New cellular markers at diagnosis are associated with isolated central nervous system relapse in paediatric B-cell precursor acute lymphoblastic leukaemia.

In childhood acute lymphoblastic leukaemia (ALL), central nervous system (CNS) involvement is rare at diagnosis (1-4%), but more frequent at relapse (~30%). Because of the significant late sequelae of CNS treatment, early identification of patients at risk of CNS relapse is crucial. Using microarray-analysis, we discovered multiple differentially expressed genes between B-cell precursor (BCP) ALL cells in bone marrow (BM) and BCP-ALL cells in cerebrospinal fluid (CSF) at the time of isolated CNS relapse. After confirmation by real-time quantitative polymerase chain reaction, selected genes (including SCD and SPP1) were validated at the protein level by flowcytometric analysis of BCP-ALL cells in CSF. Further flowcytometric validation showed that a subpopulation of BCP-ALL cells (>1%) with a 'CNS protein profile' (SCD positivity and increased SPP1 expression) was present in the BM at diagnosis in patients who later developed an isolated CNS relapse, whereas this subpopulation was <1% or absent in all other patients. These data indicate that the presence of a (small) subpopulation of BCP-ALL cells with a 'CNS protein profile' at diagnosis (particularly SCD-positivity) is associated with isolated CNS relapse. Such information can be used to design new diagnostic and treatment strategies that aim at prevention of CNS relapse with reduced toxicity.

Primary malignant lymphoma of the central nervous system in an immunocompetent child: a case report.

Primary lymphoma of the central nervous system (PCNSL) is extremely rare, especially in childhood. A 9-year-old Japanese boy was diagnosed as having precursor-B cell-type lymphoblastic lymphoma, based on morphologic and immunocytochemical analysis of mononuclear cells in the cerebrospinal fluid and a positive reaction for terminal deoxynucleotidyl transferase (TdT), CD19, CD79a, and CD179b. After seven courses of chemotherapy and craniospinal radiotherapy, the patient is alive, well, and in continuous complete remission. Despite its rarity, PCNSL should be included in the differential diagnosis in the presence of symptoms of increased intracranial pressure and/or unusual imaging findings of the brain.

Improving the diagnostic accuracy of cytologic cerebrospinal fluid examinations in acute lymphoblastic leukemia using high-power microscopy and terminal deoxynucleotidyl transferase determinations.

In patients with acute lymphoblastic leukemia (ALL), cytologic examination of cerebrospinal fluid (CSF) is becoming increasingly important for clinical management. In order to enhance the diagnostic accuracy of CSF cytology results, the value of using terminal deoxynucleotidyl transferase (Tdt) and high-power (1,000x) light microscopy, together with conventional cytologic examination was assessed. In 33 CSF samples from ten multiply examined Tdt-positive ALL patients, original cytologic interpretations were compared to Tdt results. Cytology samples were reviewed by two pathologists (one with hematopathologic expertise). The cases in which cytologic interpretation did not correlate with Tdt result were first reviewed via 1,000x microscopy without knowledge of Tdt result, then re-reviewed with knowledge of Tdt result. Conventional cytology alone diagnosed 64% of cases accurately (Tdt representing the comparative standard). High-power microscopy increased the correlation to 82%. Use of high-power microscopy and knowledge of Tdt result together produced a total of 85% of cases with correlation of results. High-power microscopic examination therefore contributes significantly to the accurate diagnosis of ALL, and knowledge of the Tdt result at the time of cytologic examination produces an additional advantage in providing an objective measure for CSF involvement by leukemia. Using all three methods in conjunction is recommended in order to increase the overall accuracy of CSF examination for the detection of leukemic involvement in ALL patients.

Terminal deoxynucleotidyl transferase (TdT)-positive cells in cerebrospinal fluid and development of overt CNS leukemia: a 5-year follow-up study in 113 children with a TdT-positive leukemia or non-Hodgkin's lymphoma.

