The use of allergen-specific IgE tests in general practice

INTRODUCTION

In Denmark, diagnosing and treating allergy is mainly performed by general practitioners (GPs), but precise expectations of the GPs are not described in guidelines. Furthermore, very little is known about GPs' use of allergen-specific immunoglobulin E (sIgE) tests. The aim of this study was to describe the use of these tests in the Central Denmark Region.

METHODS

We performed analyses on data from all sIgE tests ordered by GPs in the Central Denmark Region in 2015. A test was considered positive if the serum level of IgE was ≥ 0.35 kU/l.

RESULTS

Serum levels of sIgE were determined in 26,129 patients, equivalent to 2% of the Danish population. A total of 106,237 tests were performed, the majority as part of screening algorithms for inhalant and food allergens. Screening was ordered 20,697 times for inhalation allergens and 12,999 times for food allergens. Additionally, a considerable number of tests for antibiotics (n = 4,407), insect venom (n = 748) and other allergens were performed (n = 824). Positive rates were determined for various allergens in relation to gender and age. The rates were generally higher than rates known to be present in the background population. A higher percentage of females than males was tested. However, positive rates were generally lower in females than in males.

CONCLUSIONS

This is the first descriptive analysis of the use of testing for sIgE in general practice. Results from this study may be used to optimise how GPs order and interpret sIgE tests in the future.

FUNDING

none.

TRIAL REGISTRATION

not relevant.

IP-10 for the diagnosis of tuberculosis in children: Protocol for a systematic review and meta-analysis

BACKGROUND

Tuberculosis (TB) is a highly contagious and chronic disease. The microbiological examination to confirm children TB disease are limited due to paucibacillary Mycobacterium, specimens and detecting facilities. Considering these limitations in diagnosing children TB, new and reliable methods that detect children TB should be developed. Recently, Interferon gamma-induced protein 10 (IP-10) has been identified as a sensitive parameter in detecting children TB. The present study aims to synthesis and analysis the diagnostic value of IP-10 for children TB.

METHODS

We will search PubMed, Embase, the Cochrane Library, Web of Science, Chinese National Knowledge Infrastructure, and Chinese Biological Medical Databases. We will search relevant citations up to May 2019. The quality of individual study will be assessed using the Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2). Stata 14.0 software will be used to calculate the pooled sensitivity, pooled specificity, pooled positive likelihood ratio (PLR), pooled negative likelihood ratio (NLR), pooled diagnostic odds ratio (DOR), pre-test probability, post-test probability and the hierarchical summary receiver operating characteristic (HSROC) curve.

RESULTS

The results of this study will be published in a peer-reviewed journal.

DISCUSSION

The evidence will indicate that IP-10 test is an alternative immunological test in detecting children TB. This is a protocol of systematic review and meta-analysis, so the ethical approval and patient consent are not required.

PROTOCOL REGISTRATION NUMBER

CRD42019129743.

Differentiation between hepatic cystic echinococcosis types 1 and simple hepatic cysts: A retrospective analysis

This study aims to evaluate the clinic value of ultrasound, computed tomography (CT) and serological testing in the differentiation between hepatic Cystic Echinococcosis (CE) types 1 and simple hepatic cysts.Totally 50 patients with CE Types 1 and 50 patients with simple hepatic cysts were included. All patients examined by ultrasound, CT and serological testing respectively. The receiver operating characteristic (ROC) curve of diagnosis methods was drawn and their sensitivity, specificity, Youden index, positive likelihood ratio, negative likelihood ratio, positive predictive value and negative predictive value were compared. Pathology result was used as golden standard.The area under ROC curve of ultrasound was 0.97 and of CT and serological testing was 0.79 and 0.71 respectively. The sensitivity of ultrasound in the diagnosis of CE Types 1 was 96.00%, specificity was 98.00%, the positive likelihood ratio was 48.00, and negative likelihood ratio was 0.04. Disease prevalence was 50%, positive predictive value was 97.96%, and negative predictive value was 96.08%. The sensitivity of CT was 80.00%, specificity was 62.00%, positive likelihood ratio was 2.11, and negative likelihood ratio was 0.32. Disease prevalence was 50%, positive predictive value was 67.80%, and negative predictive value was 75.61%. The sensitivity of immunological test was 86.00%, specificity was 72.00%, positive likelihood ratio was 3.07, and negative likelihood ratio was 0.19. Disease prevalence was 50%, positive predictive value was 75.44%, and negative predictive value was 83.72%. Combined ultrasound and immunological test, the sensitivity and the specificity was 82% and 100% respectively. Combined CT and immunological test, the sensitivity the specificity was 70% and 82% respectively.In the differentiate diagnosis of CE Types 1 and simple hepatic cyst, ultrasound is better than CT with high sensitivity and specificity, therefore recommended. Immunological examination is an important complement to the imaging examination.

A Randomized Controlled Trial of Opt-in Versus Opt-Out Colorectal Cancer Screening Outreach

OBJECTIVES

METHODS:: RESULTS:: Patients randomized to opt-in agreed to participate 23.1% of the time, and only 2.5% of those in opt-out chose not to participate. FIT kits were mailed to 22.4% and 93% of patients in opt-in and opt-out arms, respectively. In intention-to-screen analysis, patients in the opt-out arm had a higher FIT completion rate (29.1%) than in the opt-in arm (9.6%) (absolute difference 19.5%; 95% confidence interval, 10.9-27.9%; P < .001). Results were similar in subgroup analysis of those sent initial messaging through the EHR portal (9.5% opt-in versus 37.5% in opt-out).

