Qualitative and quantitative comparison of allergen component-specific to birch and grass analyzed by ImmunoCAP assay and Euroline immunoblot test.

Summary: Background.In the diagnostic work up of allergy, determining allergen component-specific immunoglobulin E (IgE) is important for diagnosis, prognosis and choice of treatment. The purpose of this study was to evaluate the performance of the immunoblotting assay (Euroline) in detection of IgE antibodies against timothy grass and birch pollen allergen components compared to fluorescent enzyme assay (ImmunoCAP, Phadia 250). Methods. A total of 128 serum samples from patients allergic to timothy grass and birch pollen were analysed. The levels of IgE antibodies to timothy grass and birch pollen were measured using Euroline DPA-Dx pollen 1 and ImmunoCAP assay. The two methods were then compared on binary (positive vs negative), semi-quantitative (IgE classes) and quantitative (concentration) levels. The two methods were also compared to results from skin prick testing. Results. The Euroline method showed a positive percentage agreement of 93% and negative percentage agreement of 94% with an overall accuracy of 94% when compared to ImmunoCAP. Kappa analysis showed moderate strength of agreement between the methods in determining IgE classes for 7/11 components tested. All components showed a positive correlation when analysed using Spearman's rank correlation. Conclusions. Overall, we found that there is good correlation between the Euroline and ImmunoCAP methods in measuring IgE sensitization.

Pre-treatment allergen-specific IgE analysis and outcomes of allergen immunotherapy.

Summary: Background. Patients show varied results to allergen immunotherapy (AIT. The reason for this variability is unclear. Objective. To describe the relationship between AIT efficacy and demographic characteristics, as well as pre-treatment plasma levels of specific IgE-antibodies to grass and birch pollen. Methods. A retrospective study was performed based on medical records of 128 patients who received AIT. The patients completed a questionnaire and pre-AIT plasma levels of allergen-specific IgE to grass and birch pollen were measured using EUROLINE DPA-Dx pollen 1 method. Results. Seventy percent of patients classified their allergic symptoms as less severe after AIT. Twenty-seven percent had received AIT targeting only grass pollen, 19% targeting only birch pollen, and 55% targeting both grass and birch. A total of 35 different IgE profiles were found across our study population. On comparison of the demographic characteristics and concentration of allergen-specific IgE-antibodies, no statistically significant differences could be found.Conclusions. The majority of patients rated their allergic symptoms as less severe after AIT. No clear relationship could be demonstrated between pre-treatment allergen-specific IgE concentration, or demographic characteristics, and effect of AIT. There may be other factors underlying the different responses to AIT.

Pharmacokinetic and pharmacogenomic modelling of the CYP3A activity marker 4ß-hydroxycholesterol during efavirenz treatment and efavirenz/rifampicin co-treatment.

OBJECTIVES: To assess the effect of the major efavirenz metabolizing enzyme (CYP2B6) genotype and the effects of rifampicin co-treatment on induction of CYP3A by efavirenz. PATIENTS AND METHODS: Two study arms (arm 1, n = 41 and arm 2, n = 21) were recruited into this study. In arm 1, cholesterol and 4ß-hydroxycholesterol were measured in HIV treatment-naive patients at baseline and then at 4 and 16 weeks after initiation of efavirenz-based antiretroviral therapy. In arm 2, cholesterol and 4ß-hydroxycholesterol were measured among patients taking efavirenz during rifampicin-based tuberculosis (TB) treatment (efavirenz/rifampicin) just before completion of TB treatment and then serially following completion of TB treatment (efavirenz alone). Non-linear mixed-effect modelling was performed. RESULTS: A one-compartment, enzyme turnover model described 4ß-hydroxycholesterol kinetics adequately. Efavirenz treatment in arm 1 resulted in 1.74 (relative standard error = 15%), 3.3 (relative standard error = 33.1%) and 4.0 (relative standard error = 37.1%) average fold induction of CYP3A for extensive (CYP2B6*1/*1), intermediate (CYP2B6*1/*6) and slow (CYP2B6*6/*6) efavirenz metabolizers, respectively. The rate constant of 4ß-hydroxycholesterol formation [mean (95% CI)] just before completion of TB treatment [efavirenz/rifampicin co-treatment, 7.40 × 10(-7) h(-1) (5.5 × 10(-7)-1.0 × 10(-6))] was significantly higher than that calculated 8 weeks after completion [efavirenz alone, 4.50 × 10(-7) h(-1) (4.40 × 10(-7)-4.52 × 10(-7))]. The CYP3A induction dropped to 62% of its maximum by week 8 of completion. CONCLUSIONS: Our results indicate that efavirenz induction of CYP3A is influenced by CYP2B6 genetic polymorphisms and that efavirenz/rifampicin co-treatment results in higher induction than efavirenz alone.

