A contemporary review of Clostridioides difficile infections in patients with haematologic diseases.

Clostridioides (Clostridium) difficile (C. difficile) infection is one of the most common causes of increased morbidity and mortality. Approximately 500 000 C. difficile infections (CDIs) occur each year in the United States, and they result in more than 29 000 deaths. Patients with haematologic diseases are at a higher risk for this infection due to frequent hospitalization and exposure to treatment-associated risk factors. Whilst several currently available antimicrobial agents offer resolution, recurrence of infection remains a major concern. Recent advancement in deciphering C. difficile virulence mechanisms and identification of its allies in contributing to the infection has led to the development of alternative treatment strategies. Here, we will provide a contemporary discussion of how major risk factors in haematologic diseases, such as immunosuppression, chemoradiation, use of antibiotic, proton pump inhibitor and opioid, and deficiency in butyrate and antimicrobial peptides contribute to C. difficile infection. Next, we will highlight different approaches to control and mitigate this infection such as antibiotic stewardship and faecal microbiota transplantation. Finally, we will explore several emerging treatments such as use of pre- and probiotics, immunotherapy and microbiome-sparing agents.

Anastomotic leak after transanal total mesorectal excision: grading of severity and management aimed at preservation of the anastomosis.

AIM: The transanal approach to total mesorectal excision (TaTME) as an alternative to conventional anterior resection offers an improved view to otherwise restricted anatomical regions in obese and narrow male pelves and unfavourable tumour locations. Guidelines for the management of anastomotic leakage (AL) following low rectal resections are scarce. PATIENTS AND METHODS: Prospectively collected data of all consecutive patients undergoing TaTME between December 2014 and April 2017 in our centre were analysed retrospectively. Existing classification systems for AL were modified with regard to transanal anastomotic-preserving management. RESULTS: TaTME was performed in 66 patients with a median age of 56.2 years. The overall incidence of AL was 12.1% (n = 8). AL grading was differentiated in Grades I to V according to the severity of necrosis and abscess development. Two patients suffered from AL Grade II, one patient from Grade III, three patients from Grade IV and two patients from Grade V. Preservation of the anastomosis following AL was achieved by the damage control concept in six of eight patients (75%) with a median duration of hospital stay of 36 days. Two patients received a Hartmann procedure (Grades IV and V). CONCLUSION: Our study demonstrates that management of AL following TaTME is challenging but definitely amenable to strategies aimed at preserving the anastomosis by appropriate damage control. The modified classification system might serve as guidance for anastomosis-preserving management.

Three months of weekly rifapentine plus isoniazid for latent tuberculosis treatment in solid organ transplant candidates.

BACKGROUND: Isoniazid daily for 9 months is the recommended regimen for latent tuberculosis infection (LTBI) in solid organ transplant (SOT) candidates, but its use is controversial, due to reports of hepatotoxicity and low treatment completion rates. A 12-week course of once weekly directly observed therapy (DOT) with isoniazid plus rifapentine (3HP) is a new LTBI treatment regimen. Tolerability and safety data of 3HP LTBI treatment in SOT candidates are limited. METHODS: Twelve consecutive SOT candidates who underwent DOT with 3HP for LTBI at Westchester Medical Center, Valhalla, New York, USA, between January 2013 and August 2016 were prospectively evaluated for tolerability and safety of 3HP. The diagnosis of LTBI was made in a person with a positive interferon-gamma release test, without a history of previously treated active or latent tuberculosis infection, and without signs, symptoms, or radiographic evidence of active tuberculosis. Patients were followed up 1 month after treatment completion and at routine follow-up visits with their transplant providers. RESULTS: Eleven patients were men, and the median age was 60 years (range 44-72). Eight patients were liver, and four kidney transplant candidates. The median Model for End-Stage Liver Disease (MELD score) was 17 (range 10-31). All patients completed treatment. Only a single patient developed transaminitis greater than twice the baseline value. Three patients underwent liver transplantation. None of them developed tuberculosis at 9, 22, or 40 months following transplantation. CONCLUSION: Directly observed 3HP LTBI treatment was not associated with hepatotoxicity, even in patients with higher MELD scores. Further studies are needed to confirm the safety and efficacy of this LTBI treatment regimen in the SOT population.

Late-onset cytomegalovirus infection complicated by Guillain-Barre syndrome in a kidney transplant recipient: case report and review of the literature.

