Transient appearance of CD3+CD8+ T lymphocytes with monoclonal gene rearrangement of T-cell receptor beta locus

A benign, transient proliferation of atypical lymphocytes and a monoclonal rearrangement of the T-cell receptor beta (TRB) locus was found in a 60-year-old woman who presented with low-grade fever, anorexia and fatigue. A marked and transient atypical lymphocytosis (white blood cell count 90.5 x 10(9)/l) with CD8 surface antigen improved without specific treatment. Although tests for IgM antibodies to hepatitis A, varicella zoster, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) were all negative, a monoclonal gene rearrangement of TRB locus was observed in the DNA of the proliferated atypical lymphocytes by Southern blotting. The clonal rearrangement and the atypical lymphocytes disappeared after 14 d, and the patient has remained well for 7 years. These results suggest that monoclonal proliferation of CD8 lymphocytes can occur based on a non-neoplastic aetiology.

Pregnancy among long-term survivors of acute leukemia. A second nationwide survey

A second nationwide survey was conducted to determine the outcome of pregnancy in long-term survivors of acute leukemia and to clarify the influence of treatment on the offspring of long-term survivors. In July 1996, 336 survey responses were received from the 498 Japanese institutions surveyed. A total of 89 cases (39 spouses of male patients and 50 female patients) who had babies during their first remission were analyzed, including 43 patients from the first survey in 1991. Median age at the birth of first baby was 30.7 years for male patients and 28.6 years for female patients. A total of 109 of the 117 pregnancies resulted in live births and eight resulted in abortions. A total of 58 cases had single children and 23 cases had two or more, generally from separate pregnancies, but including two pairs of twins. The infant was male in 59 cases, female in 37 and gender was not reported in 13 cases. Ages of children ranged from 2 months to 20 years at the time of this study and all children were in good health. There were two minor anomalies, both of which were surgically corrected. Of the 81 parents bearing live infants, 75 remained in complete remission. Five fathers died (four of relapse and one of another disease). In conclusion, there was no apparent increase in pregnancy complications or congenital anomalies in the children of long-term survivors with acute leukemia.

[Therapy-related leukemia and myelodysplastic syndrome: a multi-institution study in Japan]

Therapy-related leukemia and myelodysplastic syndrome (TRL/MDS) in Japan were analysed in a multi-institution study to assess clinical, cytogenetic aspects, and prognostic factor. From 1985 to 1994, 405 cases of adult TRL/MDS were diagnosed and overall percentage of TRL/MDS in leukemia and MDS was 1.9%. Median age was 61 years old. The median latency from primary malignancies was 53.4 months, which latency was significantly shorter in the patients treated with chemotherapy. Primary malignancies were hematologic in 39%. Common symptoms were fatigue/ weakness and anemia. Chromosome 7,5, and 11 were frequently involved. MLL gene rearrangement were detected in 12 of 64 analysed cases. Overall median survival was 10.0 months. Body weight loss, neurologic abnormality, hypoproteinemia, hypofibrinogenemia, proteinuria, lack of Auer rods, and 5q-were prognostic factors in TRL/MDS. This large population study documented some datas useful for the prevention of TRL/MDS.

Progression from myelodysplastic syndrome with monosomy 7 to acute monoblastic leukemia with MLL gene rearrangement

We report a case of myelodysplastic syndrome (MDS) with the 11q23 translocation at its leukemic transformation. Southern blot analysis demonstrated that the MLL gene on chromosome 11 was rearranged during the progression from MDS to acute leukemia. The clinical observation in this case supports the notion that leukemic transformation involves multiple cytogenetic evolutionary progresses, and that MLL gene rearrangement corresponds to the final step of leukemogenesis.

Genotype of GB virus C/hepatitis G virus by molecular evolutionary analysis

GB virus C/hepatitis G virus is a newly described virus. Classification of GB virus C/hepatitis G virus into genotypes has not been established. We analyzed nucleotide sequences within the 5' untranslated region of GB virus C/hepatitis G virus isolates and segregated these isolates into genotypes. Twenty serum samples with GB virus C/hepatitis G virus RNA from Australia, Cameroon, the Congo, Japan, Mongolia, and Bangladesh were studied. Reverse transcription and polymerase chain reaction were used to obtain GB virus C/hepatitis G virus RNA. After nucleotide sequences from the 5' untranslated region were determined, 68 nucleotide sequences, including 48 previously reported sequences, were analyzed by molecular evolutionary methods. The phylogenetic tree of the 5' untranslated region showed that all strains could be divided into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3). Bootstrap analysis indicated that the strains could be divided into three major genotypes but could not be further subdivided. Moreover, frequency histograms of pairwise distances between nucleotide sequences demonstrated only one peak. These result indicated that GB virus C/hepatitis G virus can be classified into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3), and should not be divided into minor subtypes.

