Changes in thyroid function parameters three months after allogenic and autologous hematopoietic stem cell transplantation in children

BACKGROUND

Thyroid dysfunction (hypo- and hyperthyroidism) has been reported as a late effect after hematopoietic stem cell transplantation (HSCT) in children. Short term effects of HSCT on thyroid function parameters are, however, unclear.

METHODS

We prospectively evaluated thyroid function parameters before and three months after HSCT in all children (<21 years) who underwent HSCT during a two-year period in the Princess Máxima Center, the Netherlands.

RESULTS

Among 72 children, none had thyroidal hypothyroidism or hyperthyroidism three months after HSCT. Changes in thyroid function parameters (either aberrant TSH or FT4 concentrations) were found in 16% before and in 10% three months after HSCT. Reverse T3 was found elevated in 9.3% before and in 37% three months after HSCT, which could be related to poor physical condition. An individual decline in FT4 concentration of ≥20% was found in 10.5% (6/57) three months after HSCT.

CONCLUSION

In conclusion, thyroidal hypo- and hyperthyroidism are very rare three months after HSCT. These results indicate that surveillance for hypo- and hyperthyroidism may start later in time. The changes in thyroid function parameters found three months after HSCT might reflect the euthyroid sick syndrome.

A case report of a blueberry muffin baby caused by congenital self-healing indeterminate cell histiocytosis

BACKGROUND

Blueberry muffin is a descriptive term for a neonate with multiple purpuric skin lesions. Many causes are known, amongst them life-threatening diseases like congenital infections or leukemia. Indeterminate cell histiocytosis (ICH) is an exceptionally rare cause of blueberry muffin rash. ICH is a histiocytic disorder which can be limited to the skin or can present with systemic involvement. A mutation that has been described in histiocytic disorders is a MAP2K1 mutation. In ICH, this mutation has previously been described in merely one case.

CASE PRESENTATION

A term male neonate was admitted to the neonatology ward directly after birth because of a blueberry muffin rash. ICH was diagnosed on skin biopsy. The lesions resolved spontaneously. The patient is currently 3 years old and has had no cutaneous lesions or systemic involvement so far. This disease course is similar to that of the Hashimoto-Pritzker variant of LCH.

CONCLUSIONS

ICH can manifest in neonates as resolving skin lesions. It is limited to the skin in most cases, but systemic development is possible. Therefore, it is essential to confirm the diagnosis with a biopsy before the lesions resolve and to monitor these patients closely with routine follow-up.

Population Pharmacokinetics and Pharmacodynamics of Ciprofloxacin Prophylaxis in Pediatric Acute Lymphoblastic Leukemia Patients

BACKGROUND

Ciprofloxacin is used as antimicrobial prophylaxis in pediatric acute lymphoblastic leukemia (ALL) to decrease infections with gram-negative bacteria. However, there are no clear guidelines concerning prophylactic dose.

AIMS

To determine the pharmacokinetics and pharmacodynamics (PKPD) of ciprofloxacin prophylaxis in a pediatric ALL population. The effect of patient characteristics and antileukemic treatment on ciprofloxacin exposure, the area under the concentration time curve over minimal inhibitory concentration (AUC24/MIC) ratios, and emergence of resistance were studied.

METHODS

A total of 615 samples from 129 children (0-18 years) with ALL were collected in a multicenter prospective study. A population pharmacokinetic model was developed. Microbiological cultures were collected prior to and during prophylaxis. An AUC24/MIC of ≥125 was defined as target ratio.

RESULTS

A 1-compartment model with zero-order absorption and allometric scaling best described the data. No significant (P < .01) covariates remained after backward elimination and no effect of asparaginase or azoles were found. Ciprofloxacin AUC24 was 16.9 mg*h/L in the prednisone prophase versus 29.3 mg*h/L with concomitant chemotherapy. Overall, 100%, 81%, and 18% of patients at, respectively, MIC of 0.063, 0.125, and 0.25 mg/L achieved AUC24/MIC ≥ 125. In 13% of the patients, resistant bacteria were found during prophylactic treatment.

CONCLUSION

Ciprofloxacin exposure shows an almost 2-fold change throughout the treatment of pediatric ALL. Depending on the appropriateness of 125 as target ratio, therapeutic drug monitoring or dose adjustments might be indicated for less susceptible bacteria starting from ≥ 0.125 mg/L to prevent the emergence of resistance and reach required targets for efficacy.

The impact of maintenance therapy on sleep-wake rhythms and cancer-related fatigue in pediatric acute lymphoblastic leukemia

Purpose

To assess the impact of maintenance therapy and the additional impact of dexamethasone treatment on cancer-related fatigue and sleep-wake rhythms in pediatric acute lymphoblastic leukemia (ALL) patients and to determine the association between these outcomes.

Methods

A national cohort of pediatric ALL patients (≥ 2 years) was included (± 1 year post-diagnosis). Patients receiving dexamethasone were assessed twice (assessment with and without dexamethasone). Actigraphy assessments were used to calculate sleep-wake outcomes with nonparametric methods. Cancer-related fatigue was assessed with the PedsQL Multidimensional Fatigue Scale. Sleep-wake rhythms and cancer-related fatigue were compared between patients participating in the assessment without dexamethasone and healthy children (linear regression) and between assessments with and without dexamethasone (mixed models). Using linear regression, associations between sleep-wake outcomes and cancer-related fatigue were determined during assessments with and without dexamethasone.

Results

Responses were collected for 125 patients (113 assessments with and 81 without dexamethasone). The sleep-wake rhythm was less stable (p = 0.03) and less robust (p = 0.01), with lower physical activity levels (p < 0.001) and higher cancer-related fatigue levels (p < 0.001) in ALL patients compared to healthy children. Physical activity was lower (p = 0.001) and cancer-related fatigue more severe (p ≤ 0.001) during assessments with dexamethasone compared to without dexamethasone. Sleep-wake outcomes were significantly associated with cancer-related fatigue during periods without dexamethasone, but not during periods with dexamethasone.

