Elevated serum soluble CD44 level in sarcoidosis

Sarcoidosis is a chronic multi-organ granulomatous disease of unknown etiology. Several studies have suggested an involvement of immunologic background in sarcoidosis. The lymphocyte surface marker CD44 is a multifunctional molecule which mediates the adhesion of lymphocytes to the extracellular matrix. Recently, we developed a system to quantitate soluble CD44 (sCD44) which we employed to determine serum and bronchoalveolar lavage fluid (BALF) levels of sCD44 to obtain further insights into immunologic aspects of sarcoidosis. Serum sCD44 levels were measured in 13 consecutive patients with sarcoidosis and 56 normal healthy controls using enzyme-linked immunoabsorbent assay. BALF sCD44 levels were also measured in 11 patients with sarcoidosis and 10 normal healthy controls. In patients with sarcoidosis, the serum sCD44 level was significantly higher than that of normal controls (348.5+/-164.2 ng/ml vs 145.4+/-22.9 ng/ml; p<0.001). Also BALF sCD44 levels tended to be higher in sarcoidosis than in normal controls (23.7+/-13.4 ng/ml vs 18.1+/-8.4 ng/ml), but no statistically significant difference was recognized. We also found that there was a positive correlation between the serum sCD44 and angiotensin converting enzyme (r=0.78). Our data indicate that sCD44 may be related to immunologic background and may be a useful new marker of sarcoidosis.

Telomere dynamics and genetic instability in disease progression of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is characterized by a Philadelphia (Ph) translocation creating a novel BCR-ABL oncoprotein, and CML patients have a chronic phase for several years followed by an intractable blast cell proliferation, called blast transformation. In the blast phase, more than 60% of patients show additional cytogenetic changes, e. g., double Ph, +8, i(17q). In this review, we would like to address genetic changes, including genome instability, cytogenetic changes, and telomere dynamics that relate to karyotypic instability. In the chronic phase, approximately 60% of CML patients show reduced telomere length without highly elevated telomerase activity or microsatellite alterations, indicating that telomere reduction may be linked to cell replication. Therefore, the Ph translocation might be a first event to immortalize cell proliferation. In the blast phase, 50% of CML patients have high levels of elevated telomerase activity and the same number of patients had microsatellite changes. Of note is that most patients with telomerase up-regulation in the blast phase had additional cytogenetic changes and >60% of them showed microsatellite changes at least at one locus. In contrast, most patients without telomerase activity did not show microsatellite changes. These findings may indicate that telomerase up-regulation in the blast phase of CML patients is closely associated with microsatellite changes (representative of genome instability), while blast cells in the remaining patients (30%) maintain their proliferative capability without microsatellite changes and telomerase up-regulation. This further suggests that there is also an unknown mechanism for genome stability without the process of telomerase up-regulation in some patients with CML in blast crisis.

Use of real-time PCR to monitor human herpesvirus 6 reactivation after allogeneic bone marrow transplantation

Reactivation of human herpesvirus 6 (HHV-6) is common following allogeneic marrow transplantation, however, little is known about the immune control and pathogenic potential of HHV-6 infection after transplantation. In order to determine whether reactivation of HHV-6 plays an important role in the development of complications in patients undergoing allogeneic bone marrow transplantation or not, we developed a very rapid quantification of viral DNA using a LightCycler. The amount of viral DNA was determined using a supernatant of a chronically infected cell line [TaY(OK)] which contains a known amount of viral DNA. Peripheral blood cells were collected from 5 patients undergoing allogeneic bone marrow transplantation once before transplant and once per week after transplant for 8-24 weeks. The real-time PCR system revealed that there was a linear correlation in the range of 101 to 105 molecules of reference. Using this system, we have found the presence of non-diagnosed HHV-6 reactivation as well as symptomatic infection, indicating the potential for routine implementation of this technology for laboratory diagnosis of HHV-6 infection. Our study shows that this method of rapid quantification of HHV-6 genomes by the real-time PCR using a LightCycler may be useful not only to understand the reconstitution of the immune system following marrow transplantation but also to manage the care of patients.

