Association of Common Polymorphisms in the Nicotinic Acetylcholine Receptor Alpha4 Subunit Gene with an Electrophysiological Endophenotype in a Large Population-Based Sample.

Variation in genes coding for nicotinic acetylcholine receptor (nAChR) subunits affect cognitive processes and may contribute to the genetic architecture of neuropsychiatric disorders. Single nucleotide polymorphisms (SNPs) in the CHRNA4 gene that codes for the alpha4 subunit of alpha4/beta2-containing receptors have previously been implicated in aspects of (mostly visual) attention and smoking-related behavioral measures. Here we investigated the effects of six synonymous but functional CHRNA4 exon 5 SNPs on the N100 event-related potential (ERP), an electrophysiological endophenotype elicited by a standard auditory oddball. A total of N = 1,705 subjects randomly selected from the general population were studied with electroencephalography (EEG) as part of the German Multicenter Study on nicotine addiction. Two of the six variants, rs1044396 and neighboring rs1044397, were significantly associated with N100 amplitude. This effect was pronounced in females where we also observed an effect on reaction time. Sequencing of the complete exon 5 region in the population sample excluded the existence of additional/functional variants that may be responsible for the observed effects. This is the first large-scale population-based study investigation the effects of CHRNA4 SNPs on brain activity measures related to stimulus processing and attention. Our results provide further evidence that common synonymous CHRNA4 exon 5 SNPs affect cognitive processes and suggest that they also play a role in the auditory system. As N100 amplitude reduction is considered a schizophrenia-related endophenotype the SNPs studied here may also be associated with schizophrenia outcome measures.

Prenatal adversity: a risk factor in borderline personality disorder?

BACKGROUND: Patients with borderline personality disorder (BPD) show a high prevalence of early adversity, such as childhood trauma. It has also been reported that prenatal adverse conditions, such as prenatal maternal stress, drug taking, tobacco smoking or medical complications, may be associated with an increased risk of mental disorders in the offspring. Prenatal adversity is investigated here for the first time as a potential risk factor in the diagnosis of BPD. Method A total of 100 patients with a DSM-IV diagnosis of BPD and 100 matched healthy controls underwent semi-structured interviews about the course of pregnancy, maternal stressors, birth complications and childhood trauma. Further information was obtained from the participants' mothers and from prenatal medical records. RESULTS: Borderline patients were significantly more often exposed to adverse intrauterine conditions, such as prenatal tobacco exposure (p=0.004), medical complications (p=0.008), prenatal maternal traumatic stress (p=0.015), familial conflicts (p=0.004), low social support (p=0.004) and partnership problems during pregnancy (p=0.014). Logistic regression analyses revealed that the reported prenatal risk factors accounted for 25.7% of the variance in BPD. Prenatal tobacco exposure [odds ratio (OR) 3.37, 95% confidence interval (CI) 1.49-7.65, p=0.004] and medical complications (OR 2.87, 95% CI 1.29-6.38, p=0.010) emerged as important predictors. After controlling for childhood adversity and parental socio-economic status (SES), prenatal risk factors predicted relevant borderline subdomains, such as impulsivity, affective instability, identity disturbance, dissociation and severity of borderline symptoms. CONCLUSIONS: This study provides evidence of an association between prenatal adversity and the diagnosis of BPD. Our findings suggest that prenatal adversity may constitute a potential risk factor in the pathogenesis of BPD.

Hippocampal subfields predict positive symptoms in schizophrenia: first evidence from brain morphometry.

Alterations of hippocampal anatomy have been reported consistently in schizophrenia. Within the present study, we used FreeSurfer to determine hippocampal subfield volumes in 21 schizophrenic patients. A negative correlation between PANSS-positive symptom score and bilateral hippocampal subfield CA2/3 as well as CA1 volume was found on high-resolution magnetic resonance images. Our observation opens the gate for advanced investigation of the commonly reported hippocampal abnormalities in schizophrenia in terms of specific subfields.

The P300 event-related potential and smoking--a population-based case-control study.

