Proposed diagnostic algorithm for patients with suspected mastocytosis: a proposal of the European Competence Network on Mastocytosis.

Mastocytosis is an emerging differential diagnosis in patients with more or less specific mediator-related symptoms. In some of these patients, typical skin lesions are found and the diagnosis of mastocytosis can be established. In other cases, however, skin lesions are absent, which represents a diagnostic challenge. In the light of this unmet need, we developed a diagnostic algorithm for patients with suspected mastocytosis. In adult patients with typical lesions of mastocytosis in the skin, a bone marrow (BM) biopsy should be considered, regardless of the basal serum tryptase concentration. In adults without skin lesions who suffer from mediator-related or other typical symptoms, the basal tryptase level is an important parameter. In those with a slightly increased tryptase level, additional investigations, including a sensitive KIT mutation analysis of blood leucocytes or measurement of urinary histamine metabolites, may be helpful. In adult patients in whom (i) KIT D816V is detected and/or (ii) the basal serum tryptase level is clearly increased (>25-30 ng/ml) and/or (iii) other clinical or laboratory features suggest the presence of 'occult' mastocytosis or another haematologic neoplasm, a BM investigation is recommended. In the absence of KIT D816V and other signs or symptoms of mastocytosis or another haematopoietic disease, no BM investigation is required, but the clinical course and tryptase levels are monitored in the follow-up. In paediatric patients, a BM investigation is usually not required, even if the tryptase level is increased. Although validation is required, it can be expected that the algorithm proposed herein will facilitate the management of patients with suspected mastocytosis and help avoid unnecessary referrals and investigations.

Tryptase and histamine metabolites as diagnostic indicators of indolent systemic mastocytosis without skin lesions.

BACKGROUND: Risk indicators of indolent systemic mastocytosis (ISM) in adults with clinical suspicion of ISM without accompanying skin lesions [urticaria pigmentosa (UP)] are lacking. This study aimed at creating a decision tree using clinical characteristics, serum tryptase, and the urinary histamine metabolites methylimidazole acetic acid (MIMA) and methylhistamine (MH) to select patients for bone marrow investigations to diagnose ISM. METHODS: Retrospective data analysis of all adults, in whom bone marrow investigations were performed to diagnose ISM, was carried out. RESULTS: In total, 142 patients were included. SM was absent in all 44 patients with tryptase <10 µg/l, in 45 of 98 (46%) patients with tryptase ≥10 µg/l and in 18 of 52 patients (35%) with tryptase >20 µg/l. Above 43 µg/l, all patients had ISM (n = 11). Male gender, insect venom anaphylaxis as presenting symptom, tryptase, MIMA, and MH were independent ISM predictors. If tryptase was ≥10 µg/l, the diagnostic accuracy of MIMA and MH was high (areas under the ROC curve 0.92). CONCLUSIONS: In suspected patients without UP, the ISM risk is very low (if present at all) if tryptase is <10 µg/l. If tryptase is ≥10 µg/l, this risk depends on MIMA and MH, being low if these are normal, but high if these are elevated. Male gender and insect venom anaphylaxis are additional risk indicators. We recommend refraining from bone marrow examinations in suspected patients without UP if tryptase is <10 µg/l. Our results question the reliability of the minor diagnostic World Health Organization criterion of tryptase >20 µg/l.

High prevalence of fractures and osteoporosis in patients with indolent systemic mastocytosis.