Cytomegalovirus (CMV) infection remains a common infection after solid-organ transplantation. In the general population CMV disease is associated with Guillain-Barre syndrome (GBS), an autoimmune disease leading to an acute peripheral neuropathy, in 1 of 1000 cases. Interestingly, GBS is a rarely observed complication in solid-organ transplant recipients, possibly related to maintenance immunosuppression. We describe a case of CMV infection complicated by GBS in a kidney transplant recipient and review the literature.

MRSA and VRE colonization in solid organ transplantation: a meta-analysis of published studies.

The burden of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) colonization among the increasing number of solid organ transplant patients has not been systematically explored. We searched PubMed and EMBASE for pertinent articles, performed a meta-analysis of prevalence across eligible studies and estimated the risk of ensuing MRSA or VRE infections relative to colonization status. We stratified effects in the pretransplant and posttransplant period. Twenty-three studies were considered eligible. Seventeen out of 23 (74%) referred to liver transplants. Before transplantation, the pooled prevalence estimate for MRSA and VRE was 8.5% (95% confidence interval [CI] 3.2­15.8) and 11.9% (95% CI 6.8­18.2), respectively. MRSA estimate was influenced by small studies and was lower (4.0%; 95% CI 0.4­10.2) across large studies (>200 patients). After transplantation, the prevalence estimates were 9.4% (95% CI 3.0­18.5) for MRSA and 16.2% (95% CI 10.7­22.6) for VRE. Pretransplant as well as posttransplant MRSA colonization significantly increased the risk for MRSA infections (pooled risk ratio [RR] 5.51; 95% CI 2.36­12.90 and RR 10.56; 95% CI 5.58­19.95, respectively). Pretransplant and posttransplant VRE colonization were also associated with significant risk of VRE infection (RR 6.65; 95% CI 2.54­17.41 and RR 7.93; 95% CI 2.36­26.67, respectively). Solid organ transplantation is a high-risk setting for MRSA and VRE colonization, and carrier state is associated with infection. Upgraded focus in prevention and eradication strategies is warranted.

Infections following facial composite tissue allotransplantation--single center experience and review of the literature.

We reviewed medical records of all patients (n = 4) who underwent facial composite tissue allotransplantation (FCTA) at our center between April 2009 and May 2011; data were censored in June 2012. We searched for FCTA publications and reviewed them for infectious complications and prophylaxis strategies. Three patients received full and one partial FCTA at our institution. Two recipients were cytomegalovirus (CMV) Donor (D)+/Recipient (R)- and two CMV D+/R+. Perioperative prophylaxis included vancomycin, cefazolin and micafungin and was adjusted based on peritransplant cultures. Additional prophylaxis included trimethoprim-sulfamethoxazole and valganciclovir. Two recipients developed surgical site infection and two developed pneumonia early after transplantation. Both CMV D+/R- recipients developed CMV disease after discontinuation of prophylaxis, recovered with valganciclovir treatment and did not experience subsequent rejection. Other posttransplant infections included bacterial parotitis, polymicrobial bacteremia, invasive dermatophyte infection and Clostridium difficile-associated diarrhea. Nine publications described infectious complications in another 9 FCTA recipients. Early posttransplant infections were similar to those observed in our cohort and included pulmonary, surgical-site and catheter-associated infections. CMV was the most frequently described opportunist. In conclusion, infections following FCTA were related to anatomical, technical and donor/recipient factors. CMV disease occurred in D+/R- recipients after prophylaxis, but was not associated with rejection.

Non-tuberculous mycobacterial infection among lung transplant recipients: a 15-year cohort study.

