Detection of minimal residual disease in acute leukemia by Tc-99m MIBI femoral marrow imaging.

To determine the potential of Tc-99m MIBI femoral marrow imaging for detecting minimal residual disease in acute leukemia, MIBI images of 68 patients with acute leukemia and 110 control patients were examined. MIBI accumulation was classified into three patterns: not detectable, mild accumulation, and clearly visualized accumulation. Clearly visualized accumulation was interpreted as abnormal. The mean uptake ratio of the femoral marrow to muscle was calculated. Forty-five patients who were in complete remission (CR) at the time of MIBI imaging had a follow-up study (mean interval, 23 months). Clearly visualized accumulation was demonstrated in 35 patients with acute leukemia: in 7 patients before starting induction chemotherapy, in 12 patients after relapse, and in 16 of the 49 patients in the CR group. Mild accumulation was demonstrated in 14 patients in the CR group and in 13 control group patients. No detectable accumulation was observed in 19 patients in the CR group and in 97 control patients. The marrow and muscle uptake ratio of patients before starting chemotherapy (2.29 +/- 0.26) was greater compared with that in patients after relapse (1.78 +/- 0.44, P < 0.02) and in patients with abnormal accumulation despite complete remission (1.84 +/- 0.36, P < 0.01). The uptake ratio in patients with abnormal accumulation despite CR was higher compared with patients with mild accumulation in CR (1.26 +/- 0.13, P < 0.001) and controls (1.23 +/- 0.10, P < 0.001) who had mild accumulation. Fifteen patients with abnormal accumulation despite CR had a markedly greater relapse rate (66.7% > 10.0%, P < 0.005), a higher mortality rate (46.7% > 6.7%, P < 0.01), and shorter remission time (8.7 +/- 10.2 months < 35.9 +/- 20.1 months, P < 0.001) compared with 30 patients without abnormal accumulation in CR. MIBI femoral marrow imaging may be a useful and simple method for monitoring levels of residual leukemic cells. Clearly visualized MIBI accumulation may be a marker for relapse.

[JCCLS proposal for clinical allowance on values of blood cell count].

We investigated the clinically allowable error for laboratory quality control of blood cell count in Japan. We have asked 409 members of Japanese Association of Clinical Hematology for an appropriate clinical allowance on the values of red blood cell count (RBC), hemoglobin value (Hb), mean corpuscular volume (MCV), white blood cell count (WBC) and platelet count (PLT). We delivered the lists in which 5 different allowable errors (2, 3, 5, 10 and 20%) were indicated on each blood cell count so that each member could check one of them. The data were collected within a month and were analyzed with computer. The results showed that 312 (76.3%) members choose 3 or 5% as an allowable error for RBC, 393 (96.1%) selected 2, 3 or 5% for Hb, 314 (76.8%) choose 3 or 5% for MCV, 358 (77.5%) indicated 3, 5 or 10% for WBC and 294 (72.6%) selected 5 or 10% for PLT. Based on these data, we propose the following clinical allowances for the values of blood cell count; 4% for RBC, 3% for Hb, 4% for MCV, 5% for WBC and 7% for PLT.

[High dose of methotrexate-leucovorin treatment in advanced non-Hodgkin's lymphoma].

High doses of methotrexate (MTX) and leucovorin (LCV) as a rescue treatment were applied to five patients with non-Hodgkin's lymphoma, refractory to standard combination chemotherapy. Two of 5 patients showed a complete remission, and 2 patients showed a partial remission. One patient with massive pleural effusion showed an improvement by the treatment without any severe side effect under monitoring and controlling the dose of MTX. However, the remission duration of the treatment was short; therefore, additive therapy was required of later. From these results we assumed that the high dose of MTX and LCV could be effective for malignant lymphoma being resistant to other combination therapies.