Detection of t(4;14)(p16.3;q32) chromosomal translocation in multiple myeloma by reverse transcription-polymerase chain reaction analysis of IGH-MMSET fusion transcripts.

We and others have recently identified a novel recurring t(4;14)(p16.3; q32) translocation in multiple myeloma (MM) that leads to an apparent deregulation of the FGFR3 and WHSC1/MMSET genes. Because the presence of IGH-MMSET hybrid transcripts has been found in MM cell lines with t(4;14), they may represent a specific tumor-associated marker in MM. In this study, we developed a reverse transcription-PCR (RTPCR) assay for detecting chimeric transcripts from all of the 4p16.3 breakpoints identified thus far, and we used it to investigate a representative panel of 53 MM patients and 16 patients with monoclonal gammopathy of uncertain significance; in addition, t(4;14) was investigated in all of the MM patients by means of two-color fluorescence in situ hybridization. IGH-MMSET transcripts were found in 11 of the 53 (20%) MM cases and 1 of 16 (6%) cases of monoclonal gammopathy of uncertain significance. There was complete concordance between the RT-PCR and fluorescence in situ hybridization analyses of the MM cases. The results of this study indicate that RT-PCR is a sensitive and reliable method of detecting t(4;14) and suggest that it may be useful for monitoring the disease in a significant proportion of patients.

Identification of a tumor-associated mutant form of the NF-kappaB RelA gene with reduced DNA-binding and transactivating activities.

Alterations of NF-kappaB family members have been found to be associated with various forms of lymphoid malignancies. In order to determine whether alterations of the RelA gene are involved in lymphomagenesis, we analysed a large and representative panel (200 cases) of such tumors. Southern blot analysis did not reveal any rearrangements or locus amplification, suggesting that structural alterations of the RelA gene may represent rare events in lymphoid neoplasia. By means of PCR-SSCP analysis, we were able to identify a single point mutation leading to amino acid substitution (codon 494, Glu-Asp) in the transactivating (TA) domain in one case of multiple myeloma. The mutated allele was expressed in the pathological bone marrow sample but not in the peripheral blood cells of the patient. We demonstrate that the RelA protein carrying this specific mutation (called RelA494D) has less transactivating ability than the normal RelA protein. Interestingly, the mutated protein has a lower affinity for kappaB binding sites both as a homodimer or in association with the NFKB1/p50 subunit. Transfection experiments using a Gal4-RelA494D fusion protein indicated that the mutation does not alter the intrinsic transactivating ability of the TA domain of RelA. Furthermore, in vitro translated RelA494D is able to dimerize efficiently with other NF-kappaB members, such as p50, cREL and Ikappa Balpha. Our data therefore suggest that this mutation may alter the specific structural conformation needed for the DNA interaction of RelA, and provide insights into the amino acid sequences involved in mediating the biological activities of RelA.

Structural alterations of the NF-kappa B transcription factor lyt-10 in lymphoid malignancies.

We have previously reported the identification of a novel putative proto-oncogene involved in the breakpoint of a t(10;14)(q24;q32) chromosomal translocation in a case of B-cell lymphoma. This gene, called lyt-10 (NFKB2/p52), is a member of the NF-kappa B family of transcription factors and displays a high degree of homology with the NFKB1/p50. Here we describe the genomic organization of the lyt-10 gene based on the restriction analysis of genomic phage clones and the sequence determination of exon-intron boundaries. The lyt-10 gene spans a genomic region of about 8 kb on 10q24, and contains 24 exons, ranging in size between 41 and 258 base pairs. To improve the understanding of the role of lyt-10 in lymphomagenesis, we performed Southern blot analysis to detect alterations of the lyt-10 gene in a large panel of cases representative of different types of lymphoid malignancies. We found rearrangements in 5 of 228 (approximately 2%) cases analysed: two cases of B-cell lymphoma, one case of multiple myeloma and two cases of T-cell lymphoma. The use of various probes specific for different regions of the lyt-10 locus revealed that rearrangements in positive cases lead to the partial or total deletion of the carboxy-terminal region containing the ankyrin domain. Taken together, our results indicate that lyt-10 gene rearrangements represent a recurrent lesion that may be involved in the pathogenesis of both B- and T-cell malignancies, and suggest that truncation of the ankyrin domain may be a common mechanism of lesion leading to abnormal lyt-10 activation in lymphoid neoplasia.