BACKGROUND: Indolent systemic mastocytosis (ISM) is a rare disease characterized by accumulation of abnormal mast cells in various tissues, including bone marrow. Symptoms are usually related to release of mast cell mediators. The aims are to establish the prevalence of osteoporotic fractures in ISM and to investigate the association with serum tryptase and the urinary histamine metabolites, methylhistamine (MH), and methylimidazole acetic acid. METHODS: The fracture prevalence in 157 patients (65 men; 92 women), mean age 54 ± 12 years, was assessed by vertebral morphometry and data from patient records, supplemented by a questionnaire. Bone mineral density (BMD) of lumbar spine and femoral neck was measured, and tryptase and histamine metabolites were analysed. RESULTS: We registered 235 lifetime fractures in 154 patients, including 140 osteoporotic (low-energy trauma) fractures, of which 62% were vertebral, 1% hip and 36% other nonvertebral fractures. Osteoporotic fractures and osteoporosis were found in 37% and 28% of the patients, respectively. In men, the prevalence of these osteoporotic manifestations (46% <50 years; 73% ≥50 years) was much higher compared with women (18% <50 years; 58% ≥50 years). Older age, male gender, and higher urinary MH were independently related to the osteoporotic manifestations. CONCLUSIONS: This first publication about prevalence of fractures and osteoporosis in patients with ISM shows that the risk of osteoporotic fractures is high, especially in men. Higher urinary MH levels are associated with a higher risk of osteoporotic manifestations. Routine measurements of BMD and vertebral morphometry are warranted in these patients for early detection of osteoporosis.

Gene expression profile, pathways, and transcriptional system regulation in indolent systemic mastocytosis.

BACKGROUND: Mastocytosis is an uncommon disease resulting from proliferation of abnormal mast cells infiltrating skin, bone marrow, liver, and other tissues. The aim of this study was to find differences in gene expression in peripheral blood cells of patients with indolent systemic mastocytosis compared to healthy controls. The second aim was to define a specific gene expression profile in patients with mastocytosis. METHODS: Twenty-two patients with indolent systemic mastocytosis and 43 healthy controls were studied. Whole genome gene expression analysis was performed on RNA samples isolated from the peripheral blood. For amplification and labelling of the RNA, the Illumina TotalPrep 96 RNA Amplification Kit was used. Human HT-12_V3_expression arrays were processed. Data analysis was performed using GeneSpring, Genecodis, and Transcriptional System Regulators. RESULTS: Comparison of gene expression between patients and controls revealed a significant difference (P < 0.05 corrected for multiple testing) and the fold change difference >2 in gene expression in 2303 of the 48.794 analysed transcripts. Functional annotation indicated that the main pathways in which the differently expressed genes were involved are ubiquitin-mediated proteolysis, MAPK signalling pathway, pathways in cancer, and Jak-STAT signalling. The expression distributions for both groups did not overlap at all, indicating that many genes are highly differentially expressed in both groups. CONCLUSION: We were able to find abnormalities in gene expression in peripheral blood cells of patients with indolent systemic mastocytosis and to construct a gene expression profile which may be useful in clinical practice to predict the presence of mastocytosis and in further research of novel drugs.

Gene expression analysis predicts insect venom anaphylaxis in indolent systemic mastocytosis.

BACKGROUND: Anaphylaxis to insect venom (Hymenoptera) is most severe in patients with mastocytosis and may even lead to death. However, not all patients with mastocytosis suffer from anaphylaxis. The aim of the study was to analyze differences in gene expression between patients with indolent systemic mastocytosis (ISM) and a history of insect venom anaphylaxis (IVA) compared to those patients without a history of anaphylaxis, and to determine the predictive use of gene expression profiling. METHODS: Whole-genome gene expression analysis was performed in peripheral blood cells. RESULTS: Twenty-two adults with ISM were included: 12 with a history of IVA and 10 without a history of anaphylaxis of any kind. Significant differences in single gene expression corrected for multiple testing were found for 104 transcripts (P < 0.05). Gene ontology analysis revealed that the differentially expressed genes were involved in pathways responsible for the development of cancer and focal and cell adhesion suggesting that the expression of genes related to the differentiation state of cells is higher in patients with a history of anaphylaxis. Based on the gene expression profiles, a naïve Bayes prediction model was built identifying patients with IVA. CONCLUSIONS: In ISM, gene expression profiles are different between patients with a history of IVA and those without. These findings might reflect a more pronounced mast cells dysfunction in patients without a history of anaphylaxis. Gene expression profiling might be a useful tool to predict the risk of anaphylaxis on insect venom in patients with ISM. Prospective studies are needed to substantiate any conclusions.

Mastocytosis and insect venom allergy: diagnosis, safety and efficacy of venom immunotherapy.