BACKGROUND: The incidence of infection with non-tuberculous mycobacteria (NTM) after lung transplant is insufficiently defined. Data on the impact of NTM infection on lung transplant survival are conflicting. METHODS: To quantify the incidence and outcomes of colonization and disease with NTM in patients after lung transplantation, the medical records, chest imaging, and microbiology data of 237 consecutive lung transplant recipients between 1990 and 2005 were reviewed. American Thoracic Society (ATS)/Infectious Diseases Society of America and Centers for Disease Control criteria were used to define pulmonary NTM disease and NTM surgical-site infections (SSI), respectively. Incidence rates for NTM colonization and disease were calculated. Comparisons of median survival were done using the log-rank test. RESULTS: NTM were isolated from 53 of 237 patients (22.4%) after lung transplantation over a median of 25.2 months of follow-up. The incidence rate of NTM isolation was 9.0/100 person-years (95% confidence interval [CI), 6.8-11.8), and the incidence rate of NTM disease was 1.1/100 person-years (95% CI 0.49-2.2). The most common NTM isolated was Mycobacterium avium complex (69.8%), followed by Mycobacterium abscessus (9.4%), and Mycobacterium gordonae (7.5%). Among these 53 patients, only 2 patients met ATS criteria for pulmonary disease and received treatment for M. avium. One patient had recurrent colonization after treatment, the other one was cured. Four of the 53 patients developed SSI, 3 caused by M. abscessus and 1 caused by Mycobacterium chelonae. Three of these patients had persistent infection requiring chronic suppressive therapy and one died from progressive disseminated disease. A total of 47 (89%) patients who met microbiologic but not radiographic criteria for pulmonary infection were not treated and were found to have only transient colonization. Median survival after transplantation was not different between patients with transient colonization who did not receive treatment and those who never had NTM isolated. CONCLUSION: Episodic isolation of NTM from lung transplant recipients is common. Most isolates occur among asymptomatic patients and are transient. Rapidly growing NTM can cause significant SSI, which may be difficult to cure. NTM disease rate is higher among lung transplant recipients than in the general population. In this cohort, NTM isolation was not associated with increased post-transplantation mortality.

Pseudo-Leptomeningeal Contrast Enhancement at 3T in Pediatric Patients Sedated by Propofol.

BACKGROUND AND PURPOSE: Propofol is a cerebral vasoconstrictor that modulates cerebral perfusion by decreasing the metabolic rate of oxygen. Because younger children often undergo intravenous sedation for MR imaging, this study set out to evaluate the degree of leptomeningeal contrast enhancement on 3T postcontrast brain MR imaging and to determine whether this phenomenon relates to sequence, sedation dosage, or patient age or weight. MATERIALS AND METHODS: During a 2-year period, of 152 children 1-5 years of age who underwent MR imaging, 43 were included for MRI review. Of these, 37 underwent postcontrast imaging with either solely gradient-echo T1WI (n = 20) or spin-echo T1WI (n = 17); notably, 6 patients underwent both sequences. Three neuroradiologists separately graded the degree of leptomeningeal contrast enhancement (grades 0-3) that was correlated with various factors and calculated the interobserver reliability. RESULTS: For the 43 patients, the mean patient age was 3.1 ± 1.4 years. The leptomeningeal contrast-enhancement grade was significantly greater (P < .0001) on spin-echo T1WI (1.9-2.1) versus gradient-echo TIWI (1.2-1.4). Patient weight (r = -0.366 to -.418, P = .003-.01) and age (r = -0.315 to -0.418, P = .004-.032) moderately and inversely correlated with the leptomeningeal contrast-enhancement grade, while the propofol dosage, sedation duration, and time to T1WI post-contrast administration did not (each, P > .05). The interobserver κ was strong regarding the leptomeningeal contrast-enhancement grade on both spin-echo T1WI (κ = 0.609-0.693, P < .0001) and gradient-echo TIWI (κ = 0.567-0.698, P < .0001). CONCLUSIONS: Leptomeningeal contrast enhancement (or "pseudo"-leptomeningeal contrast enhancement) occurs with a greater frequency and degree on 3T postcontrast spin-echo T1WI relative to gradient-echo TIWI in younger children sedated with propofol and should not be mistaken for disease. This phenomenon may be more prominent with lower age or size and may arise from propofol-induced vascular smooth-muscle dilation.

Reversible left hemispheric ischemia secondary to carotid compression in Eagle syndrome: surgical and CT angiographic correlation.

Symptoms of ipsilateral carotid artery compression secondary to an elongated styloid process or calcified stylohyoid ligament may be seen in Eagle syndrome. The patient will typically experience cervicofacial pain due to stimulation of the arterial nervous plexus. In addition, symptoms directly attributable to compression of the carotid artery may be seen, including visual symptoms and syncope. We report here the case of a patient who developed symptoms consistent with left hemispheric ischemia within 15 seconds of turning his head to the left. These symptoms were completely reversible on returning the head to the neutral position. No long-term sequelae were detected clinically or radiographically.

Cellular events during hepatocarcinogenesis in rats and the question of premalignancy.