Chimeric MLL products with a Ras binding cytoplasmic protein AF6 involved in t(6;11) (q27;q23) leukemia localize in the nucleus

In infantile leukemias and therapy-related leukemias, the MLL gene is frequently found to be disrupted and fused to various translocation partner genes, such as AF4/FEL, LTG9/AF9 and LTG19/ENL as a result of 11q23 translocations. We previously showed that the N-terminal portion common to various chimeric MLL products, as well as to MLL-LTG9 and MLL-LTG19, localizes in the nuclei, and therefore suggested that it might play an important role in leukemogenesis. In the present study, MLL-AF6 chimeric products found in the t(6;11)(q27;q23) translocation were analysed since AF6, a Ras-binding protein, exhibits a different subcellular localization from that of LTG9/AF9 and LTG19/ENL. Immunofluorescence staining data and cell fractionation analyses demonstrated that MLL-AF6 chimeric products localize in the nuclei despite the fact that AF6 itself localizes in the cytoplasm, confirming the importance of the nuclear localization of chimeric MLL products. The region in the N-terminal portion of MLL responsible for this nuclear localization was examined and found to be a region containing AT-hook motifs.

Interferon-alpha therapy in patients dually infected with hepatitis C virus and GB virus C/hepatitis G virus--virological response of HGV and pretreatment HGV viremia level

BACKGROUND/AIMS

The response to interferon-alpha (IFN) therapy of recently isolated GB virus C and hepatitis G virus (HGV) is still unclear. To investigate the biochemical and virological response to IFN therapy in patients with chronic hepatitis C virus (HCV) infection concomitantly infected with HGV, 196 patients with HCV who had received IFN therapy were retrospectively studied.

METHODS

HGV and HCV RNA were detected by reverse transcription nested polymerase chain reaction (RT-PCR). Serum HGV RNA levels were quantified by competitive RT-PCR. The HGV genotype was detected by restriction fragment length polymorphism analysis using the PCR products.

RESULTS

Of 196 patients, 16 (8.2%) were positive for both HCV and HGV RNA before IFN therapy. There were no significant clinical and virological differences between the patients with dual infection and those with only HCV infection. During the therapy, a decrease or loss of serum HGV RNA level was observed in these patients. Six months after cessation of the therapy, five of 16 patients became negative for HGV RNA by RT-PCR. The pretreatment HGV RNA level of the patients who lost HGV RNA after cessation of IFN was low (median=10(3) copies/ml), compared to the level (median=10(7) copies/ml, p<0.01) in the patients with positive HGV RNA after the therapy. The HGV genotype of these 16 patients was the same type.

CONCLUSIONS

These data suggest that: 1) there is no significant difference in response to IFN therapy between patients with dual and single infection; 2) HGV shows sensitivity to IFN therapy; and 3) in the patients who show a low pretreatment HGV RNA level, serum HGV RNA becomes undetectable by RT-PCR after cessation of IFN therapy.

CD7+ and CD56+ myeloid/natural killer cell precursor acute leukemia: a distinct hematolymphoid disease entity

