Spectrum, and clinical and functional implications of UNC13D mutations in familial haemophagocytic lymphohistiocytosis.

OBJECTIVE: Familial haemophagocytic lymphohistiocytosis (FHL) is a fatal disorder of immune dysregulation with defective cytotoxic lymphocyte function. Disease-causing mutations have been identified in the genes encoding perforin (PRF1), syntaxin-11 (STX11), and Munc13-4 (UNC13D). We screened for UNC13D mutations and studied clinical and functional implications of such mutations in a well defined patient cohort. METHODS: Sequencing of UNC13D was performed in 38 FHL patients from 34 FHL families in which PRF1 and STX11 mutations had been excluded. RESULTS: We identified six different mutations affecting altogether 9/38 individuals (24%) in 6/34 (18%) unrelated PRF1/STX11-negative families. Four novel mutations were revealed; two homozygous nonsense mutations (R83X and W382X), one splice mutation (exon 28), and one missense mutation (R928P). In addition, two known mutations were identified (R214X and a deletion resulting in a frame-shift starting at codon 782). There was considerable variation in the age at diagnosis, ranging from time of birth to 14 years (median 69 days). Three of nine patients (33%) developed central nervous system (CNS) symptoms. Natural killer (NK) cell activity was impaired in all four patients studied. Defective cytotoxic lymphocyte degranulation was evident in the two patients investigated, more pronounced in the patient with onset during infancy than in the patient with adolescent onset. CONCLUSIONS: Biallelic UNC13D mutations were found in 18% of the PRF1/STX11-negative FHL families. Impairment of NK cell degranulation was less pronounced in a patient with adolescent onset. FHL should be considered not only in infants but also in adolescents, and possibly young adults, presenting with fever, splenomegaly, cytopenia, hyperferritinaemia, and/or CNS symptoms.

Invalidity from nonparallelism in a radioimmunoassay for erythropoietin accounted for by human serum antibodies to rabbit IgG.

An immunologic crossreactant of erythropoietin seemed to develop and persist in serum samples from a patient during treatment and remission of idiopathic aplastic anemia. It had a steeper slope to radioimmunoassay log-dose response lines and a larger molecular size than erythropoietin. On fractionation of serum, the apparent crossreactant was bound by staphylococcal Protein A at pH 7.5 and recovered by elution from it at pH 3.0. Adsorption of serum from the patient, and from one of two similarly affected children, with rabbit IgG linked to agarose appeared to remove completely the apparent crossreactant. These treated sera gave radioimmunoassay log-dose response lines essentially parallel to that given by the International Reference Preparation (IRP) for erythropoietin and estimates of immunoreactive erythropoietin appropriate to the normal hemoglobin concentrations. The apparent crossreactant of erythropoietin is thus accounted for by heterophilic antibodies to rabbit IgG. These developed in the patient following treatment with rabbit antilymphocyte globulin but seem to have arisen spontaneously in the children. Thus iatrogenic and idiopathic antibodies to rabbit IgG interfered in a radioimmunoassay for erythropoietin in serum through their ability to react with the radioimmunoassay anti-erythropoietin antiserum raised in rabbits.

Leukaemia and anaemia in AKR/O mice. II. Role of the spleen as an erythropoietic organ during leukaemia development.

In order to study the role of the spleen in erythropoiesis during AKR/O leukaemogenesis, we have cultured bone marrow and spleen erythroid colony-forming units (CFU-E) and burst-forming units (BFU-E) from AKR/O mice (n = 40) with leukemia of varying severity and type of manifestation. Mice with leukaemia/lymphoma had reduced concentrations of bone marrow CFU-E and BFU-E as compared to healthy, age-matched AKR/O mice. The spleen content of CFU-E was increased, and highest in mice with a spleen size between 500 and 1000 mg. The largest spleens had a somewhat lower CFU-E content. Mice with the highest spleen CFU-E content most often had a normal PCV; however, 4/7 had a normal bone marrow CFU-E concentration. During AKR/O leukaemogenesis with development of spleen enlargement, the spleen may act as an erythropoietic organ, and contribute to maintaining a normal PCV. This may be a temporary ability which is reduced or lost with further progress of the disease.

