Relevancia biológica y clínica del inmunofenotipaje celular en la leucemia linfoide aguda del niño / Biological and clinical importance of the cellular immunophenotyping in acute lymphocytic leukemia in children

Se estudiaron las características biológicas y clínicas de 238 niños con leucemia linfoide aguda (LLA) en un período de 13 años. El inmunofenotipaje celular de muestras procedentes de la médula ósea se realizó mediante un ultramicrométodo inmunocitoquímico. Del total de LLA estudiadas 81,4 por ciento fueron de fenotipo B y 18,5 por ciento de fenotipo T. El 48,4 por ciento de los niños con LLA de fenotipo B se encontraron en edades comprendidas entre 2-5 años, mientras que el 65,9 por ciento con LLA-T presentaron 6 o más años de edad. No se encontraron diferencias estadísticamente significativas cuando se analizaron el sexo y el color de la piel en relación con el fenotipo celular leucémico. Al diagnóstico de la enfermedad, el 59,3 por ciento de los pacientes con LLA-B mostraron cifras de leucocitos en sangre periférica < 20 x 109/L y en el 61,4 por ciento con LLA-T cifras superiores a 50 x 109/L. Se observó una mayor incidencia de organomegalia, adenopatías mediastinales, manifestaciones hemorrágicas e infiltración inicial del sistema nervioso central en enfermos con LLA-T en relación con los de LLA-B, con diferencias altamente significativas. Estos resultados demuestran que el fenotipo leucémico en la LLA del niño pudiera considerarse como un factor pronóstico positivo o negativo de la enfermedad.

The biological and clinical characteristics of 238 children with acute lymphocytic leukemia (ALL) were studied for 13 years. The cellular immunophenotyping of samples from the bone marrow was performed by an immunocytochemical ultramicromethod. Of the total of studied ALL, 81.4 percent were phenotype B and 18.5 percent phenotype T. 48.4 percent of the children with B-ALL were 2-5 years old, whereas 65.9 percent with T-ALL were 6 or over. No statistically significant differences were found when sex and colour of the skin were analyzed in relation to the cellular leukemic phenotype. On diagnosing the disease, 59.3 percent of the patients with B-ALL showed figures of leukocytes in peripheral blood < 20x109/L, whereas in 61.4 percent with T-ALL, the figures were higher than 50x109/L. It was observed a greater incidence of organomegaly, mediastinal adenopathies, hemorrhagic manifestations and initial infiltration of the central nervous system in patients with T-ALL compared with those suffering B-ALL. The differences were highly significant. These results proved that the leukemic phenotype in ALL in children could be considered as a positive or negative prognostic factor of the disease.

Desarrollo de improntas para el diagnostico del virus epstein-barr por inmunofluorescencia indirecta / Development of slides for Epstein-Barr virus diagnosis by indirect immunofluorescence

El vírus de Epstein-Barr (VEB) es el principal agente oncogénico linfotrópico dentro de la família Herpesviridae y se encuentra mundialmente distribuído. La primoinfección se produce en adultos jovenes y se manifesta como mononucleosis infecciosa. La detección de anticuerpos anti-viral cápside antigen (VCA) indica infección previa o presente com VEB. Además, se observan títulos elevados de anticuerpos anti-VCA en las enfermidades neoplásicas asociadas al VEB como los linfomas, em indivíduois HIV-positivos. El objetivo de este estúdio fue el desarrollo y puesta a punto de improntas de células P3HR1 para la detección serológica del VEB por técnicas de inmunofluorescencia indirecta (IFI). Se estimularon cultivos de células P3HR1 en crecimiento exponencial com phorbol-12-mirystoil-13-acetato y se recolectaron alícuotas a distintos tiempos para realizar improntas. Se realizó uma IFI com cada impronta usando como anticuerpo primário um suero VEB-positivo. Se observo un aumento del 11% em la expresión del VCA a las 40 horas post-estimulación, deyendo al 3.5% a las 48 horas. Estos datos fueron corroborados por ensayo de Western blot com inmunodetección. La precisión intra- e inter-lote de las improntas fue evaluada para anticuerpos IgM e IgG, com sueros probados previamente por equipos para esta determinación disponibles en el mercado para el VEB y com sueros reactivos para otros miembros de la família Herpesviridae. No se obtuvieron resultados falsos-negativos ni falsos-positivos para el VEB ni se observo reactividad cruzada com otros herpesvirus. Las improntas desarrolladas constituyen un instrumento para el diagnóstico de la primoinfección del VEB y la detección serológica de anticuerpos IgG anti-VCA de neoplasias asociadas al VEB.