Constitutive expression of lymphoma-associated NFKB-2/Lyt-10 proteins is tumorigenic in murine fibroblasts.

The NFKB-2 (Lyt-10) gene codes for an NF-kappaB-related transcription factor containing rel-polyG-ankyrin domains. Rearrangements of the NFKB-2 locus leading to the production of 3' truncated NFKB-2 proteins are recurrently found in lymphoid neoplasms, particularly cutaneous lymphomas. Such mutant NFKB-2 proteins have lost the ability to repress transcription that is typical of NFKB-2 subunit p52, and function as constitutive transcriptional activators. To verify whether the expression of abnormal NFKB-2 proteins can lead to malignant transformations in mammalian cells, we transfected human lymphoblastoid cell lines and murine fibroblasts (Balb/3T3) with expression vectors carrying the cDNAs coding for normal NFKB-2p52, Lyt-10C alpha or LB40 proteins, which are representative of the abnormal types found in lymphoma cases. The expression of both normal and mutant NFKB-2 proteins has a lethal effect on lymphoblastoid cells and a cytotoxic effect was also observed in murine fibroblasts. The fibroblast cell lines expressing Lyt-10C alpha or LB40, but not those expressing normal NFKB-2p52, were capable of forming colonies in soft agar. The analysis of individual clones revealed that cloning efficiency correlated with the expression levels of the abnormal proteins. Injection of the Lyt-10C alpha-transfected Balb cells in SCID mice led to tumor formation in all of the animals, whereas no tumors were observed in the mice injected with control or NFKB-2p52-transfected cells, thus indicating that abnormal NFKB-2 protein expression is tumorigenic in vivo. Our results show that mutant NFKB-2 proteins can lead to the transformed phenotype, and support the hypothesis that alterations in NFKB-2 genes may play a role in lymphomagenesis.

Recombinant gamma-interferon as first line therapy for high risk myelodysplastic syndromes. Italian MDS Study Group.

Thirty patients affected by previously untreated high risk myelodysplastic syndromes (MDS) were treated with human recombinant gamma-interferon (r-IFN-gamma): 15 of them with a higher dose (HD) of 0.1 mg/sqm, three times a week and 15 with a lower dose (LD) of 0.01 mg/sqm, three times a week, both doses administered subcutaneously (s.c.). The therapy was fairly well tolerated and few major toxic events were documented. Sustained improvement of one or more clinico-hematologic parameters was observed in 43.3% of the patients (26.6% and 60.0% for the lower and higher dose, respectively). Median survival time from the start of IFN-gamma therapy was 15+ months (range: 1-26) for patients with refractory anemia with excess of blasts (RAEB) versus 5 months (range 2-12) for patients with RAEB in transformation (RAEB-t); 15+ months (range 1-26) for HD patients versus 8 months (range 2-23) for patients treated with LD regimen; 16+ months (range 9-26) for responders versus 7 months (range 1-22) for nonresponders. All these three variables (diagnosis, treatment, and response to treatment) turned out to be statistically significant (p = at least less than 0.01) at Cox's analysis.

In vitro effects of IL-2 on NK-activity, clonogenic potential, blast cell proliferation and cytokine release of MDS bone marrow patients.

