Takaharu Matsuyama

Prognostic value of internal tandem duplication of the FLT3 gene in childhood acute myelogenous leukemia.

BACKGROUND Recently, an internal tandem duplication of the FLT3 gene (FLT3/ITD) was found in 20% of adult cases of acute myelogenous leukemia (AML), and this length abnormality was suggested to be associated with leukemic progression. PROCEDURE We examined the mRNA expression of the FLT3 gene by using reverse transcription-polymerase chain reaction (RT-PCR) in 64 children with AML, and further abnormal transcripts were cloned and sequenced. RESULTS An unexpected longer product was found in seven patients (11%) by RT-PCR of the FLT3 gene. Sequence analysis of these abnormal products revealed the presence of tandemly duplicated fragments in all seven patients. Three factors were identified to be associated with high incidence of FLT3/ITD; older patients (> or = 10 years) (P = 0.049), high WBC count (> or = 50,000/microl) at presentation (P = 0.002), and M3 in FAB subtypes (P = 0.002). Induction failure was observed in 3 (43%) of 7 patients with FLT3/ITD. Only FLT3/ITD was identified as a significant risk factor for induction failure by univariate analysis (P = 0.013), although it was not significant by multivariate analysis (P = 0.11). The Kaplan-Meier estimate of event-free survival rate at 5 years was 14% for patients with FLT3/ITD, which was significantly lower in comparison with 69% for patients without FLT3/ITD (P = 0.003). This finding was also identified by multivariate analysis (P = 0.01). CONCLUSIONS In this study, FLT3/ITD was observed in 11% of childhood AML and identified to be associated with poor prognosis. A large prospective study with uniform treatment is necessary to confirm our results.

Quantitative analysis of cytomegalovirus load using a real-time PCR assay.

A novel real‐time PCR assay system was developed to quantify the cytomegalovirus (CMV) genome load. The real‐time PCR assay could detect from 6 to over 106 copies of CMV‐DNA with a wide linear range. The virus load of immunocompromised patients with symptomatic CMV infections was quantified and compared to that of asymptomatic ones. In symptomatic patients, all 17 peripheral blood leukocytes were positive for CMV DNA, and its mean value was 103.3 copies/106 cells. On the other hand, only 9 of 38 samples (24%) were positive in the asymptomatic patients, and its mean titer was lower (102.0 copies/106 cells) than that of the symptomatic group (P = 0.002). In plasma, the virus genome was detected in 13 out of 17 samples from symptomatic patients (76%), and its mean value was 104.0 copies/ml. In contrast, for the asymptomatic group, only one out of 36 samples were positive (3%). Finally, this system was used to monitor two patients with CMV infections serially. The CMV DNA copy number changed with their clinical symptoms and anti‐CMV therapy, and virtually paralleled the result of the pp65 antigenemia assay in both cases. In one patient with the cord blood transplantation, however, the CMV DNA became positive faster than the antigenemia assay. These results indicate that this assay is sensitive and useful for estimating the CMV genome load not only in peripheral blood leukocytes but also in plasma. It can be very helpful for diagnosing CMV‐related diseases and monitoring the virus load in patients with CMV infections. J. Med. Virol. 60:455–462, 2000.

Human herpesvirus 6 viremia in bone marrow transplant recipients: clinical features and risk factors.

Human herpesvirus 6 (HHV-6) infection was studied in 82 bone marrow transplant (BMT) recipients (72 allogeneic, 10 autologous). All recipients and 30 donors were seropositive for HHV-6 antibody at the time of bone marrow transplantation. Thirty-one recipients (37.8%) had HHV-6 viremia 2-4 weeks after transplantation. The incidence of HHV-6 viremia was significantly higher among allogeneic BMT recipients than in autologous BMT recipients (P=.011). Therefore, the following analyses of allogeneic BMT recipients were carried out (n=72). Geometric mean antibody titers (log(10)) were significantly higher in recipients without viremia than in those with viremia (1.84+/-0.39 vs. 1.61+/-0.42; P=.022). Logistic regression analysis demonstrated that leukemia or lymphoma is an independent risk factor (P=.031) for HHV-6 viremia. Rash occurring within 1 month after transplantation was observed in 17 (54.8%) of 31 recipients with HHV-6 viremia but in only 8 (19.5%) of 41 recipients without HHV-6 viremia (P=.001).