CONCLUSIONS

.

Immunoglobulin G subclass switching impacts sensitivity of an immunoassay targeting Francisella tularensis lipopolysaccharide

The CDC Tier 1 select agent Francisella tularensis is a small, Gram-negative bacterium and the causative agent of tularemia, a potentially life-threatening infection endemic in the United States, Europe and Asia. Currently, there is no licensed vaccine or rapid point-of-care diagnostic test for tularemia. The purpose of this research was to develop monoclonal antibodies (mAbs) specific to the F. tularensis surface-expressed lipopolysaccharide (LPS) for a potential use in a rapid diagnostic test. Our initial antigen capture ELISA was developed using murine IgG3 mAb 1A4. Due to the low sensitivity of the initial assay, IgG subclass switching, which is known to have an effect on the functional affinity of a mAb, was exploited for the purpose of enhancing assay sensitivity. The ELISA developed using the IgG1 or IgG2b mAbs from the subclass-switch family of 1A4 IgG3 yielded improved assay sensitivity. However, surface plasmon resonance (SPR) demonstrated that the functional affinity was decreased as a result of subclass switching. Further investigation using direct ELISA revealed the potential self-association of 1A4 IgG3, which could explain the higher functional affinity and higher assay background seen with this mAb. Additionally, the higher assay background was found to negatively affect assay sensitivity. Thus, enhancement of the assay sensitivity by subclass switching is likely due to the decrease in assay background, simply by avoiding the self-association of IgG3.

Evaluation of the implementation of a rapid streptococcal antigen test in a routine primary health care setting: from recommendations to practice

BACKGROUND AND AIM

Pharyngitis is a common reason for consultation in General Practice. Despite the development of diagnostic criteria it remains difficult to clinically diagnose the bacterial type. Therefore, current guidelines recommend the additional use of objective tests. In Austria, the Burgenländische Gebietskrankenkasse introduced a test as service for patients and regular payment position for GPs. It was the aim of this study to analyze this implementation process in General Practice and a possible change in antibiotic prescriptions.

METHODS

The retrospective evaluation lasted from April 2006 to September 2009; in April 2007, rapid-streptococcal-antigen-tests (RSATs) were introduced. GPs were grouped into three clusters according to their use of RSATs. In addition, all antibiotic prescriptions within the evaluation period were analyzed and correlated to the three clusters before and after the implementation.

RESULTS

The overall number of RSATs performed was 6,401. Half of the GPs utilized it regularly. After its introduction, the relative antibiotic prescription frequency was significantly reduced (17.1 vs. 16.4 %, p = 0.0001). The results for the subgroup analyses yielded a significant reduction for the regular user group only (16.0 vs. 15.0 %, p = 0.0001).

CONCLUSION

GPs using the RSAT regularly seem to apply the test appropriately. The decrease of the relative antibiotic prescriptions of all GPs seems to be due to the regular user group of GPs. This could be interpreted as a consequence of the RSAT use. The results show a positive trend for an improvement in diagnostic quality and for an appropriate use of antibiotic prescriptions.

Usefulness of wheat and soybean specific IgE antibody titers for the diagnosis of food allergy

BACKGROUND

Since the first suggestion of threshold values for food specific IgE antibody levels in relation to clinical reactivity, several authors have proposed different threshold values for different allergens. We investigated the relationship between wheat/soybean specific IgE antibody levels and the outcome of wheat/soybean allergy diagnosis in children of different ages.

METHODS

A retrospective study was conducted in 536 children admitted consecutively to our clinic with the suspicion of wheat and/or soybean allergy. The children underwent an oral food challenge and blood samples for specific IgE measurement were obtained.

RESULTS

The children who reacted to the oral food challenge had higher specific IgE titers to the specific allergen compared to the non-reacting group. The risk for reaction increased 2.33-fold (95% CI 1.90-2.87) for wheat and 2.08-fold (95% CI 1.65-2.61) for soybean, with increasing levels of specific IgE. A significant difference between the ages of subjects pertained only to wheat.

CONCLUSIONS

We found a relationship between the probability of failed challenge and the concentration of IgE antibodies to both wheat and soybean. Age influences the relationship of allergen specific IgE levels to wheat and oral food challenge outcome. Younger children are more likely to react to low levels of specific IgE antibody concentration to wheat than older children.