To evaluate the clinical usefulness of IL-2 in myelodysplastic syndromes (MDS) the in vitro effects of interleukin-2 (IL-2) on blast cell proliferation, clonogenic activity, cytokine release and cell mediated cytotoxicity were examined in 49 MDS patients. Morphological analyses of bone marrow (BM) cytospin preparations showed a significant decrease in the number of blast cells in MDS after incubation with IL-2. Incubation of bone marrow mononuclear cells (BMMNCs) with IL-2 induced a significant increase in the number of CFU-GM in comparison with untreated controls. gamma-IFN and GM-CSF, but not alpha-TNF were found to be released in significant amounts by the BMMNCs cultured with IL-2. No significant differences in the surface phenotypes of fresh lymphocytes were observed between the normal and MDS subjects. After incubation with IL-2, we observed a significant increase in the number of CD3-/CD56+ cells in both normal and MDS subjects. Peripheral blood (PB) and BM NK activity against K562 was significantly greater in MDS after stimulation with IL-2. These data suggest the clinical usefulness of IL-2 in a large subgroup of patients as it may reduce the percentage of blasts and increase clonogenic capacity and cell-mediated cytotoxicity.

Diagnostic role and prognostic significance of a simplified immunophenotypic classification of mature B cell chronic lymphoid leukemias.

We verified the diagnostic and prognostic role of a simplified immunophenotypic classification (IC) in a series of 258 patients (M/F: 1.4; median age: 64 years; median follow-up: 64 months; 75 deaths) with mature B cell lymphoid leukemias (MBC-LL) for whom no histopathological diagnosis was available because of minimal or no lymph node involvement. The IC was based on the reactivity of three pivotal immunophenotypic markers: CD5, CD23 and SIg intensity. On the basis of different expression patterns, we identified four diagnostic clusters (C) characterized by distinct clinico-biological features and different prognoses: C1 (149 patients) identified most classical B cell chronic lymphocytic leukemias (CLL-type cluster; SIg(dim)/CD5+/CD23+); C2, 38 patients whose clinico-hematological characteristics were intermediate between C1 and C3 (CLL-variant cluster; SIg(bright)/CD5+/CD23+/-or SIg(dim)/CD5-/-/CD23 indifferent); C3 (16 patients) most situations consistent with mantle cell lymphoma in leukemic phase (MCL-type cluster; SIg(bright)/CD5+/CD23-); and C4, 55 cases, most of whom were consistent with leukemic phase lymphoplasmacytic/splenic marginal zone lymphomas (LP/S-type cluster; SIg(bright)/CD5-/+/CD23 indifferent). At univariate survival analysis, prognosis worsened from C1 to C4, C2 and C3 (P = 0.0001), and this was maintained at multivariate analysis (P = 0.006), together with CD11c expression (P = 0.0043), age at diagnosis (cut-off 70 years; P = 0.0008) and platelet count (cut-off 140 x 10(9)/l; P = 0.0034). Besides recognising the two well-known situations of classic B-CLL and MCL, our IC identified situations with distinct prognostic and/or clinical behaviors.

BCL10 gene mutations rarely occur in lymphoid malignancies.

BCL10, a gene involved in apoptosis signalling, has recently been identified through the cloning of chromosomal breakpoints in extranodal (MALT-type) marginal zone lymphomas carrying the t(1;14)(p22;q32) translocation. BCL10 was also found mutated in these cases as well as in other types of lymphoid and solid tumors, suggesting that its inactivation may play an important pathogenetic role; however, this has been questioned by recent studies showing a lack of somatic mutations in human cancers. We report the mutation analysis of exons 1-3 of the BCL10 gene in DNAs from 228 cases of lymphoid malignancies (30 B cell chronic lymphocytic leukemias, 123 B and 45 T non-Hodgkin's lymphomas and 30 multiple myelomas). Somatic mutations were detected in four cases (approximately 2%): one small lymphocytic, one follicular and two diffuse large cell lymphomas. The mutations were all within exon 3 and have not been previously reported. Our data suggest that BCL10 mutations may play only a limited role in the pathogenesis of lymphoid neoplasms.

In vitro effects of IL-12 and IL-2 on NK cells, cytokine release and clonogenic activity in myelodysplastic syndromes (MDS).