Leukaemia and anaemia in AKR/O mice I. Leukaemia characteristics, haematological variables and erythropoiesis stimulating factor(s).

AKR/O mice were used as a model for studying the pathogenesis of the anaemia accompanying leukaemia/lymphoma. The leukaemia incidence was 87%. Median age at diagnosis was 11.3 months. At diagnosis most of the mice had normal leukocyte counts. Clinically the mice divided into subgroups depending on the relative organ involvement: 1) thymoma group (n = 98), 2) spleen group (n = 144), 3) combined group (n = 27) and 4) mice with moderate organ changes (n = 216). Mice of group 1 were younger than the others, had a rapidly progressive disease, normal to elevated packed cell volume (PCV), and plasma erythropoietin (Epo) was normal or increased. Mice of group 2 were usually anaemic with high plasma Epo estimates and often elevated reticulocyte counts. Group 4 was the oldest group. Some of these mice were severely affected haematologically. Overall there was an inverse relation between PCV and plasma Epo estimate, indicating a normal Epo response to anaemia. In all groups increasing spleen size was associated with increased severity of anaemia and increased reticulocyte counts. The association between anaemia, elevated reticulocyte counts and spleen enlargement suggests haemolysis as a mechanism for anaemia, and also raises the question of compensatory spleen erythropoiesis.

Long-term results of NOPHO ALL-92 and ALL-2000 studies of childhood acute lymphoblastic leukemia.

Analysis of 2668 children with acute lymphoblastic leukemia (ALL) treated in two successive Nordic clinical trials (Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL-92 and ALL-2000) showed that 75% of all patients are cured by first-line therapy, and 83% are long-term survivors. Improvements in systemic and intrathecal chemotherapy have reduced the use of central nervous system (CNS) irradiation to <10% of the patients and provided a 5-year risk of isolated CNS relapse of 2.6%. Improved risk stratification and chemotherapy have eliminated the previous independent prognostic significance of gender, CNS leukemia and translocation t(1;19)(q23;p13), whereas the post-induction level of minimal residual disease (MRD) has emerged as a new risk grouping feature. Infant leukemia, high leukocyte count, T-lineage immunophenotype, translocation t(4;11)(q21;q23) and hypodiploidy persist to be associated with lower cure rates. To reduce the overall toxicity of the treatment, including the risk of therapy-related second malignant neoplasms, the current NOPHO ALL-2008 protocol does not include CNS irradiation in first remission, the dose of 6-mercaptopurine is reduced for patients with low thiopurine methyltransferase activity, and the protocol restricts the use of hematopoietic stem cell transplantation in first remission to patients without morphological remission after induction therapy or with high levels of MRD after 3 months of therapy.

Cellular drug sensitivity in MLL-rearranged childhood acute leukaemia is correlated to partner genes and cell lineage.

Rearrangements in the 11q23 region, the site of the mixed lineage leukaemia (MLL) gene, are found in both childhood acute myeloid (AML) and lymphoblastic (ALL) leukaemia. We studied the in vitro drug resistance by the fluorometric microculture cytotoxicity assay (FMCA) in 132 children with AML and 178 children with ALL (aged 0-17 years). In AML, children with t(9;11) (n = 10) were significantly more sensitive to cytarabine (P < 0.001) and doxorubicin (P = 0.005) than non-11q23 rearranged patients (n = 108). Children with other 11q23 rearrangements (n = 14) differed less from non-rearranged children. The 'AML-profile' common to all three groups included relative resistance to glucocorticoids and vincristine. In ALL, children with 11q23 rearrangement (n = 22) were significantly more sensitive to cytarabine (P = 0.026) than children without 11q23 rearrangement (n = 156), also after stratification for white blood cell count. In conclusion, the findings indicate that the cellular drug resistance is correlated to both the cell lineage and the type of 11q23 rearrangement. High cellular sensitivity to cytarabine and doxorubicin might explain the excellent treatment results in children with AML and t(9;11). The present study supports the strategy of contemporary protocols to include high-dose cytarabine in the treatment of 11q23-positive patients both in AML and ALL.

