Median Antibody Levels Research Articles

Evaluation of antibody responses to panels of M. tuberculosis antigens as a screening tool for active tuberculosis in Uganda.

BackgroundImproved systematic screening of high-risk groups is a key component of the tuberculosis (TB) elimination strategy endorsed by the World Health Organization (WHO). We used a multiplex microbead immunoassay to measure antibody responses to 28 M. tuberculosis (M.tb) antigens, and assessed whether combinations of antibody responses achieve accuracy thresholds required for a TB screening test.MethodsA random selection of plasma samples obtained from consecutive HIV-negative adults who were admitted to Mulago Hospital in Kampala, Uganda with cough ≥2 weeks’ but <6 months’ duration were analyzed for serological response to 28 M.tb antigens using an in-house multiplex microbead immunoassay. We compared the median difference of the antibody response to each antigen between patients with and without culture-confirmed TB, ranked each antigen according to variable importance (VIM), and assessed the sensitivity and specificity of combinations of antibody responses using an advanced classification algorithm, SuperLearner.ResultsAmong the 237 patients included in the analysis, 119 (50%) were female, median age was 32 years (IQR 25, 46), and 113 (48%) had TB. Median antibody levels to eight antigens were significantly different between patients with and without TB. A panel including eight of the top ranked antigens had a sensitivity of 90.6% (95% CI 89.4, 93.8) and a specificity of 88.6% (95% CI 78.2, 97.6) (Ag85B, Ag85A, Ag85C, Rv0934-P38, Rv3881, BfrB, Rv3873, and Rv2878c). With sensitivity constrained to be >90%, specificity remained close to 70% with as few as 3 antigens included in the panels.ConclusionsMeasuring antibody responses to combinations of antigens could facilitate TB screening and should be further evaluated in populations being targeted for systematic screening.

Exploring the effect of vitamin D3 supplementation on the anti-EBV antibody response in relapsing-remitting multiple sclerosis

Background: Epstein–Barr virus (EBV) infection and vitamin D insufficiency are potentially interacting risk factors for multiple sclerosis (MS). Objectives: To investigate the effect of high-dose vitamin D3 supplements on antibody levels against the EBV nuclear antigen-1 (EBNA-1) in patients with relapsing-remitting multiple sclerosis (RRMS) and to explore any underlying mechanism affecting anti-EBNA-1 antibody levels. Methods: This study utilized blood samples from a randomized controlled trial in RRMS patients receiving either vitamin D3 (14,000 IU/day; n = 30) or placebo (n = 23) over 48 weeks. Circulating levels of 25-hydroxyvitamin-D, and anti-EBNA-1, anti-EBV viral capsid antigen (VCA), and anti-cytomegalovirus (CMV) antibodies were measured. EBV load in leukocytes, EBV-specific cytotoxic T-cell responses, and anti-EBNA-1 antibody production in vitro were also explored. Results: The median antibody levels against EBNA-1, but not VCA and CMV, significantly reduced in the vitamin D3 group (526 (368–1683) to 455 (380–1148) U/mL) compared to the placebo group (432 (351–1280) to 429 (297–1290) U/mL; p = 0.023). EBV load and cytotoxic T-cell responses were unaffected. Anti-EBNA-1 antibody levels remained below detection limits in B-cell cultures. Conclusion: High-dose vitamin D3 supplementation selectively reduces anti-EBNA-1 antibody levels in RRMS patients. Our exploratory studies do not implicate a promoted immune response against EBV as the underlying mechanism.