Pharmacogenetic and pharmacokinetic aspects of CYP3A induction by efavirenz in HIV patients.

We investigated the effects of pharmacogenetic variations and efavirenz pharmacokinetics on inter-individual differences in the extent of CYP3A induction by efavirenz using 4ß-hydroxycholesterol/cholesterol (4ß-OHC/Chol) as a marker for CYP3A induction. Plasma 4ß-hydroxycholesterol and cholesterol concentrations were determined at baseline, and at the 4th, 16th and 48th week of efavirenz-based highly active antiretroviral therapy in antiretroviral therapy-naive HIV patients (n=77). Efavirenz plasma concentrations were quantified at weeks 4 and 16. CYP2B6, CYP3A5, ABCB1, UGT2B7 genotyping were done. Compared with baseline, the median plasma 4ß-OHC/Chol ratio increased at the 4th (257%), 16th (291%) and 48th (165%) week (P<0.0001). CYP2B6*6 genotype significantly influenced 4ß-OHC/Chol ratio at weeks 16 (P=0.02) and 48 (P=0.04) being highest in CYP2B6*6/*6>*1/*6>*1/*1. There were positive correlations between plasma efavirenz and 4ß-OHC/Chol ratios (week 4: P=0.02, week 16: P=0.001). CYP3A enzyme induction by efavirenz is pronounced in CYP2B6 slow metabolizers who have high efavirenz plasma exposure.

A 5-year prospective population-based study of juvenile chronic arthritis: onset, disease process, and outcome.

OBJECTIVES: To investigate, in a population-based cohort of patients with juvenile chronic arthritis (JCA), onset characteristics, progression, outcome, and prognostic factors longitudinally for 5 years. METHODS: This cohort consisted of 132 incidence cases identified between 1984 and 1986 in southwestern Sweden followed for 5 years with annual reports of subgroup, joint assessment, disease activity, eye examinations, laboratory measurements, and medication. At the 5-year follow-up, the Childhood Health Assessment Questionnaire (Child-HAQ) was evaluated. European League Against Rheumatism (EULAR) criteria for diagnosis and disease activity were used. RESULTS: During the 5 years only four patients were lost to follow-up, 34% changed subgroup and 8% developed uveitis. At the 5-year follow-up the disease was active in 12% of the patients, stable in 28%, inactive in 25%, and in remission in 34%. Among those examined, 24% had radiological changes, of whom half had advanced changes. The Child-HAQ median score at the 5-year follow-up was 0.13 (range 0.0-1.9). The number of involved joints at inclusion correlated positively with active disease at the 5-year follow-up. Age at disease onset, the number of involved joints, and the number of joints with arthritis correlated positively with continuous disease and Child-HAQ score. CONCLUSION. Our study shows a diverse disease course during the first 5 years of JCA where one-third changed subgroup and two-thirds did not reach remission. Age of disease onset, the number of involved joints, and the number of joints with arthritis at inclusion were associated with poor outcome at the 5-year follow-up.

The dopaminergic stabilizer pridopidine is to a major extent N-depropylated by CYP2D6 in humans.

