Pathways to performance in undergraduate medical students: role of conscientiousness and the perceived educational environment.

This study examined conscientiousness and the perceived educational environment as independent and interactive predictors of medical students' performance within Biggs' theoretical model of learning. Conscientiousness, the perceived educational environment, and learning approaches were assessed at the beginning of the third year in 268 medical students at the University of Geneva, Switzerland. Performance was examined at the end of the third year via a computer-based assessment (CBA) and the Objective Structured Clinical Examination (OSCE). Path analysis was used to test the proposed model, whereby conscientiousness and the perceived educational environment predicted performance directly and indirectly via students' learning approaches. A second model included interaction effects. The proposed model provided the best fit and explained 45% of the variance in CBA performance, and 23% of the variance in OSCE performance. Conscientiousness positively predicted CBA performance directly (ß = 0.19, p < 0.001) and indirectly via a deep learning approach (ß = 0.05, p = 0.012). The perceived educational environment positively predicted CBA performance indirectly only (ß = 0.02, p = 0.011). Neither conscientiousness nor the perceived educational environment predicted OSCE performance. Model 2 had acceptable, but less optimal fit. In this model, there was a significant cross-over interaction effect (ß = 0.16, p < 0.01): conscientiousness positively predicted OSCE performance when perceptions of the educational environment were the most positive, but negatively predicted performance when perceptions were the least positive. The findings suggest that both conscientiousness and perceptions of the educational environment predict CBA performance. Research should further examine interactions between personality traits and the medical school environment to inform strategies aimed at improving OSCE performance.

Sleep fragmentation and sleep-disordered breathing in individuals living close to main roads: results from a population-based study.

BACKGROUND: Nighttime traffic noise is associated with sleep disturbances, but sleep fragmentation and sleep-disordered breathing (SDB) have not been demonstrated in individuals living near busy roads. METHODS: We asked 1383 participants to answer a health questionnaire and to undergo 24-h electrocardiogram (ECG). Nocturnal ECG records were used to calculate the very low frequency index (VLFI) interval, a surrogate marker of sleep fragmentation. Distances of participants' addresses to roadways were calculated using the VECTOR25© Swisstopo roads classification, a traffic noise proxy. Distances of homes within 100 or 50 m of major roads defined proximity to busy roads. Adjusted multivariate logistic regressions analyzed associations between the distance of home to main roads and VLFI or self-reported SDB. RESULTS: Distance of participants' homes to main roads was significantly associated with the VLFI in women (odds ratio [OR], 1.58 [confidence interval {CI}, 1.03-2.42]; P = .038) but not in men (OR, 1.35 [CI, 0.77-2.35]; P = .295). Women under hormonal replacement therapy (HRT) were at higher risk for increased VLFI when living close to main roads (OR, 2.10 [CI, 1.20-3.68]; P = .01) than untreated women (P = .584). Associations with self-reported SDB were not statistically relevant. CONCLUSIONS: In our large population, women living close to main roads were at significantly higher risk for sleep fragmentation than men. The 2-fold higher risk for menopausal women under HRT underscores the vulnerability of this group.

Agreement between spirometers: a challenge in the follow-up of patients and populations?

BACKGROUND: Long-term cohort studies and lung function laboratories are confronted with the need for replacement of spirometers. Lack of agreement between spirometers might affect the longitudinal comparison of data, notably when replacing conventional by portable spirometers. OBJECTIVES: To compare the handheld EasyOne (EO) with the conventional SensorMedics (SM) spirometer, and to analyze the interdevice reproducibility of EO spirometers. METHODS: In total, 82 volunteers completed spirometry sessions with 1 SM and 2 of 3 EO spirometers following a Latin square design. Analyses of differences in forced vital capacity (FVC), forced expiratory flow in 1 s (FEV1), FEV1/FVC and mean forced expiratory flow calculated between 25 and 75% of the FVC between spirometers used a mixed effect model with a random intercept for each subject and the effect of the device as fixed effect adjusted for sex, age, height and order of spirometer tested. Bland-Altman plots show the 95% limits of agreement. RESULTS: Comparisons between EO and SM showed relatively small mean differences of <3%, but systematically lower values for FVC and FEV1 in all EO devices. The 95% agreement exceeded the limits for FEV1 by 50 ml in 2 EO spirometers. The EO interdevice comparisons showed mean differences and limits of agreement within established thresholds, thus indicating fair accuracy when comparing devices. Repeats with the same spirometer did not result in statistically significant differences. CONCLUSIONS: This study suggests fair agreement between the handheld and the conventional spirometer. Differences slightly exceeding limits for FEV1 in 2 EO devices might be considered mostly irrelevant for clinical practice. However, the systematically lower FVC and FEV1 observed with EO may be significant for epidemiological studies, thus justifying inspection before replacing devices.