Helminth infections on organic dairy farms in Spain

The aim of this study was to assess the prevalence of the major helminth infections affecting organic dairy cattle in northern Spain. Milk and faecal samples were obtained from 443 milking cows. Ostertagia ostertargi and Fasciola hepatica exposure was assessed by detection of specific antibodies in milk samples and F. hepatica infection was diagnosed by the detection of coproantigens in faecal samples. Dictyocaulus viviparus and Calicophoron daubneyi infections were diagnosed by conventional coprological techniques. The prevalence of infections caused by F. hepatica was considerable low, but similar to data reported from conventional farming in the same area. The prevalence rate of C. daubneyi infection was higher than previous data mirroring an increase of the prevalence that was also reported in other European countries in recent years. Specific antibodies against O. ostertargi were detected in all herds and the median levels of antibodies, determined by ELISA, exceeded the thresholds indicating milk production losses. The prevalence of D. viviparus was almost negligible. For each parasite, an ordinal logistic-regression analysis was used to assess the risk of infection by taking into account the administration of effective anthelmintics and the number of lactations. Treatment of cows with fasciolicides decreased the risk of F. hepatica infection in multiparous cows, whereas treatment with oxiclozanide or albendazol did not decrease the risk of C. daubneyi infection or O. ostertargi exposure, respectively. The study findings demonstrate that helminth infection in organic dairy farming is similar or even lower than previous data reported from conventional farming. Special attention should be paid to the impact of these infections on milk production.

Salivary and serum HPV antibody levels before and after definitive treatment in patients with oropharyngeal squamous cell carcinoma.

HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) is increasing in incidence. Laboratory assays that identify virally-mediated disease and predict HPV clearance in OPSCC may have important prognostic implications. Here we investigated serum, salivary HPV16 early (E) antibodies before and after definitive chemoradiotherapy (CRT) in patients with locoregionally advanced OPSCC. We prospectively measured salivary, serum samples at the beginning of and 6-7 weeks following the completion of CRT in 44 patients. IgG antibodies targeting N- and C-terminal fragments of E2 (NE2, CE2), E6 and E7 were measured by programmable enzyme-linked immunosorbent assay. We observed serum antibodies directed against HPV-associated E proteins in patients with HPV-associated OPSCC. E7 directed antibodies were detected in saliva in the majority of patients, and were associated with HPV status (p= 0.03). When analyzed longitudinally, median salivary E7 antibody levels decreased significantly post-treatment (p= 0.007). Our results demonstrate the feasibility of measuring HPV16 E antibodies in saliva and serum. E7 antibodies, in particular, are more detectable in saliva as compared with other E protein antibodies. Measuring E7 salivary antibody levels at various time points may have utility in understanding HPV clearance and should be explored for their ability to predict the risk of recurrence.

Avidity of anti-malarial antibodies inversely related to transmission intensity at three sites in Uganda

BackgroundPeople living in malaria endemic areas acquire protection from severe malaria quickly, but protection from clinical disease and control of parasitaemia is acquired only after many years of repeated infections. Antibodies play a central role in protection from clinical disease; however, protective antibodies are slow to develop. This study sought to investigate the influence of Plasmodium falciparum exposure on the acquisition of high-avidity antibodies to P. falciparum antigens, which may be associated with protection.MethodsCross-sectional surveys were performed in children and adults at three sites in Uganda with varied P. falciparum transmission intensity (entomological inoculation rates; 3.8, 26.6, and 125 infectious bites per person per year). Sandwich ELISA was used to measure antibody responses to two P. falciparum merozoite surface antigens: merozoite surface protein 1-19 (MSP1-19) and apical membrane antigen 1 (AMA1). In individuals with detectable antibody levels, guanidine hydrochloride (GuHCl) was added to measure the relative avidity of antibody responses by ELISA.ResultsWithin a site, there were no significant differences in median antibody levels between the three age groups. Between sites, median antibody levels were generally higher in the higher transmission sites, with differences more apparent for AMA-1 and in ≥5 year group. Similarly, median avidity index (proportion of high avidity antibodies) showed no significant increase with increasing age but was significantly lower at sites of higher transmission amongst participants ≥5 years of age. Using 5 M GuHCl, the median avidity indices in the ≥5 year group at the highest and lowest transmission sites were 19.9 and 26.8, respectively (p = 0.0002) for MSP1-19 and 12.2 and 17.2 (p = 0.0007) for AMA1.ConclusionAvidity to two different P. falciparum antigens was lower in areas of high transmission intensity compared to areas with lower transmission. Appreciation of the mechanisms behind these findings as well as their clinical consequences will require additional investigation, ideally utilizing longitudinal data and investigation of a broader array of responses.

Seroprevalence of Bordetella pertussis specific Immunoglobulin G antibody levels among asymptomatic individuals aged 4 to 24years: a descriptive cross sectional study from Sri Lanka.