Interleukin 6 receptor expression by human cord blood- or peripheral blood-derived primitive haematopoietic progenitors implies acquisition of different functional properties

The significance of interleukin 6 receptor (IL-6R) expression by cord blood (CB)- and peripheral blood (PB)-derived primitive haematopoietic progenitors was investigated. IL-6R was preferentially expressed by PB-derived myeloid progenitors. Most PB-derived erythroid bursts (BFU-E) and mixed colony-forming cells (CFU-Mix) did not express this receptor. However, CB-derived primitive progenitor cells possessed multipotentiality, irrespective of IL-6R expression. Interestingly, the long-term culture-initiating cell (LTC-IC) population was enriched in PB-derived CD34+ IL-6R+ cells, but the extended LTC-IC (ELTC-IC) population, which represents a less mature class of haematopoietic progenitors, seemed to be equally distributed in the IL-6R+ and IL-6R- cell populations. In contrast, the number of LTC-ICs and ELTC-ICs was similar in CB-derived CD34+ IL-6R+ or IL-6R- cells. It is noteworthy that the number of LTC-ICs and ELTC-ICs in CB-derived CD34+ cells was markedly higher than that in PB-derived CD34+ cells regardless of IL-6R expression. Telomerase activity was consistently lower in PB-derived CD34+ IL-6R- cells than in CD34+ IL-6R+ cells. In contrast, telomerase activity was similar in CB-derived CD34+ IL-6R+ or IL-6R- cells. The pattern of telomerase induction upon cytokine stimulation differed between CB- and PB-derived CD34+ IL-6R+ or IL-6R- cells. However, overall telomerase activity per dish was well correlated with the proliferative potential of both cell populations, suggesting that induction of telomerase plays an important role in the escape from replicative senescence of primitive haematopoietic progenitors. Collectively, these results suggest that CB-derived primitive progenitors are less mature than PB-derived progenitors and that the expression of IL-6R by primitive haematopoietic progenitors may have different implications for PB- and CB-derived CD34+ cells.

Quantification of human herpesvirus 6 in healthy volunteers and patients with lymphoproliferative disorders by PCR-ELISA

To determine whether actual numbers of human herpesvirus 6 (HHV-6) genome in hematologic neoplasias are associated with disease condition, we developed a quantitative PCR-ELISA for detection of HHV-6. The amount of viral DNA was determined using externally amplified known amounts of the plasmid DNA containing the viral target sequences. First, we determined a viral burden in peripheral blood leukocytes obtained from 23 healthy volunteers and four specimens of lymph nodes with reactive hyperplasia. Using 1 microg of DNA, the prevalence of HHV-6 was 43.4% (10/23), ranging from 0 to 100 HHV-6 genomes in blood obtained from healthy volunteers. The amounts of HHV-6 genomes were < 10 in four non-neoplastic lymph node specimens. We next examined the amount of viral DNA in 21 blood specimens and 19 lymph node specimens obtained from patients with lymphoproliferative diseases (LPD) at the time of diagnosis. The number of HHV-6 genomes in most of the B-cell lymphoma was < 5 in both blood and lymph node specimens, however, two lymph node specimens obtained from immunoblastic lymphadenopathy (IBL) and T-cell lymphoma had very high levels of HHV-6 viral DNA (3705 and 810, respectively). We also found that HHV-6 genomes in peripheral blood were more than 1000 in two patients with chronic lymphocytic leukemia. For all LPD patients combined, there were significantly higher levels of viral DNA (200.6 +/- 654.8 HHV-6 genomes per 1 microg purified DNA) compared to those in healthy volunteers (10.0 +/- 21.0 HHV-6 genomes per 1 microg purified DNA) (P < 0.05). This study demonstrates that a high level of HHV-6 viral DNA is occasionally associated with LPD patients. Although it is still uncertain whether HHV-6 is related to the pathogenesis in LPD or not, our results suggest that measurement of HHV-6 genomes using PCR-ELISA may be useful not only to understand the mechanism of HHV-6 infection in hemopoietic neoplasia but also to manage the care of immnocompromised patients such as bone marrow transplant patients.