The cellular, biochemical, and genetic changes that occur in the liver of rats exposed to chemical hepatocarcinogens are reviewed. Multiple new cell types appear in the liver of carcinogen-treated rats including foci, nodules, ducts, oval cells, and atypical hyperplastic areas. The application of phenotypic markers for these cell types suggests that hepatocellular carcinomas may arise from more than one cell type, including a putative liver stem cell that proliferates following carcinogen exposure. Study of DNA, RNA, and proteins produced by hepatocellular carcinomas and putative premalignant cells has so far failed to identify a gene or gene product clearly associated with the malignant or premalignant phenotype. Understanding the cellular lineage from normal cell through putative premalignant cell to cancer is critical to understanding the process of carcinogenesis. Application of new immunological (monoclonal antibody, transplantation) and molecular biological (gene cloning, oncogene identification) approaches to this problem holds promise that the process of hepatocarcinogenesis will be better known in the near future.

Differential and coordinate responses of the human genes encoding the heat stable alkaline phosphatases to cAMP and sodium butyrate in the choriocarcinoma line JEG-3.

Human heat stable alkaline phosphatases are encoded by two closely related genes: the PLAP-1, which specifies the term placental enzyme, and the PLAP-2, which is expressed primarily in germ cells. In the choriocarcioma line JEG-3, 8-Br-cAMP induced the accumulation of the mRNA of both genes, while sodium butyrate induced the accumulation of PLAP-2 transcripts only. Each agent increased the transcription rate of one or both of the genes, as assayed by run-on transcription. In transfection of JEG-3 cells with PLAP promoters fused to the firefly luciferase gene, the activity of the PLAP-2 promoter (but not PLAP-1) was induced with sodium butyrate, while both promoters were induced by 8-Br-cAMP. Inducibility of the PLAP-2 promoter by 8-Br-cAMP was still observed when the promoter was shortened to -103, leaving intact a sequence resembling a cAMP response element. The extent of transcriptional activation by either agent was not sufficient to explain the accumulation of PLAP mRNA. These studies suggest that both transcriptional and posttranscriptional processes are involved in the induction of the PLAP-1 and PLAP-2 gene in JEG-3 cells.

Partial agonists and G protein-coupled receptor desensitization.

Weak or partial agonists induce less desensitization of G protein-coupled receptors (GPCRs) than do strong agonists. However, there have been few attempts to relate partial agonism quantitatively with the various parameters of agonist-induced desensitization, and to elucidate the mechanisms involved. Our understanding of how the treatment of cells and tissues with partial agonists affects their capacity to activate receptors is based on continued progress in defining partial agonism and the mechanisms of desensitization in which protein kinases, phosphatases, endocytosis and recycling play various roles. In this review, current research concerning partial-agonist-induced desensitization of GPCRs and the nature of partial agonism is summarized, and an attempt is made to put the existing knowledge into a working hypothesis concerning the mechanisms that account for the reduced desensitization in response to partial agonists.

Graded expression patterns of ephrin-As in the superior colliculus after lesion of the adult mouse optic nerve.

The idea has been put forward that molecules and mechanisms acting during development are re-used during regeneration in the adult, for example in response to traumatic injury in order to re-establish the functional integrity of neuronal circuits. Members of the Eph family of receptor tyrosine kinases and their 'ligands', the ephrins, play a prominent role during development of the retinocollicular projection in rodents, where EphA receptors and ephrin-As are expressed in gradients in both the retina and the superior colliculi (SC). We were interested in investigating whether EphA family members are also expressed or re-expressed in the adult after optic nerve lesion, since the presence of axon guidance information is an important prerequisite for a topographically appropriate re-connection by retinal ganglion cell (RGC) axons. This analysis was encouraged by results showing that RGC axons do not exert guidance preferences in response to membranes from adult unlesioned SC, but in response to membranes from the adult deafferented SC. We found a graded expression pattern of ephrin-As in the SC both before and after deafferentation, which was remarkably similar to those found during development. EphA receptor levels were reduced in the SC after deafferentation and the expression patterns of the EphB family were not changed. In particular, the presence of a graded ephrin-A expression in the deafferented SC suggests that - if robust regeneration of RGC axons can be achieved - topographic guidance information as a likely requirement for a functionally successful re-establishment of the retinocollicular projection is available.

ß-Blockers have differential effects on the murine asthma phenotype.