BackgroundIn Sri Lanka pertussis continues to circulate in the community and cases among adolescents and adults have been reported despite 95% coverage of the four dose pertussis vaccination during early childhood. Waning of immunity following natural infection or immunization may contribute to the persistent circulation. An adolescent booster dose is not included in the national immunization schedule of Sri Lanka, although this is routine practice in many countries. Therefore information on immunity to pertussis in the adolescent group is needed prior to considering vaccination schedule changes.MethodsThe quantitative determination of specific Immunoglobulin G antibodies to Bordetella pertussis toxin was done using a commercially available validated ELISA method. The antibody values were categorized into groups according to the interpretive criteria provided by the manufacturer. The values were <55 IU/mL, negative; 55–<60 IU/mL, borderline; 60–125 IU/mL, positive; >125, strongly positive respectively. Sera of 385 asymptomatic individuals aged 4 to 24 years admitted to surgical units of Lady Ridgeway Hospital, Colombo and Colombo South Teaching Hospital were used for the study. Mann-Whitney U and Kruskal-Wallis tests were used in analysis of results and p ≤0.05 was considered as statistically significant. Details of epidemiological variables were collected using a questionnaire and correlation with significant levels of pertussis antibodies was determined.ResultsMedian age of the study population was 12 years with 212 (55.1%) females. The median anti PT antibody level was 3.31 IU/mL and 352 (91%) had anti PT levels ≤55 IU/mL. Median of anti PT levels were 3.18 IU/mL for 4–7 years, 1.43 IU/mL (IQR 0.336–6.27) for 8–11 years, 4.28 IU/mL (IQR 0.978–13.39) for 12–15 years, 6.14 IU/mL for 16–19 years and 4.89 IU/mL for 20–24 years and the differences were statistically significant (p = 0.000). Females (p < 0.003) and those having a sibling aged ≥12 years (p = 0.017) had significantly higher anti PT levels.ConclusionsThe majority of the study population, especially 8 to 11 year age group had low anti PT IgG levels. The higher antibody titers in the 12–15 year age group seem to indicate infection in early adolescence. A booster dose of acellular pertussis vaccine need to be considered.

Changes in Antibody Levels during and following an Episode of Acute Adenolymphangitis (ADL) among Lymphedema Patients in Léogâne, Haiti.

IntroductionEpisodes of acute adenolymphangitis (ADL) are often the first clinical sign of lymphatic filariasis (LF). They are often accompanied by swelling of the affected limb, inflammation, fever, and general malaise and lead to the progression of lymphedema. Although ADL episodes have been studied for a century or more, questions still remain as to their etiology. We quantified antibody levels to pathogens that potentially contribute to ADL episodes during and after an episode among lymphedema patients in Léogâne, Haiti. We estimated the proportion of ADL episodes hypothesized to be attributed to specific pathogens.MethodsWe measured antibody levels to specific pathogens during and following an ADL episode among 41 lymphedema patients enrolled in a cohort study in Léogâne, Haiti. We calculated the absolute and relative changes in antibody levels between the ADL and convalescent time points. We calculated the proportion of episodes that demonstrated a two-fold increase in antibody level for several bacterial, fungal, and filarial pathogens.ResultsOur results showed the greatest proportion of two-fold changes in antibody levels for the carbohydrate antigen Streptococcus group A, followed by IgG2 responses to a soluble filarial antigen (BpG2), Streptococcal Pyrogenic Exotoxin B, and an antigen for the fungal pathogen Candida. When comparing the median antibody level during the ADL episode to the median antibody level at the convalescent time point, only the antigens for Pseudomonas species (P-value = 0.0351) and Streptolysin O (P-value = 0.0074) showed a significant result.ConclusionAlthough our results are limited by the lack of a control group and few antibody responses, they provide some evidence for infection with Streptococcus A as a potential contributing factor to ADL episodes. Our results add to the current evidence and illustrate the importance of determining the causal role of bacterial and fungal pathogens and immunological antifilarial response in ADL episodes.

Influenza A virus antibodies show no association with pancreatic islet autoantibodies in children genetically predisposed to type 1 diabetes.

