Bakul I. Dalal

Acute Myelogenous Leukemia with t(8;21)—Identification of a Specific Immunophenotype

Association between certain surface markers and acute myelogenous leukemia (AML) with t(8;21) has been described. The specificity and the predictive values of these markers have never been assessed. In this study, we aimed, to explore whether a specific pattern could predict for this translocation. Of 405 consecutive AML, 18 (4.4%) had the t(8;21). Patients with this cytogenetic abnormality showed higher frequency of CD34 (P = 0.003), HLA-DR (P = 0.03), Tdt (P = 0.02), CD19 (P < 0.0001), and CD56 (P < 0.0001) and lower CD33 (P = 0.0001). Taken singly, the sensitivity of these markers for AML with t(8;21) ranged between 39 and 100% with CD34+ having the highest and CD33- having the lowest and the positive predictive values (PPV) ranged between 5 and 21% with CD19+ having the highest and HLA-DR+ having the lowest. When combinations of different markers were analyzed by multivariate analysis, the pattern CD34+/HLA-DR+/MPO+ was found to have the highest sensitivity (100%) with a PPV of 14% and the pattern CD34+/CD19+/CD56+ had the highest PPV (100%) with a sensitivity of 67%. We conclude that AML with t(8;21) is better identified by a combination of markers than by a single antigen pattern, the absence of CD34+, HLA-DR+ or MPO+ would preclude and the expression of the pattern CD34+/CD19+/CD56+ is highly predictive and could serve as a screening criteria for the t(8;21).

Factitious Biochemical Measurements Resulting From Hematologic Conditions

Factitious laboratory results often lead to unnecessary testing or treatment. This brief review of factitious biochemical results due to preexisting hematologic conditions focuses on the mechanisms underlying the factitious results and suggests ways to prevent them. An observant pathologist identifies these errors, intervenes in a timely fashion, investigates the sources of error diligently, and institutes measures to prevent their recurrence.

Parvovirus B19 in an immunocompetent adult patient with acute liver failure: an underdiagnosed cause of acute non-A-E viral hepatitis.

There are occasional pediatric reports of parvovirus B19-associated transient acute hepatitis and hepatic failure. A case of a 34-year-old immunocompetent woman who developed severe and prolonged but self-limited acute hepatitis and myelosuppression following acute parvovirus B19 infection is reported. Parvovirus B19 may be the causative agent in some adult cases of acute non-A-E viral hepatitis and acute liver failure.

Flow cytometric testing for paroxysmal nocturnal hemoglobinuria: CD64 is better for gating monocytes than CD33.

Paroxysmal nocturnal hemoglobinuria (PNH) is diagnosed by documenting partial or complete absence of glycosyl phosphatidyl inositol (GPI)‐associated ligands in neutrophils, monocytes, and red blood cells (RBCs). The monocytes can be separated by their bright expression of either CD33 or CD64. This paper compares the utility of CD33‐ vs CD64‐based monocyte gating in flow cytometric testing for PNH.

Correlation between karyotype and quantitative immunophenotype in acute myelogenous leukemia with t(8;21)

Acute myelogenous leukemia with t(8;21) is a distinct clinicopathologic entity in which the malignant myeloblasts display a characteristic pattern of surface antigen expression. Quantitative analysis of surface marker expression in patients with this chromosomal abnormality compared to acute myelogenous leukemia patients with a different karyotype has not been reported. From 305 consecutive newly diagnosed acute myelogenous leukemia patients underwent immunophenotyping and cytogenetic analysis at our center; 16 patients (5.2%) had a t(8;21). Fluorescence intensity values were obtained, using a set of reference microbeads, by conversion of mean channel fluorescence to molecular equivalent of soluble fluorochrome. Patients with t(8;21) displayed higher levels of CD34, HLA-DR and MPO expression (P<0.001 for each) and lower levels of CD13 (P=0.03) and CD33 (P=0.02) expression. In order to study the sensitivity, specificity and predictive value of these markers, molecular equivalent of soluble fluorochrome thresholds were statistically determined. The statistically established threshold for each of the individual markers (CD34>60.5 × 103, HLA-DR>176.1 × 103, MPO>735.1 × 103, CD13<24.3 × 103 and CD33<17.3 × 103) had a sensitivity of 100%, a specificity of 62–92% and a positive predictive value of 7–45%. In multivariate analysis, two quantitative patterns (CD34>60.5 × 103 and MPO>176.1 × 103; CD33<17.3 × 103 and MPO>176.1 × 103) had a sensitivity, specificity and positive predictive value of 100%. These aberrant phenotypic patterns might help identify patients with t(8;21) at diagnosis and could be useful in minimal residual disease monitoring.

