Aberrant expression of KOR-SA3544 antigen in childhood acute lymphoblastic leukemia predicts TEL-AML1 negativity. The Pediatric Hematology Working Group in the Czech Republic.

The antigen KOR-SA3544 is physiologically expressed exclusively on granulocytes. Aberrant expression of KOR-SA3544 has been invariably found in BCR/ABL-positive acute lymphoblastic leukemia (ALL) and in some BCR/ABL-negative ALL. In an interim analysis of a prospective clinical and cytometric study data of 73 children with newly diagnosed or relapsed ALL with and without TEL/AML1 fusion are presented. KOR-SA3544 expression over 3% was detected in the majority of TEL/AML1-negative patients with newly diagnosed common or preB ALL (19 of 31) and not in TEL/AML1-positive patients (0 of 18, P < 0.0001). The level of expression of KOR-SA3544 was 0.02-90% (median 6.0%) and 0.03-2.4% (median 0.23%) in TEL/AML1-negative and TEL/AML1-positive patients, respectively. All five newly diagnosed patients with DNA index > or =1.16 and <1.6 exhibited high levels of KOR-SA3544 expression. Membrane expression of CD79a was found to correlate with TEL/AML1 negativity, although less significantly than KOR-SA3544 (P = 0.03). Furthermore, our data confirm that TEL/AML1 positivity correlates with non-hyperdiploidy and low presenting age. In conclusion, KOR-SA3544 correlated strongly with TEL/AML1 negativity, it was a better predictor of TEL/AML1 status than other factors tested and was found at high levels in hyperdiploidy. In combination with age, KOR-SA3544 predicted TEL/AML1 status in 86% newly diagnosed preB/cALL patients.

Detection of minimal bone marrow infiltration in patients with localized and metastatic Ewing sarcoma using RT-PCR.

Ewing sarcoma and related neoplasias are characterized by the presence of specific chromosomal translocations resulting in EWS/ETS gene rearrangements. Created EWS/ETS-oncogene fusion transcripts can be detected in up to 98% of ESFT and provide tumour-specific markers useful in diagnostics. Using RT-PCR for detection of this aberration we can reveal minimal amounts of tumour cells contaminating BM, blood or apheresis products. We have examined BM samples from 22 patients (21 newly diagnosed and one recurrent disease) with histologically confirmed ESFT for the presence of contaminating tumour cells in BM at the time of diagnosis. Sixteen patients presented with localized disease, six had distant metastases at the first presentation. Ewing sarcoma cells were detected in the BM of 5/16 (31%) patients with localized disease and 3/6 (50%) with clinically detectable metastases at diagnosis. BM smears prepared from the same aspirates evaluated by light microscopy were all negative, even in two patients with multiple bone disease. We have confirmed the high sensitivity of the RT-PCR assay for detection of minimal BM infiltration in localized and metastatic ESFT. We have found that more than a quarter of patients with localized ESFT have minimal BM infiltration. Although the clinical significance of the minimal disease detected at the molecular level remains unknown, RT-PCR evaluation may enable better stratification of patients into risk groups in the future.

[Hemophagocytic lymphohistiocytosis as a manifestation of visceral leishmaniasis]. / Hemofagocytující lymfohistiocytóza jako manifestace viscerální leishmaniózy.