PURPOSE: The influence of the cytochrome P450 enzyme CYP2D6 in the metabolism of the novel dopaminergic stabilizer pridopidine was investigated in healthy Swedish Caucasians. METHODS: Six extensive metabolizers (EM) and six poor metabolizers (PM) of debrisoquine were given a single oral dose of pridopidine (EM, 50 mg; PM, 25 mg). RESULTS: The mean total plasma clearance of pridopidine was 541 and 138 mL/min in EM and PM, respectively (p = 0.003), and was slightly higher in PM than the mean renal plasma clearance (105 mL/min; p = 0.11). The mean plasma area under the time-concentration curve between time zero and 32 h (AUC(0-32 h)) of the N-depropyl metabolite ACR30 was higher in EM than in PM (1,377 vs. 61 nmol h/mL, respectively; p < 0.001). The urinary excretion of pridopidine + ACR30 was high in both EM (85 %) and PM (78 %). The dose-adjusted peak concentration (C(max)) was not statistically different in EM and PM; consequently, the oral absorption of pridopidine was close to complete. CONCLUSIONS: Following a single dose of pridopidine, the drug is N-depropylated by CYP2D6 in EM, while in PM the most important elimination pathway is renal glomerular filtration. Results of studies examining the effects of multiple repeat dosing suggest that the CYP2D6 enzyme is at least partly inactivated by pridopidine.

Voriconazole increases while itraconazole decreases plasma meloxicam concentrations.

This study investigated the effect of voriconazole, an inhibitor of cytochrome P450 2C9 (CYP2C9) and CYP3A4, and itraconazole, an inhibitor of CYP3A4, on the pharmacokinetics and pharmacodynamics of meloxicam. Twelve healthy volunteers in a crossover study ingested 15 mg of meloxicam without pretreatment (control), after voriconazole pretreatment, and after itraconazole pretreatment. The plasma concentrations of meloxicam, voriconazole, itraconazole, and thromboxane B(2) (TxB(2)) generation were monitored. Compared to the control phase, voriconazole increased the mean area under the plasma concentration-time curve from 0 to 72 h (AUC(0-72)) of meloxicam by 47% (P < 0.001) and prolonged its mean half-life (t(1/2)) by 51% (P < 0.01), without affecting its mean peak concentration (C(max)). In contrast, itraconazole decreased the mean AUC(0-72) and C(max) of meloxicam by 37% (P < 0.001) and by 64% (P < 0.001), respectively, and prolonged its t(1/2) and time to C(max). The plasma protein unbound fraction of meloxicam was unchanged by voriconazole and itraconazole. Lowered plasma meloxicam concentrations during the itraconazole phase were associated with decreased pharmacodymic effects of meloxicam, as observed by weaker inhibition of TxB(2) synthesis compared to the control and voriconazole phases. Voriconazole increases plasma concentrations of meloxicam, whereas itraconazole, unexpectedly, decreases plasma meloxicam concentrations, possibly by impairing its absorption.

Anti-tumour necrosis factor therapy in rheumatoid arthritis and risk of malignant lymphomas: relative risks and time trends in the Swedish Biologics Register.

BACKGROUND: Tumour necrosis factor (TNF) antagonists have proved effective as treatment against rheumatoid arthritis (RA), but the unresolved issue of whether the use of anti-TNF therapy increases the already elevated risk of lymphoma in RA remains a concern. METHODS: Using the Swedish Biologics Register (ARTIS), the Swedish Cancer Register, pre-existing RA cohorts and cross-linkage with other national health and census registers, a national RA cohort (n = 67,743) was assembled and patients who started anti-TNF therapy between 1998 and July 2006 (n = 6604) were identified. A general population comparator (n = 471,024) was also assembled and the incidence of lymphomas from 1999 to 31 December 2006 was assessed and compared in these individuals. RESULTS: Among the 6604 anti-TNF-treated RA patients, 26 malignant lymphomas were observed during 26,981 person-years of follow-up, which corresponded to a relative risk (RR) of 1.35 (95% CI 0.82 to 2.11) versus anti-TNF-naive RA patients (336 lymphomas during 365,026 person-years) and 2.72 (95% CI 1.82 to 4.08) versus the general population comparator (1568 lymphomas during 3,355,849 person-years). RA patients starting anti-TNF therapy in 1998-2001 accounted for the entire increase in lymphoma risk versus the two comparators. By contrast, RR did not vary significantly by time since start of first treatment or with the accumulated duration of treatment, nor with the type of anti-TNF agent. CONCLUSION: Overall and as used in routine care against RA, TNF antagonists are not associated with any major further increase in the already elevated lymphoma occurrence in RA. Changes in the selection of patients for treatment may influence the observed risk.

Indole-3-acetic acid in human cerebrospinal fluid: identification and quantification by mass fragmentography.

