A novel FIP1L1-PDGFRA mutant destabilizing the inactive conformation of the kinase domain in chronic eosinophilic leukemia/hypereosinophilic syndrome

BACKGROUND

The Fip1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) gene fusion is a common cause of chronic eosinophilic leukemia (CEL)/hypereosinophilic syndrome (HES), and patients suffering from this particular subgroup of CEL/HES respond to low-dose imatinib therapy. However, some patients may develop imatinib resistance because of an acquired T674I mutation, which is believed to prevent drug binding through steric hindrance.

METHODS

In an imatinib resistant FIP1L1-PDGFRA positive patient, we analyzed the molecular structure of the fusion gene and analyzed the effect of several kinase inhibitors on FIP1L1-PDGFRA-mediated proliferative responses in vitro.

RESULTS

Sequencing of the FIP1L1-PDGFRA fusion gene revealed the occurrence of a S601P mutation, which is located within the nucleotide binding loop. In agreement with the clinical observations, imatinib did not inhibit the proliferation of S601P mutant FIP1L1-PDGFRA-transduced Ba/F3 cells. Moreover, sorafenib, which has been described to inhibit T674I mutant FIP1L1-PDGFRA, failed to block S601P mutant FIP1L1-PDGFRA. Structural modeling revealed that the newly identified S601P mutated form of PDGFRA destabilizes the inactive conformation of the kinase domain that is necessary to bind imatinib as well as sorafenib.

CONCLUSIONS

We identified a novel mutation in FIP1L1-PDGFRA resulting in both imatinib and sorafenib resistance. The identification of novel drug-resistant FIP1L1-PDGFRA variants may help to develop the next generation of target-directed compounds for CEL/HES and other leukemias.

Testing the efficiency of aerosol containment during cell sorting

Production of droplets and microdroplets (aerosols) is part of the normal operation of a cell sorter. These aerosols may contain toxic, carcinogenic, or teratogenic fluorophores or known or unknown pathogens from viable biological specimens. Most newer models of commercially available instruments incorporate features designed to reduce the production of aerosols and prevent their release into the room. This unit presents two protocols for assessment of aerosol containment on jet-in-air flow sorters. In both procedures, lytic T4 bacteriophage is run through the instrument at high concentrations to tag aerosol droplets. The instrument is tested in normal operating mode and in simulated failure mode. Aerosols are detected by plaque formation on susceptible E. coli lawns. With the continuing increase in the sorting of viable human cells, it is vital for cytometrists to be aware of the potential dangers.

Preparation of cells and reagents for flow cytometry

Flow cytometry is widely used for analyzing the expression of cell surface and intracellular molecules (on a per cell basis), characterizing and defining different cell types in heterogeneous populations, assessing the purity of isolated subpopulations, and analyzing cell size and volume. This technique is predominantly used to measure fluorescence intensity produced by fluorescent-labeled antibodies or ligands that bind to specific cell-associated molecules. A procedure for direct and indirect staining of single-cell suspensions of lymphoid tissue or peripheral blood lymphocytes to detect cell surface membrane antigens is presented. In addition, support protocols present methods for fluorescence labeling of purified antibodies. A protocol for flow cytometric analysis of intracellular antigens in single-cell suspensions is also included. Alternate protocols describe intracellular staining of unfixed cells in the presence of a detergent and staining of nonviable cells to facilitate discrimination of dead cells in fixed or permeabilized cell preparations.

[Sepsis after pharyngitis]

We report about a 36-year-old patient, who developped 4 days after a pharyngitis a sepsis with high temperature und recurrent vomiting. The chest radiograph showed multiple pulmonary abcesses and in the computed tomography additionally a thrombosis was detected in a communicans vein between the right jugularis anterior and the jugularis interna. This disease is commonly known as Lemierre Syndrom. The most common pathogen is the Fusobacterium necrophorum, but other bacteria of the normal oropharyngeal flora can also be the causative organisms. Given an adequate antibiotic therapy and supportive care, the prognosis is favourable.

