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Summary Patients with systemic mastocytosis (SM) may acquire an associated hematologic non–mast cell (MC)–lineage disease (AHNMD). In most cases, a myeloid neoplasm is diagnosed, whereas the occurrence of a lymphoproliferative disease is an extremely rare event. We report on a patient with indolent SM associated with small lymphocytic lymphoma (SLL). The patient presented with lymphadenopathy, maculopapular exanthema, and elevated serum tryptase. The bone marrow biopsy showed focal MC aggregates together with SLL. As assessed by immunostaining, neoplastic MC were found to exhibit CD117 and CD25 but did not display CD5 or CD20, whereas SLL cells were found to coexpress CD5 and CD20 but did not express MC antigens. The KIT mutation D816V was detected in sorted CD34 + cells and unfractionated marrow cells but not in CD5 + SLL cells, confirming the coexistence of 2 distinct neoplasms.

Hyperhomocysteinemia has occasionally been reported in patients with phenylketonuria (PKU) and B-vitamin deficiency. In our study total homocysteine (tHcy) and B-vitamins were measured in treated PKU patients and healthy controls. In the patients, dietary parameters and genetic polymorphisms affecting the Hcy pathway were investigated to identify parameters modulating tHcy. A case control study including 37 PKU patients and 63 healthy controls was conducted. t -Tests for independent samples were used to test between groups. Multiple regressions with tHcy as dependent variable were calculated. Hardy–Weinberg expectations were tested against the observed distribution of genotypes applying the Chi-square goodness-of-fit method. THcy concentrations were not significantly different ( p =0.059) while folate and cobalamin (Cbl) concentrations were significantly higher in PKU patients compared to controls. However, 29.7% of patients had tHcy concentrations >97th centile. THcy did not vary with age nor correlate with folate and Cbl concentrations probably due to high saturatory levels. The presence of genetic polymorphisms had no impact on tHcy. In conclusion, in PKU patients treated with amino acid mixtures enriched with B-vitamins, tHcy is not significantly higher than in healthy controls, but tHcy concentrations exceed the 97th centile in about one third of patients. Even higher B-vitamin saturation may be required to further decrease tHcy concentrations and factors generally influencing tHcy such as betaine are to be investigated in PKU patients in the future.

In a group of patients with systemic mastocytosis (SM), marked and sustained eosinophilia is detectable (SM-eo).Although the molecular defect has been defined in some cases, little is known about the impact and clinical correlates of eosinophilia.In a cohort of 63 patients with SM, we identified 9 with permanent eosinophilia (1500/microL). According to the World Health Organization classification, 2 had indolent SM, 1 had smoldering SM, 2 had SM with associated chronic eosinophilic leukemia (SM-CEL), and 4 had aggressive SM.SM-eo was found to be associated with a significantly reduced probability of overall and event-free survival compared with SM without eosinophilia (P.05). In the 2 patients with SM-CEL, a CHIC2 deletion was found. By contrast, no KIT mutation at codon 816 was detectable in these patients. In the other patients with SM-eo, KIT D816V was demonstrable. The 2 patients with SM-CEL had cardiomyopathy, whereas other organ systems remained largely unaffected. By contrast, in all other patients with SM-eo, organopathy, if recorded, affected the bone marrow, liver, or/and skeletal system, but not the heart, even when eosinophilia persisted for many years.The biochemical basis of eosinophilia in SM is variable and predictive for the type of organopathy.In SM eosinophilia is of prognostic significance but is not a final diagnosis and is not invariably associated with cardiomyopathy. The latter might be restricted to cases with an associated primary eosinophilic disorder (SM-CEL).

