CD44 is involved in CXCL-12 induced acute myeloid leukemia HL-60 cell polarity

CXCL-12 and its receptor CXCR4 participate in breast cancer and melanoma cell metastasis to bone and lymphoid nodes. CD44, as a receptor for hyaluronic acid, is involved in lymphocyte recirculation, homing, adhesion and migration. But the role of CD44 in CXCL-12 induced leukemia cell migration still remains unclear. The present study showed that CXCL-12 stimulation induced the rapid internalization of CXCR4 and facilitated the formation of lamellipodia and uropod in acute leukemia cell line HL-60. CXCL-12 also induced CD44 translocation into the uropod, while CD44 remained evenly distributed on the untreated cell membranes. Results suggest that CD44 participates in CXCL-12 induced cell polarization and subsequent cell migration.

Chronic meningitis by histoplasmosis: report of a child with acute myeloid leukemia

Meningitis is a common evolution in progressive disseminated histoplasmosis in children, and is asymptomatic in many cases. In leukemia, the impaired of the T cells function can predispose to the disseminated form. The attributed mortality rate in this case is 20 percent-40 percent and the relapse rate is as high as 50 percent; therefore, prolonged treatment may be emphasized. We have described a child with acute myeloid leukemia (AML), that developed skin lesions and asymptomatic chronic meningitis, with a good evolution after prolonged treatment with amphotericin B deoxycholate followed by fluconazole.

Immunophenotypic profile of adult acute myeloid leukemia (AML): analysis of 267 cases in Thailand.

Little data exists in Thailand and other Southeast Asian countries regarding the biological characteristics of adult acute myeloid leukemia (AML). In this study, we performed a flow cytometric analysis of 267 Thai adult AML cases to delineate the pattern of leukemic cell surface antigens. Forty-eight cases (18%) were identified as acute promyelocytic leukemia (M3) and 219 cases as non-M3. The most frequent subtype of AML in Thailand was M1/M2 and the least frequent was M7. M3 immunophenotypes were characterized by their unique lack of expression of CD34 and HLA-DR as contrast to the high mean expression of 50% and 70%, respectively, in non-M3. Overall, 60% of cases expressed CD34. Aberrant lymphoid antigens were uniquely seen in specific subtypes of Thai AML, including CD19 (33% of non-M3 vs 23% of M3) and CD2 (12% of M3 vs 2% of non-M3). CD56 was frequently expressed in both M3 and non-M3 while CD16 appeared to be associated with M4/M5 (24% of cases) and CD7 with M1/M2 (21% of cases). Eighty-one percent of non-M3 expressed CD38 while only 53% of M3 did. We found that most Thai adult AML patients were on average 15-20 years younger than those of the West or Japan with only 25% of Thai cases over 60 years of age, although the immunophenotypes were not markedly different. Biological studies of acute leukemia in various countries should help to provide epidemiological clues that play a role in the pathogenesis of leukemia in different geographic regions of the world. Our study represents the largest series of AML ever investigated in the Southeast Asian region.

A mini-review of CD13 antigen in AML: easy induction or enhancement of expression in in vitro culture and necessary consideration for assessment.

CD13 is a pan-(MPO-positive) AML antigen, while it is expressed in some B-lineage neoplasms (ALL and PLL) and in T-linaege neoplasms at pro-thymic stage. Some reports have described the lack of this antigen in MPO-positive AML, and tried to regard such MPO-postive AML cases as an clinical entity. However, considering the easy induction or enhancement of the expression in in vitro culture, it is pertinent to interpret that the expression of CD13 in these "CD13-negative and MPO-positive AML" cases is marginally positive, which is readily induced or enhanced in expression in in vitro culture. It can, however, be pointed out that the CD13 expression in ex vivo-positive cases are significantly stronger than that in ex-vivo-negative in vitro-positive cases. Such consideration is necessary particularly in interpreting the results obtained after overnight transportation in commercial laboratories.

Estudio de los haplotipos HLA en leucemias / Study of HLA haplotypes in leukemias

Se determinaron las combinaciones alélicas de los genes HLA A y B en 144 pacientes con leucemias; 89 con leucemia linfoide aguda (LLA), 28 con leucemia mieloide aguda (LMA) y 27 con leucemia mieloide crónica (LMC), estraficados fenotípicamente en blancos, negros y mestizos, para evaluar la posible asociación entre los haplotipos HLA y esas enfermedades. Se utilizaron como controles 276 personas aparentemente estratificados también por el color de la piel. Los haplotipos A2-B12, A9-B12 y A2-B35 fueron los más frecuentes en el grupo total de enfermos y en los individuos blancos con LLA. La combinación de las especificidades A2 y B5 mostró un desequilibrio de asociación en el conjunto de enfermos y en los sujetos blancos con LMA

Production & evaluation of a monoclonal antibody against human myeloperoxidase.

We describe the production of a mouse monoclonal antibody (H2E1) against human myeloperoxidase antigen. After production and characterisation, this antibody was compared with commercially available monoclonal antibodies, cytochemical myeloperoxidase and previously produced polyclonal antibody. Reaction with various cell lines proved that this monoclonal antibody was specific for myeloid lineage. This monoclonal showed positivity in 81.8 per cent of acute myeloid leukaemias whereas the polyclonal antibody was 100 per cent positive. We found that the polyclonal antibody was more sensitive as compared to the monoclonal. This is probably due to the lack of recognition of individual epitopes on the antigen. We recommend the use of antibodies which have different epitope recognition as most specific for myeloperoxidase.

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)

Serum immunoglobulins in leukaemia and malignant lymphoma.

The serum immunoglobulin levels were studied in 25 healthy control subjects and 23 cases of leukaemia (6 cases of acute lymphatic leukaemia, 5 cases of acute myeloid leukaemia, 2 cases of chronic lymphatic leukaemia and 10 cases of chronic myeloid leukaemia) and 17 cases of malignant lymphoma (13 cases of Hodgkin's lymphoma and 4 cases of non-Hodgkin lymphoma). The mean levels of IgG, IgA and IgM in 25 control subjects were 1573.56 +/- 91.45 mg/dl, 209.64 +/- 12.55 mg/dl and 109.81 +/- 10.03 mg/dl respectively, those in 23 cases of leukaemia were 1338.23 +/- 109.74 mg/dl, 195.53 +/- 20.72 mg/dl and 127.47 +/- 13.29 mg/dl respectively and those in 17 cases of malignant lymphoma were 996.99 +/- 99.50 mg/dl, 147.47 +/- 19.61 mg/dl and 129.35 +/- 19.95 mg/dl respectively. The mean levels of IgG and IgA were found to be decreased in cases of leukaemia with elevated levels of IgM, however, it was found to be insignificant (p less than 0.4). The mean IgG, IgA and IgM levels were found to be almost identical in different leukaemia irrespective of cytological types except in 2 cases of chronic lymphatic leukaemia which showed low levels of IgG and IgA. The mean levels of IgG and IgA were found to be significantly decreased in malignant lymphoma (p less than 0.02). IgM levels were found to be increased in 3 cases of non-Hodgkin lymphoma.