Indole-3-acetic acid has been identified in human cerebrospinal fluid by the gas chromatographic-mass spectrometric technique called mass fragmentography. A specific and sensitive method for quantitative determination of indole-3-acetic acid down to 2 nanograms per milliliter of cerebrospinal fluid has been developed. Samples of cerebrospinal fluid from 24 patients with depression contained 6.1 +/- 3.1 (range 2.6 to 15.8) nanograms of indole-3-acetic acid per milliliter.

"Serotonin depression"--a biochemical subgroup within the affective disorders?

The distribution of 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the cerebrospinal fluid of 68 depressed patients was bimodal. Twenty-nine percent of the patients were in the lower mode, with a concentration of 5-HIAA below 15 nanograms per milliliter. Although there were no differences in overall severity of depression between the two modes, there was a significant correlation between the concnetration of 5-HIAA and severity of depression in the lower, but not in the upper, mode. The finding suggests the existence of a biochemical subgroup of depressive disorder, characterized by a disturbance of serotonin turnover.

CYP3A5 genotype has an impact on the metabolism of the HIV protease inhibitor saquinavir.

CYP3A is the main enzyme subfamily involved in the metabolism of the HIV protease-inhibitor saquinavir. We hypothesized that individuals homozygous for CYP3A5*1 might have a higher oral clearance of saquinavir, compared with subjects lacking functional CYP3A5 alleles. A single-dose pharmacokinetic trial of saquinavir soft gel capsules, 1,200 mg, was performed in 16 black Tanzanian healthy volunteers with two functional CYP3A5 alleles (*1/*1) and in 18 volunteers without functional CYP3A5 alleles (both alleles being either *3, *6, or *7). The median area under the plasma concentration-time curve (AUC)0-24 reached among subjects with two functional alleles was 1,410 ng h/ml (interquartile range (IQR) 826-1,929), whereas it was 2,138 ng h/ml (IQR 1,380-3,331) in subjects without (P=0.0533, Mann-Whitney U-test). The median ratio of saquinavir over its M2 plus M3 hydroxy metabolites in urine was 64 (IQR 52-73) in subjects with two functional alleles, whereas it was 145 (IQR 89-181) in those without (P=0.000078, Mann-Whitney U-test). In conclusion, saquinavir is metabolized by CYP3A5. The median AUC0-24 for saquinavir among individuals with two functional CYP3A5 alleles was 34% lower than among those with no functional alleles. To clarify the clinical importance of the CYP3A5 polymorphism, further studies should be conducted on saquinavir, dosed to steady state, in the presence of ritonavir boosting.

Monoamine metabolites in CSF and suicidal behavior.

Cerebrospinal fluid concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenyl glycol (MHPG) were measured in 30 psychiatric patients who had attempted suicide and 45 healthy volunteers. The suicide attempters had a significantly lower CSF 5-HIAA level than the controls, especially those who had made more violent attempts. After adjustment for differences in body height and age between controls and patients, the difference in 5-HIAA level became even more marked. Concentrations of 5-HIAA also were lower than normal in suicidal patients who were not diagnosed as depressed at the time of lumbar puncture, while HVA levels were lowered only in the depressives. A follow-up study of these and 89 more patients (depressed and/or suicidal) revealed a 20% mortality by suicide within a year after lumbar puncture in patients with a CSF-HIAA level below the median.

Effects of antidepressant treatments on platelet tritiated imipramine binding in major depressive disorder.

The effects of four antidepressant treatments on platelet tritiated imipramine binding have been studied in 51 hospitalized patients with severe major depressive disorder. There was an increase in maximum binding (Bmax) during the first week of treatment with antidepressants and electroconvulsive therapy, which was further magnified after three weeks' treatment with the serotonin uptake blockers alaproclate and zimeldine hydrochloride, but the Bmax values returned to baseline levels with nortriptyline hydrochloride and electroconvulsive therapy. The equilibrium dissociation affinity constant (Kd) did not change with any of the treatments. On reexamination one or two years after admission to the study, Bmax had not reached control values in clinically recovered, drug-free patients. Low pretreatment Bmax was associated with delusions during illness and with a poor long-term clinical outcome. There was no correlation between binding parameters and monoamine metabolite concentrations in the cerebrospinal fluid, either before or during treatment.