Background: Hyperlipidemia is highly prevalent in kidney transplant recipients, but the prognostic significance for mortality and allograft survival in these patients has not been established sufficiently. Methods: We prospectively enrolled 733 kidney transplant recipients between 1996 and 1998. Clinical information was collected and blood was drawn for laboratory evaluation. Information on the previous transplantation procedures and organ donor were obtained from the Eurotransplant Foundation database. We used the Austrian Dialysis and Transplantation Registry for follow-up. Using multivariate proportional hazard regression, independent relations of fasting plasma triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels to risk for death from any cause and risk for kidney allograft loss were examined. Results: During a median follow-up of 6.1 years, 154 patients died and 260 kidney allografts were lost. After careful multivariate adjustment, there were no significant associations between TG and TC levels and patient mortality. Patients in the highest quartile of TG and TC levels had no difference in risks for mortality compared with patients in the lowest quartile of these parameters (hazards ratio, 0.81; 95% confidence interval, 0.51 to 1.28; hazards ratio, 0.68; 95% confidence interval, 0.42 to 1.10, respectively). Similarly, no associations were found with allograft loss. Further analysis of associations between high-density lipoprotein cholesterol or low-density lipoprotein cholesterol categories and patient mortality or kidney allograft loss did not show associations. Conclusion: Elevated levels of TC or its subfractions and elevated TG levels are not associated with increased risk for patient mortality or allograft loss in these kidney transplant recipients.

Background: It is unknown whether traditional cardiovascular disease risk factors influence the number of endothelial progenitor cells (EPCs) and whether numbers of EPCs correlate with endothelial function in patients with end-stage renal disease. Methods: In a cross-sectional study of 38 peritoneal dialysis patients, we examined numbers of circulating CD34 + /KDR + /CD133 + cells, CD34 + hematopoietic stem cells, and EPCs cultured from peripheral blood. We also assessed conventional cardiovascular disease risk factors, such as history of vascular disease, diabetes, hypercholesterolemia, hypertension, and smoking. We determined endothelial function by measurement of endothelium-dependent and endothelium-independent reactivity of forearm resistance arteries by using strain-gauge plethysmography. Results: Numbers of EPCs cultured from peripheral blood and forearm blood flow reactivity did not differ between erythropoietin-treated peritoneal dialysis patients and healthy individuals. A history of vascular disease was associated with number of cultured EPCs, but other cardiovascular disease risk factors showed no association. Furthermore, there was no association of endothelial-dependent and endothelial-independent forearm blood flow reactivity with EPCs in peritoneal dialysis patients. Conclusion: In this first study of EPCs in peritoneal dialysis patients, we found an association between history of vascular disease and EPCs, but no association of EPCs with endothelial function or other cardiovascular disease risk factors.

Associations between MTHFR 1793G>A and plasma total homocysteine, folate, and vitamin B 12 in kidney transplant recipients. Background Currently, no evidence is available on the putative associations between a novel single nucleotide polymorphism of the 5,10-methylenetetrahydrofolate reductase gene MTHFR 1793G>A and plasma levels of vitamin B 12 , folate, or total homocysteine (tHcy). Methods In a cross-sectional study of 730 kidney allograft recipients, patients were categorized by MTHFR 1793G>A genotype. In univariate and multivariate linear regression models that allowed the outcome variables vitamin B 12 , folate, and tHcy plasma levels to follow a gamma distribution, we tested for possible associations of allelic variants of MTHFR 1793G>A and these three dependent variables. As hypothesized in previous work, we specifically evaluated possible effect modification between the MTHFR 1793G>A and 1298A>C mutations on these outcomes. Results The allele frequency for MTHFR 1793G>A was 0.052. Heterozygosity ( N = 72) or homozygosity ( N = 2) for MTHFR 1793G>A was not independently associated with plasma levels of vitamin B 12 ( P = 0.33) or tHcy ( P = 0.70), but a borderline association with higher folate concentrations was detected (Δfolate = 1.91 nmol/L) (95% CI -0.03 to 3.86 nmol/L) ( P = 0.05). Further, we found strong and significant positive interactions between the MTHFR 1793G>A and 1298A>C mutations on vitamin B 12 concentrations. Conclusion Higher folate concentrations in kidney transplant recipients with MTHFR 1793GA or 1793AA and markedly higher concentrations of vitamin B 12 in patients with combined MTHFR 1793G>A and 1298A>C mutations may contribute to the survival advantage that has been postulated for such patients showing these genotypes.