Immunophenotyping of acute lymphoblastic leukemia in pediatric patients by three-color flow cytometric analysis.

Immunophenotyping of acute lymphoblastic leukemia (ALL) in children using three-color flow cytometry was carried out at Chulalongkorn Hospital, Bangkok, Thailand. Of 38 patients with acute lymphoblastic leukemia, 65.8% were identified as common ALL, 15.8% were B-ALL, and 18.4% were T-ALL. Of these 38 cases, there were 4 cases of infantile leukemia. Relapsed cases of leukemia were found most in B-ALL up to 3 out of 6 cases and to a lesser extent in T-ALL (1 of 7 cases) and c-ALL (1 of 25 cases). Our data showed the CD markers expression for common ALL (c-ALL) were CD19+/10+ (100%), CD20+ (24%), CD22+ (100%), HLA-DR+ (70.1%), and CD34+ (58.8%). CD markers expression for B-ALL were CD19+ (100%), CD20+ (33.3%), CD22+ (80%), and HLA-DR+ (80%). CD markers expression for T-ALL were CD3+ (42.9%), CD5+ (100%), CD7+ (85.7%). Myeloid aberrant expressions were found in c-ALL (25-37.5%), B-ALL (20%), and T-ALL (14.3%). The significance of the aberration is discussed. The immunophenotyping classification of ALL as c-ALL, B-ALL, and T-ALL is useful in prognosis and treatment.

Acute leukemias with unusual immunophenotypes

Over a two-year period, immunophenotypic patterns of 266 acute leukemia cases were analyzed using a panel of tests including TdT, SmIg and 9 surface antigens by the immunofluorescence stains for the assessment of the incidence and grade of phenotypic ambiguity (lineage infidelity) and the possible clinical significance of unusual immunophenotypes. Immunophenotypes were classified into four groups according to the degree of ectopic antigen expression. We classified as Group A (91.7%, 244 of 266 cases) those expressing conventional pattern without ectopic antigen. Group B (3.0%, 8 of 266 cases) was defined to have at least two lineage specific markers and single ectopic antigen. Such a "low grade deviation" did not prevent a definite immunodiagnosis. Group C (4.2%, 11 of 266 cases) revealed a promiscuous coexpression of markers related to different lineages, including two cases (0.8%, 2 cases) of biphenotypic leukemia. Group D (1.1%, 3 cases) included unclassifiable immunophenotypes with no antigen or HLA-DR only expression. Both patients with biphenotypic leukemia and one patient with unclassifiable immunophenotypes failed to respond to induction chemotherapy, suggesting a poor prognosis in these patients. The incidence of acute myelogenous leukemia (AML) cases with one or more ectopic surface antigens was 10 (8.1%) of the 124 AML cases. Ectopic antigen expression was seen in 5 (4%) of the 125 B-lineage acute lymphoblastic leukemia (ALL) cases and 3 (25%) of the 12 T-ALL cases. It is concluded that nearly 95% of cases of acute leukemia cases can be diagnosed accurately with immunophenotyping alone including patients with a mild degree of deviation from expected antigenic patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating immunecomplexes, immunoglobulins and complements in Nigerian children with Burkitt's lymphoma

The serum levels of circulating immunecomplexes [CICs], immunoglobulins [Igs] and complements [Cs] were studied in 20 Nigerian children with Burkett's lymphoma [BL] [age: 4-10 years; 12 males, 8 females]. Of these patients, 6 patients had single facial tumor mass [SFIM] on left maxilla, 4 patients had SEIM on right maxilla, 6 patients had SFIM on left mandible and 4 patients had SFIM on right mandible. The findings were that mean serum IgM level in BL was significantly lower than that of control subjects [CS] [P < 0.01], whereas IgG and IgA levels were normal [P > 0,05]. In BL, the serum levels of CICs and CS [C3, 64] were significantly higher [P < 0.02 and lower [P < 0.05] respectively as compared to controls. It was therefore proposed that the lowered serum IgM level may be due to virus-induced IgM-specific T-cell immunosuppression. The decrease levels of Cs were explained as probably due to their increased utilization for clearance of excessive CICs