A better understanding of the factors underlying habitual tobacco smoking may further new strategies to go about this major health problem. The P300 event-related potential (ERP) has emerged as a valuable (endo)phenotype in neuropsychiatric research. Previous studies suggested the P300 ERP to be reduced in smokers. The main purpose of the present study was to provide an in-depth description of smoking-related behavioral, biological and electrophysiological phenotypes with an emphasis on the P300 ERP and its mutual relationship with other smoking-related parameters. In this case-control study N=1318 participants (smokers and never-smoking controls) were investigated at 6 German academic institutions. Study participants were randomly selected from the general population. Subjects with mental disorders including alcoholism and drug abuse were excluded. The main outcome measure was the P300 global field power (GFP). We found a lower P300 GFP in current smokers compared to never-smoking controls. Furthermore a correlation between measures of smoking severity and P300 GFP reduction was found. Non-addicted smokers exhibited normal P300 ERP measures. This study provides further evidence that the P300 ERP is reduced in current smokers even in the absence of potentially confounding psychiatric comorbidity. Thus, P300 amplitude reduction clearly is part of the electrophysiological phenotype of smokers. Our results provide the phenotypical groundwork for future multidimensional analyses of genotype-phenotype relationships in the field of smoking and nicotine dependence.

Spontaneous brain activity and EEG microstates. A novel EEG/fMRI analysis approach to explore resting-state networks.

The brain is active even in the absence of explicit input or output as demonstrated from electrophysiological as well as imaging studies. Using a combined approach we measured spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal along with electroencephalography (EEG) in eleven healthy subjects during relaxed wakefulness (eyes closed). In contrast to other studies which used the EEG frequency information to guide the functional MRI (fMRI) analysis, we opted for transient EEG events, which identify and quantify brain electric microstates as time epochs with quasi-stable field topography. We then used this microstate information as regressors for the BOLD fluctuations. Single trial EEGs were segmented with a specific module of the LORETA (low resolution electromagnetic tomography) software package in which microstates are represented as normalized vectors constituted by scalp electric potentials, i.e., the related 3-dimensional distribution of cortical current density in the brain. Using the occurrence and the duration of each microstate, we modeled the hemodynamic response function (HRF) which revealed BOLD activation in all subjects. The BOLD activation patterns resembled well known resting-state networks (RSNs) such as the default mode network. Furthermore we "cross validated" the data performing a BOLD independent component analysis (ICA) and computing the correlation between each ICs and the EEG microstates across all subjects. This study shows for the first time that the information contained within EEG microstates on a millisecond timescale is able to elicit BOLD activation patterns consistent with well known RSNs, opening new avenues for multimodal imaging data processing.

The tolerability of rTMS treatment in schizophrenia with respect to cognitive function.

INTRODUCTION: The purpose of this study was to assess tolerability and safety of high-frequency rTMS with regard to cognitive performance when conducted as "add-on" treatment in chronic schizophrenia in-patients (n=32). METHODS: Patients, who were on stable antipsychotic treatment, were randomly assigned to verum or sham condition (double-blind). In the verum group, ten sessions of 10 Hz rTMS with a total of 10 000 stimuli were applied over the left dorsolateral prefrontal cortex (PFC) at 110% of motor threshold over a period of two weeks. The sham group received corresponding sham stimulation. RTMS effects on cognitive performance were assessed with a neuropsychological test battery consisting of the following tests: trail making test A and B (TMT), Wisconsin card sorting test (WCST), D2 attention task and the "short test of general intelligence" (KAI). RESULTS: No statistically significant deterioration of cognitive performance was observed as a result of rTMS treatment. Moreover it was shown that in the verum group patients with a less favourable performance on the WCST at baseline tend to improve after rTMS treatment with regard to psychopathology as opposed to patients in the control group. DISCUSSION: The stability of cognitive function suggests good tolerability of rTMS treatment in schizophrenia. The absence of evidence for cognitive deterioration could be due to low and short stimulation parameters.

Brain activation patterns underlying fast habituation to painful laser stimuli.