Assessment of the Beryllium Lymphocyte Proliferation Test Using Statistical Process Control

Despite more than 20 years of surveillance and epidemiologic studies using the beryllium blood lymphocyte proliferation test (BeBLPT) as a measure of beryllium sensitization (BeS) and as an aid for diagnosing subclinical chronic beryllium disease (CBD), improvements in specific understanding of the inhalation toxicology of CBD have been limited. Although epidemiologic data suggest that BeS and CBD risks vary by process/work activity, it has proven difficult to reach specific conclusions regarding the dose-response relationship between workplace beryllium exposure and BeS or subclinical CBD. One possible reason for this uncertainty could be misclassification of BeS resulting from variation in BeBLPT testing performance. The reliability of the BeBLPT, a biological assay that measures beryllium sensitization, is unknown. To assess the performance of four laboratories that conducted this test, we used data from a medical surveillance program that offered testing for beryllium sensitization with the BeBLPT. The study population was workers exposed to beryllium at various facilities over a 10-year period (1992-2001). Workers with abnormal results were offered diagnostic workups for CBD. Our analyses used a standard statistical technique, statistical process control (SPC), to evaluate test reliability. The study design involved a repeated measures analysis of BeBLPT results generated from the company-wide, longitudinal testing. Analytical methods included use of (1) statistical process control charts that examined temporal patterns of variation for the stimulation index, a measure of cell reactivity to beryllium; (2) correlation analysis that compared prior perceptions of BeBLPT instability to the statistical measures of test variation; and (3) assessment of the variation in the proportion of missing test results and how time periods with more missing data influenced SPC findings. During the period of this study, all laboratories displayed variation in test results that were beyond what would be expected due to chance alone. Patterns of test results suggested that variations were systematic. We conclude that laboratories performing the BeBLPT or other similar biological assays of immunological response could benefit from a statistical approach such as SPC to improve quality management.

Allergic rhinitis

The BEACH program (Bettering the Evaluation and Care of Health) shows that allergic rhinitis was managed six times per 1000 encounters between October 2002 to September 2007. This suggests that general practitioners manage allergic rhinitis about 619 000 times nationally each year.

Basophil-activation tests in Hymenoptera allergy

PURPOSE OF REVIEW

Despite recent advances in our understanding of basophil biology and discovery of new markers for basophil activation, tests measuring basophil activation are not widely utilized in Hymenoptera allergy. Studies of the basophil-activation test in Hymenoptera allergy were examined and the clinical utility of this test was assessed.

RECENT FINDINGS

It has been demonstrated that the results of basophil-activation tests correlate quite well with those of serum IgE testing or skin-prick tests. Many studies compare test outcomes with history in patients and nonallergic controls, so that specificity in sensitized but clinically nonreactive individuals remains unknown. Although one study showed that the basophil-activation test might predict immunotherapy side effects, this could not be confirmed in a second study, and no role has been established for the basophil-activation test in the monitoring of venom immunotherapy. The basophil-activation test has no extra value in assessing sting challenges, although experience is limited.

SUMMARY

The measurement of basophil-activation markers may be useful in detecting IgE-mediated sensitization but the relevance for application of the basophil-activation test in prediction of clinical reactivity in Hymenoptera allergy is very limited. For this reason, this test currently has no established role in the diagnosis and management of patients with insect sting allergy.

Agreement between Mantoux skin testing and QuantiFERON-TB assay using dual mycobacterial antigens in current and former injection drug users

BACKGROUND

Individuals infected with non-tuberculous mycobacteria may elicit false-positive reactions on tuberculin skin testing. The QuantiFERON-TB (QFT) assay utilizes tuberculin and M. avium antigens and, therefore, may be more specific for latent tuberculosis infection. The objective of this study was to investigate the agreement between the QFT and single and dual antigen skin testing for detecting latent M. tuberculosis and assess the impact of cross-reactions from latent infection with other mycobacteria in inner-city injection drug users, a population at high risk for tuberculosis.

MATERIAL/METHODS

We studied the agreement of results from skin testing using tuberculin and purified protein derivative-Battey (PPD-B) with the QFT test using tuberculin and Mycobacterium avium sensitin (MAS) in 48 HIV-seronegative injection drug users.

RESULTS

The agreement between skin testing and the QFT assay for tuberculin was 73% (kappa = 0.45) and for PPD-B/MAS was 63% (kappa = 0.12). Agreement between skin test tuberculin dominance (tuberculin reaction > or =5 mm greater than PPD-B) and QFT tuberculin dominance (proportional difference between MAS and tuberculin reaction of > or =10%) was 75% (kappa = 0.53). All subjects tuberculin dominant by skin test were also QFT positive for tuberculin. Agreement between skin test Battey dominance and QFT avium dominance was 83% (kappa = 0.12).

CONCLUSIONS

Results from the QFT assay and skin testing demonstrated moderate concordance in identifying subjects with latent tuberculous infection, and use of dual antigens did not appreciably improve the agreement between the two methods.

Enumerating antigen-specific T-cell responses in peripheral blood: a comparison of peptide MHC Tetramer, ELISpot, and intracellular cytokine analysis

Detection of the circulating antigen-specific T-cell response to immunization is an important biologic end point in clinical trials of cancer vaccines. Typically employed assays are peptide MHC tetramer, ELISpot, and intracellular cytokine analysis. Although there is no agreement on the definition of a positive response in these assays, many groups have chosen a number of T cells greater than 2 standard deviations above the mean of the negative controls. The authors wished to determine how well this cutoff performed for each of these assays in detecting positive and negative T-cell responses to a model antigen, the immunodominant HLA-A*0201-restricted epitope of cytomegalovirus (CMV) pp65. For each assay, the mean + 2 standard deviations of the response for CMV seronegatives was the point that best separated the two groups. Using this value, each assay had a sensitivity of 87.5% and specificity of 95% to 100% and exhibited a high degree of concordance (kappa 0.76-0.9) with the other two. The authors conclude that currently available immunologic assays perform well in detecting biologically relevant levels of antigen-specific T cells. These assays will better define the quantity and quality of protective immune responses to viral disease and offer insight into the requirements for protective anti-cancer immunity.