Conclusion

Sleep-wake rhythms are disturbed, physical activity levels lower, and cancer-related fatigue levels higher during maintenance therapy. Interventions aimed to enhance sleep-wake rhythms during maintenance therapy could improve cancer-related fatigue. Families should be supported in coping with the additional burden of dexamethasone treatment to improve well-being of ALL patients.

Electronic supplementary material

The online version of this article (10.1007/s00520-020-05444-7) contains supplementary material, which is available to authorized users.

Primary ovarian insufficiency in children after treatment with 131I-metaiodobenzylguanidine for neuroblastoma: report of the first two cases

BACKGROUND

Primary ovarian insufficiency (POI) is a noted late effect in childhood cancer survivors treated with alkylating agents or after radiation to a field that includes the ovaries. Gonadal failure in children with neuroblastoma (NBL) who were exposed to 131I- metaiodobenzylguanidine (MIBG) has only been reported in those who were also treated with chemotherapy. In these cases, the cause of gonadal failure was assumed to be the cytotoxic therapy. Here, we present the first two cases of POI after 131I-MIBG treatment only for NBL, indicating that 131I-MIBG treatment may have a causative role.

PATIENTS

During follow-up after treatment for NBL in childhood, elevated gonadotropins were found in a 12-year-old girl and an 11-year-old girl (FSH values, 105 and 161 U/L, respectively), indicating POI. The first patient had been diagnosed at the age of 17 months with sacrally located (intraspinal) NBL. Treatment consisted of five courses of 131I-MIBG and local resection. The second patient had been diagnosed at the age of 8 months with an abdominal (intraspinal) NBL. She had been treated with acute (neuro) surgery for decompression of her intraspinal tumor causing neurological symptoms, followed by two courses of 131I-MIBG therapy. Both girls had normal karyotypes (46, XX). No other cause for the ovarian failure was found. Estrogen suppletion was started, and patients and parents were counseled regarding fertility options.

CONCLUSION

These two cases suggest that exposure to 131I-MIBG may damage the female gonads. Clinicians caring for childhood cancer survivors should be aware of the risk of POI after 131I-MIBG treatment. Prospective studies are warranted to confirm our observations.

No adverse effect of vincristine on handwriting in children after completion of therapy

BACKGROUND

Long-term writing difficulties in children after treatment with vincristine for acute lymphoblastic leukemia, Wilms tumor, B non-Hodgkin lymphoma, and malignant mesenchymal tumors, were investigated.

PROCEDURE

Handwriting of 33 survivors and 33 controls matched for age, sex, and grade, was assessed with the BHK-scale. The examiner was blinded for whether a child was a case or a control.

RESULTS

No significant difference in writing speed was found. Mean difference in number of letters produced during 5 min was 6.4 (+/-67.1, range -103 to +169). No significant difference was found in quality of writing scores; mean difference in points was 1.5 (+/-7.7, range -19 to +22). Cumulative vincristine dose, age at diagnosis or time since completion of treatment did not affect writing speed or quality.

CONCLUSION

Chemotherapy, including vincristine, does not lead to long-term problems in speed or quality of writing in children treated for cancer.

[A boy with acute cerebellar ataxia without opsoclonus caused by neuroblastoma]

A 2-year-old boy presented with acute cerebellar ataxia without opsoclonus. The ataxia was assumed to be post-viral. After a period of years a neuroblastoma was detected. Treatment with a curative intent was successful and consisted of metaiodobenzylguanidine I 131, chemotherapy, tumour resection, chemotherapy again and follow-up treatment with isotretinoin after irradiation. In the literature, 5 other children have been described with acute cerebellar ataxia without opsoclonus in whom neuroblastoma was detected eventually. The mean age of these children at initial presentation was 26 months. The mean time between initial presentation and diagnosis ofneuroblastoma or ganglioneuroblastoma was 12 months. Urine concentrations of catecholamine metabolites were normal in 5 of the 6 total children; concentrations were elevated in 1 child. The tumour was located paravertebrally in 5 of the 6 children. Ataxia resolved following resection of the neuroblastoma in all patients. Each child with prolonged or recurrent acute cerebellar ataxia should be extensively investigated for the presence of neuroblastoma, even in the absence of opsoclonus.

Quality of life, self-esteem and worries in young adult survivors of childhood cancer

This study assessed quality of life, self-esteem and worries in young adult survivors of childhood cancer compared to a group of young adults with no history of cancer. The impact of demographic, medical and treatment factors and self-esteem on survivors' quality of life and worries was studied. Participants were 400 long-term survivors (LTS) of childhood cancer (age range 16-49 years, 45% female) who had completed treatment an average of 16 years previously and 560 persons (age range 16-53 years, 55% female) with no history of cancer. All participants completed the MOS-24 (Medical Outcome Study Scale), a Worry questionnaire consisting of three scales (cancer-specific concerns, general health concerns, present and future concerns), and the Rosenberg Self-Esteem Scale. Small to moderate differences were found in mean MOS-24 scores between the LTS group and controls (range effect sizes -0.36-0.22). No significant difference was found in the mean self-esteem scores between LTS and controls. Female LTS had more cancer-specific concerns than male LTS. In several related areas of general health, self-image and dying, the LTS group reported less worries than controls, but LTS worried significantly more about their fertility, getting/changing a job and obtaining insurance's. Multiple linear regression analysis revealed that female gender, unemployment, severe late effects/health problems and a low self-esteem were predictors of worse quality of life in survivors. In addition, age at follow-up, unemployment, years since completion of therapy and a low self-esteem were associated with a higher degree of survivors' worries. Quality of life and the level of self-esteem in LTS of childhood cancer is not different from their peers. Although many LTS worried not more or even less about health issues than their peers, they often are concerned about some present and future concerns. The investigated factors could explain poor quality of life and worries only to a limited extent. Further research exploring determinants and indices of quality of life and worries in LTS is warranted.