C-reactive protein (CRP) is a risk factor for cardiovascular outcomes and mortality in the general population. To date, there are no prospective studies of the association between CRP and mortality or allograft loss in kidney transplant recipients (KTR). In 1995, 438 consecutive KTR were enrolled in this prospective study. Important information on demographic, clinical and immunological characteristics was collected at baseline, and CRP was measured using standard methods. Patients were then followed-up for a median 7.8 years. Time-to-event analyses (univariate and multivariate Cox proportional hazards regression models) were used to study the main outcomes: all-cause mortality and kidney allograft loss, defined as the earlier of return to dialysis, re-transplantation, or death. From univariate analyses, we found that CRP >or=0.5 mg/dL was associated with a 83% greater mortality risk compared with lower levels of this inflammatory marker [hazard ratio (HR) = 1.83; 95% confidence interval (CI): 1.23-2.72; p = 0.003]. After multivariate adjustment, patients with a CRP >or=0.5 mg/dL had a 53% higher mortality risk compared with patients whose CRP was below that threshold (HR = 1.53; 95% CI: 1.01-2.31; p = 0.04). No associations between CRP and the risk of kidney allograft loss were detected. Furthermore, we were not able to detect any effect modification between CRP and body mass index on the outcomes under study. We conclude that CRP predicts all-cause mortality, but not allograft loss in stable KTR.

Dose-dependent effect of parenteral iron therapy on bleomycin-detectable iron in immune apheresis patients. Background Iron deficiency and anemia are commonly encountered in patients with autoimmune diseases undergoing immune apheresis. This makes erythropoietin and iron substitution necessary in most patients. However, intravenous iron therapy may result in an increase of potentially toxic nontransferrin-bound iron. Methods We examined the effect of 50 mg or 100 mg of iron (III) sucrose on bleomycin-detectable iron (BDI) in immune apheresis patients. Six patients with autoimmune disorders and normal kidney function were enrolled. Before and after the injection of 50 mg or 100 mg of iron (III) sucrose, BDI was measured in serum samples at five different time points. Results There was no BDI traceable before injection of iron (III) sucrose. BDI was present in serum of all patients after the administration of 100 mg of iron (III) sucrose in concentrations up to 0.49 μmol/L. In contrast, only one patient showed BDI at a concentration of 0.16 μmol/L after the administration of 50 mg of iron (III) sucrose. Conclusion We conclude that if parenteral iron is administered after apheresis treatment, despite the equal tolerability, use of 50 mg of iron (III) sucrose is superior to 100 mg of iron (III) sucrose in avoiding the formation of potentially toxic nontransferrin-bound iron.

Effects of TCN2 776C>G on vitamin B 12 , folate, and total homocysteine levels in kidney transplant patients. Background Controversy exists regarding the possible associations between a single nucleotide polymorphism of the transcobalamin II encoding gene ( TCN2 776C>G) and plasma levels of vitamin B 12 , folate, or total homocysteine. Methods In a cross-sectional study of 732 kidney allograft recipients, patients were categorized by TCN2 776C>G genotype. In univariate and multivariate linear regression models that allowed the outcome variables vitamin B 12 , folate, and total homocysteine plasma levels to follow a gamma distribution, we tested for possible associations of allelic variants of the TCN2 776C>G gene and these three dependent variables. Results The allele frequency for TCN2 776C>G was 0.46. Heterozygosity or homozygosity for TCN2 776C>G was not associated with plasma levels of vitamin B 12 (776CG, P = 0.22; 776GG, P = 0.89), folate (776CG, P = 0.91; 776GG, P = 0.84), or total homocysteine (776CG, P = 0.11; 776GG, P = 0.33) even after adjustment for several possible confounders. Conclusion We conclude from this largest study on the subject thus far that there are no associations between allelic variants of TCN2 776C>G and plasma vitamin B 12 , folate, or total homocysteine plasma levels in kidney transplant patients.