Paroxysmal nocturnal haemoglobinuria phenotype cells and leucocyte subset telomere length in childhood acquired aplastic anaemia

The significance of paroxysmal nocturnal haemoglobinuria (PNHpos) cells and leucocyte subset telomere lengths in paediatric aplastic anaemia (AA) is unknown. Among 22 children receiving immunosuppressive therapy (IST) for AA, 73% (16/22) were PNHpos, of whom 94% achieved at least a partial response (PR) to IST; 11/16 (69%) achieved complete response (CR). Only 2/6 (33%) PNHneg patients achieved PR. PNHpos patients were less likely to fail IST compared to PNHneg patients (odds ratio 0·033; 95% confidence interval 0·002–0·468; P = 0·012). Children with AA had short granulocyte (P = 7·8 × 10−9), natural killer cell (P = 6·0 × 10−4), naïve T lymphocyte (P = 0·002) and B lymphocyte (P = 0·005) telomeres compared to age‐matched normative data.

Induction Failure in de novo Acute Myelogenous Leukemia is Associated with Expression of High Levels o CD34 Antigen by the Leukemic Blasts

The prognostic significance of CD34 antigen expression in acute myelogenous leukemia (AML) is controversial. Most studies to date have reported on CD34 positivity and not the level of antigen present. In this study of 62 patients with de novo AML, 48 (77%) patients were CD34+ in varying levels (0-85 mean channels of fluorescence (MCF)). Forty seven of 62 were treated with combination chemotherapy and 39 (83%) of them achieved complete remission (CR). Patients with CD34- blasts were more likely to achieve CR; however, this trend was not statistically significant (p = .11). On the other hand, patients with higher levels of CD34 antigen on the blasts were less likely to attain CR (p < 0.001, multivariate analysis). The patients who achieved CR expressed lower levels of CD34 (0-57; median 9 MCF) as compared to those who did not achieve CR (15-85; median 30 MCF). Of the other antigens tested, partial or complete absence of CD33 (CD33 absent in > or =25% blasts) correlated with failure to achieve CR (p = 0.0029). These results are in keeping with the hypothesis that more primitive AML blasts with high levels of CD34 are chemoresistant.

Therapy-Related Acute Myelogenous Leukemia Associated with 11q23 Chromosomal Abnormalities and Topoisomerase II Inhibitors: Report of Four Additional Cases and Brief Commentary

We report 4 additional cases of therapy-related acute myelogenous leukemia (t-AML) with the translocation t(9;11)(p22q23). Chemotherapy for the primary malignancy (breast carcinoma in 2, non-Hodgkins lymphoma in 2) included agents with topoisomerase II inhibitory activity (doxorubicin in 2; doxorubicin and etoposide in 1; doxorubicin, etoposide and mitoxantrone in 1) as well as alkylators. In agreement with previous reports, the leukemia was monoblastic (FAB M5 subtype) in all 4 patients, with only 1 having prior myelodysplasia, and the latency period from primary therapy was relatively short (24-48 months). All patients received potentially curative treatment for the leukemia which included allogeneic bone marrow transplantation in 3; however, all died (3 of t-AML and 1 of lymphoma). Therapy-related AML associated with exposure to agents with topoisomerase II inhibitory activity (epipodophyllotoxins and anthracyclines) is a distinct entity, the genetic basis and optimal treatment of which remain to be determined.

