1 year) were compared between groups.

FINDINGS

992 children had antibody titre data available for all timepoints. 14 (3.6%) of 385 children who received Edmonston-Zagreb vaccine by aerosol were seronegative 1 year after vaccination, compared with 28 (8.6%) of 326 children who received Edmonston-Zagreb subcutaneous vaccine and 39 (13.9%) of 281 children who received Schwarz subcutaneous vaccine. At 1 month, 326 (84.7%) children who received aerosol Edmonston-Zagreb vaccine had seroconverted, compared with 257 (78.8%) who received subcutaneous Edmonston-Zagreb vaccine and 176 (62.6%) who received subcutaneous Schwarz vaccine. At 1 month, only 116 (22.7%) of 511 children in the Schwarz aerosol group had seroconverted; this aerosol vaccine had no detectable potency after 2 min of nebulisation. There were no serious side-effects: about 5% of children in each group had a rash within 2 weeks of vaccination.

INTERPRETATION

An aerosol vaccination method that uses currently available devices and a suitably stable vaccine is effective and acceptable. This form of delivery is adaptable to mass campaigns, avoids the risks associated with injections, and could help measles eradication.

Immunogenetic mechanisms of antibody response to measles vaccine: the role of the HLA genes

Measles is the most transmissible human disease known to date. In the prevaccine era, virtually every member of each birth cohort was infected with this virus, leading to substantial morbidity and mortality, with millions of deaths on a global scale. At the current time, measles causes an estimated 1 to 1.5 million deaths per year world-wide. Since the advent of live, attenuated measles vaccines measles has been controlled, but not eradicated. Central to the goal of measles eradication are data relating to the influence of immunogenetics on vaccine immunogenicity. In this paper, the results of studies are reviewed executed in my laboratory examining the role of the class I and II HLA genes on the antibody response to measles vaccine.