Frequent adverse events after treatment for childhood-onset differentiated thyroid carcinoma: a single institute experience

Since the mortality rate for childhood differentiated thyroid carcinoma is nearly zero, the focus must be to minimise morbidity following treatment. Our aim was to analyse early and late adverse events. Twenty-five of 26 children treated between 1962 and 2002 were evaluated. Median follow-up was 14.2 years (range 0.9-39.4 years). All underwent total thyroidectomy, 15 (60%) with lymph node dissection and 15 (60%) with adjuvant radio-iodide therapy. Mortality was zero. Seven developed recurrent disease, two developed a third recurrence. Twenty-one (84%) had > or =1 adverse event. Eight had permanent hypoparathyroidism (PH), six permanent recurrent nerve paralysis (PRNP) and two Horner's syndrome. Risk factors for PH and PRNP were total thyroidectomy with lymph node dissection (RR: 6.45, P = 0.015) and recurrent nerve tumour encasement (RR: 8.00, P = 0.001), respectively. Other adverse events were fatigue (n = 5), scar problems (n = 4) and chronic myeloid leukaemia (n = 1). These results emphasise the need to improve treatment strategies.

Screening for late effects in survivors of childhood cancer: growth hormone deficiency from a pediatric oncologist's point of view

At the Emma Kinderziekenhuis/Academic Medical Center in Amsterdam, survivors of childhood cancer are screened annually or biennially for the occurrence of late treatment effects. The screening procedures are based on previously used treatment modalities. The data gathered at the outpatient clinic are registered in the database PLEKsys. Evaluation of the data concerning over 1000 cancer survivors screened since the start of the clinic once more illustrated the relation between cranial irradiation and the development of central endocrine abnormalities. Surprisingly, at least a proportion of the growth hormone (GH)-deficient cancer survivors were registered as not being on a replacement therapy regimen. The reasons for survivors not to be on replacement therapy are currently being evaluated. The late-effects outpatient clinic and the PLEKsys database provide a platform for additional research in fields including endocrinology, which should be aimed at improving the care for and the health status of the survivors of childhood cancer.

Decreasing the number of MOPP courses reduces gonadal damage in survivors of childhood Hodgkin disease

BACKGROUND

Children treated for Hodgkin disease are at risk for gonadal damage. Since most children were treated with radiotherapy (RT) in combination with chemotherapy, the presumed detrimental effect of MOPP (mustine, vincristine, procarbazine, and prednisone) (in contrast to schemes with less or without alkylating agents) could not be discerned completely from the effects of RT.

PROCEDURES

Children with Hodgkins disease treated without RT were included in sequential protocols containing six courses of MOPP (n = 24), six courses of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) (n = 17), or three courses of MOPP/ABVD (n = 35). Of these 76 patients, 48, who had completed treatment and had reached puberty, were investigated for gonadal damage.

RESULTS

Of the male patients, 81% of MOPP treated patients had increased follicular stimulating hormone (FSH) values, in 23% luteinizing hormone (LH) values were abnormal. In ABVD treated patients, no elevated levels of FSH or LH were noted. In 30% of patients treated with MOPP/ABVD, FSH values were abnormal, but no abnormal LH values were found. Median testicular volume per group decreased in relation to a higher number of MOPP courses. Sperm analysis revealed azoospermia in nearly all MOPP treated patients. In ABVD and MOPP/ABVD treated patients both oligospermia and azoospermia were noted. The number of sperm samples were too less to make any sound conclusions. Menarche occurred in all females, however in some at a relatively later age. One female patient treated with MOPP/ABVD had a normal pregnancy.

CONCLUSIONS

Limitation of MOPP therapy to three courses, in children treated without any RT, results in less gonadal damage as compared with six MOPP courses. From our data, MOPP damages Sertoli cells and may also damage Leydig cells as suggested by the higher LH values in conjunction with normal testosterone levels.

No excess fatigue in young adult survivors of childhood cancer

Clinical reports suggest that many survivors of childhood cancer experience fatigue as a long-term effect of their treatment. To investigate this issue further, we assessed the level of fatigue in young adult survivors of childhood cancer. We compared the results with a group of young adults with no history of cancer. The impact of demographic, medical and treatment factors and depressive symptoms on survivors' fatigue was studied. Participants were 416 long-term survivors of childhood cancer (age range 16-49 years, 48% of whom were female) who had completed treatment an average of 15 years previously and 1026 persons (age range 16-53 years, 55% female) with no history of cancer. All participants completed the Multidimensional Fatigue Inventory (MFI-20), a self-report instrument consisting of five scales (general fatigue, physical fatigue, mental fatigue, reduced activity, reduced motivation) and the Center for Epidemiologic Studies Depression Scale (CES-D). Small differences were found in the mean scores for the different dimensions of fatigue between the long-term survivors and controls (range effect sizes -0.34 to 0.34). Women experienced more fatigue than men. Logistic regression revealed that being female and unemployed were the only demographic characteristics explaining the various dimensions of fatigue. With regard to medical and treatment factors, diagnosis and severe late effects/health problems were associated with fatigue. Finally, depression was significantly associated with fatigue on all subscales. Our clinical practice suggests a difference in fatigue in young adult childhood cancer survivors and their peers. This could not be confirmed in this study using the MFI-20. The well known correlation between fatigue and depression was confirmed in our study. Further research is needed to clarify the undoubtedly complex somatic and psychological mechanisms responsible for the development, maintenance and treatment of fatigue in childhood cancer survivors.

[Children with fever peaks and bone and joint pain: systemic juvenile idiopathic arthritis or acute lymphoblastic leukemia after all?]

In two 3-year-old infants, a girl and a boy, systemic juvenile idiopathic arthritis was suspected because of daily fever peaks, signs of polyarthritis and general malaise. Drug treatment was unsuccessful, and after extensive laboratory investigation acute lymphoblastic leukaemia (ALL) was diagnosed and treated adequately. ALL is the most common malignancy in childhood. About one-third of the patients present with joint or bone pain and fever. In this group of children, it can be difficult to identify ALL because it may mimic the clinical picture of systemic juvenile idiopathic arthritis and because of the possibility of a normal blood count at presentation. ALL should always be considered in the differential diagnosis in children with musculoskeletal pain and fever, even in the face of a normal blood count. In any case, a bone-marrow examination should be done before steroid treatment is given.