Viral infections have long been considered potential triggers of beta cell autoimmunity and type 1 diabetes. Recent studies have suggested that influenza A virus might increase the risk of type 1 diabetes. The present study evaluates this risk association in prospectively observed children at the time when islet autoimmunity starts and autoantibodies are first detected. IgG class antibodies to influenza A virus were analysed in 95 case children whose antibody screening test turned permanently positive for two or more islet autoantibodies and from 186 autoantibody-negative and non-diabetic control children who were matched for time of birth, sex, date of sampling and HLA-conferred risk of diabetes in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study. Virus antibodies were measured from the first autoantibody-positive sample using an enzyme immunoassay. None of the children had been vaccinated against influenza A. The prevalence of influenza A virus antibodies did not differ between the case and control children (42% vs 38%; p = 0.392) and the median antibody levels were also comparable in the two groups (3.0 vs 3.8 enzyme immunoassay units). A similar result was obtained when case and control children were compared separately in subgroups according to different sex, age and HLA-DQ genotype. However, girls had higher antibody levels than boys among both case and control children (median antibody levels 9.0 vs 2.3 enzyme immunoassay units; p = 0.01). Our results suggest that influenza A infections are not associated with the development of islet autoimmunity in young children with increased genetic susceptibility to type 1 diabetes.

Serological evidence of vector and parasite exposure in Southern Ghana: the dynamics of malaria transmission intensity.

BackgroundSeroepidemiology provides robust estimates for tracking malaria transmission when intensity is low and useful when there is no baseline entomological data. Serological evidence of exposure to malaria vectors and parasite contribute to our understanding of the risk of pathogen transmission, and facilitates implementation of targeted interventions. Ab to Anopheles gambiae salivary peptide (gSG6-P1) and merozoite surface protein one (MSP-119) reflect human exposure to malaria vectors and parasites. This study estimated malaria transmission dynamics using serological evidence of vector and parasite exposure in southern Ghana.MethodsTotal IgG responses to both antigens in an age stratified cohort (<5, 5–14, >14) were measured from South-eastern Ghana. 295 randomly selected sera were analyzed from archived samples belonging to a cohort study that were followed at 3 consecutive survey months (n = 885); February, May and August 2009. Temporal variations in seroprevalence of both antigens as well as differences between the age-stratified cohorts were determined by χ2 test with p < 0.05 statistically significant. Non-parametric repeated ANOVA – Friedman’s test was used to test differences in antibody levels. Seroprevalence data were fitted to reversible catalytic model to estimate sero-conversion rates.ResultsWhereas parasite prevalence was generally low 2.4%, 2.7% and 2.4% with no apparent trends with season, seroprevalence to both gSG6-P1 and MSP119 were high (59%, 50.9%, 52.2%) and 57.6%, 52.3% and 43.6% in respective order from Feb. to August. Repeated measures ANOVA showed differences in median antibody levels across surveys with specific significant differences between February and May but not August by post hoc Dunn’s multiple comparison tests for gSG6-P1. For MSP119, no differences were observed in antibody levels between February and May but a significant decline was observed from May to August. Seroconversion rates for gSG6-P1 increased by 1.5 folds from February to August and 3 folds for MSP119.ConclusionData suggests exposure to infectious bites may be declining whereas mosquito bites remains high. Sustained malaria control efforts and surveillance are needed to drive malaria further down and to prevent catastrophic rebound. Operational factors for scaling up have been discussed.

Decay of Sabin inactivated poliovirus vaccine (IPV)-boosted poliovirus antibodies

IntroductionWe conducted a follow-on study to a phase I randomized, controlled trial conducted in Cuba, 2012, to assess the persistence of poliovirus antibodies at 21–22months following booster dose of Sabin-IPV compared to Salk-IPV in adults who had received multiple doses of oral poliovirus vaccine (OPV) during childhood. MethodsIn 2012, 60 healthy adult males aged 19–23 were randomized to receive one booster dose, of either Sabin-inactivated poliovirus vaccine (Sabin-IPV), adjuvanted Sabin-IPV (aSabin-IPV), or conventional Salk-IPV. In the original study, blood was collected at days 0 (before) and 28 (after vaccination), respectively. In this study, an additional blood sample was collected 21–22months after vaccination, and tested for neutralizing antibodies to Sabin poliovirus types 1, 2 and 3. ResultsWe collected sera from 59/60 (98.3%) subjects; 59/59 (100%) remained seropositive to all poliovirus types, 21–22months after vaccination. The decay curves were very similar among the study groups. Between day 28 and 21–22months, there was a reduction of ⩾87.4% in median antibody levels for all poliovirus types in all study groups, with no significant differences between the study groups. ConclusionThe decay of poliovirus antibodies over a 21–22-month period was similar regardless of the type of booster vaccine used, suggesting the scientific data of Salk IPV long-term persistence and decay may be broadly applicable to Sabin IPV.