Population-based hematologic and immunologic reference values for a healthy Ugandan population

To assess the validity of the reference values for hematologic and immunologic indices currently used in Africa, we evaluated blood samples from 3,311 human immunodeficiency virus (HIV)-negative Ugandans aged 1 week to 92 years. Erythrocyte, hemoglobin, and hematocrit levels and mean corpuscular volume all significantly increased with age (P < 0.001) and were independent of gender until the age of 13 years, after which the levels were higher in males than in females (P < 0.001). White blood cell, neutrophil, lymphocyte, basophil, and monocyte counts significantly declined with age until the age of 13 years (P < 0.001), with no differences by gender, while platelet counts declined with age (P < 0.001) and showed differences by gender only among adults older than age 24 years. CD4+- and CD8+-cell counts declined with age until the age of 18 years; thereafter, females had higher counts than males. The absolute values for many of these parameters differed from those reported for populations outside Africa, suggesting that it may be necessary to develop tables of reference values for hematologic and immunologic indices specific for the African population. This may be particularly important with regard to CD4+-cell counts among children because significant differences in absolute and percent CD4+-cell counts exist between the values for Western populations and the values for the population evaluated in our study. These differences could influence the decision to initiate antiretroviral therapy among children infected with HIV.

[Current situation of the malaria inspection in Jikei University Hospital]

The current situation of the malaria inspection in our laboratory was investigated. Malaria was detected by three different methods, May Giemsa staining(MG), acridine orange staining(AO), and antigen detecting method using NOW ICT Malaria P.f./P.v. kit(Ag). There were 207 requests a year(17.3 per month), and the holiday/night request occupied 12%. Fifteen patients were positive, 5 with plasmodium falciparum (p.f.) and 10 with plasmodium vivax(p.v.), including 3 relapsed cases. All the patients with p.f. were suffered in Africa, and 6 with p.v. were in Southeast Asia, and one with p.v. was in Central America. The rate of coincidence between MG/Ag and MG/AO were 94.4% and 96.9%, respectively. There were 7 samples that were MG negative and Ag positive, but all of these samples were obtained after the initiation of the treatment. There was no sample that showed MG positive and Ag negative. Our data suggested that no difference in detection sensitivity was found between microscopic observation and the antigen detection kit. Thus it would be a very useful and accurate strategy to use this antigen detection kit in a routine laboratory check up.

The acceptability of the introduction of a type specific herpes antibody screening test into a genitourinary medicine clinic in the United Kingdom

OBJECTIVE

To determine the uptake of a type specific herpes simplex antibody test if it were offered as part of routine screening in a genitourinary medicine clinic in a district general hospital in the United Kingdom.

METHODS

Stage 1. A series of 207 consecutive new attenders and 205 patients who had attended the clinic previously were given written information about the test and asked whether they would want to have the test if it were available. They were asked whether they would wish to discuss it further with a counsellor before making a decision. Stage 2. Another series of 434 consecutive patients were offered the test after reading an information leaflet detailing the advantages and disadvantages of being tested. They were also offered the opportunity to see a counsellor for further information.

RESULTS

In stage 1 of the study, 51% of men and 54% of women said they would want the test if it were available. 32% of men and 40% of women requested counselling. In stage 2, when the test was offered, 41% of men and 37% of women chose to have it, and 23% of men and 7% of women requested further information from the counsellor. 20 patients were herpes simplex virus type 2 (HSV-2) positive-four of whom would have been diagnosed on clinical grounds at the time of presentation. A further 12 men and 20 women excluded themselves from the study because they were known to have genital herpes. Therefore, type specific serology contributed 30% to total diagnoses in this population-16 out of a population of 52 would have remained undiagnosed without having had the test.

CONCLUSION

In this population, the uptake of the type specific herpes simplex antibody test was much less than expected and screening was of limited benefit in identifying large numbers of previously unrecognised HSV-2 positive patients.

Evaluation of the performance of Brazilian blood banks in testing for Chagas' disease

BACKGROUND AND OBJECTIVES

Due to the low sensitivity and reproducibility of available tests, in 1989 it became mandatory for all Brazilian blood donors to be screened for Chagas' disease by at least two serological techniques. In 1994 the Brazilian Ministry of health launched a program to systematically evaluate the quality of serological screening for the detection of blood-transmissible diseases as performed by public blood banks.

METHODS

A blind panel containing positive samples for blood-transmissible disease was distributed to 57 major public blood banks in four sequential programs.

RESULTS

The ELISA test was chosen by the majority of the blood banks. There were 64 (3.7%) false-negative results, 49 produced by banks using indirect hemagglutination. Since most blood banks screened with more than one test for Chagas, only 8 samples were actually missed, of which 3 were by banks using only one test.

CONCLUSION

Our data show a clear improvement in performance of Brazilian blood banks testing for Chagas' disease.