Mutation at the CK2 phosphorylation site on Cdc28 affects kinase activity and cell size in Saccharomyces cerevisiae

We have recently reported that protein kinase CK2 phosphorylates both in vivo and in vitro residue serine-46 of the cell cycle regulating protein Cdc28 of budding yeast Saccharomyces cerevisiae, confirming a previous observation that the same site is phosphorylated in Cdc2/Cdk1, the human homolog of Cdc28. In addition, S. cerevisiae in which serine-46 of Cdc28 has been mutated to alanine show a decrease of 33% in both cell volume and protein content, providing the genetic evidence that CK2 is involved in the regulation of budding yeast cell division cycle, and suggesting that this regulation may be brought about in G1 phase of the mammalian cell cycle. Here, we extended this observation reporting that the mutation of serine-46 of Cdc28 to glutamic acid doubles, at least in vitro, the H1-kinase activity of the Cdc28/cyclin A complex. Since this mutation has only little effects on the cell size of the cells, we hypothesize multiple roles of yeast CK2 in regulating the G1 transition in budding yeast.

The development of a new information model for a pediatric cancer registry on late treatment sequelae in The Netherlands

Worldwide, the need is felt for life time follow up of survivors of childhood cancer and for the establishment of registries of the late effects of pediatric oncology treatments. There is however little consensus about how this all should take place. For example, agreement on the nature of this follow up and the type of data to be collected in view of the earlier diagnosis and treatment of the patient is lacking. In a close collaboration between the 'Late Effects Study Group' (consisting of the Pediatric Oncology department of the Emma Children's Hospital and the department of Medical Oncology at the Academic Medical Center), the Netherlands Cancer institute/Antoni van Leeuwenhoek Hospital, and the department of Medical Informatics of the University of Amsterdam, consensus was reached on a new dataset on adverse late effects of pediatric oncology treatment. This dataset was used in developing an information model for the design of a computerized documentation system, PLEKsys. PLEKsys covers both standardized documentation of all relevant data items for evaluating late effects and review facilities on individual patient basis and on patient cohorts. We will install PLEKsys at all Dutch pediatric oncology centers and use the information model as a starting point in developing a National Pediatric Oncology Follow up Registry. A national programme encompassing all Dutch pediatric oncology centers has already been set up to co-ordinate the construction of this national registry.

S100A12 is expressed exclusively by granulocytes and acts independently from MRP8 and MRP14

Changes in cytosolic calcium concentrations regulate a wide variety of cellular processes, and calcium-binding proteins are the key molecules in signal transduction, differentiation, and cell cycle control. S100A12, a recently described member of the S100 protein family, has been shown to be coexpressed in granulocytes and monocytes together with two other S100 proteins, MRP8 (S100A8) and MRP14 (S100A9), and a functional relationship between these three S100 proteins has been suggested. Using Western blotting, calcium overlays, intracellular flow cytometry, and cytospin preparations, we demonstrate that S100A12 expression in leukocytes is specifically restricted to granulocytes and that S100A12 represents one of the major calcium-binding proteins in these cells. S100A12, MRP8, and MRP14 translocate simultaneously from the cytosol to cytoskeletal and membrane structures in a calcium-dependent manner. However, no evidence for direct protein-protein interactions of S100A12 with either MRP8 or MRP14 or the heterodimer was found by chemical cross-linking, density gradient centrifugation, mass spectrometric measurements, or yeast two hybrid detection. Thus, S100A12 acts individually during calcium-dependent signaling, independent of MRP8, MRP14, and the heterodimer MRP8/MRP14. This granulocyte-specific signal transduction pathway may offer attractive targets for therapeutic intervention with exaggerated granulocyte activity in pathological states.

p21(cip1) rescues human mesenchymal stem cells from apoptosis induced by low-density culture

Mammalian cells are programmed to undergo programmed cell death in response to a variety of conditions. We demonstrate that human mesenchymal stem cells (hMSCs) undergo programmed cell death upon seeding at low density. Under these conditions, we observed an increased proportion of cells in S-phase and a decreased proportion of cells in G1-phase. This indicated that a change in control of G1-S-phase transition in response to low-density seeding had occurred and, therefore, we measured the level of cyclin-dependent kinase inhibitory proteins governing this transition. Human MSCs cultured at low density exhibited lowered levels of both the p21 and p27 cyclin-dependent kinase inhibitors, and these protein levels appear to be regulated at a post-transcriptional level. Conversely, overexpression of the p21 cell cycle-dependent kinase inhibitor but not that of p27 protected hMSCs from programmed cell death upon culture at low density. Furthermore, p21 and p27 are expressed differentially during endochondrial bone development. The loss of p21 in hypertrophic chondrocytes correlates with the onset of apoptosis during endochondrial ossification. We suggest that p21 and p27 play a central role in skeletal development.

Copurification of P6, MRP8, and MRP14 from human granulocytes and separation of individual proteins

A method is described for purification of P6, MRP8, and MRP14, three calcium-binding proteins assigned to the S100 protein family. The purification procedure included preparation of human granulocytes, ammonium sulfate precipitation, and anion-exchange chromatography and resulted in the copurification of P6, MRP8, and MRP14. Individual proteins were separated by either preparative isoelectric focusing or preparative SDS-PAGE. The procedure was carried out in the course of 4 days and yielded several milligrams of essentially pure P6, MRP8, and MRP14 in either native or denatured form.