Changes in the anticitrullinated peptide antibody response in relation to therapeutic outcome in early rheumatoid arthritis: results from the SWEFOT trial

ObjectiveTo determine the relationship between changes in antibody levels towards citrullinated peptides derived from different candidate autoantigens and therapeutic outcome in early rheumatoid arthritis (RA).MethodsBaseline and 3-month serum samples from...

Tacrolimus trough level at discharge predicts acute rejection in moderately sensitized renal transplant recipients.

Goal tacrolimus concentrations for the prevention of rejection in sensitized renal transplant recipients are not well established. We evaluated the association between discharge tacrolimus trough concentration and the incidence of biopsy-proven acute rejection (BPAR) in 216 moderately sensitized renal transplant recipients (negative flow crossmatch and positive donor-specific antibodies) treated with tacrolimus. At transplant, the mean±standard deviation (SD) peak panel-reactive antibody was 60±33 and median donor-specific antibody level was a mean fluorescence intensity of 710 (interquartile range, 328-1202). The mean±SD tacrolimus trough concentration at discharge (median postoperative day, 5; interquartile range, 4-7) was 7.6±3.7 ng/dL. Patients were divided into two groups based on a discharge tacrolimus trough concentration of 8 ng/mL. Baseline characteristics were similar between groups. Thirty-four (28.6%) of the 119 patients with a tacrolimus trough concentration less than 8 ng/mL and 19 (19.6%) of 97 patients with concentrations of 8 ng/mL or greater experienced BPAR during a median follow-up of 14±4.7 months (P=0.04). Adjusting for age, race, donor status, and peak panel-reactive antibody, a discharge tacrolimus trough concentration less than 8 ng/mL was significantly associated with a higher risk of BPAR (hazard ratio, 1.84; 95% confidence interval, 1.04-3.25; P=0.04). Serum creatinine, cytomegalovirus, BK viremia, or BK nephropathy at 1 year did not differ between groups. In a patient population predisposed to BPAR, discharge tacrolimus trough concentration less than 8 ng/mL was associated with a nearly two times greater risk of BPAR.

Coffee consumption and the risk of latent autoimmune diabetes in adults--results from a Swedish case-control study.

Coffee consumption is associated with a reduced risk of Type2 diabetes. Our aim was to investigate if coffee intake may also reduce the risk of latent autoimmune diabetes in adults, an autoimmune form of diabetes with features of Type2 diabetes. We used data from a population-based case-control study with incident cases of adult onset (≥35years) diabetes, including 245 cases of latent autoimmune diabetes in adults (glutamic acid decarboxylase antibody positive), 759 cases of Type2 diabetes (glutamic acid decarboxylase antibody negative), together with 990 control subjects without diabetes, randomly selected from the population. Using questionnaire information on coffee consumption, we estimated the odds ratio of latent autoimmune diabetes in adults and Type2 diabetes adjusted for age, sex, BMI, smoking, physical activity, alcohol, education and family history of diabetes. Coffee intake was inversely associated with Type2 diabetes (odds ratio0.92, 95%CI 0.87-0.98 per cup/day). With regard to latent autoimmune diabetes in adults, the general trend was weak (odds ratio1.04, 95%CI 0.96-1.13), but stratification by degree of autoimmunity (median glutamic acid decarboxylase antibody levels) suggested that coffee intake may be associated with an increased risk of high glutamic acid decarboxylase antibody latent autoimmune diabetes in adults (odds ratio1.11, 95%CI 1.00-1.23 per cup/day). Furthermore, for every additional cup of coffee consumed per day, there was a 15.2% (P=0.0268) increase in glutamic acid decarboxylase antibody levels. Our findings confirm that coffee consumption is associated with a reduced risk of Type2 diabetes. Interestingly, the findings suggest that coffee may be associated with development of autoimmunity and possibly an increased risk of more Type1-like latent autoimmune diabetes in adults.