Contribution of anti-cyclic citrullinated peptide antibody and rheumatoid factor to the diagnosis of arthropathy in haemochromatosis

OBJECTIVE

To investigate the prevalence of antibodies to cyclic citrullinated peptide (anti-CCP) and rheumatoid factor in patients with hereditary haemochromatosis (HHC) and to evaluate their diagnostic reliability in distinguishing HHC-associated arthropathy from rheumatoid arthritis.

METHODS

Anti-CCP antibodies and rheumatoid factor levels were determined by ELISA in sera from 87 patients with HHC homozygous for the C282Y mutation of the HFE gene, 31 patients with rheumatoid arthritis and 162 healthy controls.

RESULTS

Of the 87 patients with HHC, 32 (36.8%) had joint involvement. Anti-CCP antibodies were detected in only 1 patient (1.1%) with HHC, who had no joint disease, and in (1.2%) healthy controls. In total, 18 (58.1%) patients with rheumatoid arthritis displayed anti-CCP reactivity (p<0.001). Rheumatoid factor was detected in 10 (11.5%) patients with HHC compared with 7 (4.3%) healthy control subjects (p = 0.03) and 21 of 31 (65.6%) patients with rheumatoid arthritis.

CONCLUSIONS

Testing for anti-CCP antibodies discriminates HHC arthropathy from rheumatoid arthritis, as these patients were consistently anti-CCP negative. Thus, HHC arthropathy should be considered in the differential diagnosis of CCP-negative arthritis.

Bone marrow Th2 cytokine expression as predictor for relapse in childhood acute lymphoblastic leukemia (ALL)

The immunological environment of leukemic blasts in the bone marrow might play a decisive role in determining an individual's risk for relapse. In order to identify potential predictors of relapse and to elucidate the mechanisms of immune control of leukemic blasts we examined the expression of cytokines, costimulatory molecules and members of the TNF family in leukemic marrow samples in a prospective study. Samples from 49 consecutive pediatric patients with B cell precursor acute lymphocytic leukemia (BCP ALL) were analyzed by semiquantitative RT-PCR. We identified interleukin (IL)-10 expression as a significant adverse prognostic indicator in childhood BCP-ALL. The event free survival (EFS) of patients expressing IL-10 mRNA in high quantity was significantly lower compared with patients expressing low IL-10 mRNA. Taqman RT-PCR of sorted cell populations showed that IL-10 mRNA was synthetized almost exclusively by NK or T cells. In addition, we found an increased expression of IL-1, IL-4, CD86 and VEGF mRNA in patients with late relapses. Possibly, ALL cells mediate a Th2 shift through increased expression of CD86 and thereby influence the individual relapse risk. These findings emphasize the role of the immune system for the outcome of childhood ALL.

Effects of soluble TNF receptor II (sTNF-RII), IL-1 receptor antagonist (IL-1ra), tumor load and hypermetabolism on malnutrition in children with acute leukemia

OBJECTIVE

Soluble tumor necrosis factor receptor II (sTNF-RII) and interleukin-1 receptor antagonist (IL-1ra) might modulate nutritional status in acute leukemia since they are inhibitors of tumor necrosis factor-alpha and interleukin-1 that can induce tissue wasting. On the other hand, tumor load and hypermetabolism may induce malnutrition. We determined whether serum levels of sTNF-RII and IL-1ra are upregulated to prevent overt malnutrition and whether tumor load and hypermetabolism induce overt malnutrition.

METHODS

We examined 31 children with newly diagnosed acute leukemia and correlated sTNF-RII, IL-1ra, tumor load and energy expenditure to anthropometric characteristics (weight, weight for height, height, body mass index, fat free mass) and serum protein concentrations (albumin, transferrin, prealbumin). As controls, 68 healthy children were examined for anthropometric characteristics; 33 healthy controls were included for cytokine analysis and biochemical indices.

RESULTS

We found no correlations between sTNF-RII, IL-1ra, tumor load and energy expenditure and anthropometric characteristics or protein concentrations. Mean sTNF-RII level was significantly, mean IL-1ra level slightly increased (223% and 113% of the controls). 29% of the children had a high tumor load (> 100.000/microl white blood cells) and 53% had hypermetabolism (resting energy expenditure > 110% of predicted). Anthropometric characteristics were similar to those in controls, however, serum protein concentrations were decreased.