Expression of telomerase subunits and localization of telomerase activation in hydatidiform mole

Activation of telomerase compensating for the loss of telomeres has been implicated in human cell immortalization and carcinogenesis. Telomeric repeat amplification protocol (TRAP) assay can be used to detect telomerase activity in a variety of malignant tumours, including those of the female reproductive tract which have been found to have high levels of telomerase activity. However, it is unclear whether all the cells or only a subset of cells within a tumour have telomerase activity. To determine the regulation mechanism of telomerase activity in hydatidiform moles, we studied telomerase activity at the single cell level (using an in situ TRAP assay), and expression of TLP1 (telomerase protein 1), TERC (telomerase RNA component) and TERT (telomerase reverse transcriptase component). Expression of TERC and TLP1 was observed in all normal chorionic villi, as well as in trophoblastic diseases, and various cell lines irrespective of telomerase activity. TERT expression was observed in trophoblastic diseases and normal chorionic villi with telomerase activity but not in normal chorionic villi without telomerase activity, except in some cases in the present series, indicating that TERT expression is closely associated with telomerase activity. Upregulation of TERT expression may thus play an important role in telomerase reactivation.

Telomere stability is frequently impaired in high-risk groups of patients with myelodysplastic syndromes

Genomic instability induces an accumulation of genetic changes and may play a role in the pathogenesis of myelodysplastic syndromes (MDS). To clarify the possible association between genomic instability and clinical outcome in MDS patients, we compared telomere dynamics to the recently established International Prognostic Scoring System (IPSS) risk groups for MDS. We measured the terminal restriction fragments (TRFs) of 93 patients with MDS at the time of diagnosis, and telomerase activity was analyzed in 62 patients with MDS using the PCR-based telomeric repeat amplification protocol (TRAP) assay. A total of 53 of 93 MDS patients had TRFs within the age-matched normal range, and the remaining patients showed shortened TRFs (35 patients) or elongated TRFs (5 patients). MDS patients with shortened TRFs had a significantly low hemoglobin concentration (P = 0.04), a high percentage of marrow blasts (P = 0.02), and a high incidence of cytogenetic abnormalities (P < 0.05). The incidence of leukemic transformation was significantly high in patients with shortened TRF length (P < 0.05). In addition, patients with shortened TRF length were frequently seen in the IPSS high-risk group (P < 0.01). Most of the MDS patients had normal-to-low levels of telomerase activity, suggesting that changes in TRF length rather than telomerase activity may more accurately reflect the pathophysiology of MDS. MDS patients with shortened TRF length had a very poor prognosis (P < 0.01), suggesting that telomere dynamics may be linked to clinical outcome in MDS patients. Thus, an abnormal mechanism of telomere maintenance in subgroups of MDS patients may be an early indication of genomic instability. This study demonstrates that telomere stability is frequently impaired in a high-risk group of MDS patients and suggests that, in combination with the IPSS classification system, measurement of TRFs may be useful in the future to stratify MDS patients according to risk and manage the care of MDS patients.

Improvement in detecting telomerase activity using silica-based resin treatment: An experience of urine in bladder carcinoma

To improve the telomeric repeat amplification protocol (TRAP) assay to detect telomerase activity using a small amount of sample, we used a resin-column to purify and to concentrate the TS extension DNA sequence. We used 14 samples of naturally voided urine (10 ml) from patients with bladder carcinoma and 9 urine samples from patients with non-malignant urological neoplasias. We used ethylenediamine tetraacetic acid (EDTA) to stabilize telomerase activity and resin treatment to concentrate TS-extended DNA and to exclude PCR inhibitor(s), and then performed extract-based fluorescence TRAP to detect telomerase activity. None of the urinary samples without resin-column treatment had detectable telomerase activity, whereas, in resin-column treated samples, 4/9 (44%) urine samples without EDTA and 9/14 (64%) with EDTA treatment had detectable telomerase activity. A combination of EDTA treatment and resin-column thus may be available to detect telomerase activity using a relatively small amount of secretion fluids, including exfoliated urinary cells.

The Wilms' tumor gene WT1 is a good marker for diagnosis of disease progression of myelodysplastic syndromes