[Water intoxication with hyponatremia and cramps in the newborn period]. / Vannintoksikasjon med hyponatremi og kramper i nyfødtperioden.

Acute water intoxication with hyponatraemic convulsions has been described several times in children less than two years old. We describe a two-day-old boy who developed hyponatraemia with convulsions because of water intoxication during his stay in the maternity ward. It was a hot day, and the baby was observed to sweat abundantly. The mother therefore breast fed him at frequent intervals and in addition offered him plain water, which he drank eagerly, approximately 350 ml in the course of a few hours. He then developed convulsions with bilateral clonic flexion movements of the arms, and serum sodium concentration was 113 mmol/l (114 on repeat). He was treated with diazepam and phenobarbitone and 20 mmol NaCl as slow infusion, and serum Na was 135 mmol/l after 20 hours. During treatment he passed large amounts of dilute urine and lost 110 g of weight. No abnormal loss of salt was found, and follow-up for six months has been uneventful. Neonates are at risk of developing hyponatraemia and convulsions when offered large amounts of electrolyte poor solutions, especially during hot weather.

Hyperferritinaemia-cataract syndrome.

The first family with hyperferritinaemia-cataract syndrome in Scandinavia is described. We discuss the etiology and point at this diagnosis as a differential diagnosis in case of hereditary cataract.

Variations in erythropoiesis throughout a lifetime. Studies in a high-leukaemic mouse strain, the AKR/O strain, and a non-leukaemic strain, the WLO strain.

We have studied the development of some haematological variables: erythropoiesis stimulating factor(s) (ESF), investigated with an in vitro cell culture assay; and the content of bone marrow and spleen erythroid colony forming unit(s) (CFU-E) and erythroid burst forming unit(s) (BFU-E) throughout the lifetime of 2 different mouse strains: the high-leukaemic, retrovirus infected AKR/O strain, and the non-leukaemic WLO strain. During the recovery phase of the postnatal anaemia, a peak in plasma ESF occurs in both strains. In young adult mice of both strains another peak in plasma ESF occurs at 70-110 days of age, associated with an increased number of bone marrow CFU-E, in a period when packed cell volume (PCV) remains stable. As the animals grow older PCV decreases, whereas plasma ESF and bone marrow CFU-E concentration increase. These results, together with in vitro dose-response studies, suggest reduced sensitivity to erythropoietin (Epo) of the ageing erythron. Throughout, the AKR/O strain has higher levels of plasma ESF and bone marrow CFU-E concentrations than the WLO strain, indicating both a reduced Epo responsiveness and some degree of ineffective erythropoiesis in the AKR/O strain. At all ages the AKR/O strain has a high concentration of Epo independent bone marrow CFU-E, possibly caused by the virus infection of precursor cells.

Vitamin D deficiency rickets and vitamin B12 deficiency in vegetarian children.

During the years 1978-83 four vegetarian children have been admitted to the pediatric departments of Ullevaal and Aker Hospitals in Oslo and Haukeland Hospital, Bergen, with the diagnosis of vitamin D deficiency rickets. One had vitamin B12 deficiency as well. All had been fed a vegetarian diet with some cows' milk, but without vitamin supplementation. All had marked hypocalcemia, and three had tetany or convulsions. All responded well to conventional doses of vitamin D therapy. Two of the mothers had vitamin D deficiency, and one of them also had vitamin B12 deficiency. This report describes the case histories of these children, and also discusses predisposing factors of vegetarian diets for the development of nutritional rickets.

Serum immunoreactive erythropoietin in healthy normal children.

