Retesting of bone donors 2 months after donation guarantees sufficient safety of bone allografts

Both allogeneic bone grafting and blood transfusion may transmit infections from the donor to the recipient. The most effective means to reduce the risk of infection is careful donor selection and screening of donors for markers of infection. The risk of blood transfusion-transmitted HIV infection in Finland, calculated with the incidence/window period model, is approximately 1:3,300,000. The calculated risk for hepatitis B (HBV) and C (HCV) is 1:217,000 and 1:147,000 donations, respectively. In bone banking we can further reduce the risks by retesting the living donors. Retesting 2 months after donation seems to be sufficient, at least in countries with a low incidence of transplantation-transmitted infections.

Evaluation of an ELISA test for determination of the serum transferrin receptor. Demonstration of discordance between results obtained with two methods

We undertook this study to evaluate a recently introduced ELISA kit for determining serum transferrin receptor (TfR) concentration (TfR, Ramco Laboratories, Inc.), to produce reference values for healthy adults, and to compare the results with another commercially available reagent system. The mean (SD) recovery of added TfR was 88% (6%). In dilution studies, the ratio between the measured and expected values was 0.98 (0.11). The intra-assay and interassay coefficients of variation were from 5% to 7% and from 6% to 9% in a physiological and a supraphysiological concentration range, respectively, and from 13% to 16% in a subnormal concentration range. In healthy adults between 20 and 60 years of age, we observed no age- or sex-related differences in TfR values. Thus, the same reference interval, 3.0-8.2 mg l(-1), may be used for this population. The correlation between the results obtained with the Ramco TfR test and the Amgen Diagnostics Clinigen test was satisfactory (r=0.79). The Ramco TfR test produced higher values (Tf=0.40 (-0.45-1.25)+1.46 (1.16-1.75)* Clinigen). The number of samples that fell within the same concentration interval with both methods (low, normal or high in relation to the respective reference interval) was only 45% (27/60). The Ramco TfR test had fewer values falsely suggesting iron deficiency than the Clinigen test. Serum TfR methods need to be uniformly standardized.

Multiple drug resistance mediated by P-glycoprotein is not a major factor in a slow response to therapy in childhood ALL

In childhood acute lymphoblastic leukemia (ALL), early response to treatment is an important prognostic factor and drug resistance is a major cause of poor outcome. One of the most investigated resistance mechanisms is P-glycoprotein (P-gp)-mediated multiple drug resistance (MDR). We analyzed P-gp using flow cytometry with monoclonal antibody JSB1 in a series of 118 children with ALL, 103 at diagnosis and 15 at relapse. Increased P-gp expression was found in 55 (53%) patients at diagnosis and in 11 (73%) at relapse. We also analyzed the bone marrow aspirate slides for early response to treatment in a central review. No correlation was found between P-gp and early response. Patients with T-ALL had higher P-gp levels than the others, 5.3% versus 1.0% (P = .002). We conclude that P-gp-mediated multiple drug resistance is not a factor in a slow response to ALL induction therapy.

Effects of dietary fat modification on fibrinogen, factor VII, and plasminogen activator inhibitor-1 activity in subjects with impaired glucose tolerance

Our aim was to assess the impact of a monounsaturated fat-enriched (Mono) diet and a diet recommended by the National Cholesterol Education Program (NCEP) on plasma levels of fibrinogen and activities of factor VII (FVII:C) and plasminogen activator inhibitor-1 (PAI-1) and the impact of genetic polymorphisms of these variables (HaeIII, MspI, and 4G/5G polymorphisms, respectively) in 28 subjects with impaired glucose tolerance ([IGT] 17 men and 11 women; mean age, 55.6 +/- 5.5 years). A diet rich in fat and saturated fatty acids served as a baseline diet for 3 weeks. Thereafter, subjects were randomized for the next 8 weeks to either the Mono diet (n = 12) or NCEP diet (n = 18). Fibrinogen levels or PAI-1 activities did not change with either of the diets, but fibrinogen levels were higher (3.4 +/- 0.5 v 4.0 +/- 0.6 g/L, P = .007 at baseline) throughout the study in heterozygous subjects with respect to HaeIII polymorphism. This polymorphism and age accounted for 38% of the variation of fibrinogen levels. MspI polymorphism together with body mass index explained 51% of the variation of FVII:C, which was higher in subjects with the M1M1 genotype compared with M1M2/M2M2 genotypes (127% +/- 21% v 90% +/- 12%, P < .001). FVII:C showed a decrease with the NCEP diet (P < .05), but the decline was confined to M1M1 subjects. PAI-1 activity did not differ significantly between the genotypes. The insulin sensitivity index (SI) obtained by the minimal model method was the main explanatory variable of PAI-1 activity. To conclude, despite good compliance, the fat-modified diet did not alter plasma levels of fibrinogen or PAI-1 in white subjects with IGT. FVII:C levels decreased with the NCEP diet, but this was confined to subjects with the M1M1 genotype.

