Vaccine Adherence and Postvaccination Serological Status of Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Single-center Experience.

Despite developing consensus guidelines addressing immunization after hematopoietic stem cell transplantation (HSCT), studies showed deviations from recommended immunization practices commonly occur. Difference between the ideal scenario presented in guidelines and real-life scenarios is one of the most recognized barriers to implementing recommended practices. Therefore, this study aimed to evaluate pediatric allogeneic HSCT recipients' adherence to revaccination schedule and evaluate the serological status after immunization. Transplant and vaccination records of children who were followed up at least 2 years after HSCT, postvaccination antibody results of vaccine-preventable diseases were evaluated retrospectively. Total of 173 patients have enrolled in this study. Median revaccination onset time was post-transplant 15 months. Adherence to revaccination program was 30% for inactive and 11.4% for live vaccines. Oral polio vaccine was given to 22 patients, and Bacille-Calmette-Guerin vaccine was applied to 3. Seropositivity after revaccination was >90% for Hepatitis B, Hepatitis A, pertussis, and measles, and it was 88.5% for rubella, 80% for mumps and varicella. Measles seropositivity was low in children with hemoglobinopathy. In subgroup assessments of pertussis, patients vaccinated with low antigen-containing pertussis vaccine (Tdap) had higher seropositivity of adenylate cyclase toxin. Our findings revealed the importance of careful monitoring of current practices in pediatric HSCT recipients.

Analysis of human herpes virus 6 infections with a quantitative, standardized, commercial kit in pediatric stem cell transplant recipients after transplantation.

BACKGROUND AND OBJECTIVES: The aim of the study was to assess the incidence and clinical relevance of active Human Herpes Virus 6 (HHV6) infections in pediatric patients after allogeneic stem cell transplantation. DESIGN AND SETTINGS: Retrospective analysis of samples prospectively collected at Akdeniz University Medical Faculty Hospital, Antalya, Turkey, between May 2006 and July 2007 from 15 pediatric patients with allogeneic hematopoietic stem cell transplantation (HSCT). SUBJECTS AND METHODS: A commercial quantitative real-time polymerase chain reaction kit was used to analyze plasma samples collected from 15 pediatric allogeneic HSCT recipients. RESULTS: HHV6 DNA was found positive in 8 (53%) patients. HHV6 DNA levels above 1000 copies/mL were found only in 2 patients and they were also consecutively positive for HHV6 DNA. Age at transplantation, use of ATG, and receiving grafts other than HLA identical siblings increased the risk, with a statistically significant difference, of having HHV6 reactivation with levels exceeding 1000 copies/mL (P values, respectively, P=.03, .001, .025). Active HHV6 infections with HHV6 viremia levels higher than 1000 copies/mL were associated with subsequent delayed platelet engraftment (P=.001), acute graft versus host disease (P=.001), skin rash, and fever of unknown origin. CONCLUSION: More than half of pediatric allogeneic HSCT patients develop active HHV6 infection, and especially in patients with high viremic loads, the infection can result in serious clinical situations. A clinically significant cutoff value for viremia seems to be necessary to predict serious clinical complications.

Aberrations of chromosomes 9 and 22 in acute lymphoblastic leukemia cases detected by ES-fluorescence in situ hybridization.