A 7-year-old previously healthy Czech boy was admitted due to fever, hepatosplenomegaly and pancytopenia. Aspiration of bone marrow revealed no signs of hemoblastosis (nor hemophagocytosis). He was treated with antibiotics and virostatics without effect. Progression of hepatosplenomegaly and pancytopenia induced suspicion of hemophagocytic lymphohistiocytosis (HLH). Five weeks later, bone marrow hemophagocytosis of erythrocytes, nuclear elements and platelets was detected. He was given corticoids and intravenous immunoglobulins and transferred to our haematology department. Laboratory findings of mild pancytopenia, hypofibrinogenaemia, hyperlipidaemia and elevated levels of ferritin, LDH and immunoglobulins were compatible to the diagnosis of HLH. Immunologic evaluation revealed T-lymphocyte activation. Appropriate immunosuppressive treatment with Dexamethasone, etoposide and Cyclosporine A was launched, followed by transient subside of fever and improvement of peripheral blood count, but not regression of hepatosplenomegaly. Four weeks later, relapse of fever and deterioration of blood count led to intensification of immunosuppression. However, no effect was evident. Moreover, hypertrophic cardiomyopathy with ventricular arrhythmia occurred. Treatment with antilymphocytic globulin for resistant course of HLH was planned. Before that, a fifth bone marrow aspiration was performed. Surprisingly, many Leishmania amastigotes were observed within marrow macrophages. Leishmania infection was confirmed by positive serology. Immunosuppressive treatment was withdrawn and changed for causal treatment with liposomal Amphotericin B. Positive clinical effect with subside of fever was evident in ten days, splenomegaly gradually resolved during three weeks, restoration of normal blood count lasted six weeks. No relapses of HLH nor leishmaniasis occurred. In control bone marrow aspirate performed three months later, the parasites were not detected. Ten months after the event, the patient is in complete remission of HLH with normal immunologic parameters. Most probably, he contracted visceral leishmaniasis during a visit of a Neapol area in Italy 3 months before the onset of the disease.

[Histiocytic syndromes in childhood]. / Histiocytární syndromy v detském veku.

The authors submit an account of the new classification of histiocytic diseases in childhood, they mention contemporary views on their aetiology, pathogenesis, advances in diagnosis and therapy. The paper is supplemented by case-histories from the authors' own practice.

Fibrinolysis, fibrinogen and trhombin time in newborns.

Comparative experiments were made on blood samples collected with and without addition of a potent fribinolysis-blocking agent in newborn infants aged up to 12 h. Prevention of the in vitro fibrinolysis resulted in a diminished frequency of an abnormal euglobulin clot lysis time, but there was no significant difference in fibrinogen levels and in the frequency and degree of a prolonged thrombin time. These results indicate that the prolongation of thrombin time in newborn infants cannot be prevented by blocking the in vitro fibrinolysis. The significance of these findings is discussed with regard to the possible existence of an abnormal 'fetal fibrinogen'.

Phagocytic activity of leukaemic blasts.

Phagocytic activity of leukaemic blasts in 20 adults and 16 children suffering from acute leukaemia was studied in vitro by the use of ferrioxidsaccharate. Most frequently phagocytosing blasts were encountered in myelomonocytic leukaemias. The morphological character of positive blasts resembled often that of monocytoid cells. In lymphoblastic and reticular leukaemias phagocytic ability of blasts was an exceptional finding.

Infection-associated hemophagocytic syndrome complicated by infectious lymphoproliferation: a case report.

The case of a 7-year-old boy with virus-associated hemophagocytic syndrome (VAHS) and serologically proven parvovirus B-19 infection is described. The patient with VAHS presented with fever, hepatosplenomegaly, pancytopenia, and hyperlipidemia type IV. After induction therapy with VP-16 and prednisone, partial remission was achieved. Despite maintenance therapy, reinductions, and the addition of cyclosporine A for 3 months, several relapses occurred. The therapy was stopped because of life-threatening complications (Klebsiella sepsis, neutropenic enterocolitis, and stercoral peritonitis). The complications were treated successfully. The patient status was stabilized after splenectomy. However, hepatomegaly progressed slowly and the hyperlipidemia endured. Ten months after the diagnosis leukocytosis with absolute T lymphocytosis appeared. Reactivation of VAHS was suspected and intravenous immunoglobin and then antilymphocyte immunoglobulin ALG therapy were started. The resultant decrease in leukocytosis was prompt, but lymphopenia did not occur. Virostatic treatment with foscarnet was introduced based on human herpesvirus-6 seroconversion. Twenty-six months after the diagnosis, the patient is well, without any sign of VAHS or lymphoproliferation.