Persistence of Yellow Fever Vaccine–Induced Antibodies After Solid Organ Transplantation

Immunization using live attenuated vaccines represents a contra-indication after solid organ transplantation (SOT): consequently, transplant candidates planning to travel in countries where yellow fever is endemic should be vaccinated prior to transplantation. The persistence of yellow fever vaccine-induced antibodies after transplantation has not been studied yet. We measured yellow-fever neutralizing antibodies in 53 SOT recipients vaccinated prior to transplantation (including 29 kidney recipients and 18 liver recipients). All but one (98%) had protective titers of antibodies after a median duration of 3 years (min.: 0.8, max.: 21) after transplantation. The median antibody level was 40 U/L (interquartile range: 40–80). For the 46 patients with a known or estimated date of vaccination, yellow-fever antibodies were still detectable after a median time of 13 years (range: 2–32 years) post-immunization. Our data suggest there is long-term persistence of antibodies to yellow fever in SOT recipients who have been vaccinated prior to transplantation.

OP0241 Anti-Flagellin Antibodies in Ankylosing Spondylitis (AS) Implicate Subclinical Bowel Inflammation and Differentiate as from Mechanical Back Pain Patients

BackgroundSerum antibody reactivity to microbial antigens may provide important clues to the role of gut-derived microbial antigens in ankylosing spondylitis (AS). Anti-flagellin (anti-CBir1) serum reactivity in Crohn’s disease (CD) is...

Elevated serum anti-flagellin antibodies implicate subclinical bowel inflammation in ankylosing spondylitis: an observational study

IntroductionAnkylosing spondylitis (AS) and inflammatory bowel disease (IBD) share genetic and clinical features. IBD is associated with the presence of antibodies to a variety of commensal microorganisms including anti-Saccharomyces cerevesiae antibodies (ASCA), antineutrophil cytoplasmic antibodies (ANCA), anti-I2 (associated with anti-Pseudomonas activity), anti-Eschericia coli outer membrane porin C (anti-OmpC) and anti-flagellin antibodies (anti-CBir1). Subclinical intestinal inflammation may be present in up to 65% of patients with AS. This study evaluated the presence of antimicrobial antibodies in patients with AS alone, patients with AS and concomitant IBD (AS-IBD) and a control group of patients with mechanical back pain (MBP).MethodsSera were tested by ELISA for ASCA IgG and IgA, anti-OmpC, anti-CBir1 and ANCA in 76 patients with AS alone, 77 patients with AS-IBD and 48 patients with MBP. Antibody positivity rates, median quantitative antibody levels and the proportion of patients with antibody levels in the 4th quartile of a normal distribution were compared between the three groups of patients.ResultsPatients with AS alone demonstrated higher anti-CBir1 antibody positivity rates and median antibody levels than MBP patients. Anti-CBir1 positivity in AS was associated with elevation of acute phase reactants. AS-IBD patients demonstrated elevated responses when compared to AS alone for ASCA, anti-OmpC and anti-CBir1. Quartile analysis confirmed the findings.ConclusionsThese data suggest that adaptive immune responses to microbial antigens occur in AS patients without clinical IBD and support the theory of mucosal dysregulation as a mechanism underlying the pathophysiology of AS.

Independence of measles-specific humoral and cellular immune responses to vaccination

With a larger, independent cohort and more sophisticated measures, we sought to confirm our work that indicated independence of humoral and cellular immunity following measles vaccination. We recruited an age-stratified random cohort of 764 healthy subjects from all socioeconomic strata, all with medical-record documentation of 2 age-appropriate doses of measles-containing vaccine. We quantified measles-specific neutralizing antibody levels and assayed the interferon-γ (IFN-γ) enzyme-linked immunosorbent spot assay (ELISPOT) response to measles virus. We also measured secreted cytokines from the peripheral blood mononuclear cells (PBMCs) in response to measles virus by performing enzyme-linked immunosorbent assays as secondary measures of cellular immune status. The median antibody level and median IFN-γ ELISPOT response were 844 mIU/mL (interquartile range [IQR]: 418-1,752) and 36 (IQR: 13.00-69.00) spot-forming cells (per 2 × 10(5) PBMCs), respectively. We observed only a very weak and negative correlation (Spearman's r(s) or ρ of -0.090 [95% confidence interval: -0.162--0.018]). We observed a similar lack of quantitatively important correlations between the neutralizing antibody level and any of the secondary measures. Our data confirm the independence of humoral and cellular immune responses after the second dose of measles vaccination. As researchers pursue novel measles vaccine and measles vaccine delivery systems, they must not infer that humoral responses predict cellular responses.