We evaluated the in vitro effects of IL-12, alone and in association with IL-2 on MDS bone marrow and peripheral blood cells. Thirty-six patients and 14 healthy subjects were studied. Natural killer-activity (NK-a) levels and lymphocyte immunophenotypes were determined in fresh bone marrow (BMMNC) and peripheral blood mononuclear cells (PBMNC), which then were resuspended in medium containing IL-2, IL-12 or IL-2 + IL-12 for 7 days. Re-evaluation of NK-a levels, lymphocyte immunophenotypes, clonogenic activity and cytokine release showed that, unlike IL-2, IL-12 did not significantly increase NK-a or CD3-/56+ cell levels in either bone marrow or peripheral blood; IL-2 + 12 led to a significant increase that fell between the values reached by each cytokine alone. IL-2 + 12 and, although to a lesser extent, also IL-12 alone induced the release of large amounts of gamma-IFN and alpha-TNF. In addition, the number of clusters particularly decreased in the samples treated with IL-2 + 12 and IL-12 alone. Clonogenic activity was not modified after stimulation with any of the treatment. These data suggest that IL-12 induces the release of inhibitory cytokines in normal as well as MDS cells and that it could be used in patients with elevated bone marrow blastosis.

All-trans retinoic acid (ATRA) in patients with chronic myeloid leukemia in the chronic phase.

Since in vitro observations indicated that all-trans retinoic acid (ATRA), especially in combination with IFNalpha, can exert significant suppressive effects on Ph+ cells, we investigated the effects and the pharmacokinetic profile of ATRA in a selected cohort of patients with Ph+ chronic myeloid leukemia (CML) in chronic phase. Eighteen patients were treated with ATRA at a dose of 80 mg/m2/day (p.o.), divided into two equal doses after meals, for 7 consecutive days every other week for a maximum of 12 courses (1 course = 1 week on and 1 week off). Pharmacokinetic profiles of ATRA were evaluated during intermittent therapy on days 1 and 7 of course 1; on day 1 of course 2; on day 1 of course 6. Out of the 18 patients treated with ATRA, 11 (61%) went off study before the sixth course of treatment because of progressive hyperleukocytosis (seven cases), or thrombocytosis (one case), or refusal (three cases). Seven (39%) patients completed the first six courses (12 weeks) of treatment with ATRA and two of them (11%) maintained a white blood cell (WBC) <10 x 10[9]/l which was induced by the pretreatment with hydroxyurea. One patient completed the 12th course of ATRA maintaining WBC <10 x 10(9)/l, platelets <500 x 10(9)/l and spleen not palpable. The treatment with ATRA was well tolerated and only one patient discontinued the therapy because of non-hematological side-effects. The area under the concentration-time curve (AUC) decreased significantly (P< 0.001) during the first week of therapy. By adopting an intermittent dosing regimen, 1 week on/ 1 week off (1 course), at the start of courses 2 and 6, we obtained the ATRA AUCs equivalent to the ones achieved on day 1 of course 1. In conclusion, our results showed that ATRA alone appeared to be unable to control the WBC expansion in the CML patients in chronic phase. Moreover, it did not induce any remarkable cytoreductive effects on the platelet count and on the hemoglobin level. The major interest of ATRA would be in combination with other therapies. If ATRA was given in combination with IFNalpha or other agents, dose reduction of these would not be planned. On the basis of the pharmacokinetic profile, ATRA should be administered intermittently rather than continuously.

Efficacy of N-acetylcysteine and all-trans retinoic acid in restoring in vitro effective hemopoiesis in myelodysplastic syndromes.

We evaluated the in vitro effect on clonogenic potential (CFU-GM) and apoptosis in myelodysplastic syndromes (MDS) progenitors of an anti-oxidant (N-acetylcysteine, NAC) and/or a differentiating (all-trans retinoic acid, ATRA) agent. NAC significantly reduced apoptosis, both NAC and ATRA induced an increase in CFU-GM, but NAC seemed to be particularly effective in the high risk (HR) MDS. NAC + ATRA conferred a significant advantage in terms of CFU-GM with respect to NAC and ATRA alone. Tumor Necrosis Factor-alpha (TNF-alpha) levels decreased after incubation with NAC in the MDS samples. This study shows that ineffective hemopoiesis in MDS could benefit from both NAC and ATRA, suggesting that anti-oxidant treatment may play a role in guaranteeing MDS cell survival, predisposing them towards differentiation.