The most important causative factor for anaphylaxis in mastocytosis are insect stings. The purpose of this review is to analyse the available data concerning prevalence, diagnosis, safety and effectiveness of venom immunotherapy (VIT) in mastocytosis patients. If data were unclear, authors were contacted personally for further information. Quality of evidence (A: high, B: moderate, C: low and D: very low) and strength of recommendation (strong 1 and weak 2) concerning VIT in mastocytosis patients are assessed according to the Grading of Recommendations Assessment, Development and Evaluation and are marked in square brackets. Results of VIT were described in 117 patients to date. The mean rate of side-effects during treatment in studies published so far is 23.9% (7.6% requiring adrenaline) with an overall protection rate of 72%. Based on the review we conclude that (1) mastocytosis patients have a high risk of severe sting reactions in particular to yellow jacket, (2) VIT could be suggested [2] in mastocytosis, (3) probably should be done life long [2], (4) VIT in mastocytosis is accompanied by a higher frequency of side-effects, so (5) special precautions should be taken into account notably during the built up phase of the therapy [2], (6) VIT is able to reduce systemic reactions, but to a lesser extent compared to the general insect venom allergic population [2], so (7) patients should be warned that the efficacy of VIT might be less than optimal and they should continue carrying two adrenaline auto injectors [2].

[Lifestyle intervention for the prevention of cardiovascular disease]. / Leefstijlinterventie ter preventie van hart- en vaatziekten.

The high cardiovascular disease prevalence in western countries is largely attributable to the contemporary lifestyle. Interventions in the area of nutrition and physical activity have been shown to be effective in the prevention of cardiovascular disease. Successful implementation of lifestyle intervention programmes may be just as effective as drug treatment. In combination with drug treatment, intervention in the area of nutrition and physical activity is the recommended treatment for patients at a high risk of cardiovascular disease. Addition of new drugs to those presently available is associated with low absolute risk reductions and high costs, particularly in the presence of successful lifestyle interventions.

No long-lasting or intermittent mast cell activation in acute coronary syndromes.

BACKGROUND: Unstable coronary syndromes, such as acute myocardial infarction and unstable angina pectoris are mostly due to rupture of an atherosclerotic plaque. Recently mast cells were found to participate actively in the inflammatory process of atherosclerosis by excreting proteolytic and pro-inflammatory substances with the ability to cause plaque instability and rupture. Mast cell activity can be determined by measuring serum levels of tryptase, as has been demonstrated in patients with anaphylaxis and mastcytosis. HYPOTHESIS: Acute coronary events (acute myocardial infarction and unstable angina pectoris) are associated with increased mast cell activity, reflected by elevated serum tryptase levels. METHODS: Serum levels of tryptase were determined in the following three groups of patients: 13 patients with acute myocardial infarction, 10 patients with unstable angina pectoris, and 14 patients without ischaemic cardiovascular disease who were used as controls. Patients with known IgE mediated allergic diseases and/or anti-histaminical drugs were excluded. RESULTS: The groups were comparable for sex, blood pressure, smoking and cholesterol levels. The controls tended to be younger (P=0.05). Levels of tryptase did not differ between patients with acute myocardial infarction (7.9+/-4.6 microg/l), unstable angina pectoris (6.0+/-2.1 microg/l) or controls (6.9+/-4.1 microg/l), nor could a relation with levels of C-reactive protein be demonstrated. CONCLUSION: Serum levels of tryptase are not elevated in patients with acute coronary syndromes. This implies that increased mast cell activity, if any, in unstable coronary syndromes is not reflected systemically. Other, more specific methods will be needed to determine the activity of the mast cell in vivo.

[Obstetric problems followed by stroke]. / Obstetrische problemen: soms een voorbode van naderend onheil uit onverwachte hoek.