Habitual diet, platelet function, fibrinogen and factor VII coagulant activity in young Finns

OBJECTIVES

The objective of the study was to determine whether an association between diet and platelet function, plasma fibrinogen level and factor VII coagulant activity (VII:C) could be established in young subjects.

DESIGN

Data on the habitual diet of the subjects were collected either by a questionnaire on food habits (n = 204) or by a 48-h dietary recall interview (n = 53).

SUBJECTS

The subjects were participants in the project 'Cardiovascular Risk in Young Finns' (age range 15-30 years). A total of 204 subjects having a questionnaire on food habits participated in the platelet function tests and 53 also participated in a 48-h dietary recall interview. Plasma fibrinogen concentration and factor VII: C were measured from 79 subjects.

MAIN OUTCOME MEASURES

Platelet function was tested by turbidometric measurement of platelet aggregation using ADP and collagen as aggregation agents.

RESULTS

Platelet aggregation with ADP (at up to 4.0 mumol L-1) and collagen (at up to 5.0 micrograms mL-1 platelet-rich plasma PRP) showed that the diet characterized as 'saturated', i.e. containing high-fat milk and saturated fat, was associated with platelets less sensitive to aggregating agents in vitro when compared to the unsaturated type of diet. Collagen- but not ADP-induced aggregation decreased with age of the subjects (P = 0.026-0.057, regression coefficient). An inverse regression coefficient between plasma factor VII:C (101%; range 64-145%) and serum triglycerides (P = 0.006) and the intake of rye (g 1000 kcal-1; P = 0.03) were found.

CONCLUSIONS

In this study we showed that platelet reactivity and factor VII:C already differ considerably between subjects at a young age, and diet may explain some of this variation.

Survey of major genotypes and subtypes of hepatitis C virus using RFLP of sequences amplified from the 5' non-coding region

A method is described for identifying different genotypes of hepatitis C virus (HCV) by restriction endonuclease cleavage of sequences amplified by PCR from the 5' non-coding region. Using the enzymes HaeIII-RsaI and HinfI-MvaI, followed by cleavage with BstU1 or ScrFI, it was possible to identify and distinguish HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5 and 6. The method was used to investigate the prevalence of these genotypes in 723 blood donors in 15 countries, the largest survey to date, and one which covered a wide range of geographical regions (Europe, America, Africa and Asia). These results, combined with a review of the existing literature, indicate the existence of several distinct regional patterns of HCV genotype distribution, and provide the framework for future detailed epidemiological investigations of HCV transmission.

Clinical significance of hepatitis C antibodies in blood donors

The clinical significance of hepatitis C antibodies (anti-HCV) in a healthy population was studied by liver function tests and liver biopsies. The patient population consisted of 195 (96.1%) of the 203 blood donors found to be either anti-HCV positive or indeterminate by a recombinant immunoblot assay (RIBA) during the first year of anti-HCV screening of 307,606 donors in Finland using a first generation enzyme-linked immunosorbent assay. Alanine aminotransferase (ALT) levels in 67 donors reacting positively and in 128 reacting indeterminately by a second generation RIBA (RIBA-4) were monitored to evaluate the prevalence of liver damage. Serum N-terminal type III procollagen (PIIINP) concentrations were measured in all donors who fulfilled our criterion for possible hepatitis C (ALT values over two times the normal upper limit on two occasions or over five times the normal upper limit on one occasion) and in 23 randomly selected RIBA-4 positive donors without ALT abnormalities (control group). Two (1.6%) of the RIBA-4 indeterminate donors had ALT values compatible with possible hepatitis C (negative by polymerase chain reaction) whereas there were 25 (37.3%) such individuals among the RIBA-4 positive donors (P < 0.0005). Twenty (80%) of the latter 25 RIBA-4 positive donors with possible hepatitis C consented to liver biopsy. Of these 20 donors, 11 (55.0%) were found to have chronic persistent hepatitis, four (20.0%) mild, three (15.0%) moderate, and two (10.0%) severe chronic active hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric analysis of glutathione-S-transferase-pi in acute leukemia