[The incidence of sperm antibodies in patients included in a program of assisted reproduction]

The aim of the present investigation was to establish the sperm antibody incidence among patients included in a program for assisted reproduction by the means of the classical and new methods for sperm antibody detection; to analyze the correlation between the results demonstrated by the different techniques; to evaluate the obtained data in the context of the application of new assisted reproduction technologies (ART). In the Laboratory of Reproductive Immunology, Department of Biology, Medical University of Sofia, 73 sera from patients (35 couples and 3 men) with primary and secondary infertility, aged 23-46 years, grouped according to the diagnosis and included in the program for assisted reproduction "Technobioassistance" were tested. Our results demonstrated the highest incidence of sperm antibodies amongst patients with primary unexplained infertility. The percentage of positive reacting couples for at least one of the applied tests was 31%. The highest relative share of those reacting positively, was observed with ELISA and the tray agglutination test (TAT) of Friberg. For ELISA 31.48% of the sera reacted positively, while clinically relevant liters of sperm antibodies were found with TAT in 21.92% of the tested sera. We also found that 17.46% and 13.7% of the tested sera were positive, respectively in the sperm immobilization test (SIT) of Isojima and the gelatin agglutination test (GAT) of Kibrick. The high degree of correlation (P < 0.0001) between the tests of Kibrick and Friberg showed the appropriateness of their application for patients in an ART program. At the other hand, the lack of correlation between the other applied tests (the Isojima test and ELISA) confirmed the assumption that immunity against spermatozoa should be sought with at least two diagnostic tools. Five of the tested families with clinically relevant TAT titers were included in our ART program for "in vitro" fertilization and embryo transfer, after preliminary absorption of the seminal fluid with autologous semen, or underwent the ICSI technique. For these patients, one ICSI pregnancy finished with the successful birth of a healthy child and one "in vitro" pregnancy is developing at the moment.

Survey on influenza laboratory diagnostic and surveillance methods in Europe. European Scientific Working Group on Influenza

The survey was undertaken by ESWI in order to investigate the comparability of the laboratory diagnostic methods and the influenza surveillance systems used in 24 European countries. The results indicate considerable consensus in the general approaches to collection and use of clinical specimens, rapid diagnostic techniques, virus isolation techniques in eggs or/and MDCK cell lines, virus identification and use of inhibition of hemagglutination (IHA) and complement fixation (CF) tests for serological diagnostics. However, the details of the techniques used are somewhat heterogeneous: antigen detection methods (immunofluorescence versus immuno adsorbent assay), isolation methods (eggs versus tissue culture), reagents (locally produced, WHO, commercial) are not always equivalent and results are therefore not really comparable. Some of these discrepancies are due to a lack of resources or a lack of priority for influenza in the country. The greatest differences between individual countries exist in the epidemiological part of surveillance programmes. The mode of collection of influenza related mortality and absentism from work varies considerably in different countries. These findings indicate the need to harmonize viral procedures and surveillance systems in European countries in order to improve validity and comparability of results and as a prerequisite for early information on influenza etiology and spread.

[Immobilized antigenic preparations with magnetic properties in the diagnosis and treatment of rheumatic diseases]

A procedure was first developed to prepare the immobilized granulated antigen agents (IGAA) based on collagens of types I, II, III, IgG, native DNA, RNA, cardiolipin, superoxide dismutase, and glutathione reductase. The agents were applied to both immunofluorescence and enzyme immunoassay to identify specific antibodies. IGAA were effective in early diagnosis, prognosis, and control of therapy for systemic lupus erythematosus, systemic sclerosis, rheumatoid arthritis due to their high capacity. These antigen agents were used in vitro and in vivo in hyperimmune laboratory animals as magnetic sorbents and exhibited high capacities and low traumatic properties for blood cells. IGAA may be regenerated, sterilized, and reused.

[Glycyphagus cadaverum housedust mites--a powerful source of allergens in Uzbekistan]

The house-dust mites, Glycyphagus cadaverum (Schrk.) and Dermatophagoides pteronyssinus (Trt.) are prevalent species in the houses of Uzbekistan. Their prevalence rates are 57.8 and 28.5%, respectively. G. cadaverum was detected in 62. 13% of the houses. It numbered as many as 1013 per g of dust. The tick, house dust and feeding media were extracted and allergic reactions to the extracts were examined by three immunological assays: passive hemagglutination test, indirect degranulation test, and common anaphylactic reaction: The study demonstrated that the extract from G. cadaverum had a higher allergenic potency, which is commonly used in Uzbekistan for the diagnosis of asthma.

Detection of allergen-induced basophil activation by expression of CD63 antigen using a tricolour flow cytometric method

In the field of allergy diagnosis, most in vitro functional tests are focused on basophils. Nevertheless, the very small number of circulating basophils limits these experiments and their clinical benefit remains controversial. As flow cytometry is a valuable tool for identifying cell populations, even at low concentrations, we developed a tricolour flow cytometric method for the study of allergen-induced basophil activation. Identification of cells was based both on CD45 expression and on the presence of IgE on the cell surface, since basophils express high-affinity receptors for IgE (Fc epsilon RI). Cell activation upon allergen challenge was assessed by the expression of CD63 antigen on the plasma membrane. Basophil isolation and activation (with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine) were validated in 32 non-allergic patients. In 12 allergic patients, basophil stimulation by a relevant allergen was in most cases positive (10/12). Furthermore a concentration-dependent hook effect was observed. Of the allergic and non-allergic patients, none showed non-specific activation with an irrelevant allergen (specificity 100%). Overall, our preliminary results, even in a small population, suggest that this is a reliable and valuable method for the diagnosis of allergies complementing specific allergen IgE and skin test results. Obviously, additional clinical studies are needed to validate these first results.