A painful experience is modified by processes like habituation/antinociception or sensitization. Altered habituation may be one characteristic of chronic pain syndromes. In the present study we sought to investigate the functional magnetic resonance imaging (fMRI) blood oxygen level dependent (BOLD) correlate of rapid habituation to pain using simultaneous single trial electrodermal activity (EDA)/fMRI measurements. A total of N=32 healthy subjects have been investigated. Subjects received painful laser stimulation of the left hand. The fMRI BOLD response was measured simultaneously with continuous EDA recordings. Single trial EDA responses to laser stimulation habituated over time with substantial subject-to-subject differences in the degree and speed of habituation. fMRI BOLD habituation was assessed by contrasting the first half of the experiment against the second half and was found in primary and secondary somatosensory cortices, the insula and the anterior cingulate cortex (ACC). We hypothesized that single trial EDA habituation would reflect BOLD habituation which was investigated separately in subjects with 'faster' (N=15) and 'slower' (N=14) EDA habituation. Significant habituation of the BOLD signal was only found in subjects with 'faster' EDA habituation that was accompanied by a signal increase in the rostral ACC and the periaqueductal grey. Furthermore, subjects with faster EDA habituation provided lower pain ratings. Therefore the EDA habituation profile to painful stimulation may constitute a pain-related (endo)phenotype and may be an informative additional endpoint measure in fMR-imaging of pain, especially when people suffering from chronic pain states in which pain processing is often altered are studied.

Association of a variant in the muscarinic acetylcholine receptor 2 gene (CHRM2) with nicotine addiction.

Genetic factors contribute to the overall risk of developing nicotine addiction, which is the major cause of preventable deaths in western countries. However, knowledge regarding specific polymorphisms influencing smoking phenotypes remains scarce. In the present study we provide evidence that a common single nucleotide polymorphism (SNP) in the 5' untranslated region of CHRM2, the gene coding for the muscarinic acetylcholine receptor 2 is associated with nicotine addiction. CHRM2 was defined as a candidate gene for nicotine addiction based on previous evidence that linked variations in CHRM2 to alcohol and drug dependence. A total of more than 5,500 subjects representative of the German population were genotyped and assessed regarding their smoking habits. The impact of three SNPs in CHRM2 on smoking behavior/nicotine addiction was investigated using logistic regression models or a quasi-Poisson regression model, respectively. We found the T allele of SNP rs324650 to be associated with an increased risk of smoking/nicotine dependence according to three different models, the recessive models of regular or heavy smokers vs. never-smokers (odds ratio 1.17 in both analyses) and according to the Fagerström index of nicotine addiction. In the analysis stratified by gender this association was only found in females. Our data provide further evidence that variations in CHRM2 may be associated with the genetic risk of addiction in general or with certain personality traits that predispose to the development of addiction. Alternatively, variations in CHRM2 could modulate presynaptic auto-regulation in cholinergic systems and may thereby affect an individual's response to nicotine more specifically.

Single-trial P3 amplitude and latency informed event-related fMRI models yield different BOLD response patterns to a target detection task.

Using single-trial parameters as a regressor in the General Linear Model (GLM) is becoming an increasingly popular method for informing fMRI analysis. However, the parameter used to characterise or to differentiate brain regions involved in the response to a particular task varies across studies (e.g. ERP amplitude, ERP latency, reaction time). Furthermore, the way in which the single-trial information is used in the fMRI analysis is also important. For example, the single-trial parameters can be used as regressors in the GLM or to modify the duration of the events modelled in the GLM. The aim of this study was to investigate the BOLD response to a target detection task when including P3 amplitude, P3 latency and reaction time parameters in the GLM. Simultaneous EEG-fMRI was recorded from fifteen subjects in response to a visual choice reaction time task. Including P3 amplitude as a regressor in the GLM yielded activation in left central opercular cortex, left postcentral gyrus, left insula, left middle frontal gyrus, left insula and left parietal operculum. Using P3 latency and reaction time as an additional regressor yielded no additional activation in comparison with the conventional fMRI analysis. However, when P3 latency or reaction time was used to determine the duration of events at a single-trial level, additional activation was observed in the left postcentral gyrus, left precentral gyrus, anterior cingulate cortex and supramarginal gyrus. Our findings suggest that ERP amplitudes and latencies can yield different activation patterns when used to modify relevant aspects of the GLM.

[Biological correlates of prefrontal activating and temporoparietal inhibiting treatment with repetitive transcranial magnetic stimulation (rTMS)]. / Biologische Korrelate präfrontal aktivierender und temporoparietal inhibierender Behandlung mit repetitiver transkranieller Magnetstimulation (rTMS).