Clomipramine treatment of obsessive-compulsive disorder. II. Biochemical aspects.

Concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the dopamine metabolite homovanillic acid, and the noradrenaline metabolite 4-hydroxy-3-methoxyphenyl glycol were measured in CSF before and after three weeks' treatment of severe obsessive-compulsive disorder with clomipramine hydrochloride. Patients who responded to clomipramine treatment had significantly higher CSF levels of 5-HIAA before treatment. The amelioration of obsessive-compulsive symptoms was positively correlated to the reduction of CSF concentrations of 5-HIAA during clomipramine treatment but negatively correlated to plasma concentrations of clomipramine. Reduction of CSF concentrations of 5-HIAA, which probably reflects drug action on central serotonin neurons, was maximal at a plasma clomipramine concentration of about 300 nmole/L. At higher levels, the reduction of CSF levels of 5-HIAA was smaller. The antiobsessive effect of clomipramine may be connected to its capacity to inhibit serotonin uptake.

Cortisol in the CSF of depressed and suicidal patients.

Cortisol concentrations in CSF were measured by radioimmunoassay in healthy controls, depressed patients, patients who had attempted suicide but were not depressed, and obsessive-compulsive patients. The factors that contributed most to the variance in CSF cortisol levels were a diagnosis of depression, height, and important life changes during the six months preceding the investigation. Depression was by far the most important factor. The depressed patients had significantly higher CSF cortisol levels than the controls. In obsessive-compulsive and depressed patients treated with clomipramine hydrochloride, the levels were significantly correlated with mean urinary cortisol excretion. Of the three monoamine metabolites measured, only 5-hydroxy-indoleacetic acid level was weakly correlated with CSF cortisol level. This correlation was confined to the depressed patients and could be accounted for by the common correlation with height.

A methodological investigation on the estimation of the S-mephenytoin hydroxylation phenotype using the urinary S/R ratio.

After a single oral dose of racemic mephenytoin the S/R ratio in urine can be used to phenotype extensive (EM) and poor metabolizers (PM) of S-mephenytoin. We confirmed the increased S/R ratio by storage time in EM because of the hydrolysis of a conjugate of S-mephenytoin excreted in EM, but not in PM. The S/R ratio in the 0-8 h urine increased 8- to 127-fold (from 0.22 +/- 0.16 to 9.9 +/- 11.3) after acid treatment of urine from 30 EM, but there was no effect of acid in that of 12 PM. We suggest that the phenotype of mephenytoin in combination with debrisoquine can be determined in the 0-8 h urine by estimating the mephenytoin S/R ratio before and after acid treatment.

An S-mephenytoin cysteine conjugate identified in urine of extensive but not of poor metabolizers of S-mephenytoin.

A conjugate of S-mephenytoin excreted in urine of extensive but not of poor metabolizers of S-mephenytoin has previously been reported. This conjugate, which is easily hydrolysed back to S-mephenytoin, has now been isolated and identified in urine from one extensive metabolizer after a single dose of 100 mg racemic mephenytoin. High performance liquid chromatography purification, followed by gas chromatographic, mass spectrometric and amino acid analyses showed that the isolated compound is a cysteine conjugate of S-mephenytoin. The significant mass spectrometric ions have been confirmed in three additional extensive metabolizers of S-mephenytoin, but were not detectable in urine from three poor metabolizer subjects. The exact structure of the conjugate is unknown, but we suggest that an S-N bond between cysteine and S-mephenytoin is formed via an oxidative radical mechanism catalyzed by CYP2C19.

Use of omeprazole as a probe drug for CYP2C19 phenotype in Swedish Caucasians: comparison with S-mephenytoin hydroxylation phenotype and CYP2C19 genotype.