The disease spectrum of natural killer (NK) cell leukemias and lymphomas has recently been expanding with the continuing evolution in diagnostic concepts. We describe here seven cases of acute leukemia of conceivable myeloid and NK cell precursor phenotype in six men and one woman varying from 19 to 59 years of age (median, 46 years). Striking extramedullary involvement was evident at initial presentation, with peripheral lymphadenopathy and/or mediastinal masses. Two lacked any leukemic cells in the bone marrow at diagnosis. Using cytochemical myeloperoxidase staining, less than 3% of the leukemic cells showed positive reactivity. However, expression of CD7, CD33, CD34, CD56, and frequently HLA-DR, but not other NK, T-cell, and B-cell markers was observed. Cytoplasmic CD3 was detected in three of the cases by flow cytometry and in six by Northern blotting, suggesting an origin from common progenitors between the NK cell and myeloid lineages. All but one presented germline configurations of the T-cell receptor beta and gamma chain genes and Ig heavy chain gene. With regard to morphology, the cells were generally L2-shaped, with variation in cell size, round to moderately irregular nuclei and prominent nucleoli, pale cytoplasm, and a lack of azurophilic granules. Histopathologic examination of biopsied specimens of extramedullary tumors showed a lymphoblast-like morphology, implying the differential diagnostic problem from lymphoblastic lymphomas, especially in cases lacking bone marrow involvement. Three patients were successfully treated with chemotherapy for acute myeloid leukemia (AML), whereas three other patients proved refractory to chemotherapeutic regimens for lymphoid malignancies, although two responded to subsequent AML chemotherapy. However, despite intensive chemotherapy, including allogeneic bone marrow transplantation, most persued fatal courses within 41 months. These data suggested that the CD7+ and CD56+ myeloid/NK cell precursor acute leukemia might constitute a distinct biologic and clinical disease entity. Its recognition appears to be particularly important for the clinicopathologic evaluation of CD56+ hematolymphoid malignancies and the development of therapeutic approaches to such disease.

Idiopathic CD4+ T-lymphocytopenia in a non-Hodgkin's lymphoma patient

We report a case of idiopathic CD4+ T-lymphocytopenia with malignant lymphoma (diffuse large, B-cell type) for which there was no evidence of human immunodeficiency virus type 1 or type 2 infection and no other known causes of immunodeficiency. She had never suffered from any opportunistic infection until the diagnosis of malignant lymphoma was made, and the CD4+ T-lymphocytopenia persisted after complete remission of the lymphoma. As the clinical features and immune status of the patient differed from those associated with the acquired immunodeficiency syndrome (AIDS)-related syndrome, we conclude that immunodeficiency in this case did not contribute to the opportunistic infection but may have been associated with the genesis of malignant lymphoma.

Internal tandem duplication of FLT3 associated with leukocytosis in acute promyelocytic leukemia. Leukemia Study Group of the Ministry of Health and Welfare (Kohseisho)

FLT3 is a member of receptor tyrosine kinases expressed in leukemia cells, as well as in hematopoietic stem cells. Recently, a somatic alteration of the FLT3 gene was found in acute myeloid leukemia, as an internal tandem duplication (FLT3/ITD) which caused elongation of the juxtamembrane (JM) domain of FLT3. Here we characterized the FLT3/ITD and investigated its clinical significance in acute promyelocytic leukemia (APL). Seventy-four newly diagnosed patients with APL, who were treated with the same protocol in a multi-institutional study, were studied for the FLT3/ITD. Genomic and message sequences of the FLT3 gene were amplified by means of polymerase chain reaction (PCR), and elongated PCR products were sequenced. Fifteen patients (20.3%) had FLT3/ITD, all of which were transcribed in frame. Location of the duplicated fragments (six to 30 amino acids) varied from patient to patient. However, they always contained either Y591 or Y599, but the tyrosine kinase domain was not significantly affected. This finding implied that signal transduction of FLT3 is amplified by the duplication. Clinically, the presence of FLT3/ITD was related to high peripheral white blood cell counts as well as peripheral leukemia cell counts (P < 0.0001), high LDH level (P = 0.04), and low fibrinogen concentration (P = 0.04). These data suggest that FLT3/ITD plays a significant role in progression of APL.

[Human parvovirus B19 infection mimicking systemic lupus erythematosus: case report]