Long‐term outcome of acquired aplastic anaemia in children: comparison between immunosuppressive therapy and bone marrow transplantation

A total of 100 children under the age of 17 years with acquired aplastic anaemia (AA) were initially treated with immunosuppressive therapy (IST) (n = 63) or bone marrow transplantation (BMT) (n = 37) from an HLA‐matched family donor. The projected 10‐year survival rates were 55 ± 8% and 97 ± 3% respectively (P = 0·004). Because the IST group included 11 non‐responders who were salvaged by BMT from an HLA‐matched unrelated donor, we compared failure‐free survival (FFS) between the groups. The probability of FFS at 10 years was 97 ± 3% for the BMT group, compared with 40 ± 8% for the IST group (P = 0·0001). Seven patients evolved to myelodysplastic syndrome (MDS) with monosomy 7 and the estimated cumulative incidence of MDS 10 years after diagnosis was 20 ± 7% in the IST group. We compared the outcome of children treated with IST during the two consecutive periods of 1983–91 (group A, n = 40) and 1991–8 (group B, n = 23) to assess the impact of combined therapy with anti‐thymocyte globulin and cyclosporin. The probability of FFS at 7 years follow‐up was the same in the two groups (50 ± 8% vs. 40 ± 15%, P = 0·40). We recommend BMT as first‐line therapy in paediatric severe AA patients with an HLA‐matched family donor. Alternative donor BMT is recommended as salvage therapy in patients who relapse or do not respond to initial IST.

Successful ribavirin therapy for severe adenovirus hemorrhagic cystitis after allogeneic marrow transplant from close HLA donors rather than distant donors.

Intravenous ribavirin was given to nine patients who had developed severe adenovirus-induced hemorrhagic cystitis (AD-HC) which was resistant to conventional therapy or where there was involvement of other organs after allogeneic BMT. Three patients recovered completely from AD-HC, two of whom had been resistant to vidarabine. All three had received sibling BMTs (2 HLA matched, 1 HLA mismatched). Five patients who received BMTs from related (2 HLA mismatched) or unrelated (1 HLA matched, 2 HLA mismatched) showed an improvement in symptoms but had recurrent AD-HC after discontinuation of ribavirin. Improvement in clinical symptoms and termination of virus excretion were well correlated. The last patient who received a mismatched unrelated BMT died during ribavirin therapy. Ribavirin was notably more effective among patients receiving BMTs from siblings in contrast to patients receiving BMTs from alternative donors (<0.05). One patient experienced severe pancytopenia during the second treatment with ribavirin after hc recurrence and recovered after ceasing ribavirin. Thus, ribavirin seems to be very effective for severe ad-hc for some recipients who receive transplants from a genetically close donor. Bone Marrow Transplantation (2000) 25, 545–548.

Veno-occlusive disease of the liver after allogeneic bone marrow transplantation in children with hematologic malignancies : incidence, onset time and risk factors

One hundred and forty children with hematologic malignancies undergoing allogeneic BMT were reviewed in order to clarify the incidence, onset time, and risk factors for veno-occlusive disease (VOD) of the liver. Thirty-eight patients (27.1%) developed VOD diagnosed according to the Seattle clinical criteria. Seventeen patients developed VOD within 20 days of transplantation (early-onset) and in 21 patients developed after day 20 (late-onset) including eight patients with histological confirmation. Late-onset VOD occurred from day 21 to day 508 (median day 39). Moderate or severe VOD developed in 11 early-onset and 13 late-onset patients. Death occurred in eight early-onset and 10 late-onset patients. Serum albumin and cholinesterase levels prior to the start of pretransplant conditioning were significantly lower in early-onset VOD than in late-onset VOD. Multivariate analysis showed that low serum albumin levels (⩽3.7 g/dl) prior to the start of pretransplant conditioning was most strongly associated with the development of VOD. Donor mismatch (other than HLA-matched relatives), use of minocycline, and a long interval (⩾13 months) between diagnosis and BMT were also significantly associated with the development of VOD. In contrast, use of fosfomycin was associated with a decreased risk. Our data suggest that hepatic function reserve is important in the development and onset time of VOD. Veno-occlusive disease of the liver is a complication which may occur a long time after transplantation.

Correlation between HHV-6 infection and skin rash after allogeneic bone marrow transplantation

We investigated whether a causal relationship exists between human herpesvirus 6 (HHV-6) and skin rash resembling acute graft-versus-host disease (GVHD) following bone marrow transplantation (BMT). Isolation of HHV-6 was used to monitor active HHV-6 infection in this study. We analyzed 25 episodes of skin rash in 22 recipients. All recipients were seropositive for HHV-6 before BMT. The onset of skin rash started prior to 30 days post transplantation (group A) in 15 of 25 cases, but after that (group B) in the remaining 10 cases. Twenty-five skin tissue samples were obtained from 22 recipients. The HHV-6 genome was detected in four of 15 skin samples from group A, but not detected in those from group B. HHV-6 was isolated from 11 of 22 recipients around 2 to 3 weeks after BMT (range 14 to 28 days after BMT). HHV-6 was isolated at a time between 10 days before and after the onset of skin rash (skin rash-related viremia) in nine cases in group A. Meanwhile, no skin rash-related viremia was observed in group B. Of the four recipients with positive detection of HHV-6 genome in their skin tissue (group A), two had HHV-6 viremia at the same time. The association between the timing of HHV-6 infection and the onset of skin rash was analyzed statistically. HHV-6 viremia (skin rash-related viremia) was found in nine of 15 (60%) cases in group A, compared with none of 10 (0%) cases in group B. This difference was statistically significant (P = 0.008). Moreover, HHV-6 infection (skin rash-related viremia and/or positive detection of HHV-6 DNA in skin tissue) was demonstrated in 11 of 15 (73.3%) cases in group A, compared with none of 10 (0%) cases in group B (P = 0.001). Thus, this study suggests that HHV-6 may be involved in the development of skin rash in the first month after allogeneic BMT. Bone Marrow Transplantation (2001) 28, 77–81.