[What is the role of outdoor air pollution in asthma?]. / Quel est le rôle de la pollution atmosphérique dans l'asthme?

Strong scientific evidence has shown that ordinary peaks of outdoor air pollution worsen the symptoms and control of asthma. As for chronic exposure, elevated mean level of local, near-road air pollution may cause increased incidence of asthma among children, and probably also among adults. By contrast, while there is no doubt that air pollution worsens allergic inflammatory processes, it is not clearly established that it may increase allergic sensitization among the general population. In this regard, more research is needed, particularly on the effects of outdoor air pollution in the early periods of life.

Effect modification of immunoglobulin E-mediated atopy and rhinitis by glutathione S-transferase genotypes in passive smokers.

BACKGROUND: Experimental studies suggest that glutathione S-transferase (GST) genotypes modify nasal allergen responses induced by secondhand smoke (SHS) exposure. OBJECTIVE: We aimed to investigate whether GSTs affected systemic IgE and allergic rhinitis (AR) in SHS-exposed individuals from a population-based cohort. METHODS: Analyses comprised 2309 never-smokers from the Swiss study on air pollution and health in adults cohort, reporting SHS status at baseline and 11 years later. Outcomes were defined by total serum IgE≥100 kU/L, specific serum IgE determined by Phadiatop® ≥0.35 kU/L and self-reported AR. GSTP1 Ile105Val, GSTM1 and GSTT1 gene deletion genotypes were identified at the follow-up survey. RESULTS: After adjustment for relevant covariates, the homozygous GSTP1 105-Val genotype was negatively associated with high total IgE and high-specific IgE by Phadiatop®, notably in subjects persistently exposed to SHS (OR: 0.20, 95% CI 0.05-0.75; P=0.02, for high total IgE and OR: 0.29, 95% CI 0.10-0.89; P=0.03, for high specific IgE by Phadiatop®). Carrying at least one copy of the GSTM1 gene (non-null) showed a similar association for high specific IgE by Phadiatop® (OR: 0.41, 95% CI 0.22-0.76; P=0.004). No significant associations were found between GSTs and rhinitis. CONCLUSION AND CLINICAL RELEVANCE: In this large cohort, homozygosity for GSTP1 105-Val or carrying the GSTM1 non-null genotype decreased the risk of high total IgE or high specific IgE using Phadiatop® by nearly half in subjects exposed to SHS, as compared with subjects carrying opposite alleles. These findings underline the value of genetic susceptibility when evaluating the effects of environmental exposure on allergic illness. The potential long-term effects of persistent SHS exposure in genetically vulnerable individuals may be of public health relevance.

Determinants of change in airway reactivity over 11 years in the SAPALDIA population study.

We investigated determinants of change in bronchial reactivity in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA), a population-based cohort with wide age range (29-72 yrs at follow-up). The role of sex, age, atopic status, smoking and body mass index (BMI) on percentage change in bronchial reactivity slope from the baseline value was analysed in 3,005 participants with methacholine tests in 1991 and 2002, and complete covariate data. Slope was defined as percentage decline in forced expiratory volume in 1 s from its maximal value per micromole of methacholine. Bronchial hyperreactivity prevalence fell from 14.3 to 12.5% during follow-up. Baseline age was nonlinearly associated with change in reactivity slope: participants aged <50 yrs experienced a decline and those above an increase during follow-up. Atopy was not associated with change, but accentuated the age pattern (p-value for interaction = 0.038). Smoking significantly increased slope by 21.2%, as did weight gain (2.7% increase per BMI unit). Compared with persistent smokers, those who ceased smoking before baseline or during follow-up experienced a significant decrease in slope (-27.7 and -23.9%, respectively). Differing, but not statistically different, age relationships and effect sizes for smoking and BMI between sexes were found. Mean bronchial reactivity increases after 50 yrs of age, possibly due to airway remodelling or ventilation-perfusion disturbances related to cumulative lifetime exposures.