BACKGROUND AND PURPOSE: Our previous studies have shown the ß2 -adrenoceptor and its endogenous ligand, adrenaline, are required for development of the asthma phenotype in murine asthma models. Chronic administration of some, but not other, ß-blockers attenuated the asthma phenotype and led us to hypothesize that biased signalling was the basis of their differential effects, experimentally and clinically. EXPERIMENTAL APPROACH: We used mice with no detectable systemic adrenaline (PNMT(-/-) ) and wild-type (WT) mice to study the effects of four ß-blockers, alprenolol, carvedilol, propranolol and nadolol, in an ovalbumin sensitization and challenge (Ova S/C) murine model of asthma. The parameters measured were inflammatory cell infiltration, mucous metaplasia and airway hyperresponsiveness. To interpret the pharmacological action of these ligands quantitatively, we conducted computer simulations of three-state models of receptor activation. KEY RESULTS: Ova S/C PNMT(-/-) mice do not develop an asthma phenotype. Here, we showed that administration of alprenolol, carvedilol or propranolol in the absence of interference from adrenaline using Ova S/C PNMT(-/-) mice resulted in the development of an asthma phenotype, whereas nadolol had no effect. Ova S/C WT mice did develop an asthma phenotype, and administration of alprenolol, propranolol and carvedilol had no effect on the asthma phenotype. However, nadolol prevented development of the asthma phenotype in Ova S/C WT mice. Computer simulations of these four ligands were consistent with the isolated three-state receptor model. CONCLUSION AND IMPLICATIONS: ß-Blockers have different effects on the murine asthma phenotype that correlate with reported differences in activation or inhibition of downstream ß2 -adrenoceptor signalling pathways.

Two gene duplication events in the evolution of the human heat-stable alkaline phosphatases.

There are at least three alkaline phosphatase (AP) isoenzymes in man: a heat-stable placental enzyme (PLAP), a less heat-stable intestinal form (IAP), and the very heat-labile AP enriched in liver, bone and kidney. In addition to these enzymes, there is a heat-stable activity in the thymus and testis that is similar but not identical to the PLAP (the PLAP-like enzyme). Previous work has demonstrated a close structural relatedness among the IAP, PLAP and PLAP-like enzymes. Thus, it is possible that there are three human genes encoding heat-stable AP enzymes. To test this hypothesis, we have used a PLAP cDNA clone to screen a human genomic library cloned into the phage vector lambda EMBL-3. Three sets of clones were isolated, each bearing a distinct coding region homologous to the PLAP cDNA probe. Nucleotide sequence analysis of the 5' ends of these genes allowed comparison of their derived peptide sequences and positive identification of two of the genes. One of the genes encodes the PLAP (the PLAP-1 gene), another encodes the IAP, and a third closely resembles the PLAP-1 gene, but is distinct from it (the PLAP-2 gene). The PLAP-2 gene is highly homologous (greater than 95%) with the PLAP-1 except in the first exon, where sequences encoding the hydrophobic signal peptide are nearly identical with the same region of the IAP gene. These results demonstrate the existence of a small family of PLAP-related genes which is the result of at least two duplication events during the descent of man.

(-)1-(Benzofuran-2-yl)-2-propylaminopentane, [(-)BPAP], a selective enhancer of the impulse propagation mediated release of catecholamines and serotonin in the brain.

1. The brain constituents beta-phenylethylamine (PEA) and tryptamine enhance the impulse propagation mediated transmitter release (exocytosis) from the catecholaminergic and serotoninergic neurons in the brain ('catecholaminergic/serotoninergic activity enhancer, CAE/SAE, effect'). (-)Deprenyl (Selegiline) and (-)1-phenyl-2-propylaminopentane [(-)PPAP] are amphetamine derived CAE substances devoid of the catecholamine releasing property. 2. By changing the aromatic ring in PPAP we developed highly potent and selective CAE/SAE substances, structurally unrelated to the amphetamines. Out of 65 newly synthetized compounds, a tryptamine derived structure, (-)1-(benzofuran-2-yl)-2-propylaminopentane [(-)BPAP] was selected as a potential follower of (-)deprenyl in the clinic and as a reference compound for further analysis of the CAE/SAE mechanism in the mammalian brain. 3. (-)BPAP significantly enhanced in 0.18 micromol 1(-1) concentration the impulse propagation mediated release of [(3)H]-noradrenaline and [(3)H]-dopamine and in 36 nmol 1(-1) concentration the release of [(3)H]-serotonin from the isolated brain stem of rats. The amount of catecholamines and serotonin released from isolated discrete rat brain regions (dopamine from the striatum, substantia nigra and tuberculum olfactorium, noradrenaline from the locus coeruleus and serotonin from the raphe) enhanced significantly in the presence of 10(-12) - 10(-14) M (-)BPAP. BPAP protected cultured hippocampal neurons from the neurotoxic effect of beta-amyloid in 10(-14) M concentration. In rats (-)BPAP significantly enhanced the activity of the catecholaminergic and serotoninergic neurons in the brain 30 min after acute injection of 0.1 microg kg(-1) s.c. In the shuttle box, (-)BPAP in rats was about 130 times more potent than (-)deprenyl in antagonizing tetrabenazine induced inhibition of performance.