Low plasma stem cell factor levels correlate with in vitro leukemic growth in myelodysplastic syndromes.

We evaluated the effect of SCF on myeloid differentiation by correlating clonogenic potential (as CFU-GM), bone marrow (BM) plasma SCF levels and CD34/c-kit expression in 57 MDS samples. There was a significant correlation between low SCF levels and 'leukemic' in vitro growth, the number of clusters and the colony/cluster ratio. No correlation was found between BM plasma SCF levels, the pattern of growth and CD34+ c-kit+ expression. These data seem to exclude any direct effect of SCF on leukemogenesis, but suggest that low plasma SCF levels may be at least partially responsible for leukemic growth in MDS.

Induction of follicle maturation and ovulation by gonadotropin administration in women with beta-thalassemia.

The objective of this paper was to assess the ability of gonadotropin administration to induce ovarian steroidogenesis, follicle maturation and ovulation in hypogonadal women affected by beta-thalassemia. Thirteen hypogonadal thalassemic women underwent a test with gonadotropin-releasing hormone (GnRH), with estimation of serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. They were then administered human menopausal gonadotropin (hMG) for a period ranging from 11 to 15 days with a total dose variable from 3,300 to 4,200 IU. In each patient, the initial dosage of 300 IU daily, adopted for the first 9 days, was modified subsequently according to the ovarian morphology, as shown by serial echographic examinations and by serum estradiol levels. In those patients in whom a dominant follicle was evidenced and the occurrence of pregnancy could be excluded, induction of ovulation was attempted by administration of 10,000 IU of human chorionic gonadotropin (hCG). All patients displayed a reduced LH and FSH rise in response to GnRH. Upon hMG administration, they exhibited echographic evidence of follicular growth with a clear-cut increase of serum estradiol, which peaked between the 9th and the 16th day from the start of treatment. In two out of three patients in whom a dominant follicle developed, ovulation was induced successfully by hCG injection, as shown by the increase of serum progesterone and by the ultrasonographic demonstration of a corpus luteum. This study has shown that, by proper pharmacological stimulation, the steroidogenic function of the gonads and even ovulation can be reinstated in hypogonadal thalassemic women.(ABSTRACT TRUNCATED AT 250 WORDS)

OPP-EBV-CAD regimen as salvage treatment in advanced refractory or resistant multiple myeloma.

With the aim of developing an effective therapy for heavily pretreated refractory MM outpatients, we evaluated the OPPEBVCAD regimen, a Hodgkin's disease-derived protocol that includes many drugs effective in MM administered in a sequential schedule. Twenty-two pts aged 42-72 years, with symptomatic highly-pretreated refractory (18 cases), or primary resistant MM (four cases. including two pts with plasma cell leukemia-PCL) received this therapy every 28 days (2-4 cycles, followed by a maintenance program). Therapeutic response (Chronic Leukemia-Myeloma Task Force criteria) and performance status (PS) and pain (W.H.O.) were evaluated. All of the pts were evaluable for response. There were 9 (40%) objective responses (OR: stabilization of blood counts and bone lesions, serum calcium normalization, 50% or more reduction in the concentration of serum monoclonal component (MC), 90% reduction in Bence-Jones proteinuria), 8 (36%) partial responses (PR: 25-50% reduction in serum MC), 1 no response or stable disease (NR), and 4 (18%) cases of progressive disease (PD). OR plus PR were 77%. Of the 4 primary resistant tumors (2 PCL and 2 MM), 2 achieved PR, 1 OR (a PCL case) and 1 progressed. Median survival was 15 months for responding pts (OR plus PR) and 4.5 months for non-responders (NR plus PD). PS and pain improved in 15 pts and did not change in 9. The most frequent side effects were cytopenias, with one drug related infective death. The OPPEBVCAD regimen proved to be an effective therapy for refractory relapsing or primary resistant MM: in responders (two-thirds of the pts), survival was prolonged by about 10 months. Its efficacy in anthracycline-treated pts, as well as the feasibility of using it on an outpatient basis without any continuous drug infusions, make this regimen a promising third line salvage therapy.