Repetitive transcranial magnetic stimulation (rTMS) is a tool that enables clinicians and neuroscientists to modulate cortical activity in a non-invasive way. High-frequency rTMS has predominantly an activating effect on the stimulated brain region while low-frequency rTMS has an inhibitory effect. In addition to its usefulness as a research tool and in neurological diagnostics, rTMS may prove useful as a therapeutic option in psychiatry, especially in disorders that are associated with regional changes in cortical activity. For instance, rTMS is under current investigation in the treatment of depression and negative symptoms of schizophrenia. A hypofrontality or a fronto-limbic imbalance associated with both syndromes could be corrected by activating, high frequency rTMS. Conversely, a regional hyperactivity in the temporo-parietal cortex has been described in subjects suffering from auditory hallucinations and tinnitus. Low frequency, inhibitory rTMS is currently evaluated as a therapeutic option in these subjects. In addition to the effects on the directly stimulated brain area, other biological effects of rTMS may exert a beneficial influence on brain function. Amongst these are a modulation of cortico-cortical circuits (e. g. fronto-cingular and fronto-parietotemporal circuits), effects on monoaminergic neuromodulation and neuroendocrine effects. The current knowledge about the therapeutically relevant neurophysiological and neuroendocrine effects of rTMS are reviewed. An improved understanding of the neurophysiological basis of the therapeutic effects of rTMS and of the pathophysiology underlying neuropsychiatric diseases may lead to optimized therapeutic rTMS applications and new clinical indications for rTMS.

Laser-evoked potential P2 single-trial amplitudes covary with the fMRI BOLD response in the medial pain system and interconnected subcortical structures.

Pain is a complex experience with sensory, emotional and cognitive aspects. The cortical representation of pain - the pain matrix - consists of a network of regions including the primary (S1) and secondary (S2) sensory cortex, insula, and anterior cingulate cortex (ACC). These structures interact with brain regions such as the prefrontal cortex and the amygdalae. Simultaneous EEG/fMRI (electroencephalography/functional magnetic resonance imaging) has recently been introduced as a method to study the spatiotemporal characteristics of cognitive processes with high spatial and high temporal resolution at the same time. The present study was conducted to clarify if single trial EEG-informed BOLD modeling supports the definition of functional compartments within the pain matrix and interconnected regions. Twenty healthy subjects received painful laser stimulation while EEG and the fMRI blood oxygen level dependent (BOLD) signal were recorded simultaneously. While the laser-evoked N2 potential provided no additional information for BOLD modeling, the regressor obtained from the single trial laser-evoked P2 potential explained additional variance in a network of cortical and subcortical structures that largely overlapped with the pain matrix. This modeling strategy yielded pronounced activation in the ACC, right amygdala and thalamus. Our results suggest that laser-evoked potential (LEP) informed fMRI can be used to visualize BOLD activation in the pain matrix with an emphasis on functional compartments (as defined by the temporal dynamics of the LEP) such as the medial pain system. Furthermore, our findings suggest a concerted effort of the ACC and the amygdala in the cognitive-emotional evaluation of pain.

Fluctuations in electrodermal activity reveal variations in single trial brain responses to painful laser stimuli--a fMRI/EEG study.

Pain is a complex experience with sensory, emotional and cognitive aspects. It also includes a sympathetic response that can be captured by measuring the electrodermal activity (EDA). The present study was performed to investigate which brain areas are associated with sympathetic activation in experimental pain; an issue that has not been addressed with fMRI (functional magnetic resonance imaging) thus far. Twelve healthy subjects received painful laser stimulation to the left hand. The event-related fMRI BOLD (blood oxygen level dependent) response was measured together with simultaneous EEG (electroencephalography) and EDA recordings. Laser stimuli induced the expected EDA response, evoked EEG potentials and BOLD responses. Single trial EDA amplitudes were used to guide further analysis of fMRI and EEG data. We found significantly higher BOLD responses in trials with high EDA vs. low EDA trials, predominantly in the insula and somatosensory cortex (S1/S2). Likewise, in the EEG we found the N2 laser evoked potentials to have significantly higher amplitudes in trials with high vs. low EDA. Furthermore EDA-informed BOLD modeling explained additional signal variance in sensory areas and yielded higher group level activation. We conclude that the sympathetic response to pain is associated with activation in pain-processing brain regions, predominantly in sensory areas and that single trial (EDA)-information can add to BOLD modeling by taking some of the response variability across trials and subjects into account. Thus, EDA is a useful additional, objective index when pain is studied with fMRI/EEG which might be of particular relevance in the context of genetic- and pharmacoimaging.

The molecular and cellular neurobiology of nicotine abuse in schizophrenia.