Obstetrical problems sometimes portend manifestations of atherosclerosis, as illustrated by two case reports. The first patient had the combination of hyperhomocysteinaemia due to chronic vitamin deficiencies in the diet, and smoking. The second was also a smoker and had a genetically determined mild hyperhomocysteinaemia, aggravated by chronic vitamin deficiencies resulting from poor dietary habits; she also had an increased folic acid requirement because of use of anti-epileptic drugs in combination with a familial predisposition for premature atherosclerotic manifestations. The first patient had four pregnancies, two of which ended in intrauterine foetal death due to placental infarction, and one in the birth of a dysmature boy. The second patient's four pregnancies ended twice in abortion and twice in the birth of a dysmature child; in one of the latter cases placental infarction was observed. Both women subsequently suffered cerebrovascular accidents while in addition, older cerebral infarctions were found to be present. Women with recurrent abortion, pre-eclampsia, placental infarction, placental detachment and foetal growth retardation should be examined, even if other risk factors are also present, for (mild) hyperhomocysteinaemia, and treated for it with vitamin suppletion (folic acid, vitamins B6 and B12), even although admittedly more research is necessary to make certain that such treatment has a preventive effect on the manifestations of this disorder.

The dietary fatty acids of patients with coronary artery disease and control in Curacao: implications for primary and secondary prevention

Patients with coronary artery diseases are advised to augment their dietary linoleic acid intakes at the expense of saturated fatty acids. We investigated whether the dietary linoleic acid intake of 57 patients with coronary artery disease (47 males, 10 females; ages 61 ñ 10 years) in Curacao is higher as compared with 77 controls (51 males, 26 females; ages 56 ñ 7 years). For this, we measured plasma cholesterol ester fatty acids, which reflect the dietary fatty acid composition of the preceeding weeks. Patients with coronary artery disease and controls had minor differences in cholesterol ester fatty acids. Their cholesterol ester linoleic acid content suggests that the dietary polyunsaturated/saturated fatty acid ratio is far below 1. Comparison with data reported for the the Netherlands, Greenland and Crete showed that the dietary fatty acid composition in Curacao is typically Western with a high intake of saturated fatty acids, a low intake of monounsaturated fatty acids and the consumption of linoleic acid as the predominant polyunsaturated fatty acid. Intake of long chain polyunsaturated fatty acids from fatty fish is low. Reduction of dietary saturated fatty acids, augmentation of fish consumption, and an increase of the Ó-linolenic/linoleic acid ratio are likely to be of benefit to both primary and secondary prevention from coronary artery disease in Curaco.

Clinical chemistry of common apolipoprotein E isoforms.

Apolipoprotein E plays a central role in clearance of lipoprotein remnants by serving as a ligand for low-density lipoprotein and apolipoprotein E receptors. Three common alleles (apolipoprotein E(2), E(3) and E(4)) give rise to six phenotypes. Apolipoprotein E(3) is the ancestral form. Common apolipoprotein E isoforms derive from nucleotide substitutions in codons 112 and 158. Resulting cysteine-arginine substitutions cause differences in: affinities for low-density lipoprotein and apolipoprotein E receptors, low-density lipoprotein receptor activities, distribution of apolipoprotein E among lipoproteins, low-density lipoprotein formation rate, and cholesterol absorption. Accompanying changes in triglycerides, cholesterol and low-density lipoprotein may promote atherosclerosis development. Over 90% of patients with familial dysbetalipoproteinaemia have apolipoprotein E(2)/E(2). Apolipoprotein E(4) may promote atherosclerosis by its low-density lipoprotein raising effect. Establishment of apolipoprotein E isoforms may be important for patients with diabetes mellitus and several non-atherosclerotic diseases. Apolipoprotein E phenotyping exploits differences in isoelectric points. Isoelectric focusing uses gels that contain pH 4-7 ampholytes and urea. Serum is directly applied, or prepurified by delipidation, lipoprotein precipitation or dialysation. Isoelectric focusing is followed by immunofixation/protein staining. Another approach is electro- or diffusion blotting, followed by protein staining or immunological detection with anti-apolipoprotein E antibodies and an enzyme-conjugated second antibody. Apolipoprotein E genotyping demonstrates underlying point mutations. Analyses of polymerase chain reaction products are done by allele-specific oligonucleotide probes, restriction fragment length polymorphism, single-stranded conformational polymorphism, the primer-guided nucleotide incorporation assay, or denaturating gradient gel electrophoresis. Detection with primers that either or not initiate amplification is performed with the amplification refractory mutation system. Disparities between phenotyping and genotyping may derive from isoelectric focusing methods that do not adequately separate apolipoprotein E posttranslational variants, storage artifacts or faint isoelectric focusing bands.