A reciprocal translocation between chromosomes 9 and 22 creates oncogenic BCR/ABL fusion in the breakpoint region of the derivative chromosome 22. The aim of this study was to evaluate the importance of atypical fluorescence in situ hybridization (FISH) signal patterns in pediatric and adult acute lymphoblastic leukemia (ALL) cases. We evaluated t(9;22) translocation in 208 cases with ALL (294 tests), including 139 childhood and 69 adult cases by FISH technique using BCR/ABL extra signal (ES) probe. FISH signal patterns observed in pediatric ALL cases were as follows; Major-BCR/ABL (M-BCR/ABL) (1.4%), minor-BCR/ABL (m-BCR/ABL) (3.6%), trisomy 9 (4.3%), trisomy 22 (4.3%), trisomy or tetrasomy of both chromosomes 9 and 22 (2.9%), monosomy 9 (1.4%), monosomy 22 (0.7%), ABL gene amplification (1.4%), derivative chromosome 9 deletion (1.4%), and extra copies of the Philadelphia chromosome (1.4%). FISH signal patterns observed in adult ALL cases were as follows; M-BCR/ABL (5.8%), m-BCR/ABL (11.6%), two different cell clones with major and minor BCR/ABL signal pattern (2.9%), extra copies of Philadelphia chromosome (4.3%), derivative chromosome 9 deletion (1.4%), trisomy 9 (2.9%), tetraploidy (1.4%), monosomy 9 (1.4%), trisomy 22 (1.4%), and coexistence of both trisomy 22 and monosomy 9 (1.4%). Trisomy 9, trisomy 22, and polyploidy of chromosomes 9 and 22 were specific atypical FISH signal patterns for childhood B cell acute lymphoblastic leukemia (B-ALL) patients. However, monosomy 9 and ABL gene amplification were highly specific for childhood T cell acute lymphoblastic leukemia (T-ALL) patients. Our report presents the correlation between atypical FISH signal patterns and clinical findings of a large group of ALL cases.

Can serum cystatin C reflect the glomerular filtration rate accurately in pediatric patients under chemotherapeutic treatment? A comparative study with Tc-99m DTPA two-plasma sample method.

OBJECTIVE: It was assessed whether cystatin C (cysC) could be used as a marker of glomerular filtration rate (GFR) by considering the technetium-99m diethylenetriamine penta-acetate (Tc-99m DTPA)-two blood sample method (GFRTc-99m DTPA) as the reference in pediatric patients under chemotherapeutic treatment. METHODS: The chemotherapy group (CG) consisted of 31 patients (21 females, 10 males median age: 8.2 years; range: 2-16 years) who had been planned to receive allogenic hematopoietic stem cell transplantation. All patients in the CG received conditioning regimen (includes chemotherapy protocol) before hematopoietic stem cell transplantation. In addition, 21 patients (14 females, seven males median age: 9.5 years; range: 4-16 years) without any chemotherapy (nonchemotherapy group: nCG) were also prospectively investigated. Serum cysC, serum creatinine, GFRTc-99m DTPA, and GFR with a cysC-based formula (GFRcysC) were analyzed. Tubular function was also assessed. RESULTS: Although we found good correlation between GFRTc-99m DTPA and cysC (r = -0.78), GFRTc-99m DTPA and GFRcysC (r = 0.91), cysC and creatinine (r = 0.91) in nCG, the same correlations were poor in CG (r = -0.42, r = 0.43, r = 0.46, respectively). Tubular function was impaired after chemotherapy. Bias+/-1.96 SD values were -6+/-15.7 and -3+/-54.8 ml/min/1.73 m in nCG and CG, respectively. Precision was also better in nCG (10 ml/min/1.73 m) than in CG (27.6 ml/min/1.73 m). CONCLUSION: Serum cysC and GFRcysC cannot reflect GFR accurately in pediatric patients under chemotherapeutic treatment. Tubular cell damage induced by chemotherapeutics could be a responsible factor through the impairment of tubular absorption and metabolism of cysC.

Renal function after hematopoietic stem cell transplantation in children.