Transplantation of human umbilical cord blood cells in macrophage-depleted SCID mice: evidence for accessory cell involvement in expansion of immature CD34+CD38- cells

In vivo expansion and multilineage outgrowth of human immature hematopoietic cell subsets from umbilical cord blood (UCB) were studied by transplantation into hereditary immunodeficient (SCID) mice. The mice were preconditioned with Cl2MDP-liposomes to deplete macrophages and 3.5 Gy total body irradiation (TBI). As measured by immunophenotyping, this procedure resulted in high levels of human CD45(+) cells in SCID mouse bone marrow (BM) 5 weeks after transplantation, similar to the levels of human cells observed in NOD/SCID mice preconditioned with TBI. Grafts containing approximately 10(7) unfractionated cells, approximately 10(5) purified CD34+ cells, or 5 x 10(3) purified CD34+CD38- cells yielded equivalent numbers of human CD45+ cells in the SCID mouse BM, which contained human CD34+ cells, monocytes, granulocytes, erythroid cells, and B lymphocytes at different stages of maturation. Low numbers of human GpA+ erythroid cells and CD41+ platelets were observed in the peripheral blood of engrafted mice. CD34+CD38+ cells (5 x 10(4)/mouse) failed to engraft, whereas CD34- cells (10(7)/mouse) displayed only low levels of chimerism, mainly due to mature T lymphocytes. Transplantation of graded numbers of UCB cells resulted in a proportional increase of the percentages of CD45+ and CD34+ cells produced in SCID mouse BM. In contrast, the number of immature, CD34+CD38- cells produced in vivo showed a second-order relation to CD34+ graft size, and mice engrafted with purified CD34+CD38- grafts produced 10-fold fewer CD34+ cells without detectable CD34+CD38- cells than mice transplanted with equivalent numbers of unfractionated or purified CD34+ cells. These results indicate that SCID repopulating CD34+CD38- cells require CD34+CD38+ accessory cell support for survival and expansion of immature cells, but not for production of mature multilineage progeny in SCID mouse BM. These accessory cells are present in the purified, nonrepopulating CD34+CD38+ subset as was directly proven by the ability of this fraction to restore the maintenance and expansion of immature CD34+CD38- cells in vivo when cotransplanted with purified CD34+CD38- grafts. The possibility to distinguish between maintenance and outgrowth of immature repopulating cells in SCID mice will facilitate further studies on the regulatory functions of accessory cells, growth factors, and other stimuli. Such information will be essential to design efficient stem cell expansion procedures for clinical use.

Facilitated engraftment of human hematopoietic cells in severe combined immunodeficient mice following a single injection of Cl2MDP liposomes

Transplantation of normal and malignant human hematopoietic cells into severe combined immunodeficient (SCID) mice allows for evaluation of long-term growth abilities of these cells and provides a preclinical model for therapeutic interventions. However, large numbers of cells are required for successful engraftment in preirradiated mice due to residual graft resistance, that may be mediated by cells from the mononuclear phagocytic system. Intravenous (i.v.) injection of liposomes containing dichloromethylene diphosphonate (Cl2MDP) may eliminate mouse macrophages in spleen and liver. In this study outgrowth of acute myeloid leukemia (AML) cells and umbilical cord blood (UCB) cells in SCID mice conditioned with a single i.v. injection of Cl2MDP liposomes in addition to sublethal total body irradiation (TBI) was compared to outgrowth of these cells in SCID mice that had received TBI alone. A two- to 10-fold increase in outgrowth of AML cells was observed in four cases of AML. Administration of 10(7) UCB cells reproducibly engrafted SCID mice that had been conditioned with Cl2MDP liposomes and TBI, whereas human cells were not detected in mice conditioned with TBI alone. As few as 2 x 10(4) purified CD34+ UCB cells engrafted in all mice treated with Cl2MDP liposomes. In SCID mice treated with macrophage depletion unexpected graft failures were not observed. Histological examination of the spleen showed that TBI and Cl2MDP liposomes i.v. resulted in a transient elimination of all macrophage subsets in the spleen, whereas TBI had a minor effect. Cl2MDP liposomes were easy to use and their application was not associated with appreciable side-effects. Cl2MDP liposome pretreatment in combination with TBI allows for reproducible outgrowth of high numbers of human hematopoietic cells in SCID mice.

Human mesenchymal stem cells respond to fibroblast growth factors

Human mesenchymal stem cells can be isolated from bone marrow aspirates, purified and cultured for many passages without losing their unique properties. One of the hallmarks of stem cells is pluripotency, and human mesenchymal stem cells can be induced to assume phenotypes of mesenchymal tissues including, but not limited to, those of osteocytes, chondrocytes and adipocytes. Due to their ability to form cartilage, bone, fat and other connective tissue, human mesenchymal stem cells have great potential in regenerating diseased or injured tissues. Successful growth of human mesenchymal stem cells is essential to this process, and we have examined the response of human mesenchymal stem cells towards FGF1 and FGF2, two potent growth factors for human tissues. We provide evidence that: 1) human mesenchymal stem cells produce mRNA for receptors for FGF1 and FGF2; 2) these receptors can be detected on the surface of human mesenchymal stem cells; 3) FGF1 and FGF2 increase the rate at which human mesenchymal stem cells proliferate.

Phosphorylation of MRP14, an S100 protein expressed during monocytic differentiation, modulates Ca(2+)-dependent translocation from cytoplasm to membranes and cytoskeleton