Long-term follow-up of indolent mastocytosis in adults.

OBJECTIVE: To evaluate the natural course of indolent mastocytosis in adults. DESIGN: A retrospective long-term follow-up study. SETTING: The Department of Endocrinology of a University Hospital. PATIENTS: Sixteen adult patients with a diagnosis of indolent mastocytosis and sufficient biochemical data for statistical analysis. One patient had paediatric-onset cutaneous mastocytosis, whilst the others had adult-onset systemic mastocytosis. Ages at the end of follow-up ranged from 23 to 79, median 50 years. Follow-up periods per patient lasted from 13 to 135 months, median 90 months. MEASUREMENTS: Urinary excretions of the histamine metabolites N tau-methylhistamine (MH) and N tau-methylimidazoleacetic acid (MIMA), and signs and symptoms of the disease. RESULTS: The excretion of MH but not MIMA increased in four patients (ages 37, 45, 61 and 65 years) and decreased in two patients (ages 26 and 48 years), including the only patient with paediatric-onset cutaneous mastocytosis. The excretion of MIMA but not MH increased in none and decreased in one patients (age 51 years). The excretions of both MH and MIMA increased in one patient (age 23 years) and decreased in two patients (ages 65 and 79 years). The excretion of MH and MIMA can be considered to have been stable in one patient (age 49 years). In the five remaining patients, observation periods were rather short. A definite judgement on the course of their disease could not be given. In the two patients in whom the excretion of both MH and MIMA decreased, the enlarged spleen decreased in size, whilst in the other patients, signs and symptoms did not change. There were no accompanying myeloproliferative disorders in any patient. No special treatment aiming at a reduction in mast cell load has been given. Rates of change over the whole follow-up period ranged from -8.4 to +25.1% per year. CONCLUSION: The natural course of indolent adult-onset mastocytosis is not always progressive. Our data show that the activity of adult-onset indolent mastocytosis, as measured by urinary excretion of MH and MIMA and clinical signs and symptoms, can substantially decline, especially in older patients.

Triiodothyronine rapidly lowers plasma lipoprotein (a) in hypothyroid subjects.

BACKGROUND: Increases in plasma low-density-lipoprotein (LDL) cholesterol and apolipoprotein B (apo-B) are well known in primary hypothyroidism, but it is uncertain whether thyroid dysfunction is associated with elevated levels of the atherogenic lipoprotein (a) (Lp(a)). METHODS: The effect of short-term hypothyroidism on plasma Lp(a) was studied in 14 patients who had undergone a total thyroidectomy because of a well-differentiated thyroid carcinoma. They were studied 2 weeks after withdrawal of triiodothyronine (T3) therapy and 7 (5-9) weeks after resumption of T3 treatment (75-100 micrograms T3 daily). Fourteen euthyroid subjects served as controls. RESULTS: In the hypothyroid phase the athyreotic patients had higher levels of Lp(a) (105 [12-536] vs. 42 [1-321] mg/l, p < 0.05), apo-B (p < 0.001) and LDL cholesterol (p < 0.001) as compared with the euthyroid control subjects. T3 therapy lowered Lp(a) by 29% to 50 (12-535) mg/l, p < 0.01. Apo B and LDL cholesterol fell by 42% (p < 0.001) and by 53% (p < 0.001), respectively. After resumption of T3 therapy the levels of Lp(a), apo-B and LDL cholesterol were not different from those of the control subjects. The mean percentual decreases in Lp(a) and in apo-B were similar, although the individual changes in Lp(a) were more variable. CONCLUSIONS: Short-term hypothyroidism increases plasma Lp(a) and T3 therapy rapidly lowers Lp(a) together with apo-B and LDL cholesterol. Our findings support the hypothesis that thyroid hormone regulates plasma Lp(a) and apo-B in a parallel manner. Elevated concentrations of Lp(a) in combination with LDL cholesterol may be involved in the increased risk of cardiovascular disease assumed to be associated with hypothyroidism.