Background Oral ingestion of proteins or amino acids is associated with endothelial dysfunction. The effect of commercial amino acid peritoneal dialysis solutions on vascular function is unknown. Objective We compared the acute effect of intraperitoneal amino acid administration with that of intraperitoneal glucose administration on vascular function in peritoneal dialysis patients. Design In an open-label randomized, controlled, crossover and observer-blinded trial, we examined the acute effect of an intraperitoneal application of 2 L commercial 1.1% amino acid solution compared with that of a 2.27% glucose solution in 13 peritoneal dialysis patients. The primary endpoint was the change in forearm reactive hyperemia 6 h after instillation of either dialysis solution. Results After 6 h of dwell time, reactive hyperemia was substantially impaired after administration of the amino acid solution compared with the glucose solution (median difference: 202%; 95% CI: 57%, 368%; P = 0.007). In a comparison of differences between values at 6 h and those before treatment, reactive hyperemia significantly decreased during the dwell with the amino acid dialysis solution compared with that with the glucose dialysis solution (median difference: 242%; 95% CI: 53%, -457%; P = 0.013). In an analysis of smoking and nonsmoking patients separately, the difference in forearm blood flow between the 2 treatments was still statistically significant. Conclusions One 6-h dwell with a commercial amino acid dialysis solution acutely impairs forearm reactive hyperemia in smoking and nonsmoking peritoneal dialysis patients. Because endothelial dysfunction is associated with increased morbidity and mortality, the long-term use of these solutions may increase the risk of cardiovascular disease.

Effect of TCN2 776C>G on vitamin B 12 cellular availability in end-stage renal disease patients. Background Transcobalamin II is a serum protein that transports vitamin B 12 from the intestine to the tissues. This complex, holo-transcobalamin II, may reflect vitamin B 12 availability in the body. Conflicting data exist with regard to the effect of a polymorphism in the gene coding for transcobalamin II, TCN2 776C>G, on transcobalamin II levels in the general population, which in turn may affect holo-transcobalamin II, vitamin B 12 , as well as total homocysteine (tHcy) plasma levels. The effect of TCN2 776C>G on vitamin B 12 cellular availability in dialysis patients is unknown. Methods We examined the effect of TCN2 776C>G on holo-transcobalamin II, vitamin B 12 , and tHcy plasma concentrations in 120 dialysis patients. Results Holo-transcobalamin II levels were normal or supranormal in all patients and showed a linear association with albumin ( r = 0.205, P = 0.025) and with vitamin B 12 ( r = 0.778, P = 0.001), but not with age, creatinine, body mass index, tHcy, ln-tHcy, vitamin B 6 , plasma folate, and red blood cell folate concentration. TCN2 776C>G showed no effect on holo-transcobalamin II, vitamin B 12 , and tHcy concentration [one-way analysis of variance (ANOVA), post-hoc Scheffe test]. Multiple linear regression analyses showed that albumin and B 12 are independently associated with holo-transcobalamin II, whereas TCN2 776C>G and MTHFR 677C>T had no effect. Independent predictors of ln-tHcy included creatinine, red blood cell folate, and the MTHFR 677TT genotype. There was also an effect of the TCN2 776CC genotype on ln-tHcy levels in this multivariate analysis, however, that deserves cautious interpretation because there was no effect of TCN2 genotypes by ANOVA and Scheffe test [median ln-tHcy concentrations according to TCN2 genotypes (μmol/L): CC, 3.22; CG, 3.30; GG, 3.23]. Conclusion TCN2 776C>G does not influence holo-transcobalamin II or vitamin B 12 levels, and has no major effect on tHcy concentrations of end-stage renal disease patients.

Effects of the glutamate carboxypeptidase II ( GCP2 1561C>T) and reduced folate carrier ( RFC1 80G>A) allelic variants on folate and total homocysteine levels in kidney transplant patients. Background The effect of the glutamate carboxypeptidase II GCP2 1561C>T and the reduced folate carrier 1 RFC1 80G>A polymorphisms on folate and total homocysteine (tHcy) plasma levels of kidney transplant patients are unknown. Methods In a cross-sectional study of 730 kidney allograft recipients, GCP2 1561C>T, RFC1 80G>A, folate, and tHcy plasma levels were analyzed using linear regression models that allowed dependent covariates to follow a gamma distribution for univariate and multivariate analyses. Results The allele frequency for GCP2 1561C>T was 0.05, and 0.43 for RFC1 80G>A. Heterozygosity or homozygosity for GCP2 1561C>T was associated with higher folate plasma levels compared to patients without mutation ( P RFC1 80G>A showed no influence. Multiple testing, also including MTHFR 677C>T and MTHFR 1298A>C, revealed no interaction between the different genotypes and the folate plasma concentration. Neither GCP2 1561C>T nor RFC1 80G>A showed an association with tHcy plasma levels. Conclusion We conclude that GCP2 1561C>T is associated with elevated folate levels. GCP2 1561C>T and RFC1 80G>A are no major determinants of tHcy plasma levels in kidney transplant patients.