The Wilms' tumor gene, WT1, is a tumor marker for leukemic blast cells. The WT1 expression levels were examined for 57 patients with myelodysplastic syndromes (MDS) (refractory anemia (RA), 35; RA with excess of blasts (RAEB) 14; RAEB in transformation (RAEB-t), six; and MDS with fibrosis, two) and 12 patients with acute myeloid leukemia (AML) evolved from MDS. These levels significantly increased in proportion to the disease progression of MDS from RA to overt AML via RAEB and RAEB-t in both bone marrow (BM) and peripheral blood (PB). WT1 expression levels in PB significantly correlated with the evolution of RAEB or RAEB-t to overt AML within 6 months. Therefore, WT1 expression levels in PB were superior to those in BM for early prediction of the evolution to AML by means of quantitation of the WT1 expression levels. Furthermore, WT1 expression in PB of patients with overt AML evolved from MDS was significantly decreased by effective chemotherapy or allogeneic stem cell transplantation and became undetectable in long-term survivors. These results clearly showed that WT1 expression levels are a tumor marker for preleukemic or leukemic blast cells of MDS and thus reflect the disease progression of MDS. Therefore, monitoring of WT1 expression levels has made continuous assessment of the disease progression of MDS possible, as well as the prediction of the evolution of RAEB or RAEB-t to overt AML within 6 months. The results also showed that quantitation of WT1 expression levels is useful for diagnosis of minimal residual disease of MDS with high sensitivity, thus making it possible to evaluate the efficacy of treatment for MDS.

A combination of semiquantitative telomerase assay and in-cell telomerase activity measurement using exfoliated urothelial cells for the detection of urothelial neoplasia

BACKGROUND

Telomerase is a ribonucleoprotein that synthesizes telomeres. It is detected in more than 85% of samples obtained from cancer tissues, including urologic neoplasia. The authors determined telomerase activity semiquantatively and in-cell telomerase activity in exfoliated urothelial cells obtained from urologic neoplasia specimens. The goal of this study was to provide additional information regarding a noninvasive approach to the detection of urologic neoplasia.

METHODS

The authors used voided urine from 23 patients with urologic neoplasia, 2 patients with nonmalignant urologic disorders, and 10 normal individuals. Semiquantative determination of telomerase activity was performed using a fluorescence-based telomeric repeat amplification protocol (TRAP), and telomerase activity at the cellular level was determined by an in situ TRAP assay.

RESULTS

The fluorescence-based TRAP assay detected urinary telomerase activity in samples from 10 of 13 patients with urologic neoplasia before treatment, whereas urinary cells obtained from 3 of 10 patients (including 1 patient with relapse) during or after treatment had detectable telomerase activity. In contrast, the in situ TRAP assay detected telomerase positive cells in samples from 11 of 13 patients before treatment and 6 of 10 patients during or after treatment. Of note was a dissociation of the results of the fluorescence-based TRAP assay and those of the in situ TRAP assay for some patients. Some patients for whom telomerase activity was not detected with the fluorescence-based TRAP assay had a low frequency of telomerase positive cells in their urine.

CONCLUSIONS

A combination of semiquantative analysis and an in situ TRAP assay to detect telomerase positive cells might be a useful tool in the identification and monitoring of patients with urothelial neoplasia.

Late appearance of t(5;12)(q31;p12) in acute myeloid leukemia associated with eosinophilia

We report here a case of acute myeloid leukemia with eosinophilia and t(5;12)(q31;p12) at the second relapse. This cytogenetic anomaly is thus associated with one step toward leukemia and eosinophilia.

Serum soluble CD44 levels for monitoring disease states in acute leukemia and myelodysplastic syndromes

To determine the clinical implications of soluble CD44 (sCD44) levels in hematologic neoplasias, we developed an enzyme-linked immunosorbent assay for sCD44 using two monoclonal antibodies to the standard 90 kDa form, and assessed the serum concentration of sCD44 in normal healthy volunteers, patients with acute leukemia, myelodysplastic syndromes (MDS), and those with chronic myeloid leukemia (CML). Compared to that in normal individuals (n=51; 145. 1 24.6 ng/ml), the serum sCD44 level was significantly elevated in patients with acute myeloid leukemia (AML; n=18; 331.9 99.0 ng/ml, P=0.0001), acute lymphoid leukemia (ALL; n=16; 551.3 427.8 ng/ml, P=0.0001) and CML (n=18; 262.0 97.5 ng/ml, P=0.0001). The sCD44 level was slightly elevated in patients with MDS (n=43; 173.8 54.9 ng/ml, P=0.0071). In patients with acute leukemia, serum sCD44 concentrations decreased significantly in response to treatment and reached nearly normal levels after complete remission (P=0.0005 in AML and P=0.0032 in ALL). The sCD44 levels in patients with MDS increased after they developed acute leukemia, whereas no significant difference in sCD44 levels was observed between the chronic and the blastic phases in patients with CML. Our results indicate that serum sCD44 levels may be a useful marker for monitoring response to treatment and disease progression, especially in acute leukemia.