Human parvovirus B19 (HPV-B19) has been known as the etiologic agents of erythema infectiosum in normal childhood, and chronic anemia and thrombocytopenia in immuno-compromised patients. Recently, this virus has been reported as the association with rheumatic manifestation such as rheumatoid arthritis and systemic lupus erythematosus (SLE). We described here a patient whose HPV-B19 infection was mimiking atypical symptoms of SLE at diagnosis, and was persistent because of immuno-suppressive therapy for SLE. A 34-year-old female was admitted to our hospital on 22 June 1995, presenting fever episode and cervical lymph node swelling. Before eighteen months, she was received methyl-predonisolone pulse therapy and plasma exchange by fresh frozen plasma for the treatment of Stevens-Johnson syndrome, and after several weeks these therapy she was suffered from viral infection with lymphadenopathies with a transient appearance of atypical lymphocytes in her peripheral blood smear. On laboratory examination at the present admission, her peripheral blood showed anemia, thrombocytopenia with atypical lymphocytes. Throughout her hospitalization, anti-nuclear antibody (ANA) suspected SLE including anti-DNA and anti-Sm antibody were all negative except of transient week positive ANA screening test. Her physical condition presented poor clinical course with fever elevation, increased ascites and renal dysfunction showing the elevation of CRP and circulating immune-complex (Clq binding method). Her serum was positive for IgM and IgG antibody against VP-1 and VP-2 antigen of HPV-B19 by ELISA in April 1996. And then, HPV-B19 DNA by polymerase chain reaction (PCR) was positive in bone marrow sample in March 1996, and also positive in spleen necropsy at death. We confirmed persistent chronic HPV-B19 infection by measurement of HPV-B19 IgM and IgG antibody by ELISA and HPV-B19 DNA by PCR. The plasmapheresis and administration of intravenous immunoglobulin showed the possible efficacy for her symptom throughout this clinical course. Moreover, bone marrow smear showed the finding of virus-associated hemophagocytic syndrome, and finally, she was died of cervical hemorrhage accompanied with disseminated intravascular coagulation syndrome on July 1996. HPV-B19 infection can present an atypical clinical picture that is highly suggestive of SLE. We suggest that the therapy of steroids and immuno-suppressive agents should be cautious, because these may potentially cause persistent chronic HPV-B19 infection and induced life-threatening clinical course.

Distinct regulation of two hydroxysteroid sulfotransferases, ST2A1 and ST2A2, by growth hormone: a unique type of growth hormone regulation in rats

In the present study, changes in the mRNAs of two major forms of hydroxysteroid sulfotransferases (STs), ST2A1 and ST2A2, have been determined in different growth hormone (GH) states. Hepatic ST2A1 mRNA was detected in both sexes of mature Sprague-Dawley rats. The level was 5 times higher in the females than in the males. ST2A1 mRNA was undetectable in GH-deficient animals, such as hypophysectomized rats and spontaneous dwarf rats. Continuous infusion of GH (mimicking the female secretory pattern) increased hepatic levels of ST2A1 mRNA in both GH-deficient animals. ST2A2 mRNA was detected only in the livers of mature female rats and in both sexes of GH-deficient animals. Intermittent injection of GH (mimicking male secretory pattern) strongly suppressed hepatic levels of ST2A2 mRNA in both GH-deficient animals. These results indicate that pituitary GH independently regulates both ST2A1 and ST2A2 at the pretranslational levels. These differences in GH responses between ST2A1 and ST2A2 are in good agreement with their female-dominant and female-specific modes of expression in normal rats. Furthermore, the present study demonstrates a unique response of ST2A2 to the secretory pattern of GH among the drug-metabolizing enzymes in rat livers, in which ST2A2 mRNA levels are suppressed by the male secretory pattern but not by the female secretory pattern of GH.

Treatment with a new synthetic retinoid, Am80, of acute promyelocytic leukemia relapsed from complete remission induced by all-trans retinoic acid

Differentiation therapy with all-trans retinoic acid (ATRA) has marked a major advance and become the first choice drug in the treatment of acute promyelocytic leukemia (APL). However, patients who relapse from ATRA-induced complete remission (CR) have difficulty in obtaining a second CR with a second course of ATRA therapy alone. We tested the efficacy of a new synthetic retinoid, Am80, in APL that had relapsed from CR induced by ATRA in a prospective multicenter study. Am80 is approximately 10 times more potent than ATRA as an in vitro differentiation inducer, is more stable to light, heat, and oxidation than ATRA, has a low affinity for cellular retinoic acid binding protein, and does not bind to retinoic acid receptor-gamma. Patients received Am80, 6 mg/m2, orally alone daily until CR. Of 24 evaluable patients, 14 (58%) achieved CR. The interval from the last ATRA therapy was not different between CR and failure cases. The clinical response was well correlated with the in vitro response to Am80 in patients examined. Adverse events included 1 retinoic acid syndrome, 1 hyperleukocytosis, 9 xerosis, 8 cheilitis, 16 hypertriglyceridemia, and 15 hypercholesterolemia, but generally milder than those of ATRA, which all patients had received previously. Am80 is effective in APL relapsed from ATRA-induced CR and deserves further trials, especially in combination with chemotherapy.

