Positive and negative predictive values of HLA-DR and CD34 in the diagnosis of acute promyelocytic leukemia and other types of acute myeloid leukemia with recurrent chromosomal translocations.

The predictive value of HLA-DR and CD34 in the diagnosis of four distinct genetic entities of acute myeloid leukemia (AML) is presently not established. We evaluated the positive and negative predictive values (PPV and NPV, respectively), sensitivity, specificity, and correlation coefficients of HLA-DR and CD34 in AML pa-tients with t(15;17), t(8;21), inv(16), and abn(11q23). In AML with t(15;17) (n = 64), HLA-DR was expressed in 4.68% and CD34 was expressed in 15.62% and none of the cases expressed both HLA-DR and CD34. In AML with t(8;21) (n = 99), HLA-DR, CD34 or both antigens were expressed in the majority of cases (90.90%, 80.80%, and 79.79%, respectively). AML patients with inv(16) (n = 18) and abn(11q23) (n = 31) also highly expressed HLA-DR and CD34. Eight cases of t(8;21) and 1 case of abn(11q23) did not express either antigen. The highest corre-lation between CD34 and HLA-DR expression values was observed in cases with t(8;21) (r = 0.72) with the lowest correlation in inv(16) (r = 0.035). The PPV and NPV of HLA-DR-negativity plus CD34-negativity to predict t(15;17) was 85% and 100%, respectively, with 100% sensitivity and 92.74% specificity. The PPV and NPV of other mye-loid markers such as CD117, MPO and CD11c to diagnose t(15;17) were much lower than those of HLA-DR and CD34. It was concluded that the absence of double negativity of HLA-DR and CD34 strongly predicts against t(15;17). Rare HLA-DR-positive/CD34-negative cases exist in patients with t(15;17) and 8% of t(8;21) cases ex-pressed neither antigen. Further studies should determine whether HLA-DR-positive t(15;17) and HLA-DR-negative/CD34-negative t(8;21) represent a special entity associated with significant prognostic relevance.

Collection and processing of umbilical cord blood for cryopreservation.

Umbilical cord blood (UCB) is being increasingly used as an alternative source of hematopoietic stem cells for allogeneic bone marrow transplantation. UCB transplantation has been successfully used to treat a variety of genetic, hematological, and oncological disorders in children and adults. The objectives of this study was to establish a closed-system technique for UCB collection and buffy coat separation by Optipress I device. Thirty-four UCB were collected by triple-bag system from pregnant mothers whose fetuses were not affected by thalassemic diseases after prenatal diagnosis. The mean volumn of UCB collection were 120 +/- 5 ml (range 65-180 ml). Total WBC, CD34+ cells, the progenitor cell erythroid burst-forming unit (BFU-E) and granulocyte-macrophage colony-forming unit (CFU-GM) in the UCB units were (9.36 +/- 0.84) x 10(8), (3.61 +/- 0.52) x 10(6), (9.12 +/- 1.60) x 10(5), and (5.32 +/- 1.23) x 10(5), respectively. Good correlation between the nucleated cell and net cord blood volume could be demonstrated (p < 0.0001). The correlation between CD34+ cells and the following parameters: nucleated cell, BFU-E or CFU-GM were also demonstrated (p = 0.001, 0.0105 or 0.0001, respectively). Buffy coat was subsequently separated from 18 UCB units by Optipress I device. 70 +/- 3 ml of buffy coat were collected and cryoprocessing was done by automatic controlled-rate freezer. Good recovery of total WBC, CD34+ cells, progenitor cells BFU-E and CFU-GM after buffy coat separation were observed 89 per cent, 95 per cent, 109 per cent, and 102 per cent respectively. There was no aerobic bacterial or fungal contamination in the separated blood products. By using this technique, the UCB units were easily collected, rapidly separated within one hour, and high recovery of the hematopoietic progenitor cells could be obtained.

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.