OBJECTIVES: The aim of this study was to assess glomerular and tubular renal function after HSCT in children in a prospective trial. METHODS: Renal function was assessed prospectively before HSCT (on day -10), on days +30, +100, and at least 6 months after transplantation in 34 patients (21 females/13 males) with a mean age of 8.2 years. The following parameters were investigated: glomerular filtration rate (GFR) by creatinine clearance (CrCl), cystatin C (CysC)-based formula and plasma clearance of radiolabeled diethylenetriaminepentaacetic acid ((99m)Tc-DTPA), urinary excretion of beta(2)-microglobulin (beta(2)M), beta-N-acetylglucosaminidase (beta-NAG), fractional excretion of sodium (FE(Na)) and fractional tubular phosphate reabsorption (TP/CrCl). RESULTS: Nine patients (26.4%) suffered from acute renal insufficiency within the first 100 days after transplantation. All patients who developed acute renal insufficiency were treated successfully without renal replacement therapy. Age, sex, primary diagnosis, sepsis, veno-occlusive disease, acute graft versus host disease, and use of vancomycin were not significant risk factors for the development of acute renal insufficiency. The medians (99m)Tc-DTPA-based GFR of patients after HSCT showed a statistically significant decrease when compared with pre-transplant values. beta-NAG excretion was significantly elevated in the first 30 days after HSCT. CONCLUSION: Acute and chronic renal impairment can be developed in patients who undergo HSCT even though the pre-transplant renal function is in normal limits and the conditioning regimen does not include TBI. Both glomerular and tubular renal function evaluation should be part of a long-term follow-up in children following HSCT.

Unrelated cord blood transplantation in children with severe congenital neutropenia.

SCN is an inherited hematological disorder with severe neutropenia and recurrent infections. Although there are some reports that recombinant rhG-CSF improves clinical outcome, allogeneic HSCT appears to be the only curative treatment for these patients. We report here two children with SCN successfully treated by CBT from unrelated donors. They were refractory to rhG-CSF treatment and have no identical family donor. Bu + CY were given as conditioning. Case 1 and Case 2 received 6/6 and 5/6 HLA-matched unrelated umbilical cord blood, respectively. The number of infused nucleated cells was 6, 18 x 10(7)/kg and CD34(+) cell number was 3, 74 x 10(5)/kg in Case 1. Those cell numbers were 8, 8 x 10(7)/kg and 5, 34 x 10(5)/kg for Case 2, respectively. Neutrophil/platelet engraftments were 45/49 days in Case 1 and 24/36 days in Case 2. Grade II cutaneous acute GVHD was seen in Case 2 that was treated successfully with prednisolone. Both patients are well with normal hematological findings and full donor chimerism for post-transplant 20 and 24 months, respectively. We conclude that UCB can be considered as a safe source of stem cell in patients with SCN who need urgent HSCT.

Heart rate variability in patients with thalassemia major.

Cardiac dysfunction, including congestive heart failure and fatal arrhythmia, is a frequent cause of death among children with thalassemia major (TM). Autonomic nervous system activity typically is measured by a series of cardiovascular autonomic function tests, but these tests are unsuitable for young patients because they are invasive or complex. Heart rate variability assessment is a technique that measures the beat-to-beat variability in R-R intervals. This variability reflects changes in autonomic activity and their impact on cardiovascular function. This study examined 32 patients with TM to evaluate heart rate variability (HRV) in a preclinical phase of cardiac involvement. The study patients showed no evidence of heart failure or signs of peripheral or autonomic neuropathy. All HRV parameters were significantly reduced in the TM patient group compared with the control group. The results of this study can be interpreted as evidence of early cardiac autonomic neuropathy in young thalassemic patients. Therefore, all TM patients should be screened using HRV analysis for that complication.

An unusual localization of embryonal rhabdomyosarcoma in a neonate.

Rhabdomyosarcoma (RMS) is a common, highly malignant, uniformly fatal childhood malignancy, which presents extremely rarely in the neonatal period; there are only a few reports about this tumor in this age group. While the primary tumor may arise virtually anywhere in the body, the extremity, orbit and genitourinary region are the most frequent sites; the retromammary region is extremely rare. Herein, we report a neonate with embryonal RMS arising from the anterior chest wall musculature at birth.

Donor cell-derived acute myeloblastic leukemia after allogeneic peripheral blood hematopoietic stem cell transplantation for juvenile myelomonocytic leukemia.