We investigated whether an indirect nuclear terminal deoxynucleotidyl transferase (TdT) immunofluorescence (IF) assay on single cells present in the cerebrospinal fluid (CSF) is more effective than conventional cytomorphology for early detection or exclusion of (minimal) meningeal leukemic infiltration in patients with a TdT+ malignancy. During a 5-year follow-up study, 1,661 consecutive CSF samples from 113 children with a TdT+ acute lymphoblastic leukemia (ALL) (n = 100), a TdT+ acute nonlymphoblastic leukemia (ANLL) (n = 8), or a TdT+ non-Hodgkin's lymphoma (NHL) (n = 5) were analyzed. In 1,511 (91.9%) of 1,643 evaluable CSF samples, the positive and negative findings of both cytomorphology and the TdT-IF assay were concordant. In 47 (2.9%) samples from 28 patients, the cytomorphology was suspect while the TdT-IF assay was negative; follow-up as long as 58 months revealed no CNS leukemia in any patient. In 85 (5.2%) samples, cytomorphology was negative (n = 70) or suspect (n = 15) but TdT+ cells were detected. RBC contamination seriously hampered evaluation in 31 of these 85 samples. From the remaining 54 TdT+ samples from 29 patients, 40 samples preceded overt CNS leukemia in 20 patients. Two consecutive findings of TdT+ cells in the CSF were always followed by overt CNS leukemia. At initial diagnosis, 11 children had TdT+ cells in their RBC-free CSF. In one of these children, morphology was suspect; a repeated lumbar puncture was positive on both assays. Thus, initial CNS leukemia was diagnosed. In the other ten children, morphology was negative. In six of them, CNS leukemia was diagnosed 2 to 20 months later. In 32 other children examined at initial diagnosis, neither TdT+ cells nor blasts were observed in the CSF. In none of these patients was a CNS leukemia diagnosed after a follow-up of 2.5 to 57 months (median 24 months). In 207 control CSF samples from 58 children with TdT- oncologic, hematologic, or infectious diseases, no TdT+ cells could be detected. The TdT-IF assay is easy to perform and is a more reliable diagnostic tool for detection of CNS leukemia at an early stage than is cytomorphology. At initial diagnosis, the finding of Tdt+ cells in a RBC-free CSF sample with a negative cytomorphology is highly predictive for development of overt CNS leukemia.

Diagnosis of meningeal involvement in childhood acute lymphoblastic leukemia: cytomorphology and TdT.

Between December, 1984, and May, 1986, 98 CSF samples were sent to a central laboratory by postal express. The samples could be kept in a medium for up to 24 hours after the lumbar puncture. The quality of the cells proved to be good. Excluded were 5 samples delayed in delivery and 13 samples contaminated with blood, defined as the macroscopical presence of blood. The microscopical presence of erythrocytes in the cytocentrifuge preparation can make interpretation of the results difficult. Especially when leukemic blasts are present in the blood, extreme caution is necessary. A total of 71 samples could be studied by cytomorphology as well as by TdT-IF. When cytomorphological leukemic blasts were present, this was confirmed by TdT-IF positivity in all cases. But in 6 of 71 samples, TdT-IF was positive without the presence of cytomorphological leukemic blasts. Follow-up of these patients will show whether the therapeutic regimen has to be changed.

[Terminal deoxynucleotidyltransferase (TdT)-positive cells in cerebrospinal fluid of children with leukemia or non-Hodgkin lymphoma: implications for the diagnosis of central nervous system leukemia]. / Terminal deoxynucleotidyl transferase (TdT) positieve cellen in de liquor cerebrospinalis van kinderen met een leukemie of non-Hodgkin lymfoom: implicaties voor de diagnose centraal zenuwstelsel leukemie.

Identification of terminal deoxynucleotidyl transferase (TdT) positive cells in sites other than bone marrow, thymus, lymph nodes and peripheral blood is indicative of a TdT positive lymphoproliferative disease. We therefore employed both a TdT-immunofluorescence (IF) assay and conventional cytomorphology to examine the cells in 421 cerebrospinal fluid samples from 60 children with a TdT positive acute lymphoblastic leukemia or non-Hodgkin lymphoma, at diagnosis as well as during follow-up. The results of the TdT assay were compared with those obtained by cytomorphological analysis of the same sample. The authors conclude that the TdT-IF assay is a valuable additional tool in diagnosing TdT positive central nervous system leukemia. It offers more reliable and conclusive diagnoses than cell count and cytomorphology alone, which might avoid both under- and overtreatment of the patient.