Local allergic rhinitis: Allergen tolerance and immunologic changes after preseasonal immunotherapy with grass pollen

Local allergic rhinitis: Allergen tolerance and immunologic changes after preseasonal immunotherapy with grass pollen

Humoral immunity to diphtheria, tetanus, measles, and hemophilus influenzae type b in children with acute lymphoblastic leukemia and response to re‐vaccination

Loss of immunity to previous vaccination and timing of re-vaccination in children receiving chemotherapy remains controversial. The aim of this study was to investigate the immunity to vaccine preventable diseases in children with acute lymphoblastic leukemia (ALL). Sixty-one patients with ALL and 13 healthy siblings were enrolled. Three study groups included newly diagnosed patients (group 1), patients on maintenance chemotherapy (group 2), and patients that completed chemotherapy (group 3). Blood samples for baseline antibody titers were obtained from all the patients and controls. Patients in group 2 were vaccinated with diphtheria, tetanus, and hemophilus influenzae type b (Hib). Patients in group 3 and controls received the measles vaccine in addition to all the above vaccines. In groups 2 and 3, post-vaccination antibody titers were also obtained. Patients and controls had no Hib vaccine during primary vaccination. After chemotherapy median antibody levels against diphtheria, tetanus, measles, and Hib were decreased but tetanus antibodies were still at the protective levels. Proportions of the patients with protective levels were 11.1%, 83.3%, 16.7%, and 16.7% for diphtheria, tetanus, Hib, and measles, respectively. Vaccination achieved protective antibody levels in 81%, 100%, 89.5%, and 70% of the patients for diphtheria, tetanus, Hib, and measles, respectively. Vaccine responses during maintenance were also satisfying. We recommend re-vaccination after 3 months of cessation of chemotherapy. Administration of Hib vaccine may be beneficial after the first 3 months of maintenance chemotherapy especially in children with no primary vaccination followed by a second booster dose after cessation of therapy to increase immunity.

Low density parasitaemia, red blood cell polymorphisms and Plasmodium falciparumspecific immune responses in a low endemic area in northern Tanzania

BackgroundLow density Plasmodium falciparum infections, below the microscopic detection limit, may play an important role in maintaining malaria transmission in low endemic areas as well as contribute to the maintenance of acquired immunity. Little is known about factors influencing the occurrence of sub-microscopic parasitaemia or the relation with immune responses.We investigated possible associations between the occurrence of sub-microscopic P. falciparum parasite carriage and antibody responses to the asexual stage antigens, G6PD deficiency and α+-thalassaemia in 464 subjects from a low endemic area in northern Tanzania.MethodsWe used samples collected from two cross sectional surveys conducted during dry and wet season in 2005. Submicroscopic parasitaemia was detected by using quantitative nucleic acid sequence based amplification (QT-NASBA). Genotyping for G6PD and α+-thalassaemia were performed by high throughput PCR; the prevalence and level of total IgG antibodies against MSP-1, MSP-2 and AMA-1 were determined by ELISA.ResultsCompared to parasite free individuals, individuals carrying sub-microscopic densities of P. falciparum parasites had significantly higher median antibody levels to MSP-1 (p = 0.042) and MSP-2 (p = 0.034) but not to AMA-1 (p = 0.14) while no clear relation between sub-microscopic parasite carriage and G6PD deficiency or α+-thalassaemia was observed.ConclusionOur data suggest a role for sub-microscopic parasite densities in eliciting or maintaining humoral immune responses without evidence for a modulating effect of G6PD deficiency or α+-thalassaemia.