Prospective monitoring of the Epstein–Barr virus DNA by a real‐time quantitative polymerase chain reaction after allogenic stem cell transplantation

Epstein‐Barr virus (EBV)‐related lymphoproliferative disorder (LPD) is a serious complication of haematopoietic stem cell transplantation (HSCT). To clarify the frequency, natural course and risk factors for LPD, we prospectively monitored 38 allogeneic (allo)‐HSCT patients, focusing on the use of anti‐thymocyte globulin (ATG). We used a recently developed real‐time polymerase chain reaction assay to monitor EBV genome load. The subjects consisted of 19 patients given ATG for conditioning and 19 patients not given ATG. Of the 19 patients given ATG, 47·4% (nine patients) had a significant increase in EBV genome load (102·5 copies/µg DNA). Of these nine patients, two developed LPD. Therefore, 10·5% of the patients receiving allo‐HSCT with ATG developed LPD. In contrast, none of the 19 patients without ATG had a significantly increased EBV load. The increases in viral load were observed in the second or third month after HSCT. We found that the peak viral loads of LPD patients were > 104·0 copies/µg DNA. On the other hand, the viral loads of most patients with no symptoms were < 102·5 copies/µg DNA. In conclusion, routine monitoring of EBV load during the second and third months after transplantation may benefit patients undergoing HSCT with ATG. We propose that an EBV load > 102·5 copies/µg DNA is the reactivation of EBV, and that an EBV load > 104·0 copies/µg DNA is indicative of developing LPD.

IgM Neutralizing Antibody Responses to Human Herpesvirus-6 in Patients with Exanthem Subitum or Organ Transplantation

The assay for detecting IgM neutralizing (NT) antibody activity to human herpesvirus‐6 (HHV‐6) was developed by using pretreatment of blood sample with staphylococcal protein A. The activity was mostly present in IgM fractions of serum but not in IgA fractions separated by ultracentrifugation. The assay was used for seroepidemiological studies for HHV‐6 infection. In primary HHV‐6 infection, IgM NT antibodies appeared 5 to 7 days after onset of exanthem subitum, reached maximum titers at 2 to 3 weeks, and tended to decline to undetectable levels after 2 months. In contrast, reactivation of HHV‐6 observed in organ transplants showed somewhat greater degree of IgM NT antibody responses that persisted for 2 to 3 months and became undetectable 5 to 6 months after transplantation. The level and persistence of NT antibody titers measured by the conventional method was generally greater than those of the IgM titers. The prevalence of the IgM NT antibodies was examined in healthy individuals. The antibody was first detected at 4 to 7 months of age (5%), reached maximum level at 8 to 11 months (40%), and was detectable by 4 to 6 years (17%). A few (4 to 5%) of adolescents and adults were positive for the antibody.

Late-onset hemorrhagic cystitis after hematopoietic stem cell transplantation in children

We analyzed the incidence, complications, and risk factors for late-onset hemorrhagic cystitis (HC) in 256 children undergoing hematopoietic stem cell transplantation (HSCT). Twenty-six recipients (10.2%) developed late-onset HC between 3 and 270 days (median, 33 days) after HSCT. In most patients, the severity of HC was mild to moderate, and spontaneous resolution occurred. Three children developed bladder tamponade, and one required suprapubic cystotomy. Four children died in the early post-transplant period without resolution of HC, but HC was not the direct cause of death in any patient. Twenty-two patients recovered within 6–86 days (median, 16 days) of onset. Three predisposing factors were identified for development of late-onset HC by multivariate analysis: allogeneic HSCT, older age (⩾7 years), and busulphan for pretransplant conditioning were significantly associated with late-onset HC (P = 0.022, P = 0.044 and P = 0.036, respectively). Excretion of adenovirus type 11 was demonstrated in six of 22 patients at the onset of cystitis. We suspect that reactivation of virus may be a major pathogenic factor in late-onset HC, but several clinical factors are also associated.