Frequency of RAS and p53 mutations in acute promyelocytic leukemias.

The frequency of RAS and p53 mutations was investigated in 30 acute promyelocytic leukemias by single strand conformation polymorphism analysis and direct sequencing of genomic DNA. Only two cases bore N-RAS codon 12 mutations and none had p53 mutations responsible for aminoacid substitutions. It would, therefore, seem that neither RAS nor p53 are involved in acute promyelocytic leukemogenesis.

Hyperhomocysteinemia in myelodysplastic syndromes: specific association with autoimmunity and cardiovascular disease.

Hyperhomocysteinemia (HH) has been associated with cardiovascular and autoimmune diseases and oxidative cell damage. Myelodysplastic syndromes (MDS) are associated with autoimmunity (AI) and increased oxidative stress. We tested the association of HH and oxidative stress in 33 MDS patients, by measuring plasma homocysteine and malondialdehyde (MDA). HH was found in 42% of cases, (4/5) cases with associated cardiovascular events (CVE)(80%), and 9/15 cases with associated AI (60%). Thus in MDS, HH was significantly associated with AI/CVE (chi(2) : p=0.0011), and this association seems to be specific, as demonstrated by the comparison of MDS presenting AI/CVE with the ischemic cardiopathy/rheumatoid arthritis control group (13/20, 65% vs 19/69, 27%; chi(2) : p=0.0021). The levels of MDA indicated increased oxidative stress. Our data may suggest that in a subset of MDS, HH may simultaneously contribute to bone marrow myelodysplasia, CVE and AI pathogenesis, possibly through oxidative cell damage.

Terminal deoxynucleotidyl transferase, TdT, as a marker for leukemia and lymphoma cells.

Terminal deoxynucleotidyl transferase, TdT, was assayed in the mononucleate cells of blood and bone marrow from 121 patients with leukemias at the onset of disease and from 95 subjects with malignant lymphomas at diagnosis. This intracellular marker was also investigated by cytoimmunofluorescent tests in 17 other cases of initial leukemias and in 3 diagnosed lymphoblastic lymphomas. Generally, the TdT levels were significantly enhanced in the blasts of the following: acute undifferentiated leukemias; the more immature types of acute lymphoblastic leukemias i.e., the null, non-T non-B, common, early T and pre-B subgroups; a fraction of blastic crises in chronic myelogenous leukemias; and many lymphoblastic lymphomas. TdT might also be slightly increased in the mononucleate blood cells obtained from the most immature forms of acute myelogenous leukemias. Relapses with changes in cell phenotypes were occasionally observed in previously TdT-positive leukemias as a result of clonal evolution of the disease. The leukemias with blasts containing high levels of TdT were usually responsive to treatment with corticosteroids and vincristine. TdT is an oligoclonal marker characterizing several populations of undifferentiated or poorly differentiated blasts that tend to develop towards or along the lymphoid pathway. Together with specific immunological markers, this enzyme is useful to define the particular type of leukemic cells. It also serves to identify the quasi-lymphoblastic nature of the malignant clone, a helpful indication for the choice of therapy.

Immunoreactive calcitonin: a tumor marker for myelogenous leukemias.

In a series of 59 patients with chronic or acute myelogenous leukemia (CML, AML) we investigated whether circulating immunoreactive human calcitonin (i-hCT) levels correlate with diagnosis, response to therapy and clinical course. I-hCT was detectable in plasma samples of 88% of patients with CML in the chronic phase and in 100% of patients with CML in blastic transformation. In the AML patients, a significant relation was observed between the cytological subtype and i-hCT levels at diagnosis. In sequentially studied patients the i-hCT plasma concentration was related to the overall mass of leukemic cells, being lower when complete remission was achieved than at diagnosis and increasing at time of recurrence. These data suggest that circulating i-hCT levels can serve as a "tumor marker" in human myelogenous leukemias.