People with schizophrenia suffer from a variety of symptoms that can be categorized as positive, negative and cognitive symptoms. Cognitive symptoms are not properly treated with antipsychotic medication and are the major cause of disability associated with the disorder. People with schizophrenia smoke more frequently and heavily than the general population. This observation in view of the well established role of nicotinic, cholinergic neurotransmission in cognition led to the hypothesis that people with schizophrenia may use nicotine as a self-medication to ameliorate cognitive symptoms associated with their disease. Furthermore genetic and post-mortem studies point to additional links between nicotinic cholinergic neurotransmission and schizophrenia. This article provides an insight in the possible relationship between schizophrenia and smoking behavior. We focus on the effects of nicotine on individual neurons as well as on neuronal networks. With respect to single neurons the immediate electrophysiological consequences of nicotinic stimulation and the more "metabotropic" effects related to intracellular signal transduction cascades that may lead to plastic changes in the neuron are discussed. With respect to the network level, three systems are discussed: cognition, reward and stress response. The effects of nicotine on cognition may be most pertinent to the problem of schizophrenia, but schizophrenics may also smoke to regulate mood and reduce stress. A better understanding of the molecular and cellular effects of nicotine and how they are related to the pathophysiology and symptomatology of schizophrenia may help to identify new targets for the pharmacotherapy of schizophrenia and of nicotine addiction in schizophrenia.

[Mechanisms of nicotine dependence]. / Mechanismen der Nikotinabhängigkeit.

About 30 % of the population in Western societies smoke. Most smokers do so due to nicotine dependence. In concert with ongoing education about the detrimental consequences of tobacco abuse and further restriction of public smoking, further scientific effort is needed to investigate the mechanisms of nicotine dependence, in order to develop more effective treatments and smoking cessation programmes. This review summarises our current knowledge of the mechanisms of nicotine dependence, focussing mainly on the cellular effects of nicotine and the effects on three neurophysiological systems that contribute to nicotine dependence: a) reward system, b) cognition/attentional networks and c) stress response system. The reward system that is connected with the mood regulatory system is activated by nicotine and other addictive substances. Furthermore, nicotine modulates cognitive networks involved in attention and learning/memory. Most data point to positive effects of acute nicotine administration on these networks. Finally nicotine influences the stress response system, however, the effects depend on the stage of nicotine addiction. Nicotinic modulation of these networks by means of smoking may reflect an attempt to self-medicate clinical or subclinical symptoms in the areas of mood regulation/depression, attention and learning/memory and stress coping, at least in a subset of smokers.

[Treatment of borderline personality disorder with atypical antipsychotic drugs]. / Behandlung der Borderline-Persönlichkeitsstörung mit atypischen Antipsychotika.

Pharmacotherapy of Borderline personality disorder with atypical antipsychotics has recently been the subject of several mostly small studies and case reports. In contrast to the frequent clinical use of this substance class in borderline patients the amount of data on that subject is still sparse. The clinical data gathered thus far suggest a potential use of atypical antipsychotics in the areas of psychotic symptoms, impulsivity and possibly affective symptoms. The drugs were sufficiently well tolerated; however, the observation period in most studies was short and the dosage low. The current set of clinical data does not support the frequently applied polypharmacy. However, recent data suggest that a therapeutic approach combining atypical antipsychotics and psychotherapy may reveal synergistic effects. Future trials should study larger sample sizes over a longer period of time. Open questions are the required dose and the optimal treatment duration.

Potential clinical targets of repetitive transcranial magnetic stimulation treatment in schizophrenia.

Despite the introduction of atypical antipsychotic drugs, treatment-resistant symptoms still represent a serious problem in schizophrenia. Currently, there is evidence from clinical studies suggesting that treatment with repetitive transcranial magnetic stimulation (rTMS) may improve schizophrenia symptoms. Our review provides an overview of clinical rTMS studies in schizophrenic patients. A systematic search of the literature (Cochrane and Medline databases up to December 2005) was conducted. Most studies showed methodological problems due to their explorative character and small sample sizes. In some studies, a treatment effect of high-frequency rTMS applied over the prefrontal cortex was seen with respect to negative symptoms. On the other hand, low-frequency rTMS in the temporal lobe area might lead to a suppression of auditory hallucinations. It is concluded that larger sham-controlled studies are required to allow an adequate assessment of the clinical and neurobiological effects of rTMS in schizophrenic patients. The currently available data provide insufficient evidence to support the use of rTMS as an adjuvant treatment for schizophrenic psychopathology, but encourage further investigation of rTMS as a novel treatment approach.

