Comparison of Molecular Multiplex and Singleplex Analysis of IgE to Grass Pollen Allergens in Untreated German Grass Pollen-Allergic Patients.

BACKGROUND: The ImmunoCAP ISAC 112 platform is the only commercially available molecular allergy IgE multiplex test. Data on the comparison of this rather novel test with the molecular singleplex ImmunoCAP IgE platform are lacking. OBJECTIVE: To compare the multiplex ISAC 112 platform and the singleplex ImmunoCAP platform in regard to IgE to grass pollen allergens in untreated grass pollen-allergic patients in Germany. METHODS: Serum samples from 101 adults with grass pollen allergy were analyzed for specific IgE (sIgE) to 8 allergenic molecules from timothy grass pollen and to the 112 allergenic molecules included in the ISAC panel. The results for the multiplex and singleplex tests were subsequently analyzed statistically. RESULTS: Comparison of sIgE to grass pollen allergens detected by ISAC 112 and the singleplex ImmunoCAP assay revealed the following correlation coefficients: 0.88 (rPhl p 1), 0.96 (rPhl p 2), 0.70 (nPhl p 4), 0.94 (rPhl p 5b), 0.92 (rPhl p 6), 0.85 (rPhl p 11), and 0.78 (rPhl p 12). CONCLUSION: Molecular testing with ISAC 112 correlates well with the ImmunoCAP platform for respective molecular timothy grass pollen allergens.

Comparison of molecular multiplex and singleplex analysis of IgE to grass pollen allergens in untreated german grass pollen–allergic patients

Antecedentes: El ImmunoCAP ISAC 112, es el único sistema comercial con determinación simultánea de múltiples alérgenos comercializado para el diagnóstico alergológico molecular. No existen estudios comparativos de este sistema con el ImmunoCAP para la determinación de IgE frente a un único alérgeno. Objetivos: Realizar un estudio comparativo para la determinación de IgE específica a alérgenos de polen de gramíneas en pacientes alemanes con alergia a estos pólenes, utilizando los sistemas ISAC IgE y el ImmunoCAP IgE. Métodos: Se estudiaron 101 sueros de adultos con alergia a pólenes de gramíneas, determinando la IgE específica a 8 alérgenos de hierba timotea mediante ImmunoCAP y a 112 alérgenos presentes en la plataforma ISAC. Posteriormente se realizó un análisis estadístico comparativo entre los resultados de ambos sistemas. Resultados: La comparación de los valores de IgE específica frente a los alérgenos de pólenes de gramíneas hallados en los sistemas ISAC e ImmunoCAP mostraron los siguientes coeficientes de correlación: 0.88 (rPhl p 1), 0.96 (rPhl p 2), 0.70 (nPhl p 4), 0.94 (rPhl p 5b), 0.92 (rPhl p 6), 0.85 (rPhl p 11) y 0.78 (rPhl p12). Conclusiones: El diagnóstico molecular con el Sistema ISAC guarda buena correlación con los resultados del ImmunoCAP para los alérgenos de hierba timotea presentes en ambas plataformas (AU)

Background: The ImmunoCAP ISAC 112 platform is the only commercially available molecular allergy IgE multiplex test. Data on the comparison of this rather novel test with the molecular singleplex ImmunoCAP IgE platform are lacking. Objective: To compare the multiplex ISAC 112 platform and the singleplex ImmunoCAP platform in regard to IgE to grass pollen allergens in untreated grass pollen–allergic patients in Germany. Methods: Serum samples from 101 adults with grass pollen allergy were analyzed for specific IgE (sIgE) to 8 allergenic molecules from timothy grass pollen and to the 112 allergenic molecules included in the ISAC panel. The results for the multiplex and singleplex tests were subsequently analyzed statistically. Results: Comparison of sIgE to grass pollen allergens detected by ISAC 112 and the singleplex ImmunoCAP assay revealed the following correlation coefficients: 0.88 (rPhl p 1), 0.96 (rPhl p 2), 0.70 (nPhl p 4), 0.94 (rPhl p 5b), 0.92 (rPhl p 6), 0.85 (rPhl p 11), and 0.78 (rPhl p12). Conclusion: Molecular testing with ISAC 112 correlates well with the ImmunoCAP platform for respective molecular timothy grass pollen allergens (AU)

Application of the optimized CO-rebreathing method for determination of hemoglobin mass in patients with polycythemia vera.

Determination of red cell volume (RCV) might contribute to establishing the diagnosis of polycythemia vera (PV). A novel simplified method to detect RCV through CO rebreathing is nowadays applied in healthy young individuals but was not tested in a clinical or PV setting. The aim of the present study is to evaluate whether this spirometric approach is applicable in older subjects and contributes to PV diagnosis in a proof-of-concept approach. At first, RCV was determined by the optimized CO-rebreathing method in healthy subjects >50 years of age (n = 81, age 66 ± 9 years). Failure rate and age distribution of subjects who failed with CO rebreathing were analyzed. Then, RCV was measured in male PV patients (n = 7) and compared to healthy male controls (n = 35). RCV values in relation to several anthropometric references (body weight, body surface area (BSA), lean body mass (LBM)) were calculated to determine the sensitivity and specificity of established RCV thresholds when using optimized CO rebreathing. In healthy subjects, test failure rate was 9.9 %, but failure was not associated with age. Sensitivity and specificity (sens/spec) to detect PV was 100 %/83 % using the criteria of the PV study group. Using criteria based on BSA, sens/spec was 14 %/100 %. An arbitrary threshold of 50 ml/kg LBM yielded sens/spec of 100 %/97 %. In conclusion, this proof-of-concept indicates that optimized CO rebreathing is applicable in older subjects and allows determining RCV for the diagnosis of PV. Normalized values for RCV measures obtained from CO rebreathing are needed to grant sufficient sensitivity and/or specificity.