Salmeterol-induced desensitization, internalization and phosphorylation of the human beta2-adrenoceptor.

1. Partial agonists of the beta2-adrenoceptor which activate adenylyl cyclase are widely used as bronchodilators for the relief of bronchoconstriction accompanying many disease conditions, including bronchial asthma. The bronchodilator salmeterol has both a prolonged duration of action in bronchial tissue and the ability to reassert this activity following the temporary blockade of human beta2-adrenoceptors with antagonist. 2. We have compared the activation and desensitization of human beta2-adrenoceptor stimulation of adenylyl cyclase induced by salmeterol, adrenaline and salbutamol in a human lung epithelial line, BEAS-2B, expressing beta2-adrenoceptor levels of 40-70 fmol mg(-1), and in human embryonic kidney (HEK) 293 cell lines expressing 2-10 pmol mg(-1). The efficacy observed for the stimulation of adenylyl cyclase by salmeterol was only approximately 10% of that observed for adrenaline in BEAS-2B cells expressing low levels of beta2-adrenoceptor, but similar to adrenaline in HEK 293 cells expressing very high levels of receptors. Salmeterol pretreatment of these cells induced a rapid and stable activation of adenylyl cyclase activity which resisted extensive washing and beta2-adrenoceptor antagonist blockade, consistent with binding to a receptor exosite and/or to partitioning into membrane lipid. 3. The desensitization and internalization of beta2-adrenoceptors induced by the partial agonists salmeterol and salbutamol were considerably reduced relative to the action of adrenaline. Consistent with these observations, the initial rate of phosphorylation of the receptor induced by salmeterol and salbutamol was much reduced in comparison to adrenaline. 4. Our data suggest that the reduction in the rapid phase of desensitization of beta2-adrenoceptors after treatment with salmeterol or salbutamol is caused by a decrease in the rate of beta2-adrenoceptor kinase (betaARK) phosphorylation and internalization. In contrast, the rate of cyclic AMP-dependent protein kinase (PKA)-mediated phosphorylation by these partial agonists appears to be similar to adrenaline.

Trace expression of the germ-cell alkaline phosphatase gene in human placenta.

We have developed hybridization probes that clearly distinguish the RNA transcripts of the two closely related human heat-stable alkaline phosphatase genes. RNA from the PLAP-1 gene, encoding the term placental alkaline phosphatase, is the predominant transcript in placenta from 8 weeks to term. Transcripts from the PLAP-2 gene, encoding the germ-cell or PLAP-like enzyme, are also detectable in the placenta, but at no more than 2 per cent the level of PLAP-1 transcripts.

Serum protein s100beta in patients with malignant melanoma detected by an immunoluminometric assay.

S100 protein is well established as a diagnostic tool in malignant melanoma immunohistology. In this study we measured S100beta in serum with a recently developed luminometric immunoassay with a detection limit of 0.02 microg/l. By measuring S-100beta in a group of apparently healthy individuals a mean value of 0.031 +/- 0.026 microg/l was found. In the reference group, serum S100beta was below 0.12 microg/l in all cases. To assess the sensitivity of the assay we investigated serum S-100beta levels in 371 serum samples of 315 patients with histological proven malignant melanoma at different disease stages. Staging was performed according to the German Society of Dermatology classification. Significant differences were observed between the control group and stages IIb (P = 0.01) and IV (P = 0.001). In tumour-bearing patients of stages IIIb and IV, the difference was highly significant (P < 0.0001). S100beta > 0.20 microg/l helps to distinguish between tumour-free and tumour-bearing patients with a specificity of 97.0% and a sensitivity of 64.6%. Our results demonstrate the serum S100beta is of limited value as a melanoma marker. However, it has clinical significance for identifying tumour-positive patients in advanced malignant melanoma stages III and IV.