MRP8 and MRP14 are two Ca(2+)-binding proteins expressed in myelomonocytic cells. Complexes of MRP8 and MRP14 colocalize with membranes and intermediate filaments in a Ca(2+)-dependent manner. MRP14, unlike MRP8, exists in two isoforms, the smaller of which (MRP14') has been shown to lack the first four amino acids; both MRP14 and MRP14' are also present as phosphorylated forms. As shown in the present work by metabolic labeling of monocytes with [35S]methionine, MRP14 and MRP14' are translated simultaneously. By PCR analysis we found no evidence for the presence of different mRNA species. Since MRP14 is encoded by a single copy gene, our data indicate that MRP14' formation is due to alternative translation of a single mRNA species. Two-dimensional electrophoresis of [32P]orthophosphate-labeled monocyte proteins followed by Western blotting and autoradiography revealed that the two phosphorylated MRP14 isoforms incorporated the bulk of the radioactivity found in monocytic proteins. Using differential centrifugation we demonstrated the presence of distinct isoform patterns in different subcellular locations. Further, in response to elevated Ca2+ concentrations we observed a preferential translocation of phosphorylated MRP14 isoforms from the cytosol toward membranes and the cytoskeleton. This might be caused by altered calcium binding, and indeed, using isoelectric focusing and 45Ca2+ overlay the MRP14 band containing phosphorylated MRP14 revealed increased Ca2+ binding compared with bands containing other MRP14 isoforms. This represents the first evidence for functional differences in phosphorylated MRP14 isoforms compared with nonphosphorylated MRP14 isoforms. These functional differences suggest that MRP14 represents the regulatory subunit of MRP8/MRP14 complexes.

Phosphorylation of MRP14, an S100 protein expressed during monocytic differentiation, modulates Ca(2+)-dependent translocation from cytoplasm to membranes and cytoskeleton

MRP8 and MRP14 are two Ca(2+)-binding proteins expressed in myelomonocytic cells. Complexes of MRP8 and MRP14 colocalize with membranes and intermediate filaments in a Ca(2+)-dependent manner. MRP14, unlike MRP8, exists in two isoforms, the smaller of which (MRP14') has been shown to lack the first four amino acids; both MRP14 and MRP14' are also present as phosphorylated forms. As shown in the present work by metabolic labeling of monocytes with [35S]methionine, MRP14 and MRP14' are translated simultaneously. By PCR analysis we found no evidence for the presence of different mRNA species. Since MRP14 is encoded by a single copy gene, our data indicate that MRP14' formation is due to alternative translation of a single mRNA species. Two-dimensional electrophoresis of [32P]orthophosphate-labeled monocyte proteins followed by Western blotting and autoradiography revealed that the two phosphorylated MRP14 isoforms incorporated the bulk of the radioactivity found in monocytic proteins. Using differential centrifugation we demonstrated the presence of distinct isoform patterns in different subcellular locations. Further, in response to elevated Ca2+ concentrations we observed a preferential translocation of phosphorylated MRP14 isoforms from the cytosol toward membranes and the cytoskeleton. This might be caused by altered calcium binding, and indeed, using isoelectric focusing and 45Ca2+ overlay the MRP14 band containing phosphorylated MRP14 revealed increased Ca2+ binding compared with bands containing other MRP14 isoforms. This represents the first evidence for functional differences in phosphorylated MRP14 isoforms compared with nonphosphorylated MRP14 isoforms. These functional differences suggest that MRP14 represents the regulatory subunit of MRP8/MRP14 complexes.

Increase of calcium levels in epithelial cells induces translocation of calcium-binding proteins migration inhibitory factor-related protein 8 (MRP8) and MRP14 to keratin intermediate filaments

Migration inhibitory factor-related protein 8 (MRP8) and MRP14, two S-100-like Ca(2+)-binding proteins, have been described in cells of the epithelial lineage where they are either expressed constitutively (e.g. by mucosal squamous epithelium) or induced during disease (e.g. in keratinocytes during the course of psoriasis). Their biological function, however, is not yet clear. Recent studies have provided evidence that S-100-like proteins may interact with cytoskeletal components; we have therefore studied the biochemical properties and subcellular distribution of MRP8 and MRP14 in epithelial cells. TR146 human squamous carcinoma cells, which were found to express MRP8 and MRP14 in Northern and Western blot studies, were chosen for analysis. Cross-linking experiments using bis(sulphosuccinimidyl)suberate followed by SDS/PAGE and Western blot analysis revealed formation of heteromeric MRP8-MRP14 complexes. On subjecting TR146 cell lysates to two-dimensional gel electrophoresis and Western blotting, four distinct MRP14 isoforms could be identified resembling those described earlier in macrophages. A differential centrifugation technique revealed a Ca(2+)-dependent translocation of MRP8-MRP14 from the cytoplasm to the membrane and the Nonidet P40-insoluble cytoskeletal fraction. Double-label immunofluorescence microscopy of Ca2+ ionophore A23187-stimulated TR146 cells and cytochalasin B and demecolcine cytoskeleton disruption studies identified these structures as keratin intermediate filaments. Ca(2+)-dependent binding of MRP8-MRP14 to keratin filaments was additionally confirmed by an in vitro binding assay. In conclusion, our data suggest that MRP8 and MRP14 may be involved in Ca(2+)-dependent reorganization of cytoskeletal filaments in epithelial cells, which could be of importance for events associated with differentiation and inflammatory activation.

Expression of the calcium-binding proteins MRP8 and MRP14 in monocytes is regulated by a calcium-induced suppressor mechanism

MRP8 and MRP14 are two calcium-binding proteins of the S-100 family the expression of which is restricted to distinct stages of monocytic differentiation. Heteromeric MRP8/MRP14 complexes have been shown to represent their biologically active forms. However, it is not as yet clear whether biochemical modification of complexes, or regulation on the transcriptional level, are responsible for the control of MRP8/MRP14 expression. Employing Western-blot analysis and metabolic labelling we have demonstrated that patterns and metabolism of MRP8/MRP14 complexes do not change during up- or down-regulation of MRP8/MRP14. By Northern-blot analysis it was shown that MRP8/MRP14 are regulated at the transcriptional level rather than by biochemical modification of the complexes. Elevation of intracellular calcium levels by A23187, as well as by thapsigargin, was found to lead to specific down-regulation of MRP8/MRP14 mRNA which is in contrast with data reported for inflammatory factors such as interleukin-1 or tumour necrosis factor alpha. Concomitant application of actinomycin D and calcium ionophore indicated that this suppressive effect is mediated by decreased synthesis rather than increased degradation of MRP8/MRP14 mRNA. Finally, we demonstrated that calcium-mediated down-regulation of MRP8-MRP14 can be antagonized by cycloheximide, suggesting that a calcium-induced repressor protein is responsible for suppression of MRP8-MRP14 at the transcriptional level. Our data indicate that the function of MRP8-MRP14 is restricted to events associated with early stages of myelomonocytic activation.