Aripiprazole pharmacotherapy of borderline personality disorder.

We report three consecutive cases of women with borderline personality disorder with psychotic symptoms, who received pharmacotherapy with the new atypical antipsychotic drug aripiprazole. Therapeutic effects were measured using the SCL-90R (symptom check list) and the BSL (borderline symptom list). We observed different responses to aripiprazole. In the first patient we had to discontinue the drug before we were able to observe any therapeutic effects. The second patient also complained about initial side effects. However, after the dose was lowered, the drug was tolerated and she responded well to aripiprazole with respect to all psychopathological aspects. The third patient did not suffer from any side effects under aripiprazole. She responded partially to the drug. Aripiprazole may have a potential role in the pharmacotherapy of borderline personality disorder and may not only target psychotic symptoms in these patients.

Guillain-Barré syndrome after septicemia following clozapine-induced agranulocytosis. A case report.

We report the case of a patient with schizophrenia, who experienced agranulocytosis during clozapine treatment, followed by bronchopulmonal infection and Guillain-Barré syndrome. The case was recorded within the German surveillance project "drug safety in psychiatry" (AMSP).

[A new method for the treatment of depression: repetitive transcranial magnetic stimulation]. / Ein neues Behandlungsverfahren der Depression: Die repetitive transkranielle Magnetstimulation (rTMS).

Recent data suggest that repetitive transcranial magnetic stimulation (rTMS) is effective in treating depressive symptoms to a lesser extent compared with classical electroconvulsive therapy. However, rTMS represents an economical and well tolerable procedure in relation to the expenditure of electroconvulsive therapy with anaesthesia. Usually, rTMS is applicated as an add-on-therapy accompanying psychopharmacological treatment. So far, it has predominantly been used for patients with long-standing and so called treatment-refractory symptoms. However, even in the early phase of a depressive episode rTMS would be possibly more effective. In many cases, the standard procedure-application of up to 10 rTMS-sessions will not be enough to produce therapeutic benefit. Therefore rTMS series including up to 20 sessions are recommended. Long-term studies are needed to clarify the role of rTMS for relapse prevention and to determine the optimal frequency and duration of rTMS in such an indication. Although numerous results of newer studies suggest a moderate antidepressive effect of rTMS, its application in daily clinical routine practice cannot be recommended yet. Larger, accurate designed and controlled studies, especially involving patients of old age, are needed to evaluate the true tolerability and effectiveness of rTMS as a new treatment option for depressive symptoms.

Molecular studies of chimerism and minimal residual disease after allogeneic peripheral blood progenitor cell or bone marrow transplantation.

We investigated 23 patients for their chimerism status who underwent allogeneic transplantation using peripheral blood progenitor cells (PBPCT) for chronic myelogenous leukemia (CML) (n = 14), acute myelogenous leukemia (AML) (n = 5), acute lymphoblastic leukemia (n = 1), myelodysplasia (MDS) (n = 1), and Hodgkin's disease (HD) (n = 2). These data were compared with those of patients after allogeneic BMT after matching them for disease and disease stage, sex of donor and recipient, GVHD prophylaxis, conditioning therapy and degree of HLA disparity. Patients were studied monthly up to 16 months post-transplant. In 11 of 23 (48%) patients who were transplanted with PBPCs and in 18 of 23 (78%) patients after BMT a mixed chimerism was detected at 1 month post-transplant. After 3 months, six of 21 (29%) evaluable patients after PBPCT remained mixed chimeric as opposed to 12 of 21 (57%) patients after BMT. We also assessed minimal residual disease using detection of the chimeric BCR/ABL transcripts by PCR of CML patients in this study. In four of 14 (29%) patients who underwent PBPCT, the BCR/ABL chimeric transcript was detected, while after BMT eight of 14 (57%) CML patients remained BCR/ABL positive. In two of these BMT patients, a cytogenetic relapse developed subsequently, and one other patient suffered a hematological relapse, whereas one of the CML patients relapsed after PBPCT. The present data may indicate that after PBPCT the incidence of leukemic relapse is similar or even lower than after BMT.