Analysis of partial variance to control for day-to-day variability in functional immune tests in depression

Recently, analysis of partial variance (APV) was proposed as a technique to control for day-to-day variance in mitogen-induced lymphoproliferative responses whereby data obtained from controls, run in the laboratory on the same day, are used as covariates in regression analysis. In order to check the utility of the APV method in the interpretation of functional immune tests, we have reanalyzed lymphoproliferative responses in experimental subjects with depression (n = 38) stimulated by phytohemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A (Con A) in relation to responses obtained in laboratory controls. There were no significant relationships between the depressed patients' and laboratory controls' lymphoproliferative responses to PHA, PWM or Con A. Controlling for day-to-day variation by means of regression analysis did not significantly alter the significant relationships between the patients' lymphoproliferative responses and clinical variables, such as depressive classification and severity of illness. It is argued that the APV method may not be used to adjust for an inappropriately high day-to-day variability in immune assays.

Frequency and significance of antinuclear antibodies in multiple sclerosis

In a prospective sample of patients with multiple sclerosis (MS) we found a high frequency of antinuclear antibodies (ANA), 22.5%, confirming results from previous studies. ANA occurrence did not correlate with gender, age, duration of MS, MS course, or disability in either the prospective and retrospective samples of MS patients. In 16 patients with MS tested at two time points, ANA occurrence did correlate with MS disease activity. This suggests that the high frequency of ANA in MS reflects ongoing immune dysregulation.

[Characteristics of immunologic test values in the elderly]

The immune system changes during the lifespan of man. Many described changes in the immune system of the elderly were dependent on illness or chronic diseases. To exclude these pathological changes in the immune system and to exclusively describe age-dependent changes, Ligthart et al. defined immunogerontological criteria to study the immune system in the elderly, the SENIEUR-Protocol. Most changes in the immune system of elderly are within the normal ranges of the appropriate parameter. However, there are many significant differences between the status of the immune system in healthy young and elderly individuals, within these normal ranges. The comparison between SENIEUR-elderly and healthy young and the additional comparison of these two groups with centenarians allows the discussion of potential pathological effects of these changes. In this article we summarize the described changes of the immune system in SENIEUR-elderly and centenarians. The serum levels of the immunoglobulins G, M and A increased with age, as well as the number of benign monoclonal gammopathies and the number of autoantibodies. The titers of zinc are significantly decreased in the serum of the elderly. The production of the acute phase protein C-reactive protein is not age-dependent, whereas the serum levels of alpha 2-macroglobulin are significantly increased in the elderly. The number of lymphocytes decreased and the number of neutrophils increased with aging. Monocytes, basophils, and eosinophils are without changes during life. There are many descriptions about changes of the leukocyte sub-population in aging, which are not always comparable. However, the number of T cells (CD3) decreases. Within the T cells the CD8 cells decreased more than the CD4 cells, resulting in an increased CD4/CD8 ratio. Memory T cells (CD45RO) increase during life, whereas naive T cells (CD45RA) decrease. Interestingly, centenarians have more naive T cells SENIEUR-elderly. The number of B cells (CD19) decreased also, whereas the number of natural killer (NK) cells (CD16, CD56, CD57) increases with aging. The capacity of leukocytes from the elderly to produce cytokines is also significantly different from those of the young. The release of the TH1-cytokines interleukin (IL)-2 and interferon (IFN)-gamma is decreased, whereas the production of the TH2-cytokines IL-4 and IL-10 is increased in the elderly. The production of proinflammatory cytokines such as IL-1, IL-6, IL-8, and tumor necrosis factor-alpha is increased in the elderly. In contrast, the capacity to produce the antiviral cytokine IFN-alpha is reduced in elderly individuals. In conclusion, the immune system shows many age-dependent changes, but we know little about the reason and the potential pathological effects of these changes.

Evaluation of the recombinant 38-kilodalton antigen of Mycobacterium tuberculosis as a potential immunodiagnostic reagent

The diagnosis of infection caused by Mycobacterium tuberculosis is of increased public health concern following increases in the number of cases in developed countries and major increases in developing countries associated with the spread of human immunodeficiency virus (HIV) infection. The specificity of purified protein derivative skin testing for the detection of infection is compromised by exposure to environmental mycobacteria. Examination of sputum detects the most infectious patients, but not those with extrapulmonary disease. The 38-kDa antigen of M. tuberculosis contains two M. tuberculosis-specific B-cell epitopes. We overexpressed the gene for this antigen in Escherichia coli and evaluated the recombinant product in in vitro assays of T-cell function and as a target for the antibody response in humans. The sensitivity and specificity of the antigen as a skin test reagent were also assessed in outbred guinea pigs. We found that 69% of healthy sensitized humans recognize the antigen in vitro, as manifested by both cell proliferation and the production of gamma interferon. Untreated patients initially have a lower frequency of response (38%); this recovers to 72% during therapy. A total of 292 patients (20 with HIV coinfection) and 58 controls were examined for production of antibody to the 38-kDa antigen by using a commercially available kit. The sensitivity of the test in comparison with that of culture was 72.6%, and the specificity was 94.9%. The antigen was also tested for its ability to induce skin reactions in outbred guinea pigs sensitized by various mycobacterial species. The antigen provoked significant skin reactions in M. tuberculosis-, M. bovis BCG-, and M. intracellulare-sensitized animals. The significance of these findings and the usefulness of this antigen in immunodiagnosis are discussed.