Influence of mycophenolic acid and tacrolimus on homocysteine metabolism.BackgroundThe effect of mycophenolate mofetil (MMF) on homocysteine (Hcy) metabolism is unknown.MethodsThis in vitro study examined whether mycophenolic acid or tacrolimus influences the formation of Hcy as determined by measuring the total Hcy (tHcy) concentrations in supernatants of human renal proximal tubule epithelial cells. Cells were incubated with and without vitamins (folate, vitamin B6 and B12) in the presence of low or high methionine concentrations at different mycophenolic acid (0, or 5, or 20 μg/mL) or tacrolimus (0, or 10, or 25 ng/mL) concentrations for 24, 48 or 72 hours. The concentration of tHcy in culture supernatants was measured by a fluorescence polarization immunoassay. The effect of MMF on tHcy plasma levels was also examined in 454 kidney graft recipients.ResultsComparisons of tHcy levels in culture supernatants over time by four way ANOVA showed that methionine concentration (P < 0.00001), time (P < 0.00001), vitamins (P = 0.002728), and mycophenolic acid concentration (P = 0.000095) were all significant predictors of tHcy concentrations. This was due to significantly lower tHcy levels with using mycophenolic acid at a high concentration versus control at the 48- and 72-hour time points. By contrast, tacrolimus showed no effect in vitro. Among the kidney graft recipients, male patients on MMF therapy showed lower plasma tHcy concentrations as compared to those on azathioprine (P = 0.03).ConclusionOur study suggests a tHcy lowering effect of MMF in male transplant recipients, which improves the cardiovascular disease risk profile, whereas tacrolimus showed no effect.

Effect of MTHFR genotypes and hyperhomocysteinemia on patient and graft survival in kidney transplant recipients. Background The total homocysteine (tHcy) plasma level, which is partly determined by the MTHFR 677C→T genotype, may be associated with vascular disease. We prospectively examined the influence of MTHFR genotypes (677C→T, 1298A→C) and tHcy plasma concentration on all cause mortality and graft outcomes of renal transplant recipients. Methods Baseline tHcy plasma levels of 189 patients (three groups with either the MTHFR 677CC, CT or TT genotype, including 63 patients in each group, were matched for age, gender, body mass index and creatinine clearance at baseline), were obtained between September 1996 and May 1997. Follow-up data (time until return to dialysis therapy, time and cause of death) were collected from April to June 1999. Kaplan-Meier survival estimations were calculated and plotted, the groups (three MTHFR 677C→T genotype groups, or three MTHFR 1298A→C genotype groups, or two groups with tHcy plasma levels above/below 15 μmol/L) were compared by log-rank test. Age, gender, body mass index (BMI), time since transplantation, serum creatinine, creatinine clearance, combined MTHFR 677C→T/1298A→C genotypes, tHcy, folate and vitamin B 12 plasma levels were evaluated with regard to graft and patient survival in a multivariate Cox-proportional hazard regression model. Results During the follow-up period of 2.26 ± 0.66 years, 9 patients died (5 in the TT, 2 in the CT and 2 in the CC genotype group; P = 0.34) and 22 returned to dialysis treatment (7 in the TT, 9 in the CT and 6 in the CC genotype group; P = 0.65). There was also no influnce of MTHFR 1298A→C genotypes (AA genotype, 114 patients; AC genotype, 64 patients; CC genotype, 11 patients) on patient or graft survival ( P = 0.7087 and P = 0.1633, respectively). Two of 93 patients with a tHcy plasma level ≤15 μmol/L died, in contrast to 7 of 96 patients in the low tHcy > 15 μmol/L group, P = 0.0778. Two patients in the low tHcy group had to return to dialysis, in contrast to 20 patients in the high tHcy group ( P = 0.0001). In the multivariate model there was no significant predictor of patient survival, and the serum creatinine was the only predictor of graft survival ( P Conclusions In summary, our study shows that neither MTHFR 677C→T/1298A→C genotypes nor hyperhomocysteinemia are independently associated with patient or graft survival following kidney transplantation.