Prevalence and molecular epidemiology of GB virus C/hepatitis G virus infection in Mongolia

We studied the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection among 112 patients with liver disease and 121 blood donors in Ulaanbaatar, Mongolia. Reverse transcription and polymerase chain reaction were employed to detect GBV-C/HGV RNA using the specific primers derived from the 5'-untranslated region (5'-UTR) of the GBV-C/HGV genome. Nucleotide sequences of all positive samples for GBV-C/HGV RNA were determined. The sequences were analyzed by a molecular evolutionary method. Twenty-five (10.7%) of 233 people were positive for GBV-C/HGV RNA. Eight (6.6%), 11 (9.1%), and 30 (24.8%) blood donors were positive for GBV-C/HGV RNA, HBsAg, and anti-HCV, respectively, although 17 (15.2%), 65 (58.0%), and 64 (54.5%) patients with liver disease were positive for each viral marker. The prevalences of GBV-C/HGV RNA, HBV, and HCV in the patients were significantly higher than those in blood donors (P < 0.05). There was no significant difference in the prevalence of anti-HCV among people with and without GBV-C/HGV RNA, while the prevalence of HBsAg among people with GBV-C/HGV RNA was significantly higher than among those without GBV-C/HGV RNA (P < 0.05). The molecular evolutionary tree showed that GBV-C/HGV was a heterogeneous virus and all strains could be divided into 2 types. One is the same phylogenetic type as HGV, and the other is a new type that is different from GBV-C and HGV.

Polymorphism in the angiotensin-converting enzyme (ACE) gene and sarcoidosis

It has recently been shown that an insertion (I)/deletion (D) polymorphism exists in the angiotensin-converting enzyme (ACE) gene, and that this polymorphism affects the serum ACE level. There are three genotypes: DD, DI, and II, with the ACE level highest in DD, intermediate in DI, and lowest in II. In the present investigation of the possible significance of the polymorphism for sarcoidosis, a total of 207 patients and 314 normal control subjects were examined. There were no significant differences in the I/D ratio and the genotype distribution between the two groups, and no significant variation in organ involvement (i.e., eye, skin, and heart) was noted among the three genotypes. To determine any prognostic influence of the polymorphism, we examined the disappearance ratio of abnormal shadow on chest radiography over 3 and 5 yr. No significant difference among the three genotypes was observed. New normal ranges of serum ACE level were determined for each genotype, and found to be 22% more sensitive overall than the conventional normal range and 39% more so for II type, suggesting an advantage for diagnosis and assessment of the disease activity of sarcoidosis.

DNA damage-associated dysregulation of the cell cycle and apoptosis control in cells with germ-line p53 mutation

Lymphoblastoid cell lines (LCLs) with heterozygous p53 mutations at residues 286A, 133R, 282W, 132E, and 213ter were established from five independent Li-Fraumeni syndrome families. When cell cycle regulation in response to gamma-irradiation was studied, these LCLs showed an abnormal G1 checkpoint associated with defective inhibition of cyclin E/cyclin-dependent kinase 2 activity in all cases except for 282W LCL, which showed a normal G1 checkpoint. On the other hand, the control of S-phase-G2 as determined by cyclin A/cyclin-dependent kinase 2 activity was defective in all these LCLs. The mitotic checkpoint was also defective in the two LCLs analyzed as either competent or incompetent for G1 arrest. When radiation-induced apoptosis, which requires wild-type p53 function under optimal conditions, was studied, all of these LCLs showed significant failure compared to normal LCLs. These findings indicate that although p53-dependent transactivation and G1-S-phase cell cycle control are variably dysregulated, the induction of apoptosis and control of the cell cycle at S-phase-G2 and the mitotic checkpoint in response to DNA-damaging agents are consistently dysregulated in heterozygous mutant LCLs. This suggests that these dysfunctions underlie, at least in part, the susceptibility of Li-Fraumeni syndrome families to cancer. Furthermore, the approach presented is a potentially useful method for studying individual carriers of different germ-line p53 mutations and different biological features.