A single oral dose of omeprazole (20 mg) was given orally to 160 healthy Caucasian Swedish subjects and tested as a probe for CYP2C19. The study was nonrandomized and included seven subjects previously classified as poor metabolizers (PM) of S-mephenytoin. The ratio between the plasma concentrations of omeprazole and hydroxyomeprazole (metabolic ratio; MR) was determined by HPLC in a blood sample drawn 3 h after drug intake. In 17 subjects the test was repeated and the MRs of omeprazole on the two occasions were correlated (rs = 0.85; p < 0.0001). There was a significant correlation between the MR of omeprazole and the S/R mephenytoin ratio among 141 subjects, in whom both ratios were determined (rs = 0.63, p < 0.001). All seven PMs of S-mephenytoin had higher MRs of omeprazole (7.1-23.8) than extensive metabolizers (EM) (0.1-4.9). All 160 subjects and another 15 Caucasian Swedish PMs previously phenotyped with mephenytoin were analysed with respect to the presence of the CYP2C19m1 allele by PCR amplification of the intron 4/exon 5 junction followed by Sma I digestion. EMs heterozygous for the CYP2C19m1 gene had MRs of omeprazole and S/R ratios of mephenytoin that were higher than those of subjects who were homozygous for the wild-type allele (p = 0.0001). Nineteen of the 22 PMs were homozygous for the CYP2C19m1 gene. Three were heterozygous for this allele. Thus, 41 of the 44 alleles (93%) of PMs were defective CYP2C19m1. One of the remaining three PM alleles was subsequently found to contain the CYP2C19m2 mutation, which has earlier been shown to be associated with the PM phenotype in Oriental populations. In conclusion, the phenotype determined by omeprazole correlated with that of mephenytoin, and was in good agreement with the genotype.

S-mephenytoin hydroxylation phenotype and CYP2C19 genotype among Ethiopians.

The polymorphic metabolism of S-mephenytoin and the distribution of two known deleterious mutant CYP2C19 alleles was determined among 114 healthy unrelated black Ethiopians. Six subjects (5.2%) were poor metabolizers (PMs) of S-mephenytoin. The frequencies of the defective CYP2C19*2 (CYP2C19m1) and CYP2C19*3 (CYP2C19m2) alleles were 0.14 and 0.02, respectively. Three of the PMs were homozygous for the CYP2C19*2 allele and the remaining three PMs were heterozygous for both the CYP2C19*2 and CYP2C19*3 mutant alleles. It is concluded that the frequency of PMs for S-mephenytoin is similar in Ethiopians, Zimbabweans and Caucasians and that the CYP2C19*3 allele, for the first time identified in a black population, together with the CYP2C19*2 allele account for all of the defective CYP2C19 alleles among the Ethiopian PMs.

Polymorphic hydroxylation of S-mephenytoin and omeprazole metabolism in Caucasian and Chinese subjects.

Twelve Caucasian healthy men and women, of whom six were poor metabolizers (PMs) and six were extensive metabolizers (EMs) of S-mephenytoin, together with 13 Chinese healthy men and women (five PMs and eight EMs), received a single oral 20 mg dose of omeprazole. Plasma levels of omeprazole and its two main metabolites, omeprazole sulphone and hydroxyomeprazole, were determined by HPLC. The mean (+/- SD) area under the plasma concentration-time curve (AUC) for omeprazole was 11.1 +/- 2.6 and 0.9 +/- 0.4 microM h in the Caucasian PMs and EMs, respectively. Corresponding values for elimination half-life were 2.3 +/- 0.4 and 0.7 +/- 0.4 h. In the Chinese PMs and EMs the AUC of omeprazole as 13.3 +/- 5.6 and 2.6 +/- 1.8 microM h. The AUCs of omeprazole were significantly higher in the Chinese EMs than in the Caucasian EMs possibly due to the higher proportion of heterozygotes in the former than in the latter group. The elimination half-life in the Chinese PMs and EMs was 2.4 +/- 0.2 and 0.8 +/- 0.2 h--similar to the observations in the Caucasian subjects. The maximum plasma concentration of hydroxyomeprazole was five-fold and four-fold higher in EMs compared to PMs among Caucasians and Chinese, respectively. The elimination half-life of the hydroxy metabolite was also longer in PMs than in EMs in both populations. The ratio between AUC for omeprazole and AUC for hydroxyomeprazole was 11.9 +/- 2.1 and 0.6 +/- 0.1 in Caucasian PMs and EMs, respectively. Corresponding values in the Chinese were 13.1 +/- 2.9 and 1.6 +/- 0.5.(ABSTRACT TRUNCATED AT 250 WORDS)