To provide reference data for normal children, serum immunoreactive erythropoietin (siEp) was estimated by radioimmunoassay in samples from 130 healthy children, 57 girls and 73 boys, with ages between 1 month and 16 years. In 128 of the children the (geometric) mean siEp was 15.8 miu/ml (iu: international units) with 95% range (the range within which 95% of the observations are predicted to fall) 9.1-27.6 miu/ml. There was no relation between siEp and the variables haemoglobin (Hb), PCV, age and sex. There were two outliers, both girls, aged 9.5 and 9.8 years, in whom siEp was greater than 256 miu/ml. In both, Hb and PCV were normal and we are unable to account for these atypical findings. Estimates of siEp in the 128 children were not significantly different from those in 22 healthy adults investigated simultaneously (mean 16.2 miu/ml, with 95% range 11.2-23.3 miu/ml).

An immunological cross-reactant of erythropoietin in serum which may invalidate EPO radioimmunoassay.

Atypically high radioimmunoassay estimates of erythropoietin in serum samples from two out of a series of 130 normal Norwegian children have been found to be invalid. Invalidity was due to non-parallelism of radioimmunoassay (RIA) response dilution lines given by these two sera when compared with the second International Reference Preparation (IRP). In contrast, immunoreactive erythropoietin in other sera usually shows parallelism with the IRP. Fractionation by gel filtration of the sera showing non-parallelism in the RIA showed them to contain an erythropoietin cross-reactant which was eluted before both an 125I recombinant human erythropoietin marker and normal erythropoietin. In family studies, non-parallelism of RIA response dilution lines and the large molecular size erythropoietin cross-reactant was found in serum from one sibling but not in five other family members of one of the two index cases. Radioimmunoassays based on two different antisera differed in recognition of the abnormal cross-reactant of erythropoietin.

Immune thrombocytopenic purpura in childhood in Norway: a prospective, population-based registration.

A prospective, population-based registration of children with immune thrombocytopenic purpura (ITP) was performed in Norway in 1996 and 1997. Ninety-two cases were identified, indicating an incidence of 5.3 per 100,000 children under 15 years. The sex ratio (female/male) was 1.2/1. Fifty-six percent presented with cutaneous signs only. The lowest platelet count was < 20 x 10(9)/L in 91%. In spite of mild bleeding symptoms, medical treatment was given in 68%, in most cases (57/63) with intravenous immunoglobulin. A total of 41/44 patients with platelet counts of < or = 5 x 10(9)/L were treated, regardless of whether they had mucous bleedings or not. Eighteen percent had platelet counts < 150 x 10(9)/L at 6 months, and 9% at 12 months following diagnosis. One patient with therapy-resistant chronic ITP died 16 months after diagnosis from an anesthesia complication related to profound epistaxis. This study shows a relatively high incidence. As in other studies, there was a tendency to treat platelet counts rather than bleeding symptoms.

Serum immunoreactive erythropoietin in children with acute leukaemia at various stages of disease--and the effects of treatment.

Most children with leukaemia are anaemic at diagnosis and at various times during treatment. Serum erythropoietin (EPO) was estimated in 27 children with acute leukaemia (n = 26) or lymphoma (n = 1) at diagnosis (n = 16), in relation to treatment with high-dose methotrexate (MTX, n = 11) or cytosine arabinoside (Ara-C, n = 8), and during oral maintenance therapy (n = 10). At diagnosis, in children with anaemia serum EPO was increased, and was inversely related to haemoglobin (Hb). After treatment with high-dose MTX, in some children serum EPO increased where Hb was unchanged or increased. After treatment with high-dose Ara-C, Hb declined, and serum EPO increased markedly in everyone. During oral maintenance therapy without significant anaemia, serum EPO was slightly increased in some children. In conclusion, children with leukaemia respond to anaemia with increased serum EPO concentration, but in relation to treatment with high-dose MTX and Ara-C, additional mechanisms may influence the EPO concentration.

Possible X linked congenital mitochondrial cardiomyopathy in three families.