Increased expression of glutathione-S-transferase isoenzyme pi (GST-pi) may account for drug resistance and treatment failure in hematologic malignancies when alkylating agents like cyclophosphamide, chlorambucil, busulfan and melphalan, or doxorubicin are used. We have studied the expression of GST-pi in peripheral blood lymphocytes of healthy blood donors. In peripheral and bone marrow lymphocytes/blasts of patients with other diseases than hematologic malignancies, and of patients with acute leukemia by using flow cytometry. We studied bone marrow cells of 35 patients diagnosed as having acute leukemia at initial presentation, 16 patients in the refractory stage, 20 in morphological remission and 15 controls. None of the samples obtained in remission contained more GST-pi-positive cells than the controls, whereas 51% of the samples obtained at diagnosis and 56% of those obtained in the refractory stage were GST-pi-positive. The mean proportion of GST-pi-positive cells in the lymphocyte/blast cell gate of bone marrow cells of controls was 2.6% and of patients with acute leukemia studied at diagnosis 16.6%, respectively. We analyzed the samples also for P-glycoprotein expression. There was a significant positive association between GST-pi and P-glycoprotein expression in acute leukemia.

Geographical distribution of hepatitis C virus genotypes in blood donors: an international collaborative survey

The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of the type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.

Hepatitis C antibodies in dialysis patients and patients with leukaemia

The prevalence of hepatitis C antibodies (anti-HCV) among multitransfused patients was studied and compared with predicted values obtained from a post-transfusion hepatitis study and from data on the prevalence of anti-HCV among blood donors. The prevalence of hepatitis B core antibodies (anti-HBc) was also studied to determine the routes of transmission of hepatitis C virus. The patients consisted of 65 dialysis patients (57 on haemodialysis and 8 on continuous ambulatory peritoneal dialysis) and 71 leukaemia patients in long-term remission [49 with acute myeloid leukaemia (AML) and 22 with acute lymphatic leukaemia (ALL)]. The presence of anti-HCV was investigated using a second generation enzyme-linked immunosorbent assay. Reactive samples were confirmed by a second generation recombinant immunoblot assay. Anti-HBc was studied in the 65 dialysis patients and in 40 of the leukaemia patients. Three (4.6%) of the 65 dialysis patients and 12 (24.5%) of the 49 AML patients were anti-HCV positive whereas all of the ALL patients were seronegative. The total number of blood units transfused to 134 patients (data on two dialysis patients were not available) was 18,148, out of which 17,575 units had been transfused prior to the initiation of anti-HCV screening of blood donors. On the basis of the anti-HCV prevalence among blood donors and the incidence of post-transfusion hepatitis, the predicted number of seropositive patients was 11 and 18, respectively. Five of the 65 dialysis patients were anti-HBc positive, compared with only one of the 40 leukaemia patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of P-glycoprotein expression in acute leukaemia as analysed by immunocytochemistry

Multidrug resistance, mediated by the overexpression of an energy-dependent transport protein, P-glycoprotein, has been one of the major targets of interest in solving the mechanisms of clinical drug resistance of malignant cells. To evaluate the correlation between P-glycoprotein overexpression and the response to chemotherapy, we analysed cytospin preparations of gradient-separated blood or bone marrow mononuclear cells from 79 patients with acute leukaemia by means of the P-glycoprotein-directed monoclonal antibody JSB-1 and immunocytochemistry using the alkaline phosphatase-antialkaline phosphatase technique. P-glycoprotein expression was detected in all disease phases of acute leukaemia. Thirteen out of 51 patients at diagnosis, 10/29 patients in relapse or during residual disease and 8/27 patients in remission overexpressed P-glycoprotein. Seven out of the 8 positive remission samples were collected between the cycles of consolidation treatment. Our results suggest that increased P-glycoprotein expression in samples collected between the cycles of consolidation treatment during remission may be induced in normal leukocytes by cytotoxic drug treatment, infections, or by some physiological mechanisms related to the disease. Patients older than 45 years of age were significantly more often P-glycoprotein-positive (11/25) at diagnosis than younger patients (2/26). P-glycoprotein expression at diagnosis was significantly correlated with a low remission rate after the first cycle of induction therapy. Of 34 P-glycoprotein-negative patients, 25 achieved remission after the first cycle as compared to 4/12 of the P-glycoprotein-positive patients. Our results indicate that the method used is specific and sensitive enough for the analysis of P-glycoprotein expression and that the expression at initial presentation is inversely correlated with the outcome of induction therapy.