Telomerase activity in lung cancer cells obtained from bronchial washings

BACKGROUND

Telomerase, a ribonucleoprotein enzyme that functions in the maintenance of telomeres (specialized structures at the ends of chromosomes), has been reported to be a novel diagnostic marker for malignant diseases. We sought to determine whether measurement of telomerase activity in bronchial washings is of value in the diagnosis of lung cancer.

METHODS

Extracts of cells in bronchial washings were analyzed for telomerase activity by use of a telomeric repeat amplification protocol (TRAP) assay. Telomerase activity inside cells was evaluated by use of an in situ TRAP assay. The results of both TRAP assays were compared with those obtained from cytologic examination, which employed standard Papanicolaou staining.

RESULTS

When results from the two TRAP assays were combined, telomerase activity was detected in bronchial washings from 18 (82%; 95% confidence interval [CI] = 60%-95%) of 22 patients with lung cancer. In contrast, cancer cells were detected by cytologic examination in the bronchial washings of nine (41%; 95% CI = 21%-64%) of the same 22 patients, a statistically significant difference (two-sided P = .0061). In patients with lung cancer, telomerase-positive cells could be detected in bronchial washings irrespective of tumor location--11 of 14 (79%; 95% CI = 49%-95%) peripheral cancerous lesions and seven of eight (88%; 95% CI = 47%-100%) central cancerous lesions were detected by use of TRAP assays (for comparison, two-sided P = .5349).

CONCLUSIONS

A high percentage of patients with lung cancers had detectable telomerase activity in bronchial washings. Thus, the use of a cell extract-based or an in situ TRAP assay in addition to cytologic examination may make the diagnosis of lung cancer more reliable.

Human cord blood-derived primitive progenitors are enriched in CD34+c-kit- cells: correlation between long-term culture-initiating cells and telomerase expression

We studied the functional characteristics of subpopulations of cord blood-derived CD34+ cells expressing different levels of CD38 and c-kit antigens, using clonal cell culture and long-term culture with allogeneic bone marrow stromal cells or the MS-5 murine stromal cell line to assay long-term culture-initiating cells (LTC-IC) in each subpopulation. To investigate the capacity for replication, proliferation, and differentiation of each subpopulation of CD34+ cells, we also studied the correlation between LTC-IC and telomerase activity. After 5 weeks of coculture, LTC-IC accounted for one out of 32 CD34+CD38- cells and one out of 33 CD34+c-kit- cells. In contrast, the frequency of LTC-IC was low in their antigen-positive counterparts (one per 84 CD34+CD38+ cells, one per 90 CD34+c-kit(low) cells, and very low among CD34+c-kit(high) cells). It was noteworthy that some LTC-IC derived from CD34+CD38- as well as CD34+c-kit- cells generated colony-forming cells (CFCs) after up to 9 weeks of coculture. Telomerase activity was consistently low in CD34+CD38- and CD34+c-kit- cells compared to CD38+ or c-kit(high or low) cells, suggesting that CD34+CD38- or c-kit- cells are likely to be more quiescent. These results suggest that the CD34+CD38- and CD34+c-kit- cell populations are primitive stem/progenitor cells, and that the telomerase activity of these cells correlates with their proliferative capacity as well as their stage of differentiation.

[Development of in situ TRAP assay detecting telomerase activity in cell]

Telomerase is a ribonucleoprotein that is detected in more than 85% of primary cancer tissues using a telomeric repeat amplification protocol (TRAP) assay. Thus, telomerase is considered to be a novel marker for cancer. Telomerase activity is not detectable in somatic cells, except for hematopoietic cells and cryptic cells in the intestine and hair follicles, thus, detection of telomerase is important to delineate clinical implication of telomerase activity. We have developed semiquantitative fluorescence-based TRAP assay using fluorescence-end-labeling primers. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Using these TRAP assays, we are able to detect telomerase activity in various kinds of extracts or cytological specimens and therefore these applications may have additive information in the early detection of cancer and monitoring disease condition.