Despite its rarity, donor cell leukemia (DCL) is a most intriguing entity. We report here the case of a 5 year-old girl with juvenile myelomonocytic leukemia and normal female karyotype who developed acute myeloblastic leukemia with a karyotype of 46, X, t(X; 7) (p21; p11.2), der(7) t(3; 7) (q13.3; q22) 5 months after peripheral blood hematopoietic stem cell transplantation from her HLA-matched sister. We performed the analysis of short tandem repeat sequence markers to DNA obtained from donor peripheral blood, patient's peripheral blood including leukemic blasts and patient's hair root. This analysis showed that the leukemic blood DNA matched the donor blood DNA and not the patient's DNA, thus confirming DCL. To our knowledge, this is the first case of DCL after peripheral blood SCT for juvenile myelomonocytic leukemia.

Cytomegalovirus antigenemia and outcomes of patients undergoing allogeneic peripheral blood stem cell transplantation: effects of long-term high-dose acyclovir prophylaxis and preemptive ganciclovir treatment.

Cytomegalovirus (CMV) disease is a frequent cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. In order to investigate the relationships between antigenemia, high-dose acyclovir (HDACV) prophylaxis, preemptive ganciclovir (GCV) therapy, and outcomes, we analyzed the records of 105 patients, including both pediatric and adult populations, who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) and who were at risk for CMV reactivation and disease (both recipient and donor seropositive). All received HDACV until neutrophil engraftment, but prophylaxis was continued till post-transplant day 180 only in pediatric patients in conjunction with weekly CMV pp65 antigenemia monitoring. Antigenemia-guided preemptive strategy with GCV was used for all patients. CMV antigenemia developed in 45 patients (42.9%) and CMV disease in 13 (12.4%). The frequencies for antigenemia were 31.3 and 63.2% in pediatric and adult groups (P = 0.002). All CMV diseases were in the adult group (P<0.001). Age at transplantation, underlying disease, long-term HDACV prophylaxis and acute graft versus host disease (aGVHD) were all found to be a significant risk factors for antigenemia. All of these factors other than aGVHD and conditioning regimen were also the significant risk factors for CMV disease. However, when we analyzed the pediatric and adult patients separately, dropping "long-term HDACV prophylaxis," none of these parameters were significant risk factors for CMV disease. In conclusion, we hypothesize that long-term HDACV prophylaxis in the GCV era results in a low incidence of CMV reactivation and disease in patients undergoing PBSCT.

Episodes of fever and neutropenia in children with cancer in a tertiary care medical center in Turkey.

The aim of this study was to determine the clinical features and microbiological spectrum during episodes of fever and neutropenia (FEN) in children with cancer. Demographics, clinical information, treatment approaches, and outcomes of the patients admitted to Akdeniz University Department of Pediatric Hematology and Oncology from October 1996 to June 2004 were evaluated retrospectively. Of the total 621 episodes, 345 (55.5%) were microbiologically documented (MDI) (36.4%) or clinically suspected (CSI) (19.2%) infections. A total of 425 infections were diagnosed in 345 episodes, in which lower respiratory tract infections were the most common (32.7%). Among the microbiologically documented infections, Staphylococci (both coagulase-negative and coagulase-positive) (38.7%) and Escherichia coli (12.9%) were the most frequently isolated gram-positive and gram-negative organisms, respectively. Monocytopenia less than 100/microL (p = 0.01), duration of neutropenia (p = .01) and fever (p < .001) were significantly associated with documented infection by univariate analysis. In addition, presence of previous FEN episode (p = .001) and hypotension (p = .029) were also found to be risk factors. However, using the multivariate analyses, only the duration of fever was found to be an independent risk factor for MDI. The rate of mortality was significantly higher among under 1-year-old patients (p = .039). Hypotension and uncontrolled cancer were the significant determinants of poor prognosis. These results may help to consider a more selective management strategy for children with these problems.