Flow cytometric analysis of terminal deoxynucleotidyl transferase. A simplified method

The authors evaluated a new cell membrane permeabilization method for the flow cytometric detection of terminal deoxynucleotidyl transferase (TdT). In this method, gradient-separated leukocytes or unseparated blood or bone marrow cells were incubated in a commercially available diethylene glycol-based red blood cell lysing solution, which not only lyses red blood cells, but also permeabilizes leukocyte cell membranes; the light scattering properties of the cells are retained. The validity of the current method was demonstrated by the good concordance of the findings with previously published data as follows: (1) practically identical results were obtained when an established method for cell permeabilization was used in parallel on the same samples; (2) the proportion of TdT-positive cells in normal peripheral blood was negligible; (3) the proportion of TdT-positive cells in normal bone marrow averaged 1%, and a significant portion of TdT-positive cells in normal bone marrow expressed CD10 and CD34; and (4) TdT-positive cell populations were seen with the expected frequencies in various types of leukemia. This method for TdT flow cytometry provides significant advantages over previously used methods and is especially suitable for TdT detection in routine laboratories.

Risk factors for hepatitis C virus antibody positivity in blood donors in a low-risk country

Demographic variables, sexual risk behavior and prevalence of parenteral risk factors were studied in 305 randomly selected donors seronegative for hepatitis C virus, in 170 randomly selected donors reactive on solely enzyme-linked immunosorbent assay (ELISA C-100), in 71 consecutive donors reacting indeterminately according to the second-generation recombinant immunoblot assay (RIBA II) and in 46 consecutive donors found to be positive using the RIBA II. Donors who were positive by RIBA II had significantly more often a risk factor, for example use of intravenous drugs or previous blood transfusion, than donors reacting indeterminately (34 out of 46) (73.9%) versus 14 out of 71 (19.7%, p = 0.0000). Donors reacting indeterminately by RIBA II had one of those risk factors significantly more often than seronegative donors (14 out of 71) (19.7%) versus 23 out of 280 (7.8%, p < 0.005). When donors either positive or indeterminate by RIBA II were compared with donors negative for hepatitis C antibodies, the odds ratio for a possible parenteral source of infection was 7.6 (p = 0.0000). Subjects who had received a poor education (odds ratio 0.3, p < 0.001) or who lived in southern Finland (odds ratio 2.3, p < 0.05) were also at higher risk for being positive or indeterminate in RIBA II. First-time donors were also prone to having antibodies according to RIBA II (odds ratio 2.2, p = 0.1), whereas sexual risk behavior, gender, age, occupational class and type of residential area were not risk factors for hepatitis C antibodies in RIBA.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric analysis of P-glycoprotein in normal and leukemic cells

Classical multidrug resistance is characterized by overexpression of a membrane protein, P-glycoprotein, which acts like a drug-extruding pump, reducing accumulation of cytotoxic drugs inside malignant cells. We have developed a simple method for detecting an intracellular epitope of P-glycoprotein in normal and leukemic cells by the monoclonal antibody JSB-1 and fluorescence-activated flow cytometry. Permeabilization of blood and bone marrow cells in unprocessed samples is achieved by a commercially available red blood cell lysing solution which excellently preserves the light scatter properties of leukocytes. The method is suitable for analyzing samples in clinical routine. Lower than 1% reactivity was seen in the lymphoid gate of normal peripheral blood and bone marrow samples as compared with over 60% of reacting cells in some leukemic samples. Twelve patients with acute de novo leukemia were studied at presentation, 13 patients at a refractory stage, and 28 in remission. There was a positive correlation between the P-glycoprotein and the CD34 expression in acute myelogenous leukemia and an association between the P-glycoprotein expression and the blast count in both acute myelogenous and lymphatic leukemias.