Effect of MTHFR 677C>T on plasma total homocysteine levels in renal graft recipients.BackgroundHyperhomocysteinemia is an established, independent risk factor for vascular disease morbidity and mortality. The 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T has been shown to result in increased total homocysteine concentrations on the basis of low folate levels caused by a decreased enzyme activity. The effect of this polymorphism on total homocysteine and folate plasma levels in renal transplant patients is unknown.MethodsWe screened 636 kidney graft recipients for the presence of the MTHFR C677T gene polymorphism. The major determinants of total homocysteine and folate plasma concentrations of 63 patients, who were identified to be homozygous for this gene polymorphism compared with heterozygotes (N = 63), and patients with wild-type alleles (N = 63), who were matched for sex, age, glomerular filtration rate (GFR), and body mass index, were identified by analysis of covariance. The variables included sex, age, GFR, body mass index, time since transplantation, folate and vitamin B12 levels, the use of azathioprine, and the MTHFR genotype. To investigate the impact of the kidney donor MTHFR genotype on total homocysteine and folate plasma concentrations, a similar model was applied in 111 kidney graft recipients with stable graft function, in whom the kidney donor C677T MTHFR gene polymorphism was determined.ResultsThe allele frequency of the C677T polymorphism in the MTHFR gene was 0.313 in the whole study population [wild-type (CC), 301; heterozygous (CT), 272; and homozygous mutant (TT), 63 patients, respectively] and showed no difference in the patient subgroups with various renal diseases. The MTHFR C677T gene polymorphism significantly influenced total homocysteine and folate plasma concentrations in renal transplant recipients (P = 0.0009 and P = 0.0002, respectively). Furthermore, a significant influence of the GFR (P = 0.0001), folate levels (P = 0.0001), age (P = 0.0001), body mass index (P = 0.0001), gender (P = 0.0005), and vitamin B12 levels (P = 0.004) on total homocysteine concentrations was observed. The donor MTHFR gene polymorphism had no influence on total homocysteine and folate levels. Geometric mean total homocysteine levels in patients homozygous for the mutant MTHFR allele were 18.6 μmol/liter compared with 14.6 μmol/liter and 14.9 μmol/liter in patients heterozygous for the MTHFR gene polymorphism and those with wild-type alleles (P < 0.05 for TT vs. CT and CC). Geometric mean folate levels were lower in CT and TT patients (11.2 and 10.2 nmol/liter) compared with CC patients (13.6 nmol/liter, P < 0.05 vs. CT and TT).ConclusionsThis study demonstrates that homozygosity for the C677T polymorphism in the MTHFR gene significantly increases total homocysteine concentrations and lowers folate levels in kidney graft recipients, even in patients with excellent renal function (GFR more than median). These findings have important implications for risk evaluation and vitamin intervention therapy in these patients who carry an increased risk for the development of cardiovascular disease.