Selective advantage of normal erythrocyte production after bone marrow transplantation of alpha-thalassemic mice

Anemia resulting from alpha-thalassemia in mice was corrected by transplantation of normal bone marrow cells following sublethal total body irradiation, resulting in partial hematopoietic chimerism with a preponderance of normal peripheral blood red cells. Peripheral blood red cell chimerism in recipients of graded numbers of bone marrow cells from sex-mismatched donors, determined by cytometric analysis, was directly compared with immature hematopoietic cell (CFU-S) chimerism and peripheral blood white cell chimerism. The latter two were assessed by fluorescent in situ hybridization with a murine Y-chromosome-specific probe. Peripheral blood white cell chimerism consistently corresponded with immature hematopoietic cell chimerism, emphasizing the selective advantage of normal red cell production in partially chimeric alpha-thalassemic mice.

Stable multilineage hematopoietic chimerism in alpha-thalassemic mice induced by a bone marrow subpopulation that excludes the majority of day-12 spleen colony-forming units

We have investigated the contribution of highly purified day-12 spleen colony-forming units (CFU-S-12) as well as more primitive cells to sustained blood cell production using in vivo and in vitro assays that allow frequency analysis. Normal or day-6 post-5-fluorouracil light-density bone marrow (BM) was sorted on the basis of differences in rhodamine-123 (Rh123) retention or wheat germ agglutinin (WGA) affinity and tested in vivo using a recently developed alpha-thalassemic chimeric mouse model. In addition, short-term and long-term clonal activity was assessed in vitro using a limiting dilution-type long-term BM culture, the cobblestone area forming cell assay. When sublethally irradiated alpha-thalassemic mice were transplanted with as many as 281 purified WGAbright CFU-S-12, derived from a fraction containing 95% of all CFU-S-12 from day-6 post-5-fluorouracil light-density BM of wild-type mice, detectable chimerism was not observed at 6 months posttransplantation. In contrast, only three CFU-S-12 were included in the Rh123dull and WGAdim subpopulations that induced 29% to 58% and 21% to 31% stable multilineage donor-type chimerism of erythrocytes and leukocytes, respectively. The Rh123dull and WGAdim cells were up to 240-fold enriched for long-term repopulating ability (LTRA) as compared with unseparated BM. A comparable level of chimerism was found in the different hematopoietic organs and at the level of BM CFU-S-12. The frequency of the LTRA unit capable of inducing a 10% sustained level of donor-type erythrocytes was calculated to be 1 to 2 per 10(5) BM cells. Several reports have suggested that LTRA and spleen colony formation could be capacities of the same stem cell subset. However, the present results show that the majority of CFU-S-12 have only short-term repopulating ability and are physically separable from more primitive stem cells with long-term multilineage reconstituting capacities.

Acute side effects of homologous interleukin-3 in rhesus monkeys

Interleukin-3 treatment of juvenile rhesus monkeys elicits a dose- and time-dependent syndrome that includes urticaria, palpable lymph nodes, splenomegaly, thrombocytopenia, anemia, vomiting, diarrhea, intestinal bleeding, edema, and arthritis, apart from a strong stimulation of hemopoiesis. Arthritis was found to occur significantly more often in animals expressing the major histocompatibility complex alleles B9 and Dr5. Histological analysis revealed an abundance of mast cells in urticaria and, to a lesser extent, in lungs and synovia of arthritic joints. Active osteoclasts were abundant in ribs and arthritic joints. Extramedullary hemopoiesis was encountered in liver, spleen, and kidneys. The spleen showed deposits of hemosiderin, and in the liver, Kupffer cells were loaded with iron, indicating enhanced turnover of hemoglobin. Lymph nodes and bone marrow showed macrophages involved in hemophagocytosis, which probably contributed to the development of anemia and thrombopenia. Biochemical parameters in sera were indicative of parenchymal liver damage, with cholestasis and increased erythrocyte destruction. The side effects were strongly reduced in monkeys subjected to total body irradiation just before interleukin-3 treatment. Histamine antagonists were not significantly effective in preventing side effects, which is explained by the perpetual stimulation of basophilic granulocytes by exogenous interleukin-3. The nature of the side effects indicates that interleukin-3 may be involved in the pathogenesis of acute type hypersensitivity reactions and arthritis.

Pharmacokinetic basis for optimal hemopoietic effectiveness of homologous IL-3 administered to rhesus monkeys

To design an interleukin-3 (IL-3) administration schedule for optimal hemopoietic effectiveness, serum half-life (t1/2) was determined after intravenous (i.v) and subcutaneous (s.c.) bolus injections. The initial t1/2 in serum after i.v. injection was about 10 minutes and the terminal t1/2 close to 2 hours. Subcutaneous administration resulted in plateau levels after 2 to 4 hours, while the apparent terminal t1/2 was similar to that after i.v. infusion. The bioavailability of IL-3 following subcutaneous administration was only about 40% of that following i.v. administration. Hemopoietic effects of continuous i.v. infusion of IL-3 was then compared to s.c. administration in either one, two, or three daily injections. Doses chosen ranged from 1 to 30 micrograms/kg per day. In agreement with the more limited bioavailability of IL-3 following s.c. administration, continuous i.v. infusion was much more effective in stimulating hemopoiesis than s.c. administration. Two or three daily s.c. injections did not improve the hemopoietic response compared to a single s.c. injection, which is in agreement with the apparent terminal t1/2 of 101 min. It is concluded that IL-3 is more effective by continuous i.v. infusion than by subcutaneous administration.