Transmission of HCV infection by RIBA indeterminate and positive blood units

A retrospective study was carried out on the recipients of 73 units of blood from 53 donors found reactive for anti-HCV. The donors were screened with anti-HCV enzyme-linked immunosorbent assay (ELISA C-100) and reactivity was confirmed with the first generation recombinant immunoblot assay (RIBA I). Fifty-two patients were recipients of blood from donors reacting as RIBA I 'indeterminate' and 21 of blood from RIBA I 'positive' donors. Only three recipients (5.8%) from 'indeterminate' donors were anti-HCV positive indicating that such donors are very seldom infectious. Eleven (52.4%) recipients from 'positive' donors had antibodies to HCV, indicating that not all RIBA-positive donors are necessarily infectious. Pretransfusion samples of the seropositive recipients were unavailable. All samples were analyzed with the first generation ELISA and with either the second-generation ELISA or RIBA (RIBA II) in order to evaluate test sensitivity. RIBA II was more sensitive than RIB I. One RIBA I indeterminate donor was positive by RIBA II. His recipient had antibodies to HCV. Twelve RIBA I indeterminate and three RIBA I positive donors were negative by RIBA II. All their recipients were anti-HCV negative. The second-generation ELISA was also shown to be more sensitive than ELISA C-100. The second-generation ELISA detected six confirmed anti-HCV positive recipients who were negative by ELISA C-100.

Expression of decorin in human tissues and cell lines and defined chromosomal assignment of the gene locus (DCN)

Earlier studies had shown that the expression of the gene coding for one eminent connective tissue proteoglycan, decorin (DCN), is deficient in the fibroblasts of 3 out of 15 Marfan patients (Pulkkinen et al., 1990). To obtain more information on the expression of this gene, various human tissues and cell lines were studied. High mRNA levels of decorin were detected in aorta, lung, skin, kidney, smooth muscle, and placenta, whereas significantly lower mRNA levels were found in the rest of the tissues analyzed. Two sizes of transcripts were observed in all tissues. The two transcripts of decorin most probably do not represent two different genes, since in situ hybridization gave only one strong signal, placing the gene in 12q21----q22. No tissue-specific differences in the two mRNA species of decorin were detected. This is in contrast to the gene of versican, another connective tissue proteoglycan gene, that was analyzed as a control; high expression of a longer transcript of the versican gene was found in brain and smooth muscle, whereas the shorter transcript was predominant in all other tissues studied. DCN was actively transcribed in cultured mesenchymal cells, whereas in cells of endothelial or epithelial origin, the transcription level was undetectable. These tissue- and cell type-specific variations in the expression of DCN may help to explain the complex phenotypic variation typical of individuals with Marfan syndrome.

Determination of anti-IgA antibodies with a flow cytometer-based microbead immunoassay (MIA)

A flow cytometer-based microbead immunoassay (MIA) was employed to detect anti-IgA antibodies in patients with IgA deficiency. 3 microns latex particles were coated with purified IgA and serum anti-IgA antibodies of the IgG class were detected with FITC-conjugated anti-human IgG. Antibodies against three different IgA preparations were tested from 22 patients samples as well as 20 controls and compared with a conventional enzyme-linked immunosorbent assay (ELISA) and a passive hemagglutination assay (HA). There was a very close correlation between the results obtained with the MIA and the ELISA assay and between MIA and the HA. Because of the low intra-assay variation and good linearity of the assay, the analysis of one single serum dilution was sufficient to determine the anti-IgA level of a patient and no titration series was required. We conclude that MIA is a satisfactory alternative method for routine anti-IgA antibody determinations. For laboratories already equipped with a flow cytometer the assay is cost effective.

Multidrug resistance

Resistance of malignant cells to cytotoxic agents is often a limiting factor to successful chemotherapy. The classical multidrug resistance is characterised by overexpression of a membrane protein, P-glycoprotein, which acts like a drug extruding pump reducing accumulation of cytotoxic agents inside malignant cells, thereby preventing their function. Resistance is expressed simultaneously towards several structurally unrelated drugs. P-glycoprotein is also expressed in many normal human tissues, e.g., in the gastrointestinal tract, and this may be the reason for intrinsic resistance observed clinically in cancers derived from certain tissues. More often multidrug resistance is acquired during chemotherapy. The physiological function of P-glycoprotein is still unknown but it may have a role in cellular detoxification and secreting mechanisms. Interest in the phenomenon of multidrug resistance centres on the correlation of P-glycoprotein expression to clinical drug resistance. Another goal is to find mechanisms by which the function of P-glycoprotein as a multidrug transporter is prevented and drug resistance reversed.