Anaphylactoid shock following Hymenoptera sting as a presenting symptom of systemic mastocytosis.

Systemic mastocytosis is a rare and chronic disorder characterized by a pathologically increased number of mast cells in various tissues and overproduction of mast cell mediators. From a group of 15 patients (10 females, 5 males) with systemic mastocytosis five female patients presented with a history of an anaphylactoid shock reaction to wasp sting. Three of them had no demonstrable specific IgE against wasp or bee venom in serum, and a skin test that was only weakly positive for wasp venom. One patient had specific IgE against wasp venom and a clearly positive skin test to wasp venom. The other patient had specific IgE against both wasp and bee venom and a skin test that was only weakly positive to wasp venom. Two patients had to stop a hyposensitization procedure because of systemic side effects. The five patients did not differ from the other patients with systemic mastocytosis with regard to either clinical symptoms and signs or urinary excretion of histamine metabolites. From the latter group two female and three male patients said they had been stung by a wasp in the past. Thus, anaphylactoid shock after Hymenoptera sting can be a presenting symptom of systemic mastocytosis and may be caused by an IgE- as well as a non-IgE-mediated mechanism. In cases of anaphylactoid reaction to Hymenoptera sting, especially when there is no IgE demonstrable in serum or in cases of intolerance of hyposensitization, the diagnosis of systemic mastocytosis should be considered, also in the absence of the clinical hallmarks of urticaria pigmentosa.

Detection of the Pro664-Leu mutation in the low-density lipoprotein receptor and its relation to lipoprotein(a) levels in patients with familial hypercholesterolemia of Dutch ancestry from The Netherlands and Canada.

From a large cohort of hyperlipidemic patients, who attended the Lipid Research Clinic in Amsterdam, The Netherlands and in Vancouver, Canada, 915 consecutive patients with familial hypercholesterolemia (FH) of Dutch descent, were selected. This group of FH patients was screened for the presence of a cytosine to thymidine nucleotide substitution in exon 14 of the LDL-receptor gene, in order to determine the frequency of this mutation in patients of Dutch descent and to investigate the relationship between the mutation and the level of lipoprotein(a). The mutation was detected in seven individuals. All patients with this mutation shared the same haplotype, which is suggestive of an ancient mutation. The index patients and a large kindred with this mutation were further analyzed at the biochemical and clinical level. Except for total and LDL-cholesterol, there was no statistically significant difference in biochemical parameters between family members with and without FH. In contrast to previous reports, there was no difference in plasma levels of lipoprotein(a) between patients with the mutation in exon 14 and unaffected individuals.

Optimized determination of malondialdehyde in plasma lipid extracts using 1,3-diethyl-2-thiobarbituric acid: influence of detection method and relations with lipids and fatty acids in plasma from healthy adults.

We investigated the influence of different concentrations of Fe3+, phosphoric acid, butylated hydroxytoluene and glutathione on the production of the malondialdehyde-1,3-diethyl-2-thiobarbituric acid adduct in plasma lipid extracts. Following organic solvent extraction the stable product was analyzed by spectrophotometry (537 nm), fluorometry (547 nm) and high-performance liquid chromatography with fluorometric detection. Using optimized reaction conditions there was good agreement between the three methods, with slightly higher values for the spectrophotometric method. Plasma total lipid malondialdehyde reference values for 24 healthy adults amounted to 1.30 +/- 0.23 mumol/l (spectrophotometric method) and 1.11 +/- 0.31 mumol/l (fluorometric method). Plasma lipid malondialdehyde concentrations correlated significantly with plasma triglycerides (r = 0.527), total cholesterol (r = 0.612) and total fatty acids (r = 0.810) and with the total number of double bonds present in plasma fatty acids with three or more double bonds (r = 0.923).