Homocysteine, vitamin B12, serum and erythrocyte folate in peritoneal dialysis patients.

Plasma homocysteine (tHcy) is an important risk factor for atherosclerosis in dialysis patients. Few data were reported on the prevalence and severity of hyperhomocysteinemia in peritoneal dialysis (PD) patients. In addition, little attention was paid to the search of factors possibly involved in the pathogenesis of hyperhomocysteinemia in these patients. A cross-sectional study was performed in 107 stable PD patients. None of them was given folate or vitamin B12 supplementation before or during the study. Plasma tHcy, serum vitamin B12, serum and erythrocyte folate were measured by immunoenzymatic methods. Genetic analysis of the methylentetrahydrofolate-reductase thermolabile mutation (tMTHFR) was performed in 61 patients. 97% of patients had tHcy levels higher than normal. tHcy was not different between men and women, patients with or without malnutrition, with or without clinically evident atherosclerotic vasculopathy, with or without anemia. tHcy levels were significantly higher in homozygotes for the tMTHFR mutation than in patients carrying the wild type form. Significant univariate correlation was found between hyperhomocysteinemia and time since the start of dialysis, serum and erythrocyte folate and vitamin B12. The best fitted model equation was log tHcy = 108.53 + 0.1606 (duration of dialysis) -1.1053 (s-F) -0.7980 (age) 0.0215 (vitamin B12). Our results agree with those reported by other authors in hemodialysis patients. Despite the large number of PD patients with normal serum vitamin B12 and folate status, the relation between tHcy and vitamin B12 or folate suggests that the supplementation of these vitamins could be useful irrespective of their serum levels, especially in younger patients or in those treated for a long period of time with peritoneal dialysis.

Homocysteine, vitamin B12, and serum and erythrocyte folate in peritoneal dialysis and hemodialysis patients.

BACKGROUND: Plasma homocysteine (Hcy) is an independent risk factor for cardiovascular disease. High levels of plasma Hcy have been observed in end-stage renal disease patients. Few studies have compared peritoneal dialysis (PD) and hemodialysis (HD) patients and few data are available on erythrocyte folate (ery-F) levels in dialysis patients. OBJECTIVES: To evaluate plasma Hcy concentrations, vitamin B12 (B12), and folate status in dialysis patients; to analyze the possible causes of high Hcy levels; to follow up changes in folate and B12 concentrations after 6 months. DESIGN: A cross-sectional observational study. SETTING: Nephrology division and laboratory of hematology in a university and clinical research hospital. PATIENTS: The study included 82 patients treated with PD for 37 + 37 months and 70 patients treated with HD for 136 + 95 months. LABORATORY METHODS: Plasma Hcy was measured by the immunoenzymatic IMx Hcy FPIA method (Abbott Laboratories, Diagnostic Division, Abbott Park, IL, U.S.A.), serum folate (s-F) and ery-F by the Stratus folate fluorometric enzyme-linked assay, and B12 by the Stratus vitamin B12 fluorometric enzyme-linked assay (DADE-Behring, Newark, DE, U.S.A.). RESULTS: Ninety-six percent of PD and 97% of HD patients had Hcy levels above the cutoff (13.5 micromol/L). Homocysteine level was higher in HD than in PD patients, while the prevalence of hyperhomocysteinemia was similar with the two techniques. Erythrocyte folate was significantly higher in PD (1333 +/- 519 pmol/L) than in HD (1049 +/-511 pmol/L, p < 0.01). Statistically significant correlations were observed between Hcy and B12, s-F, ery-F, and dialysis duration. Multivariate analysis showed a strong correlation between s-F and Hcy. After 6 months there were no differences in Hcy, B12, s-F, and ery-F levels. CONCLUSIONS: Plasma Hcy levels were high in more than 95% of our dialysis patients, with no relation to the type of dialysis. Vitamin B12 and folate were normal in the majority of our patients. However, serum folate was the major determinant of Hcy levels. Such a relation between Hcy and folate suggests that levels of folate within the reference interval are inadequate for dialysis patients.