Prevalence of airflow obstruction in smokers and never-smokers in Switzerland.

The aim of the present study was to measure age-specific prevalence of airflow obstruction in Switzerland in smokers and never-smokers using pulmonary function tests and respiratory symptoms from 6,126 subjects participating in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults. The lower limit of normal of the forced expiratory volume in 1 s/forced vital capacity ratio was used to define airflow obstruction. Severity of airflow obstruction was graded according to the recommendations of the Global Initiative for Chronic Obstructive Lung Disease. Prevalence of airflow obstruction ranged from 2.5% in subjects aged 30-39 yrs to 8.0% in those aged ≥ 70 yrs. In multivariate analysis, age (OR 2.8, ≥ 70 yrs versus 30-39 yrs), smoking (OR 1.8) and asthma (OR 6.7) were associated with airflow obstruction. Never-smokers constituted 29.3% of subjects with airflow obstruction. Never-smokers with airflow obstruction were younger, more likely to be male and reported asthma more frequently than obstructive smokers. Obstructive smokers and never-smokers had similar level of symptoms and quality of life impairment. The prevalence of airflow obstruction in Switzerland is similar to other developed countries. Never-smokers account for a third of the prevalence, which is higher proportion than elsewhere. Airflow obstruction in never-smokers deserves attention because of its frequency and its similar health impact to that in smokers.

Prioritised research agenda for prevention and control of chronic respiratory diseases.

The 2008-2013 World Health Organization (WHO) action plan on noncommunicable diseases (NCDs) includes chronic respiratory diseases as one of its four priorities. Major chronic respiratory diseases (CRDs) include asthma and rhinitis, chronic obstructive pulmonary disease, occupational lung diseases, sleep-disordered breathing, pulmonary hypertension, bronchiectiasis and pulmonary interstitial diseases. A billion people suffer from chronic respiratory diseases, the majority being in developing countries. CRDs have major adverse effects on the life and disability of patients. Effective intervention plans can prevent and control CRDs, thus reducing morbidity and mortality. A prioritised research agenda should encapsulate all of these considerations in the frame of the global fight against NCDs. This requires both CRD-targeted interventions and transverse NCD programmes which include CRDs, with emphasis on health promotion and disease prevention.

Longitudinal change of prebronchodilator spirometric obstruction and health outcomes: results from the SAPALDIA cohort.

BACKGROUND: Understanding the prognostic meaning of early stages of chronic obstructive pulmonary disease (COPD) in the general population is relevant for discussions about underdiagnosis. To date, COPD prevalence and incidence have often been estimated using prebrochodilation spirometry instead of postbronchodilation spirometry. In the SAPALDIA (Swiss Study on Air Pollution and Lung Disease in Adults) cohort, time course, clinical relevance and determinants of severity stages of obstruction were investigated using prebronchodilator spirometry. METHODS: Incident obstruction was defined as an FEV(1)/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio >or=0.70 at baseline and <0.70 at follow-up, and non-persistence was defined inversely. Determinants were assessed in 5490 adults with spirometry and respiratory symptom data in 1991 and 2002 using Poisson regression controlling for self-declared asthma and wheezing. Change in obstruction severity (defined analogously to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) classification) over 11 years was related to shortness of breath and health service utilisation for respiratory problems by logistic models. RESULTS: The incidence rate of obstruction was 14.2 cases/1000 person years. 20.9% of obstructive cases (n = 113/540) were non-persistent. Age, smoking, chronic bronchitis and non-current asthma were determinants of incidence. After adjustment for asthma, only progressive stage I or persistent stage II obstruction was associated with shortness of breath (OR 1.71, 95% CI 0.83 to 3.54; OR 3.11, 95% CI 1.50 to 6.42, respectively) and health service utilisation for respiratory problems (OR 2.49, 95% CI 1.02 to 6.10; OR 4.17 95% CI 1.91 to 9.13, respectively) at follow-up. CONCLUSIONS: The observed non-persistence of obstruction suggests that prebronchodilation spirometry, as used in epidemiological studies, might misclassify COPD. Future epidemiological studies should consider both prebronchodilation and postbronchodilation measurements and take specific clinical factors related to asthma and COPD into consideration for estimation of disease burden and prediction of health outcomes.