Familial cases of childhood congestive cardiomyopathy with X linked recessive inheritance and abnormalities of heart muscle mitochondria have been previously reported. We report here three families with possible X linked congestive cardiomyopathy and specific mitochondrial abnormalities. The heart disorder presented as endocardial fibroelastosis with neonatal death in two brothers in one family, and as heart failure and death in infancy in two brothers in the other two families. In one family a maternal uncle may also have been affected. Pyodermia and neutropenia was reported in one of the boys. Electron microscopy of heart muscle after necropsy showed increased numbers of mitochondria and abnormal mitochondrial crystal condensations and paracrystalline inclusions in all sibships. Barth's syndrome has been mapped to Xq28 and includes cardiomyopathy, skeletal muscle myopathy, neutropenia, and mitochondrial abnormalities similar to those found in the three families reported here. Since the clinical picture differed in the three families, they may represent more than one entity.

Erythropoietin, protein, and iron supplementation and the prevention of anaemia of prematurity.

The effectiveness of recombinant human erythropoietin (r-HuEpo) in raising haemoglobin concentrations in very low birthweight infants was examined in a randomised multicentre study. Twenty nine 'healthy' appropriate for gestational age infants with birth weights 900-1400 g entered the study at 3 weeks of age. All infants received breast milk supplemented with 9 g/l human breast milk protein from 3 to 8 weeks of age. Eighteen mg iron was given daily from week 3 and was doubled if serum iron concentration fell below 16.0 mumol/l. Fourteen infants were randomised to receive 100 U/kg r-HuEpo subcutaneously three times a week from week 3 to week 7; 15 infants served as controls. After one week reticulocyte and haemoglobin concentrations were significantly higher in the r-HuEpo treated group and the haemoglobin values remained significantly higher throughout r-HuEpo treatment and at the concentrations observed in full term infants. No adverse effects were associated with the treatment. In stable very low birthweight infants with optimal iron and protein intakes, moderate dose r-HuEpo can produce significant gains in red cell production that may be clinically useful.

Long-term survival and quality of life in patients treated with a national all protocol 15-20 years earlier: IDM/HDM and late effects?

In a follow-up matched control study the 93 (70.5%) survivors of 132 children treated with a national protocol for acute lymphoblastic leukemia (ALL) and 5 survivors of the other 21 cases of ALL in childhood diagnosed in the same period were evaluated. Thus it was also a population-based study. The national treatment protocol was used in the period 1975-1980. Methotrexate (MTX) infusions combined with intrathecal MTX were used as prophylaxis against neuroleukemia instead of irradiation. Neither doxorubicin (Adriamycin) nor cyclophosphamide was used in the protocol. A questionnaire covering demographic data, number of offspring, learning problems, level of athletic performance, education, and work status as well as medical information was used. Forms were received from 94 (96%) of the 98 adult surviving cases and corresponding controls in the family. Interviews were performed in the remaining four cases (4%). There were no statistical differences between the two groups with respect to physical and mental health and quality of life. Hospital records of all patients were also checked for possible late effects. There was no definite case of secondary malignant neoplasm; however, there was one case of prolactinoma and only one case of serious sequelae (hemiparesis during therapy), probably due to intrathecal and intravenous MTX.

[Adults treated as children for acute lymphocytic leukemia--methotrexate, late effects and quality of life]. / Voksne behandlet for akutt lymfatisk leukemi som barn--metotreksat, seneffekter og livskvalitet.

From 1975 to 1980, 153 Norwegian children were diagnosed with acute lymphocytic leukaemia. In 1995, all 98 survivors were studied and compared to matched family controls. 132 children were treated with the national protocol. Of these, 93 (70.5%) were survivors at the time of the study. The remaining five survivors were treated with different treatment schemes. The national protocol included methotrexate infusions combined with intrathecal methotrexate as prophylactics against neuroleukaemia, instead of the irradiation. Neither doxorubicin nor cyclophosphamide were included. In this study, a questionnaire was used that covered demographic data, quality of life, and medical information the response rates were 96% (94 persons) for survivors and 92% (90 persons) for family controls. Information was also obtained for the remaining four survivors. No significant differences were found between survivors and controls with regard to quality of life and demographics, with one exception, Somatisation on the GHQ-28. Hospital records of all patients were checked for possible late effects. One case of serious sequela (hemiparesis during therapy) was found, probably related to methotrexate therapy. Seven other serious, possible sequelae were recorded, but probably not related to methotrexate. There were no cases of secondary malignant neoplasm.