MRP8 and MRP14, S-100-like proteins associated with myeloid differentiation, are translocated to plasma membrane and intermediate filaments in a calcium-dependent manner

MRP8 and MRP14 are two Ca(2+)-binding proteins of the S-100 family expressed by myelomonocytic cells. Both proteins assemble to noncovalently associated complexes in a Ca(2+)-dependent manner. Members of the S-100 family are known to play a role in cytoskeletal-membrane interactions; therefore, we investigated the subcellular distribution of MRP8/MRP14 and their complexes in human monocytes. Using differential centrifugation and subsequent Western blot or enzyme-linked immunosorbent assay analysis, we found that MRP8/MRP14 were almost completely translocated from the cytoplasma to membrane and cytoskeletal structures in a Ca(2+)-dependent manner. Using a cross-linking technique, complexed forms of MRP8/MRP14 were found to be associated with the plasma membrane. Analysis of MRP-transfected L132 cells showed that the MRP8 as well as the MRP14 component of the MRP8/MRP14 complex may independently bind to membrane and cytoskeletal structures. Furthermore, immunogold electron microscopy showed a colocalization of MRP8/MRP14 and the intermediate filament type III protein vimentin in A23187-treated monocytes. Our data indicate that, in analogy to other S-100-like proteins, MRP8 and MRP14 play a role in Ca(2+)-dependent cytoskeletal-membrane interactions. Restriction of MRP8/MRP14 expression to distinct stages of myelomonocytic differentiation suggests that these proteins are involved in highly specific pathways of intracellular signaling in phagocytes.

Correction of murine beta-thalassemia by partial bone marrow chimerism: selective advantage of normal erythropoiesis

beta-Thalassemic mice were transplanted with normal congeneic BM cells after sublethal total body irradiation, which resulted in partial RBC chimerism and correction of anemia. Enumeration of donor-type early hemopoietic progenitor cells (CFU-S) demonstrated that the correction of anemia originated from a minority of normal immature BM cells. It is concluded that successful BMT in beta-thalassemia does not necessarily require ablation of endogenous BM.

Loss of long-term repopulating ability in long-term bone marrow culture

We have studied the maintenance of stem cells with long-term multilineage repopulating ability from murine bone marrow, cultured on a pre-established bone marrow-derived stromal cell layer, both in a qualitative and quantitative way. Female bone marrow cells were cultured for a period of 1-4 weeks and compared with uncultured cells for their ability to establish and maintain a level of 50% chimerism in a sex-mismatched bone marrow transplantation model. Chimerism was determined in nucleated cells using fluorescence in situ hybridization with a murine Y-chromosome-specific probe. We observed a rapid decline in the ability of cultured marrow cells to repopulate the blood, bone marrow, spleen, and thymus of sublethally irradiated male recipients. After 4 weeks of culture only 5% of the long-term repopulating ability of the inoculated bone marrow cells remained. The remaining long-term repopulating cells, however, had similar qualities to establish and maintain long-term engraftment compared to fresh bone marrow, as judged from their ability to give stable chimerism over a period of 6 months. These observations are relevant for the therapeutic applications of long-term bone marrow cultures in purging protocols prior to autologous bone marrow transplantation of acute and chronic myeloid leukemic patients, and for the use of long-term marrow cultures when introducing foreign genetic material in hematopoietic stem cells.

Expression of calcium-binding proteins MRP8 and MRP14 is associated with distinct monocytic differentiation pathways in HL-60 cells

MRP8 and MRP14 are two calcium-binding proteins of the S-100 family which are expressed during distinct stages of monocytic maturation. To further investigate their regulation the human leukemic cell line HL-60 which can be induced to differentiate to monocytes/macrophages by 12-O-tetradecanoylphorbol 13-acetate (TPA), 1,25-(OH)2 Vitamin D3 (VD3), tumor necrosis factor-alpha (TNF-alpha) and interferon-g (IFN-g) were analyzed for expression of MRP8/MRP14. Employing Northern blotting, a sandwich enzyme-linked immunosorbent assay and immunocytochemical analysis we determined MRP8/MRP14 mRNA and protein levels, which were found to be elevated after VD3 and reduced after TPA treatment. TNF-alpha and IFN-g did not affect MRP8/MRP14 levels. Western blot analysis revealed that formation of MRP8/MRP14 to biologically active complexes which has previously been shown to be a calcium-mediated process is not dependent on the differentiation stages of HL-60 cells. Restriction of MRP8/MRP14 expression to only distinct pathways of monocytic differentiation in HL-60 cells may thus reflect different functional phenotypes of monocytes/macrophages in vivo.

Compensatory splenic hemopoiesis in beta-thalassemic mice

beta-Thalassemic mice, homozygous for the deletion of the beta major-globin gene, were investigated for compensatory hemopoiesis in bone marrow and spleen. Apart from characteristic severe anemia, these mice have a marked granulocytosis, monocytosis and lymphocytosis. A large compensatory expansion of late (CFU-E) erythroid progenitor cells was demonstrated, predominantly in the spleen. Immature hemopoietic cells (CFU-S) were also expanded, as were early progenitor cells of erythroid (BFU-E), as well as granulocyte/macrophage (GM-CFU) and megakaryocytic (CFU-Meg) lineages. It is concluded that the persistent erythropoietic stress results in a selective expansion of immature hemopoietic cells and inappropriate production of nonerythroid blood cells from excess production of progenitor cells.

Flow cytometric analysis of peripheral blood erythrocyte chimerism in alpha-thalassemic mice

A rapid and reliable method for longitudinal studies on the degree of red cell chimerism following bone marrow transplantation of alpha-thalassemic recipient mice is presented. Blood obtained by tail clipping from transplanted mice was analyzed by measuring forward light scatter (FLS) distribution of red cells using a flow cytometer. Amplification and threshold of FLS were specifically adjusted. For flow cytometric analysis, the red cells needed to be suspended in hypotonic saline (103 mmol/l NaCl). Osmotic fragility testing showed that lysis of erythrocytes did not significantly influence the measurements. Flow cytometric measurement allowed for a rapid determination of the degree of red cell chimerism.