Endothelial cell adhesion molecule and PMNL response to inflammatory stimuli and AGE-modified fibronectin. Background Atherosclerotic vascular disease is the leading cause of death in patients with diabetes mellitus and end-stage renal disease. Advanced glycation end products (AGEs) are strongly suggested to be involved in the pathogenesis of atherosclerosis in these patients who also frequently experience infectious complications. We hypothesized that the interaction of AGEs and inflammatory mediators contributes to the up-regulation of endothelial cell activation. Methods We investigated the effect of advanced glycated fibronectin in the presence or absence of inflammatory stimuli on the endothelial cell surface and mRNA expression of cell adhesion molecules. Furthermore, the influence of advanced glycated fibronectin on the transendothelial migration pattern of polymorphonuclear cells was analyzed. Results Exposure to advanced glycated fibronectin together with inflammatory stimuli such as interleukin (IL)-1α, tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS) led to a significant increase in the surface expression of the cell adhesion molecules E-selectin, ICAM-1, VCAM-1 and PECAM-1 on endothelial cells. Soluble AGEs in combination with advanced glycated fibronectin significantly enhanced the endothelial cell surface expression of ICAM-1, VCAM-1 and PECAM-1, whereas this was not the case for E-selectin. At the transcriptional level short-time exposure of endothelial cells to advanced glycated fibronectin and inflammatory mediators resulted in an increased expression of E-selectin, ICAM-1 and VCAM-1 mRNA levels, whereas PECAM-1 repeatedly showed a significant decrease of gene transcript levels. An increase of mRNA levels was also observed for E-selectin, ICAM-1, VCAM-1 and PECAM-1 following incubation with a combination of advanced glycated fibronectin and soluble advanced glycation end-products. Furthermore, polymorphonuclear cells responded with a sevenfold increase in transendothelial migration following exposure of endothelial cells to advanced glycated fibronectin and inflammatory mediators. Conclusions These results suggest that the combination of matrix glycation and inflammation up-regulates the activation of the endothelial cell adhesion cascade, a mechanism that might contribute to the increased burden of atherosclerotic morbidity and mortality in patients suffering from diabetes mellitus or chronic renal failure.

The expression of the natural killer (NK) cell marker CD56 has been reported to occur in NK cell lymphomas/leukemias and a small group of peripheral T-cell lymphomas but has not been studied extensively in primary intestinal non-B-cell lymphomas. Normal human jejunal intraepithelial lymphocytes (IELs) are mainly T-cell receptor (TCR)-αβ + CD3 + CD8 + CD5 low and include an ∼15% fraction of CD56 + cells that could be the cells of origin for CD56 + intestinal T-cell lymphoma (ITL). To test this hypothesis, 70 cases diagnosed as ITL were immunophenotyped, and 15 CD56 + cases (21%) were identified. The majority of the CD56 + lymphomas was of monomorphic small to medium-sized histology, shared the common phenotype βF1 ± CD3e/cyt + CD8 + CD4 − CD5 − CD57 − TIA-1 + and had clonally rearranged TCR γ-chain genes. In contrast, the CD56 − lymphomas were mainly composed of pleomorphic medium and large cells or had a morphology most consistent with anaplastic large-cell lymphoma and were mostly CD8 − . These findings suggest that the majority of CD56 + intestinal lymphomas are morphologically and phenotypically distinct T-cell lymphomas most likely derived from activated cytotoxic CD56 + CD8 + IELs. Some overlapping histological and clinical features between CD56 + and CD56 − ITLs indicate that the former belong to the clinicopathological entity of ITL. The consistent expression of cytotoxic-granule-associated proteins introduces ITL (both CD56 + and CD56 − ) into the growing family of usually aggressive extranodal lymphomas of cytotoxic T-cell and NK-cell derivation. In contrast to putative NK-cell lymphoma of the sinonasal region, intestinal NK-cell lymphoma seems to be very rare.

Major determinants of hyperhomocysteinemia in peritoneal dialysis patients. The mechanisms leading to elevated total homocysteine concentrations in peritoneal dialysis patients are only partially understood. We show that a common polymorphism in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene (C677T transition) results in increased total homocysteine levels in peritoneal dialysis patients compared to age- and sex-matched healthy individuals. The allelic frequency of the C677T transition in the MTHFR gene in peritoneal dialysis patients (0.29) was comparable to the frequency in healthy individuals (0.34). Separate comparison of the total homocysteine plasma levels between non-carriers of the MTHFR polymorphism (C/C), heterozygous (C/T) and homozygous (T/T) subjects was performed by analysis of covariance in the patient and the control group. In the patient group the mean total homocysteine level was 61.7 ± 40.1 μmol/liter in individuals with the (T/T) genotype, which was significantly higher than the total homocysteine concentration of 23.1 ± 15.8 μmol/liter in (C/T) patients and 22.2 ± 11.1 μmol/liter for non-carriers ( P = 0.0001). Vitamin B 12 ( P = 0.0001), folate ( P = 0.0005), serum creatinine ( P = 0.016), albumin ( P = 0.0157) and dialysis center ( P = 0.0173) significantly influenced total homocysteine plasma levels in peritoneal dialysis patients, whereas this was not the case for age, gender, weekly Kt/V, weekly creatinine clearance, residual renal function, duration of dialysis, mode of peritoneal dialysis and vitamin intake. Folate levels in peritoneal dialysis patients were significantly affected by the MTHFR genotype ( P = 0.016). Elevated total homocysteine levels in diabetic patients with cardiovascular disease were associated with increased cardiovascular morbidity. In summary, the present study provides evidence that homozygosity for the C677T transition in the MTHFR gene, low vitamin B 12 and low folate levels result in elevated total homocysteine levels in peritoneal dialysis patients.