Traffic-related air pollution correlates with adult-onset asthma among never-smokers.

BACKGROUND: Traffic-related pollution is associated with the onset of asthma in children. Its effect on adult-onset asthma is poorly investigated. The SAPALDIA cohort study was used to investigate associations between the 11-year change (1991-2002) in home outdoor traffic-related particulate matter up to 10 microm in diameter (TPM(10)) and the incidence of asthma. METHODS: Never-smokers without asthma at baseline aged 18-60 years in 1991 were eligible for inclusion in the study. Subjects reporting doctor-diagnosed asthma at follow-up were considered incident cases. TPM(10) at baseline and follow-up was predicted and interpolated to subjects' place of residence by dispersion models using emission and meteorological data. Cox proportional hazard models for time to asthma onset were adjusted (age, gender, baseline atopy, body mass index, bronchial reactivity, maternal allergies). RESULTS: Of 2725 never-smokers, 41 reported asthma onset in 2002. Home outdoor TPM(10) concentrations improved during the interval (mean -0.6; range -9 to +7.2; IQR 0.6 microg/m(3)). The incidence of asthma was associated with a change in TPM(10). The hazard ratio (1.30; 95% CI 1.05 to 1.61) per 1 microg/m(3) change in TPM(10) (IQR) was not sensitive to further adjustments (education, workplace exposure, passive smoking, parental asthma or allergies, random area effects, lung function or co-pollutants such as regional, secondary, total PM(10) or proximity to busy roads). CONCLUSION: The data suggest a role for traffic-related pollution in adult-onset asthma. Space, time and source-specific individual assignment of exposure to traffic-related pollution is a key strength of SAPALDIA. It may explain why findings were statistically significant despite the limited number of new cases. As traffic-related pollution prevails, the finding may be of substantial public health relevance.

Sex-specific effect of body weight gain on systemic inflammation in subjects with COPD: results from the SAPALDIA cohort study 2.

Systemic inflammation may mediate the association between chronic obstructive pulmonary disease (COPD) and extrapulmonary comorbidities. We measured high-sensitivity C-reactive protein (hs-CRP) in COPD and quantified the effect modification by body weight change and sex. Using data from the Swiss study on Air Pollution and Lung Diseases in Adults (SAPALDIA; n = 5,479) with measurements of forced expiratory volume in 1 s (FEV(1)), body weight and hs-CRP, we examined the association of hs-CRP and categories of body weight change (lost weight and weight gained 0-5%, 5-9%, 9-14% and >14%) with fast FEV(1) decline. hs-CRP was elevated both in association with fast FEV(1) decline and body weight gain. Subjects with fast FEV(1) decline and weight gain (>14%) had higher hs-CRP (2.0 mg L(-1) for females versus 1.6 mg L(-1) for males). After adjustment for age, smoking, physical activity, hormonal therapy and diabetes, elevated hs-CRP (>3 mg) was found to be more likely in subjects with fast FEV(1) decline (OR(males) 1.38, OR(females) 1.42) and in those with weight gain >14% (OR(males) 2.04, OR(females) 4.51). The association of weight gain and fast FEV(1) decline predicts a higher level of systemic inflammation. Since the effect of weight gain on systemic inflammation is larger in females than in males, weight gain may be a risk factor for extrapulmonary comorbidities in females with COPD.

Long-term decline in lung function, utilisation of care and quality of life in modified GOLD stage 1 COPD.