CONCLUSION

sTNF-RII and IL-1ra are upregulated in children with leukemia and may therefore prevent overt malnutrition. Tumor load and hypermetabolism do not induce overt malnutrition. The children presented with an early stage of malnutrition as evidenced by low serum protein concentrations but normal anthropometric characteristics.

[Supratentorial primitive neuroectodermal tumor: a single center experience and comparison with the literature]

Supratentorial primitive neuroectodermal tumors (stPNETs) are malignant tumors. We saw within three years six children with stPNETs. In four of the six children radical resection could be achieved. All had craniospinal irradiation and chemotherapy according to the HIT-91 protocol. The two children with incomplete resection died due to tumor progression after 7 and 10 months. Two of the 4 children with complete tumor resection had local relapses 8 months after diagnosis and died after 14 and 18 months. One child had a diffuse meningeal relapse 12 months after diagnosis. Despite (high-dose) systemic chemotherapy and intraventricular mafosfamide, he died 21 months after diagnosis due to tumor although remission could be achieved. Only one child is still in remission 86 months after diagnosis.

Clustered root distribution in mature stands of Fagus sylvatica and Picea abies

Distribution of small roots (diameter between 2 mm and 5 mm) was studied in 19 pits with a total of 72 m(2) trench profile walls in pure stands of Fagus sylvatica and Picea abies. Root positions within the walls were marked and transformed into x-coordinates and y-coordinates. In a GIS-based evaluation, zones of potential influence around each root were calculated. The total potential influence produced isoline maps of relative root influence zones, thus indicating small root clustering. The questions studied were (1) whether there were marked clusters of small roots in the soil and (2) whether trees surrounding the pit (defined as tree density) correlate with the root abundance and distribution on the trench profile walls. Small roots of both species showed maximum abundance in the top 20 cm of the soil, where pronounced root clusters occurred next to areas with only low root accumulation. The area of root clusters did not differ significantly between the two stands. Weighted clumping, WC, calculated as a product of root class, and its area was used as an index of root clustering, which again did not differ between beech and spruce stands. However, evaluations on a single root level showed that beech achieved the same degree of clustering with lower number of roots. Regardless of soil properties related to root clusters, a significantly higher clustering acquired per root for beech than for spruce suggests beech to be more efficient in belowground acquisition of space. Because none of the parameters describing root clustering were correlated with tree density around the investigated soil profiles, clusters of small roots are inherently present within the tree stands.

Ileoileal intussusception caused by a Ewing sarcoma tumour. An unusual case report

Intussusception typically occurs in childhood, presenting with a well-known medical history and clinical symptoms. Pathologically, a "leading point" may be attributed to lymphadenomatosis, polyps, or a tumour. In older patients and adolescents, the diagnosis can be complicated due to the lower incidence and variable subacute symptoms. We report on an 18-year-old patient with increasing abdominal discomfort over several weeks. External diagnostics showed no pathological signs or were misinterpreted as a malfunction of intestinal motility. The patient experienced increasing colics, recurrent vomiting, dehydration and weight loss. Finally he was transferred to our paediatric surgical department and laparotomy had to be performed for the clinical and radiological signs of an ileus. An ileoilealic intussusception was found, caused by a small bowel tumour, which almost completely obstructed the intestinal lumen. It was resected and bowel continuity was re-established. Histopathology revealed a very rare, highly malignant mesenchymal Ewing sarcoma, infiltrating the complete bowel wall. After the postoperative course, the patient was transferred to our oncological department for chemotherapy. In older children or young adults, intestinal malignancies are extremely rare. Nevertheless, if these patients suffer from unspecific complaints of chronic intestinal obstruction, a tumour must be ruled out. A Ewing sarcoma may be responsible for an intussusception.