[The use of 4 immunological exams for the determination of Chagas disease prevalence in streetsweepers of the City Sanitation Service in the Federal District]

Seropositivity for Trypanosoma cruzi infection was studied in 368 street-sweepers of the SLU, Federal District, Brazil, with the aid of haemaglutination, immunofluorescence and, also, a delayed-type skin test to the parasite T12E antigen. It showed 32.1%, 42.1% and 38.6% positive results, respectively for each assay. Among these, however, only 47% were positive with each of three exams performed. In addition, 19.7% were positive with two out of three exams performed. The remaining 33.3% sera yielded one positive result out of three exams employed and were submitted to the immunoblot assay. This analysis confirmed 3 cases (37.5%) positive by hemmaglutination, 3 (11.5%) positive by skin test, and 1 (3.7%) positive by immunofluorescence. At the end of the analysis, it was shown that 129 (35%) individuals yielded at least two positive assays and, therefore, they should be considered as T. cruzi-infected individuals.

Management of primary antibody deficiency by consultant immunologists in the United Kingdom: a paradigm for other rare diseases

Variation in clinical practice and its effect on outcome is little known for rare diseases such as primary antibody deficiency. As part of a national audit a survey of all 30 consultant immunologists in the United Kingdom dealing with primary antibody deficiency syndromes in adults and children was carried out in 1993 to ascertain their practices in diagnosis and management. Consensus guidelines were published after the survey was completed. Comparison of the survey results of clinical practice at the time the guidelines were published with the standards identified highlighted that the practice of a minority of specialists was at variance with their peers and with the consensus document, particularly in the use of intramuscular immunoglobulin, the dose and frequency of intravenous immunoglobulin, and target trough immunoglobulin G concentration, which has implications for the quality of patient care. However, much closer agreement existed in the key areas of management, such as diagnosis and selection of intravenous immunoglobulin. The approach and the problems identified are relevant to the management of other rare diseases, in which diagnosis and management is complex and there are few specialists with the necessary knowledge to undertake such care. This survey, the first attempted audit of practice, shows that within a motivated group of specialists highly significant differences in practice may exist and the authors emphasise the importance of setting clear guidelines against which care can be assessed.

[The use of serological tests for detecting HIV infection in general clinical consultations and hospital consultations]

AIMS

To determine the number and type of HIV tests requested in general practice (GP) and in hospital outpatient clinics, to identify principle risk behaviors, to determine the percentage of HIV positive tests and to identify possible factors associated with the request of HIV tests.

METHODS

Cross-sectional, analytical and observational study, involving 80 GPs and 45 hospital specialists in the region of Lisbon. All requests for HIV tests were analysed during a 12 month period.

RESULTS

936 HIV tests were requested, with a mean of 12.47 in GP and 0.69 in the hospital. Risk behaviors observed were mainly heterosexual contacts and intravenous drug abuse (IVDA). The motives of the requests mainly were pregnancy, risk behaviors in GP and the presence of symptoms suggesting HIV infection in the hospital. The initiative of the request came from doctors in 70% of the cases. The percentage of HIV positive tests (ELISA + Western blot) was 4.2% in GP and 32% in the hospital. According to risk behaviors, the percentage of seropositivity was 33% in homo/bisexuals, 13% in IVDA, 7% in heterosexuals with risk behaviors and 0.2% in individuals with unidentified risk behaviors.

CONCLUSIONS

The patterns of request of HIV tests differ in hospital and in GP. In a significant percentage of cases, no informed consent was obtained prior to HIV testing, both in hospital and GP. This study may serve as an indicator of the need for information and education programs concerning HIV testing directed to health professionals and the general population.

[The effectiveness of immunological methods in the diagnosis of leptospirosis]

The effectiveness of Leptospira antigenic erythrocyte diagnosticum increases 4- to 8-fold due to the preliminary activation of erythrocytes and Boivin's antigen with 0.001-0.002 M solution of potassium periodate. ELISA with the use of conjugate based on antiglobulin serum and catalase is twice as sensitive as ELISA with conjugate on the basis of penicillinase, 3 times as sensitive as ELISA with conjugate on the basis of Leptospira hyperimmune serum and catalase and 10-20 times as sensitive as the passive hemagglutination test and the microagglutination and lysis test.

