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Introduction: Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood. Immunodeficiency occurs very often during ALL treatment. Therefore, patients are susceptible to various infections (including hepatitis B)., Material and Methods: The study group consisted of 66 children with ALL treated at the Department of Pediatric, Hematology and Oncology in Zabrze. Patients were divided into two groups with regard to active HBV prophylaxis before diagnosis. Group I included 22 patients who were vaccinated before diagnosis. Group II included 44 patients who were not vaccinated before diagnosis. After diagnosis active, passive and/or active-passive prophylaxis were administered to the patients., Results: In most patients, the anti-HBV titers were protective after ALL treatment completion. In the remaining children, with anti-HBV titers < 100 IU/ml, the HBV prophylaxis was also successful, because none of them experienced de novo HBV infection., Conclusions: Despite various models of HBV prophylaxis, the protection from new infection was effective in all children treated for ALL.

Purpose: The aim of the present study was to compare the blast immunophenotype of acute lymphoblastic leukaemia (ALL) at diagnosis and at relapse and to define the most frequent shifts in marker expression., Patients and Methods: Bone marrow samples from 14 patients were analyzed by flow cytometry both at diagnosis and at relapse - in 12 patients with B-cell precursor (BCP)-ALL and in 2 patients with T-ALL., Results: The conversion in blast immunophenotype was observed in 12 out of 14 patients (86%). Antigen CD34 turned out to be the most unstable antigen - the shift in the signal expression was present in 57% of BCP-ALL and in both T-ALL cases. Regarding B-lineage markers, the shifts most frequently concerned CD20 (shifts present in 41.5% of cases) and CD22 (27%). Among the T-lineage markers: CD3, CD4 and CD8 demonstrated the highest incidence of altered signal expression. On the other hand, the most stable antigen included CD19 and CD10 for the BCP-ALL group and CD1a, CD2, CD5, CD7 for T-ALL patients. Expression of HLA-DR, TdT and CD45 antigens remained unchanged in both BCP-ALL and T-ALL groups., Conclusions: The results of the present study support the requirement to monitor at least two different leukaemia specific antigen combinations for detection of MRD to prevent a false-negative result and to increase the effectiveness of monitoring minimal residual disease.

Increasing intensity of treatment of childhood malignancies as well as administration of the new generation broad-spectrum antibiotics is associated with increased risk of fungal infections. In this paper, we describe two patients, in whom anti-neoplastic treatment was complicated by systemic fungal infection. Early suspicion and/or detection of fungal infection enables more effective and shorter treatment. Administration of an anti-fungal drug should be considered in every neutropenic patient after chemotherapy and/or with protracted fever. Since the anti-fungal treatment is usually prolonged, this results in significant interruption of the chemotherapy.

Objective: Initiation and popularization of routine molecular diagnostics of minimal residual disease (MRD) are currently one of the most urgent challenges in Polish hemato-oncology. The paper is aimed to present preliminary results of identification of immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements and quantitative assessment of MRD levels in Polish children with acute lymphoblastic leukemia (ALL). The results are presented in the context of clinical significance of MRD study, current methodology of MRD assessment and standardization process in Western Europe., Material: DNA isolated from bone marrow / bone marrow mononuclear cells obtained at diagnosis from 26 children (25 B-precursor ALL, 1 T-ALL) aged 1.3-16.5 years., Methods: PCR-heteroduplex analysis, based on standard BIOMED-1 and BIOMED-2 primer combinations and protocols for detection of rearrangements and clonality assessment; sequencing of clonal PCR products and comparison with germline sequences of Ig/TCR genes for identification of the rearranged genes andjunctional regions; real-time quantitative PCR (RQ-PCR) with the use of TaqMan probes for assessment of follow-up MRD levels (in 11 patients)., Results: Clonal TCRG, incomplete TCRD, Vdelta2-Jalpha, TCRB, IGK-Kde and IGH gene rearrangements were detected in 61, 61, 35, 13, 39 and 83% of patients, respectively, which was generally concordant with published data for patients of other European nations., Conclusions: There is an urgent need to broaden the scope of minimal residual disease study in Poland and to develop Polish standards of MRD diagnostics, based on current European experience and standards.

We present two patients with chronic myeloid leukemia and hyperleukocytosis above 350 x 10(9)/l causing the symptoms of pulmonary leukostasis. Therapeutic leukapheresis procedures with concomitant chemotherapy were initiated within 12 hours from the diagnosis. After the therapy commencement the general condition of the patients systematically improved and leukocytosis gradually decreased from the second day of treatment with disappearance of pulmonary leukostasis symptoms. Thanks to application of such treatment procedures during the cytoreductive period, severe complications related to leukostasis could be prevented.

We present a case of 3-week-old infant, in whom we established the diagnosis of congenital acute lymphoblastic leukemia (ALL), characterized by the immunophenotype of the most immature B-cell precursors (pro-B-ALL) and chromosomal translocation t(4;11) associated with the rearrangement of MLL and AF4 genes. The clinical course of this leukemia deserves particular attention, because it was different from classical presentation: diagnosis--not immediately after birth--but at the age of 3 weeks, no signs of hemorrhagic diathesis, lack of nodular skin infiltrates, and no central nervous system involvement. Exchange blood transfusions performed during the remission induction treatment saved the child from life-threatening symptoms of leukostasis at the initial stage of leukemia. Despite successful remission induction in bone marrow, the infant relapsed during the fifth month of treatment. After subsequent chemotherapy course the child died owing to fatal infectious complications. Despite enormous progress in treatment of childhood ALL, this type of leukemia in infants below 6 months of age, and particularly in cases of congenital leukemia is still associated with a very poor prognosis.

Leukemia diagnosed during the first year of life is a rare but highly malignant disease of hematopoietic system. In contrast to leukemias diagnosed after the first year of life, infant leukemia is characterized by distinct biological and genetic features, which influence the clinical course and disease outcome. Approximately 60% of acute leukemias in infants are associated with aberrations of chromosome 11q23 with the rearrangement of the MLL gene. Despite major progress in treatment of childhood leukemias, prognosis of infant leukemia (particularly in acute lymphoblastic leukemia--ALL) remains poor. The most unfavorable prognostic factors in infant ALL are age at diagnosis below 6 months, CD10 negativity, myeloid antigen co-expression, presence of MLL gene rearrangements and in particular poor response to steroids. Long-term event free survival (EFS) in infant ALL ranges from 20 to 40%, depending on treatment protocol. Slightly better results are achieved in infant acute myeloid leukemia.