[Telomere, telomerase and cytogenetic changes in myelodysplastic syndromes]

Myelodysplastic syndrome (MDS) is a heterogenous but clonal disorder characterized by cytopenia and dysplastic features. Telomere length in MDS vary but some of them show shortened telomeres. Telomerase activity in MDS also vary but about 60% of them show slightly elevated telomerase activity. According to the disease progression of MDS, MDS patients categorize into 3 groups, i.e., (1) normal telomere length before and after disease progression, (2) short telomere length before and after progression, and (3) shortened telomere with disease progression. Telomerase change with disease progression is not obscure, indicating impairment of telomere dynamics in MDS. These observations may indicate that some MDS show telomerase upregulation possible due to telomere shortening, while the another pathway without telomerase upregulation associated with complex chromosome changes may link to the pathogenesis of MDS.

Telomeric length and telomerase activity vary with age in peripheral blood cells obtained from normal individuals

The telomerase activity and length of telomeres of peripheral blood mononuclear cells obtained from 124 healthy individuals aged 4-95 years was measured. Telomerase activity level was semiquantitatively assessed by a fluorescent-telomeric repeat amplification protocol (fluorescent-TRAP) using an internal telomerase assay standard, fluorescent primers and an automated laser fluorescent DNA sequencer. Telomeric length, measured by assay of terminal restriction fragments (TRFs), was determined in HinfI-digested DNA by Southern blot analysis using a (TTAGGG)4 probe. TRF length was determined in 80 individuals and age-related progressive reduction of size was observed. TRF length in peripheral blood mononuclear cells obtained from normal individuals (aged 4-39 years) decreased by approximately 84 bp per year, while in individuals aged > or = 40 years it decreased by 41 bp per year. In contrast, telomerase activity showed an apparent biphasic pattern with aging. Individuals aged 4-39 years showed a progressive decrease in telomerase activity, whereas 65% of those aged > or = 40 years showed relatively stable but very low telomerase activity, and the remaining individuals aged > or = 40 years had no detectable telomerase activity. These data obtained from normal individuals might in the future be of value to help risk stratify and manage the care of patients with leukemia.

Comparison of telomerase activity in normal chorionic villi to trophoblastic diseases

Trophoblasts are derived from the normal placenta, and they infiltrate into the endometrium and the maternal blood vessels under strict control but, unlike malignant cells, never metastasize. To understand the proliferative characteristics of trophoblasts and its related disorders, we assessed telomerase activity in chorionic villi obtained from 27 normal individuals, 9 hydatidiform moles, and 2 choriocarcinomas. Telomerase activity was detected in 13/27 (48%) normal chorionic villi samples. The detectability and the level of telomerase activity depended on gestational age; 8/10 (80%) villi samples in the first trimester (relative telomerase activity; 1.77 +/- 1.37), whereas 2/8 (25%) villi samples in the second trimester (0.78 +/- 1.52) and 3/9 (33%) in the third trimester (0.28 +/- 0.43) had telomerase activity. Telomerase activity of normal chorionic villi in the first trimester was higher than that of the third trimester (P = 0.0251). In contrast, all mole samples had increased telomerase activity compared to normal villi (3.17 +/- 2.81, P = 0.0152). Thus, a relationship may exist among cell proliferation, telomerase activity, and progression to trophoblastic disease.

[Detection of telomerase activity and its clinical application]

Telomerase is a ribonuclear protein that is detected in more than 90% of primary cancer tissues using a telomeric repeat amplification protocol (TRAP) assay, thus, telomerase is considered to be a novel marker for cancer. Telomerase activity is not detectable in somatic cells, except for hematopoietic cells and cryptic cells in the intestine and hair follicles, thus, quantitation of telomerase is important to delineate clinical implication of telomerase activity. We have developed semiquantitative fluorescence-based TRAP assay. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Thus, using these TRAP assays, we are able to detect telomerase activity in various kinds of extracts or cytological specimens and therefore these applications may have additive information in the early detection of cancer and monitoring disease condition.

Cytological detection of telomerase activity using an in situ telomeric repeat amplification protocol assay

A previously reported highly sensitive assay for measuring telomerase activity on cell and tissue extracts indicates that most human tumor tissues, but not cells adjacent to tumors, have detectable telomerase activity. Although this assay has provided a significant amount of information about the presence or absence of telomerase activity, it does not indicate whether all cells within a tumor have telomerase activity or whether only a subset does. The present report demonstrates the ability to advance this technology to an in situ assay. Using fluorescent telomerase primers and in situ PCR, we show that telomerase activity can be detected at the cellular level. This study demonstrates that telomerase activity is not detected in normal cells but is detected in tumor cells of clinical specimens and in tumor-derived cell lines.