BACKGROUND: Little is known about the long-term outcomes of individuals with mild chronic obstructive pulmonary disease (COPD) as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). METHODS: A population cohort of 6671 randomly selected adults without asthma was stratified into categories of modified GOLD-defined COPD (prebronchodilator spirometry). Further stratification was based on the presence or absence of respiratory symptoms. After 11 years, associations between baseline categories of COPD and decline in forced expiratory volume in 1 s (FEV(1)), respiratory care utilisation and quality of life as measured by the SF-36 questionnaire were examined after controlling for age, sex, smoking and educational status. RESULTS: At baseline, modified GOLD criteria were met by 610 (9.1%) participants, 519 (85.1%) of whom had stage 1 COPD. At follow-up, individuals with symptomatic stage 1 COPD (n = 224) had a faster decline in FEV(1) (-9 ml/year (95% CI -13 to -5)), increased respiratory care utilisation (OR 1.6 (95% CI 1.0 to 2.6)) and a lower quality of life than asymptomatic subjects with normal lung function (n = 3627, reference group). In contrast, individuals with asymptomatic stage 1 COPD (n = 295) had no significant differences in FEV(1) decline (-3 ml/year (95% CI -7 to +1)), respiratory care utilisation (OR 1.05 (95% CI 0.63 to 1.73)) or quality of life scores compared with the reference group. CONCLUSIONS: In population-based studies, respiratory symptoms are of major importance for predicting long-term clinical outcomes in subjects with COPD with mild obstruction. Population studies based on spirometry only may misestimate the prevalence of clinically relevant COPD.

Glutathione S-transferase genotype increases risk of progression from bronchial hyperresponsiveness to asthma in adults.

BACKGROUND: Bronchial hyperresponsiveness (BHR) and variation in glutathione S-transferase (GST) genes have been associated with asthma risk. The relationship of these two risk factors with adult onset asthma in the general population was investigated. METHODS: GSTP1 Ile105Val single nucleotide polymorphism and GSTM1 and GSTT1 gene deletion polymorphisms were genotyped in the population-representative SAPALDIA cohort. BHR was assessed at baseline by methacholine challenge and defined as a fall of > or =20% in forced expiratory volume in 1 s. Independent effects of GST polymorphisms and BHR on new onset of asthma after 11 years of follow-up were estimated by multiple logistic regression analysis, adjusting for relevant baseline measures. Effect modification was assessed by including interaction terms in the model. RESULTS: Among 4426 asthma-free participants at baseline, 14% had BHR. At follow-up, 3.3% reported new onset of physician-diagnosed asthma. BHR (p<0.001) and GSTP1 Ile105Val genotype (p = 0.005) were independently associated with incident asthma, but no association was seen for GSTT1 and GSTM1 gene deletion polymorphisms. Among subjects free of respiratory symptoms at baseline, the effect of BHR on the risk of physician-diagnosed asthma at follow-up was restricted to GSTP1 105 Ile/Ile carriers (OR 4.57, 95% CI 2.43 to 8.57 vs 1.40, 95% CI 0.58 to 3.39; p for interaction = 0.023). CONCLUSIONS: If confirmed by independent studies, our results suggest that GSTP1 Ile105Val genotype strongly determines the progression of BHR to physician-diagnosed asthma in the general population.

Incidence of asthma and net change in symptoms in relation to changes in obesity.

The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.

Assessing clinical competence: a pilot project to evaluate the feasibility of a standardized patient -- based practical examination as a component of the Swiss certification process.

PURPOSE: advances in the assessment of clinical competence have prompted medical schools and licensing authorities to complement written and oral tests with practical ones. The purposes of this project were to (1) determine how clinical competencies not effectively addressed on the present Swiss federal examinations can be assessed adequately on a standardised patient-based practical examination (SCE) and (2) evaluate the SCE validity, reliability and feasibility. METHOD: a bilingual, three-hour standardised patient-based clinical examination was pilot tested in 2003 with 48 volunteered fifth and sixth-year students from the five Swiss medical schools. All students took the same eight 15-minute patient cases. To ensure the test content validity, test cases were selected by a multi-disciplinary and -institutional committee of clinical faculty on the basis of predefined exam blueprint criteria and in reference to the Swiss catalogue of learning objectives. RESULTS: moderate correlations between the SCE and the existing Federal final written examinations (0.46) and the newly pilot-tested structured oral examination or SOE (0.56) [3] suggested that they were complementary to one another and that each might emphasise aspects of the clinical competence which others might not. The reliability (a coefficient) of the SCE scores ranged from 0.73 to 0.77. CONCLUSIONS: limited experiences gathered throughout the SCE pilot project demonstrated its feasibility. Preliminary results suggested that SCE scores had a good level of construct validity and reliability and seemed to complement scores obtained on the final certification written examinations and the newly tested SOE. These results, however, need to be further confirmed with larger samples studies.