Detection of chimeric mRNAs by reverse transcriptase-polymerase chain reaction for diagnosis and monitoring of acute leukemias with 11q23 abnormalities

Recurrent translocations involving chromosome band 11q23 are often found in human acute leukemias. Recently, the MLL gene on 11q23 and 10 partner genes involved in these translocations have been cloned and characterized. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the resultant der(11) chimeric mRNAs of the 3 types of 11q23 translocations including t(4;11), t(9;11), or t(11;19), in 14 leukemia patients with MLL gene rearrangements. At diagnosis or relapse, chimeric mRNA could be detected in all of the 4 patients with t(4;11), 2 of 3 with t(9;11), 2 of 3 with t(11;19), and 1 of 4 with unsuccessful karyotype. In 5 patients, we could monitor minimal residual disease (MRD) serially through the clinical course. One patient, in whom chi-meric mRNA was detected during complete remission (CR) just after the induction chemotherapy, relapsed within 2 months and died, while 2 patients in which chimeric mRNA was not detected remained in CR from 10-23 months. These findings suggest that RT-PCR is a useful approach for detecting which partner gene is involved in the translocation and monitoring MRD in patients with MLL gene rearrangement. Nonetheless, the clinical relevance of MRD evaluation by RT-PCR monitoring remains controversial. Long-term and prospective investigation of a larger series of patients is needed to confirm the clinical significance of monitoring MRD by RT-PCR method.

Three different GB virus C/hepatitis G virus genotypes. Phylogenetic analysis and a genotyping assay based on restriction fragment length polymorphism

The 5'-untranslated region (5'-UTR) sequences of 33 GB virus C/hepatitis G virus (GBV-C/HGV) obtained from different geographic areas were determined through reverse-transcription polymerase chain reaction and dideoxy chain termination sequencing, the alignment of sequences, the estimation of the number of nucleotide substitution per site, and construction of phylogenetic trees. The 5'-UTR of GBV-HGV was found to be heterogeneous, with 70.9-99.5% homology. Three distinct phylogenetic branches were observed consistently in all phylogenetic trees. GBV-C is the prototype for one, HGV for another, and there is a new branch which consisted of GBV-C/HGV isolates from Asia. Genotype-specific restriction sites for the restriction enzymes, ScrFI and BsmFI, were identified, and a simple restriction fragment polymorphism analysis was developed for genotyping. These data provide evidence that GBV-C/HGV consists of three different genotypes. Our simple genotyping assay will also provide a tool for epidemiological studies of GBV-C/HGV infection.

Immunostaining of PRAD1/cyclin D1 protein as a marker for the diagnosis of mantle cell lymphoma

The overexpression of PRAD1/cyclin D1 gene activated by the 11q13 translocation and its molecular counterpart BCL-1 rearrangement is frequently associated with mantle cell lymphomas (MCLs). Recently, we produced a monoclonal antibody, 5D4, against the PRAD1/cyclin D1 product, and demonstrated that the positive nuclear staining by this antibody correlates with PRAD1/cyclin D1 mRNA overexpression in MCLs. In the present study, we have immunohistochemically examined the cyclin D1 protein in a large series of 315 malignant lymphomas including 39 MCLs on paraffin sections. The nuclear positive pattern was found in 35 (90%) of 39 MCLs with an exceptional case of immunocytoma among the B-cell lymphomas examined. In the other cases, the positivity was absent or appeared to lie within the cytoplasm without nuclear staining. We therefore propose that the immunolocalization of cyclin D1 protein is an essential marker for the definite diagnosis of MCL.

Re-induction of complete remission with a new synthetic retinoid, Am-80, for relapse of acute promyelocytic leukaemia previously treated with all-trans retinoic acid

Two patients with relapsed acute promyelocytic leukaemia previously treated with all-trans retinoic acid (ATRA), were treated with a new synthetic retinoid, Am-80. In both patients pancytopenia gradually resolved without an increase in leukaemic cells, and differentiation of leukaemic cells was observed morphologically in bone marrow. Without the use of anti-leukaemic agents, both cases achieved complete remission (CR) on days 52 and 38 of treatment, respectively. On the day of CR, PML gene rearrangement and the t(15;17) translocation disappeared, though PML-RAR alpha chimaeric messenger RNA was still detected by reverse transcriptase polymerase chain reaction. Both patients then received conventional chemotherapy for consolidation of CR. These clinical experiences suggest that Am-80 may be an active agent for APL patients who have relapsed from ATRA-induced remission.