T-cell-depleted peripheral blood stem cell transplantation for alpha-mannosidosis

Alpha-mannosidosis (alpha-mannosidosis) is a lysosomal storage disease characterized by accumulation of oligosaccharides in various tissues leading to symptoms such as coarse facial features, dysostosis multiplex, hearing disabilities, mental developmental delay and skeletal involvement (dysostosis multiplex). Without treatment, the severe infantile onset form of this autosomal recessive disease leads to progressive neurodegeneration and sometimes to early death. Stem cell transplantation has been shown to be an effective treatment. In the five patients published so far, correction of skeletal abnormalities and improvement of neuropsychological capabilities have been observed. We report the first patient who received a T-cell-depleted peripheral blood stem cell transplantation (PBSCT) for alpha-mannosidosis. The diagnosis of alpha-mannosidosis was made at the age of 14 months. At the age of 24 months, he underwent PBSCT with T-cell depletion by CD34-positive selection from his HLA phenotypically identical mother. Conditioning was carried out with busulfan (20 mg/kg), cyclophosphamide (200 mg/kg), OKT3 and methylprednisolone. The patient is alive and well 27 months after PBSCT and has made significant developmental progress. The pattern of urinary oligosaccharides has returned to almost normal. CD34-positive-selected PBSCT is a feasible option to reduce risk for GVHD for these patients.

Guidelines for the intramuscular positioning of EMG electrodes in the semispinalis capitis and cervicis muscles

The objective of the study was to establish guidelines for the application of fine-wire or needle electrodes in the semispinalis cervicis and semispinalis capitis muscles. First of all, measured data for the puncture angle and puncture depth of each muscle were determined in CT scans. Using a regression approach, a model relation of these data with the neck circumference was established. This made it possible to accurately determine the puncture angle and puncture depth on the basis of the known neck circumference. In a further step, the neck muscles of seven human cadavers were punctured with wires in order to check the workability of these guidelines. At the same time, the wires' positions in relation to important structures (nerves, vessels) were studied. Both muscles can be punctured with a high degree of reliability. However, when puncturing the semispinalis cervicis muscle, one has to pass through a layer that contains vessels, nevertheless the risk of injury is regarded as very small. The technique enables intramuscular EMG measurements of the two muscles in manifold clinical problems.

Blinded speech evaluation following pharyngeal flap surgery by speech pathologists and lay people in children with cleft palate

METHODS

In order to assess intermediate-term speech outcome after pharyngeal flap surgery for velopharyngeal dysfunction in children with cleft palate between 1980 and 1998, their pre- and postoperative speech performance was analyzed in a blinded fashion by speech pathologists and adult lay people. Speech was evaluated on the basis of tape recordings with regard to resonance, intelligibility, articulation, voice and secondary speech disorders.

RESULTS

Twenty-three patients could be evaluated. Both lay assessors and speech pathologists noted a significant improvement in speech performance after pharyngeal flap surgery. The percentage of children who improved was 83% (19/23, 95% confidence interval: 0.68-0.98, p = 0.002) when rated by lay people, and 87% (20/23, CI 0.73-1.01, p < 0.0001) when rated by professionals. Rated on a 5-point scale, the mean improvement per speech characteristic was 0.52 +/- 0.32 scale points when judged by lay people, and 0.75 +/- 0.8 points when judged by experts. Experts considered none of the children to have normal speech after surgery. Agreement with regard to outcome between lay people and speech pathologists occurred in 87% of the patients.

CONCLUSION

The cranially based pharyngeal flap can improve speech performance in cleft palate children with chronic velopharyngeal insufficiency. However, it cannot be expected that this type of surgery will result in normal speech.

[Results of surgical management of abducens paralysis]

BACKGROUND

The pre- and postsurgical results after mono- and bilateral transposition surgery for abducens nerve palsy are reported.

PATIENTS AND METHODS

In 13 eyes from 11 patients with 6th nerve paralysis, transposition surgery modified after Kaufmann was performed after a median duration of 13 months (range 6-28 months). The actual angle of strabismus, the capability of abduction and the field of binocular single vision with the tangent screen according to Harms were measured prior to surgery, immediately after surgery (1-3 weeks) and in the later postsurgical period (9-12 months).