Bronchial hyperresponsiveness and the development of asthma and COPD in asymptomatic individuals: SAPALDIA cohort study.

BACKGROUND: Bronchial hyperresponsiveness (BHR) is a common feature of asthma. However, BHR is also present in asymptomatic individuals and its clinical and prognostic significance is unclear. We hypothesised that BHR might play a role in the development of chronic obstructive pulmonary disease (COPD) as well as asthma. METHODS: In 1991 respiratory symptoms and BHR to methacholine were evaluated in 7126 of the 9651 participants in the SAPALDIA cohort study. Eleven years later 5825 of these participants were re-evaluated, of whom 4852 performed spirometric tests. COPD was defined as an FEV1/FVC ratio of <0.70. RESULTS: In 1991 17% of participants had BHR, of whom 51% were asymptomatic. Eleven years later the prevalence of asthma, wheeze, and shortness of breath in formerly asymptomatic subjects with or without BHR was, respectively, 5.7% v 2.0%, 8.3% v 3.4%, and 19.1% v 11.9% (all p<0.001). Similar differences were observed for chronic cough (5.9% v 2.3%; p = 0.002) and COPD (37.9% v 14.3%; p<0.001). BHR conferred an adjusted odds ratio (OR) of 2.9 (95% CI 1.8 to 4.5) for wheezing at follow up among asymptomatic participants. The adjusted OR for COPD was 4.5 (95% CI 3.3 to 6.0). Silent BHR was associated with a significantly accelerated decline in FEV1 by 12 (5-18), 11 (5-16), and 4 (2-8) ml/year in current smokers, former smokers and never smokers, respectively, at SAPALDIA 2. CONCLUSIONS: BHR is a risk factor for an accelerated decline in FEV1 and the development of asthma and COPD, irrespective of atopic status. Current smokers with BHR have a particularly high loss of FEV1.

Early chimerism of macrophages and lymphocytes in lung transplant recipients is predictive of graft tolerance.

BACKGROUND: The persistence of donor cells derived from the graft (chimerism) has been documented in various tissues after organ transplantation. It was suggested that stable chimerism might reflect a state of donor-specific tolerance. Chimerism of macrophages and lymphocytes were studied over time after lung transplantation as well as its impact on graft tolerance. MATERIAL AND METHODS: Macrophages and lymphocytes were purified from bronchoalveolar lavage sequentially obtained from 24 patients between 1 and 41 months posttransplantation (20, 22, 24, and 17 patients at, respectively, 1, 3, 6, and 12 months). DNA was extracted from these cells and their recipient-donor origin was evaluated by PCR amplification of highly polymorphic DNA regions (minisatellites). RESULTS: We show that the remaining donor cells over the first month vary from 10 up to 50% and 5 up to 55% for lymphocytes and macrophages respectively (+/-2 SD). All patients presented some chimerism up to the 6th postoperative month. Good correlation was observed between the residual amount of donor lymphocytes and macrophages during the first 3 months (P<0.001). Patients with at least 30% donor lymphocytes at 1 month after transplantation had less rejections (> or =stage II) in the follow up (P=0.0007). The same observation is true for donor macrophages although to lower extend (P=0.02). The chimerism lost its predictive value beyond 3 months. CONCLUSIONS: These data demonstrate that a level of chimerism above 30% of either donor lymphocytes or macrophages at 1 month is related to a better state of graft tolerance. However, chimerism decreases markedly beyond 3 months and has then no predictive value.