Are 10 min of seating enough to guarantee stable haemoglobin and haematocrit readings for the athlete's biological passport?

Haemoglobin (Hb) and haematocrit (Hct) are measured as indirect markers of doping in athletes. We studied the effect of posture on these parameters in a typical antidoping setting. Venous blood samples were obtained from nine endurance athletes (six males, three females) and nine control subjects (six males, three females) immediately and after 5, 10, 15, 20 and 30 min after having adopted a seated position from normal daily activity. Hb (CV 0.72%) and Hct (CV 0.87%) were determined using an automated cell counter, plasma volume changes were calculated. Differences between the time points, gender and groups were calculated using a mixed-model procedure. Significant changes were observed in the first 10 min after sitting down but no further changes were noted between 10 and 30 min. Mean directional change for Hb and Hct between 0 min and the average of the period from 10 to 30 min was -2.4% (-0.35 g/dl) for Hb and -2.7% (-1.2%) for Hct. Plasma volume increased accordingly. Neither group nor gender had significant effects. Under typical conditions encountered during blood testing in doping control, a period of 10 min in a seated position is sufficient for the vascular volumes to re-equilibrate and to adapt to the new posture.

Relations between haemoglobin mass, cardiac dimensions and aerobic capacity in endurance trained cyclists.

AIM: Chronic endurance exercise triggers increased cardiac dimensions, blood volumes and haemoglobin mass (Hb mass). Cardiac output and Hb mass are considered as independent contributors to aerobic performance. Therefore, increased Hb mass could counterbalance for a relative deficiency in cardiac adaptation. The purpose of the present study is to investigate relations between Hb mass and cardiac dimensions in a group of endurance athletes with respect to aerobic capacity. METHODS: Two groups of highly trained cyclists featuring high (HHB group, N.=13) and low (LHB group, N.=13) Hb mass (measured by a CO-rebreathing method) were compared for measures of aerobic performance, cardiac wall thickness, cavity size and left ventricular mass (determined by 2-D-echocardiography). Lean body mass (LBM) was chosen as anthropometrical reference for Hb mass. RESULTS: HHB featured higher cardiac wall thickness than LHB, but no difference appeared in cardiac cavity size, left ventricular mass and the performance parameters. Normalising Hb mass for body weight instead of LBM improved correlations between Hb mass and performance parameters. CONCLUSIONS: Our data provides new evidence for a connection between cardiac wall thickness and Hb mass in endurance athletes but no further evidence for a counterbalance between Hb mass and cardiac adaptation was found. Moreover, we postulate that Hb mass loses predictive value for aerobic performance when normalised for LBM.

Evaluation of anthropometrical reference parameters for hemoglobin mass in endurance athletes.

AIM: Blood volume and hemoglobin mass (tHb) are new emerging parameters in exercise physiology. The appropriate anthropometrical reference for these variables has not yet been investigated. In most current investigations, body weight is used in this context. The aim of the present study was therefore to evaluate three different anthropometrical parameters (body weight, body surface area [BSA] and lean body mass [LBM] with respect to tHb. METHODS: Sixty-five healthy male endurance athletes underwent a tHb determination (optimised CO rebreathing method) and anthropometrical evaluation (skinfold measurement) with estimation of body weight, LBM and BSA. Correlation analysis was performed; the correlations of the different anthropometrical reference ratios were compared and evaluated with regards to body composition. RESULTS: LBM showed the best correlation with tHb (R=0.81), although no significant differences between the three anthropometrical references were found (BSA R=0.76, body weight R=0.77). In contrast to tHb/body weight, tHb/LBM was independent of body fat content and thus body composition. CONCLUSION: The current study demonstrated no statistical difference between various anthropometrical references for tHb, which might be due to the anthropometrically homogenous study group of lean, endurance trained athletes. However, the significance dependence of body weight on body fat content indicates that this might not be the case in athletes of other somatotypes. It is therefore suggested that LBM instead of body weight should be used as anthropometrical reference when investigating tHb in athletes.

Haemoglobin mass in cyclists during stage racing.

Haemoglobin mass is a main determinant of maximal oxygen uptake. Blood doping aims at increasing this variable. Limits for haematocrit and haemoglobin concentration are used as indicators of blood doping. However, these variables are measures of concentration, do not represent total haemoglobin mass and are altered by vascular volumes shifts. Direct estimation of haemoglobin mass could improve blood tests. It is unknown if physical exercise alters haemoglobin mass. The purpose of this study was to investigate the reaction of haemoglobin mass and other vascular compartments to heavy exercise in athletes. Haemoglobin mass and vascular compartments were evaluated using the optimised CO rebreathing method in 7 elite cyclists during a stage race. Simultaneously, haemoglobin concentration and haematocrit were analysed. Haemoglobin mass (pre-race 958 +/- 123 g, end race 948 +/- 106 g) and red cell volume did not change significantly over the study period, while plasma volume and blood volume tended to increase. Haematocrit (pre-race 44.1 +/- 2.5 %, end race 40.9 +/- 1.59 %) and haemoglobin concentration (pre race 15.8 +/- 0.9 g/dl, end race 14.7 +/- 0.7 g/dl) decreased. During the study, a plasma volume expansion as adaptation to prolonged exercise occurred. Haemoglobin concentration and haematocrit decreased accordingly, whereas haemoglobin mass remained stable. Haemoglobin mass might therefore be a suitable screening tool for blood manipulations.