Detection of CD34, TdT, CD56, CD2, CD4, and CD14 by Flow Cytometry Is Associated With NPM1 and FLT3 Mutation Status in Cytogenetically Normal Acute Myeloid Leukemia

UNLABELLED In 83 patients with cytogenetically normal acute myeloid leukemia (CN-AML), those with NPM1 and wild-type FLT3 (FLT3-wt) mutation and their poor prognostic combination had distinctive flow cytometric findings: CN-AML with a mutation of NPM1 (NPMI-Mt) were CD34(-), CD14(-), and CD2pos and CD4; those with FLT3-internal tandem duplications (ITD) were CD56pos, those with NPM1-Mt and FLT3-wt were CD34(-) and CD56(-); and those with poor prognostic combination NPM1-wt and FLT3-ITD were CD34pos and TdTpos. METHODS We retrospectively correlated NPM1 and FLT3 mutation status with flow cytometric profile of leukemic blasts in 83 adult patients with cytogenetically normal acute myeloid leukemia (CN-AML). RESULTS Mutation of the NPM1 gene (NPM1.mt) was found in 39 (47%) of 83 patients, and internal tandem duplication (ITD) of the FLT3 gene (FLT3-ITD) was seen in 38 (46%) of 83 patients. Patients with CN-AML and with NPM1.mt were less likely to express CD34 (33% vs. 93%; 2P = .0001), CD2 (0% vs. 14%; 2P = .0187), and CD14 (6% vs. 22%, 2P = .0476), and were more likely to express CD4 (65.5% vs. 37%; 2P = .0367) and CD19 (49% vs. 27%; 2P = .0506). The patients with CN-AML and with FLT3-ITD were more likely to express CD56 (47% vs. 23%; 2P = .0393). Moreover, patients with favorable prognostic combination of NPM1.mt and wild-type (wt) FLT3 (n = 18) were less likely to express CD34 (33% vs. 74% all others; 2P = .0021) and CD56 (6% vs. 37% all others; 2P = .0072). The group with an unfavorable prognostic combination of NPM1-wt and FLT3-ITD (n = 17) were more likely to express CD34 (88% vs. 45% all others; 2P = .0011) and TdT (40% vs. 2% all others; 2P = .0054). CONCLUSIONS In patients with CN-AML, characteristic flow cytometric profile is associated with NPM1 and FLT3 mutation status.

Drug-induced haemolysis and methaemoglobinaemia in glucose 6-phosphate dehydrogenase deficiency.

A 59-year-old Filipino man who had been treated for metastatic renal cell carcinoma with two doses of a ribonucleotide reductase inhibitor, 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP or Triapine), presented with marked cyanosis, headache, dizziness and exertional dyspnoea that had developed over an 8 h period. His peripheral O2 saturation was 64%, pO2 was normal, arterial O2 saturation was 83%, and methaemoglobin level was 35%. Haemoglobin was 13Æ9 g/dl, bilirubin was 72 lmol/l, lactate dehydrogenase was 372 U/l and haptoglobin was <0Æ09 g/l. The patient was treated with methylene blue for methaemoglobinaemia without success. The patient’s plasma (top, left tube) was red-brown in colour [in contrast to haemolysed (top, centre tube) and normal (top, right tube) plasma] due to methaemoglobin, and a blood film (bottom) showed oxidative haemolysis with many blister and bite cells (arrows), spherocytes (double arrows), ghost cells (arrowhead) and coarse basophilic stippling (double arrowheads). Glucose 6-phosphate dehydrogenase activity was <1%. 3-AP and methylene blue were discontinued, and the patient recovered uneventfully with hydration, erythrocyte transfusions and oxygen supplementation.