RESULTS

Of the patients 7 achieved fusion with binocular single vision, 5 of these patients had to accept an ocular torticollis of 10 degrees (range 5-15 degrees) and 4 patients had a tendency to exclusion. Of the 11 patients, 9 were treated successfully with one single surgical procedure 2 of which had bilateral abducens nerve palsy and 2 patients needed 2 further operations. The median preoperative convergent angle in the primary position was reduced from 28 degrees (range 16 degrees-60 degrees) to a median angle of 0 degree, sometimes only latent (range D 7 degrees-C 4 degrees) in the late postoperative period. The median postoperative abduction over the midline was 10 degrees (range 3 degrees-25 degrees).

CONCLUSIONS

Bilateral 6th nerve paralysis was treated effectively with simultaneous transposition surgery in both eyes. In most cases an additional weakening of the medial rectus muscle was not necessary. An initial overcorrection with exotropia in the early postoperative period is desired and is a predictive factor for a good late postoperative result.

Megestrol acetate to correct the nutritional status in an adolescent with growth hormone deficiency: Increase of appetite and body weight but only by increase of body water and fat mass followed by profound cortisol and testosterone depletion

Megestrol acetate (MA) is a synthetic, orally active derivative of the naturally occurring hormone progesterone. MA is increasingly used to correct loss of appetite and improve the nutritional status. We used MA in an adolescent with growth hormone (GH) deficiency due to former irradiation therapy in order to evaluate if MA can improve the nutritional status. In fact, MA increased appetite and weight dose-dependent. The energy expenditure measured by indirect calorimetry changed from hypo- to normometabolism. However, weight gain was first primarily due to an increase in body water and then in fat mass. The gain of fat mass was much more prominent than the gain of fat free mass. As important side-effect, MA lead to rapid and profound cortisol and testosterone depletion after only 10 days with a long-lasting effect on testosterone depletion. Therefore, MA as a single therapy cannot be recommended to improve the nutritional status. If MA is given, cortisol and testosterone levels have to be monitored and supplemented as needed.

Severe life-threatening diarrhea caused by azathioprine but not by 6-mercaptopurine

Azathioprine and its active metabolite 6-mercaptopurine are of increasing importance in the treatment of chronic inflammatory bowel disease. Most of the toxicity and the side effects of the medications are well known. However, it is relatively unknown that azathioprine toxicity itself can produce devastating diarrhea in patients with inflammatory bowel disease. This leads to great difficulties in differential diagnosis. We describe 2 patients with severe intestinal toxicity. This was life-threatening in 1 patient after reintroducing the drug. We therefore believe that any rechallenge with azathioprine should be only undertaken in a controlled hospital environment when a reaction to azathioprine is suspected. In addition, we found that this devastating intestinal toxicity did not reoccur after rechallenge with its active metabolite 6-mercaptopurine. Azathioprine and 6-mercaptopurine therefore cannot be used interchangeably.

Allogeneic bone marrow transplantation for active Epstein-Barr virus-related lymphoproliferative disease and hemophagocytic lymphohistiocytosis in an infant with severe combined immunodeficiency syndrome

A 5-month-old male presented with fever, hepatosplenomegaly, leukocytosis with atypical lymphoblasts, anemia and thrombocytopenia. Severe combined imunodeficiency syndrome (T-, B+, NK+), B lymphoproliferative disease and hemophagocytic lymphohistiocytosis triggered by Epstein-Barr virus (EBV) were diagnosed. As his clinical situation deteriorated rapidly, BMT was performed with unmanipulated marrow stem cells from his EBV-positive HLA-identical sister after conditioning with dexamethasone (1.75 mg/kg/day), cyclophosphamide (114 mg/kg) and etoposide (10 mg/kg), with no immunosuppression given post transplant. Engraftment occurred on day 6 with explosive proliferation of donor CD8(+) T cells. The patient died 3 days later from acute respiratory distress syndrome. Autopsy revealed full donor engraftment and no signs of hemophagocytic lymphohistiocytosis or B lymphoproliferative disease. Thus, transplanted T cells can expand very rapidly within days after BMT and clear EBV lymphoproliferative disease and hemophagocytic lymphohistiocytosis.