[Essential thrombocythemia in transformation to acute leukemia (FAB-M0) as a natural history from myelofibrosis with t(1;7)]

A 34-year-old man was found to have leukocytosis and thrombocytosis in 1983. In 1988, his leukocyte count was 10,400/microliter, Hb 16.5g and a platelet was 73 x 10(4)/microliter. A bone marrow examination showed megakaryocyte hyperplasia. Essential thrombocythemia (ET) was diagnosed but no treatment was given. In February 1993, anemia and hepatosplenomegaly developed and cytogenetic study of the peripheral blood demonstrated t(1;7) (q10;p10). Myelofibrosis was diagnosed as by bone marrow biopsy. The patient was treated with blood transfusion, oxymetholone and prednisolone, but without effect. In 1995, acute myeloid leukemia developed, and he died in December 1995 due to septicemia. We report here a case of the ET developed myelofibrosis with t(1;7) (q10;p10) anomaly and acute leukemia.

The relationship between telomere length and therapy-associated cytogenetic responses in patients with chronic myeloid leukemia

BACKGROUND

Chronic myeloid leukemia (CML) is a clonal disease with specific cytogenetic changes involving the Philadelphia (Ph) translocation. The authors examined the relationship between telomere length (terminal restriction fragment [TRF]) and therapy-associated cytogenetic responses in CML patients.

METHODS

The authors examined the telomere length and telomerase activity in 44 patients with Ph-positive CML in the chronic phase. TRF was determined by Southern blot analysis using the (TTAGGG)4 probe and telomerase activity was assessed by the telomeric repeat amplification protocol and fluorescent-labeled primers.

RESULTS

At the time of CML diagnosis, 19 patients had TRFs within the age-matched normal range (mean +/- 2 x standard deviation [SD]) and the remaining 25 patients had TRFs shorter than the age-matched normal range (< mean +/- 2 x SD). Hematologic findings, including leukocyte count, hemoglobin level, platelet count, and percentage of bone marrow blasts at the time of diagnosis did not significantly differ between patients with normal and shortened TRFs; however, those with shortened TRFs had high levels of telomerase activity (P = 0.045). In a group of patients treated with alpha-interferon (n = 32), those with normal TRFs had a significantly lower frequency of blast crises (P = 0.0328), a significantly higher incidence of cytogenetic responses (P = 0.0185), and a favorable prognosis (P < 0.01) compared with those with shortened TRFs.

CONCLUSIONS

These findings suggest that normal TRFs in a small number of CML patients at the time of diagnosis may have a significant amount of normal stem cells remaining. The authors suggest that normal TRFs at the time of diagnosis indicate a subset of CML patients who may respond favorably to alpha-interferon therapy.

Clinical implications of telomerase activity levels in acute leukemia

In the present study, we used the telomeric repeat amplification protocol assay, an internal telomerase assay standard, and an automatic DNA sequencer to detect and quantitate telomerase activity in blood samples obtained from normal and acute leukemia patients. Telomerase activity was analyzed in 78 acute leukemia patients and ranged from 0.65 to 147 relative to the internal standard. Compared to the age-matched normal levels of telomerase activity in the peripheral blood cells, we determined that 45 (81.8%) of 55 acute myeloid leukemia (AML) and 16 (69.6%) of 23 acute lymphoid leukemia patients had elevated telomerase activity. There was no relationship between peak telomere length and telomerase activity in both acute lymphoid leukemia and AML patients. In AML, the level of telomerase activity was associated with French-American-British subtypes and cytogenetics, and patients with elevated telomerase activity had high leukocyte counts and more frequent extramedullary involvement during the disease. Among 78 patients, 5 had high levels of telomerase activities similar to immortalized leukemia cell lines; these 5 patients had a very poor prognosis (P < 0.05). The levels of telomerase activity significantly decreased in patients in complete remission. Most of the patients in complete remission showed a normal level of telomerase activity; however, two of them had low to moderate telomerase activity, and they relapsed shortly after entering complete remission. In relapsed patients, there is a general trend for increased telomerase levels, and 2 of the 13 patients retained high telomerase activity, whereas the other 11 had normal to moderate telomerase activity. These results suggest that telomerase activity may be a useful additional method for monitoring the disease condition in acute leukemia patients.