Comparison of different methods for the investigation of antisperm antibodies on spermatozoa, in seminal plasma and in serum

Since there is no gold standard for the diagnosis of immunological infertility, comparison between different methods and of their results with biological tests for the detection of antisperm antibodies must be used in defining the most reliable and clinically relevant method. We have evaluated the results of direct (n = 100) and indirect tests in serum (n = 140) and seminal plasma (n = 100) using the SpermMAR and Immunobead (IB) techniques for the detection of sperm antibodies of the immunoglobulin (Ig) classes G, A and M, and we have compared the results with those of the tray agglutination test and the adenosine triphosphate release cytotoxicity test. Results indicate the higher specificity and sensitivity of the SpermMAR results for IgG and IgA, as compared to the outcome of the IB test. It appears that the IB test for IgA may detect non-specific antibodies in serum. Little information is obtained from the tray agglutination test in seminal plasma, and the indirect SpermMar test for IgG in seminal plasma was the only independent variable associated with the outcome of the former test. Since the SpermMAR tests for IgG and IgA are more accurate and biologically relevant, as well as easier to perform than the respective IB tests, the former must be considered the method of first choice.

The prick test and specific IgE (RAST and MAST-CLA) compared with the oral challenge test with milk, eggs and nuts

In spite of the development of numerous in vivo and in vitro diagnostic techniques for food allergy, the oral challenge test (OCT) is still the "gold standard". Consequently, we have compared it with some of the more recent techniques. We studied 36 patients with a medical history compatible with food allergy (to milk, eggs or nuts) and 11 patients without food allergy (6 nonatopic and 5 with acarid allergy). A prick test, specific IgE (RAST and MAST-CLA) and an OCT with the suspected food were performed in all patients. The following parameters were calculated for all patients overall and for each of the three allergic groups separately: sensitivity, specificity and match with the OCT. We also studied the RAST-MAST-CLA correlation and the variability of the MAST-CLA. The prick test was the most sensitive (95%) and the MAST-CLA (13% divergence in two measurements) the most specific (92%). The RAST and the MAST-CLA (68% match) gave similar results, with an acceptable match (75% and 77%, respectively) with the OCT. The medical history could only suggest the diagnosis (39% false-positives). After comparing the results with those in the literature, it is suggested that greater attention should be paid to the limitations of these techniques compared with the OCT.

[Allergy to cow's milk proteins: the sensitivity of specific and nonspecific laboratory tests]

Authors report their experience of a population of 308 children affected by cow's milk allergy who presented gastrointestinal, respiratory and cutaneous symptoms. Diagnosis was based on challenge with cow's milk proteins and on laboratory specific tests (RAST, prick test) and non specific ones (PRIST, eosinophil count, 1-h xylose test, occult blood in the stools), following ESPGAN criteria. The patients were subdivided in 3 groups: a) patients with prevalent gastrointestinal symptoms; b) patients with prevalent cutaneous symptoms and c) patients with both, gastrointestinal and cutaneous symptoms. The sensitivity of the employed tests was evaluated either in the whole patient population or in the there group according to symptoms. Our data show a high sensitivity of the RAST for cow's milk (70%) versus a lower sensitivity of prick test (53%) when the whole patients population was considered. Moreover statistically important differences of the sensitivity of the various tests were found when the three groups of patients were considered, as well as when such a comparison was done in patients subdivided according to age (more or less than 6 months). Finally the concord between RAST and prick test was evaluated in the three groups.

Rapid detection of Vibrio cholerae O1 in stools of Peruvian cholera patients by using monoclonal immunodiagnostic kits. Loyaza Cholera Working Group in Peru

We compared stool culture with two commercial Vibrio cholerae O1 rapid diagnostic kits which detect antigen in 100 adults with cholera in Peru. Serum vibriocidal-antibody titer was used as an external reference. Both rapid diagnostic kits appeared to detect cholera more frequently than did culture and were highly specific.

Audit of diagnosis and investigations in patients with recurrent aphthous stomatitis

The responses of clinicians to results of hematologic and serologic investigation of 79 patients with recurrent aphthous stomatitis have been reviewed. Twenty percent of patients with abnormal results were not adequately managed by attending clinicians.

[Annual cost of microbial immunological tests for HIV-positive individuals in a hospital center]

The goal of this study is to increase the knowledge of the AIDS cost in a hospital. We have studied the HIV patients diagnosed during a year in our hospital and the charges of the serological tests performed to them. 20.8% of the tests were to study antibodies against HIV (only 20% were positive). After patient distribution between extra or intrahospital origin, we highlight that 61% of the charges are attributed to patients who do not belong to the hospital but to its catchment area. We emphasize the problem that AIDS patients are creating to hospital, being necessary that personal select only useful tests honestly.

An immunocytochemical test for the diagnosis of antibodies to Plasmodium vivax

An immunocytochemical peroxidase test (ICPT) has been developed to allow serological measurement of the antibody response to Plasmodium vivax by light microscopy. Acetone fixed P. vivax erythrocyte stages were used as source of antigen. The immunofluorescent antibody test (IFAT) was used as reference test. In testing sera from individuals infected with P. vivax in southeastern Venezuela a high correlation (100%) was obtained between the ICPT and the IFAT. There were cross reactions with sera from patients with malaria by P. falciparum but not with those from patients with other parasitic diseases. Antibody titres as measured by the ICPT showed a positive correlation with past P. vivax malarial experiences.