Katsuyasu Saigo

Acute promyelocytic leukemia (APL) is characterized by the specific PML-RARa fusion gene resulting from translocation t(15;17) (q22;q12). Internal tandem duplication (ITD) of the FLT3 gene has been observed in approximately 35% of APLs, and large-scale studies have identified the presence of ITD as an adverse prognostic factor for acute myeloblastic leukemia (AML) patients. Aberrant expressions of surface antigens, such as CD2, CD34, and CD56, have been found in APL, but the implications of this are not well understood. We investigated the incidence of the FLT3/ITD mutation and FLT3/D835 (I836) point mutation in 25 APL patients. Incidence ratios of FLT3/ITD, D835 (I836), and both FLT3/ITD and D835 (I836) were 36%, 36% and 8%, respectively. FLT3/ITD+ cases showed a predominance of the bcr3 isoform (P = 0.008) and M3v morphology (P < 0.001). We found that all FLT3/ITD+ cases expressed CD2 (9 of 9) more frequently than that of FLT3/ITD− (1 of 16) (P < 0.001), while only one of the CD2+ cases (1 of 10, 10%) did not harbor FLT3/ITD, and all CD2+CD34+ cases (5 of 5, 100%) harbored FLT3/ITD. In addition, quantitative polymerase chain reaction analysis showed that FLT3 mRNA was more abundantly expressed in FLT3/ITD+ than that in FLT3/ITD− (P = 0.025), while there was no difference between D835(I836)+ and D835(I836)− with regards to aberrant surface-antigen expression, expression levels of FLT3 mRNA, M3v morphology, and the bcr3 isoform of PML-RARa mRNA. This study demonstrates that the presence of FLT3/ITD, but not D835 (I836), is closely related to aberrant CD2 expression and high expression levels of FLT3 mRNA. Our findings also suggest that FLT3/ITD as a secondary genetic event may block differentiation at the immature stage of APL.

To evaluate the specific reactivity of HLA Class I antibodies (HLA‐I Abs) in acute non‐hemolytic transfusion reactions (ANHTRs) using solid phase assays (SPAs) and conventional complement‐dependent lymphocyte cytotoxicity test (LCT). ANHTRs are major issues in transfusion medicine. Anti‐leukocyte antibodies have been implicated as one of the causative agents of transfusion‐related acute lung injury (TRALI) and febrile reaction. Antibodies to HLA Class I and/or Class II (HLA Abs) have been intensively studied using SPAs for TRALI, but not for febrile reaction. About 107 patients and 186 donors associated with ANHTRs were screened for HLA Abs by SPAs such as enzyme‐linked immunosorbent assay (ELISA) and the Luminex method. When HLA‐I Ab was detected, its specific reactivity was evaluated by comparing its specificity identified by the Luminex method using recombinant HLA molecules and cognate HLA antigens (Ags), as well as LCT with or without anti‐human globulin (AHG). The incidences of HLA Abs were as high as 32·7% of patients' serum samples and 16% of donors' serum samples. The incidence of HLA‐I Abs did not differ significantly between cases of febrile and allergic reactions. However, HLA‐I Abs associated with febrile reaction showed a significantly higher rate of possessing specific reactivity to cognate HLA Ags than those associated with allergic reactions. In addition, the Luminex method enabled the detection of HLA‐I Abs much earlier than AHG‐LCT in serum samples from a patient with febrile reaction and platelet transfusion refractoriness (PTR). SPAs seem more useful than AHG‐LCT for evaluating reactivity of antibodies in ANHTR cases.

We report the case of a 61-year-old man with pyoderma gangrenosum (PG) who was successfully treated with high-dose intravenous immunoglobulin (IVIg). He was transported to hospital with fever, pain and ulcer of the left inner thigh, and pancytopenia. PG associated with myelodysplastic syndrome was diagnosed, and treatment with methyl-prednisolone at 1.0 g/day for 3 days was followed by oral prednisolone. As the ulcer deteriorated when prednisolone dose was reduced, he was admitted to our hospital. IVIg was administered twice, with high fever promptly subsiding and the ulcer markedly decreasing in size. IVIg may represent a good option when steroid therapy proves insufficient.

A quantitative nested reverse transcriptase polymerase chain reaction (QN‐RT‐PCR) method was developed using a plasmid cDNA containing the AML1/ETO (MTG8) fusion transcript from Kasumi‐1 cells, an acute‐myelogenous leukemia cell line with the t(8;21) translocation. In this method, the plasmid was detectable at a concentration of 10⁻¹⁷ m. The fusion transcript in a mixture of 10⁷ Rice94 (Burkitt lymphoma cell line) cells containing two Kasumi‐1 cells was detectable at 10⁻¹⁷ m. In a previously published real‐time PCR method, the plasmid containing the fusion transcript was detectable at 10⁻¹⁶ m or higher, and 20 or more Kasumi‐1 cells were detectable in 10⁷ Rice94 cells. Thus, this QN‐RT‐PCR method is more sensitive than the real‐time PCR. When the same samples were examined by real‐time PCR and our QN‐RT‐PCR method, in one patient in clinical remission after chemotherapy and allogeneic‐bone marrow transplantation (BMT), the transcript was detected by QN‐RT‐PCR 60 days prior to hematological relapse, in contrast to 10 days before hematological relapse by real‐time PCR. The transcript level was below 10⁻¹⁷ m (undetectable) with this QN‐RT‐PCR in patients in clinical remission after chemotherapy and BMT, while it was 10⁻¹⁵–10⁻¹⁶ m in patients in clinical remission after chemotherapy alone. The quantitative difference of the transcript level in minimal residual disease (MRD) between these two different types of clinical remission was estimated to be at least 10²‐fold. This QN‐RT‐PCR method is useful for predicting hematological relapse and for quantitatively estimating MRD in different types of clinical remission.

This report concerns a female patient with B-precursor acute lymphoblastic leukemia with concomitant expression of CD13 and CD33. A rare chromosomal abnormality, t(2;17)(p13:q21), was detected in 70% of metaphases analyzed. A new subgroup of acute leukemia is proposed, consisting of our case and 12 reported cases with similar chromosomal abnormalities. This subgroup has a poor prognosis and a high incidence of biphenotypic characteristics.