Recent progress in molecular mechanisms of leukemogenesis: the cyclin-dependent kinase 4-inhibitor gene in human leukemias

In order to clarify the significance of p16 gene (CDKN2) inactivation and its disease specificity among hematopoietic tumors, configurations of the p16 gene as well as those of the adjacent p15 and interferon alpha (IFN alpha) genes were examined in primary hematopoietic tumors. Loss of the p16 gene is frequent in and highly specific to lymphoid tumors among hematopoietic tumors. Gene deletions but not minute mutations should be the predominant mechanism of p16 gene inactivation in these types of tumors. The p16 gene is most frequently deleted among the p16, p15 and IFN alpha genes and thus should be the target of deletions in this locus. Deletions of the p16 gene were frequently observed in tumors carrying chromosome 9p abnormalities while a significant number of cases showed loss of the p16 gene without chromosome 9p abnormalities. So far inactivation of p53 and Rb tumor suppressors have also been found in lymphoid tumors. In our study, we detected homozygous deletions of p16 gene in 20%, loss of Rb protein in 28%, and p53 gene alterations in 8% of lymphoid tumors. Notably, 44% of lymphoid tumors showed inactivation of at least one of the three tumor suppressors, suggesting these tumor suppressors are important for lymphoid tumorigenesis. Inactivations of these tumor suppressors should independently occur in development of lymphoid tumors.

High prevalence of GB virus C/hepatitis G virus infection among the Jewish population in Uzbekistan

Although a new virus, GB virus C/hepatitis G virus (GBV-C/HGV), has been isolated from patients with hepatitis by two different research groups, its prevalence in the world and pathogenesis are still unknown. In this study, 92 samples from the Jewish population of Uzbekistan were investigated for the prevalence of GBV-C/HGV. GBV-C/HGV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) using specific primers derived from the 5'-untranslated region (5'-UTR). Sequences were analyzed by a molecular evolutionary method. Of 92 samples, GBV-C/HGV RNA was detected in ten (10.9%), HCV RNA was present in two (2.2%), and HBsAg in eight (8.7%). HTLV-I and HIV infection was not detected. Single GBV-C/HGV infection was detected in eight (80%), and co-infection with HBV or HCV was detected in only two of the GBV-C/HGV infections. Alanine aminotransferase (ALT) levels were elevated in three (3.3%), but none with single GBV-C/HGV infection had an elevated ALT level. Nine people (90%) with GBV-C/HGV infection were distributed under the mean age of the population (P < 0.05). Molecular evolutionary analysis showed all GBV-C/HGV strains in this study were related to the HGV derived from the US. These results indicate that (1) GBV-C/HGV infection is highly prevalent among the Jewish population in Uzbekistan; (2) single GBV-C/HGV infections without persistent hepatitis are common; and (3) GBV-C/HGV infection is present among the younger generation.

Case-control study of leukemia and diagnostic radiation exposure

A case-control study of leukemia and diagnostic X-ray exposure was conducted by a multi-institution co-operative study group. The subjects were 134 patients with acute myelogenous leukemia, 57 with chronic myelogenous leukemia, 56 with acute lymphocytic leukemia and 50 with myelodysplasia syndrome, who were between 15 and 79 years old, and diagnosed at one of 27 hospitals between September 1993 and August 1995. The controls were 479 first-visit patients seen at eight of these 27 hospitals. History of diagnostic X-ray tests between 1982 and 1991 was determined by an anonymous self-administered questionnaire. The total relative dose of radiation exposure was calculated by summing the products of given weights and frequencies of each test. The relative risk was 0.83 (95% confidence interval (C.I.), 0.58-1.19) for relative dose of 10-30 (equivalent to 4-11 times of UGI series), 0.76 (0.48-1.20) for relative dose of 30 or more (more than 12 times of UGI series), when compared with relative dose of 0-10 (0-3 times of UGI series). Analysis according to type of leukemia revealed that only acute myelogenous leukemia had an estimated relative risk above unity (1.08, 95% C.I. 0.69-1.69, for relative dose 10-30). This study did not support the hypothesis that diagnostic X-ray tests increases leukemia risk.