For a long time the biology of mast cells has remained an enigma. During the past few decades, molecular research has filled many of the gaps in our understanding of this multifunctional cell type. Several concepts are now established about the origin and development of mast cells. However, the mechanisms leading to autonomous proliferation of mast cells in patients with indolent or aggressive mastocytosis still require further investigation. This article focuses on the recent advances in the field of mast cell development and abnormal mast cell proliferation, and reviews data from the most significant mouse models, which have provided the basis for many of these new insights.

Entamoeba histolytica has an unusual nuclear structure characterized by a low degree of chromatin condensation and the absence of stainable metaphase chromosomes. Although nucleosome-like particles were observed, no information about histones was available so far. In this paper we describe a cDNA clone with significant homology to H3 histones that was isolated from a library of pathogenic E. histolytica. The complete cDNA encodes a 15-kDa polypeptide, which like the histone sequence from Volvox carteri is shorter by one residue than the human homologue. The amino acid sequence has only 69% identity with human H3.3 histone and 67% identity with the human H3.1 histone. This is the highest degree of sequence divergence observed for any eukaryote H3 histone sequence. Our results indicate that this divergence may contribute to the unusual chromatin structure of E. histolytica.

TO THE EDITOR: Keay et al.1 recently reported detection of bacterial 16s rRNA in about 60% of needle biopsy samples obtained from patients with localized adenocarcinoma of the prostate using a two-step polymerase chain reaction (PCR) protocol.2,3 Application of the same PCR protocol allowed detection of bacterial DNA in 77% of transperineal prostate biopsies of patients with chronic prostatitis.4 The authors therefore conclude that the presence of bacterial 16s rRNA in prostate tissue is not specific for chronic prostatitis and localized prostate cancer. PCR analysis is a very sensitive method that allows for the detection of a single DNA target in a sample. In the past, the extremely high sensitive two-step PCR has been introduced into routine molecular diagnostics for therapeutic monitoring of patients with minimal residual leukemia.5 In contrast, two-step PCR protocols are usually not applied in microbiologic diagnostics because of the questionable clinical relevance of a positive result that may have arisen from as few as a single bacterial DNA molecule. Because of the exquisite sensitivity of PCR, precautions have to be taken to ensure that positivity indeed indicates the presence of bacterial DNA in the tissue sample and that the positive signal does not result from exogenous sources.6 Moreover, to avoid false negativity, a DNA control has to be amplified to exclude the possibility that a negative result is due to the lack of DNA in the samples (ie, failure of the DNA isolation procedure) or the presence of PCR inhibitors. Among the studies that have used the two-step PCR protocol published by Domingue et al.2 and Keay et al.,3 controversial detection rates have been reported with respect to bacterial DNA detected in samples of patients with interstitial cystitis and in those of healthy controls.2,3 Beside the possibility of false positivity resulting from exogenous contamination of the specimens during manipulation of the cystoscope,3 these differences may also be due to false negativity of PCR because neither of the investigators included a DNA control in the PCR protocol to confirm the presence of amplifiable DNA in the samples. Because one-step PCR protocols represent a useful tool to investigate the prevalence of bacteria that fail to grow in culture, we highly recommend inclusion of a DNA control (ie, amplification of the human beta-globin gene)7 in all PCR protocols to avoid false negativity of PCR in tissue biopsy samples.