IgG4-related disease and lymphocyte-variant hypereosinophilic syndrome: A comparative case series.

OBJECTIVE: To compare the clinical and laboratory features of IgG4-related disease (IgG4-RD) and lymphocyte-variant hypereosinophilic syndrome (L-HES), two rare diseases that often present with lymphadenopathy, gastrointestinal symptoms, eosinophilia, and elevated immunoglobulins/IgE. METHOD: Comparative case series of 31 patients with IgG4-RD and 13 patients with L-HES. RESULTS: Peripheral blood eosinophilia was present in eight of 31 patients with IgG4-RD compared to 13 of 13 patients with L-HES (median eosinophils 0.4 vs 7.0 giga/L, P=.001) and 12 of 20 patients with IgG4-RD had increased serum IgE compared to eight of 13 patients with L-HES, P=.930. Twenty-seven of 30 patients with IgG4-RD had elevated serum IgG4 compared to five of 12 patients with L-HES (median IgG4 9.6 g/L vs 0.80 g/L, P=.002). Flow cytometry demonstrated an aberrant T-cell phenotype in 7 of 23 patients with IgG4-RD and 13 of 13 patients with L-HES (P<.001). T-cell clonality by PCR was positive in 12 of 23 patients with IgG4-RD vs 10 of 13 patients with L-HES (P=.143). Patients in both groups received corticosteroids as first-line therapy. For refractory disease in IgG4-RD, rituximab was the most common steroid-sparing agent, whereas in L-HES, it was pegylated interferon-α-2a. CONCLUSION: The overlapping features of these two diseases with divergent treatment options demonstrate the importance of familiarity with both entities to optimize diagnosis and treatment.

Deep profiling of multitube flow cytometry data.

MOTIVATION: Deep profiling the phenotypic landscape of tissues using high-throughput flow cytometry (FCM) can provide important new insights into the interplay of cells in both healthy and diseased tissue. But often, especially in clinical settings, the cytometer cannot measure all the desired markers in a single aliquot. In these cases, tissue is separated into independently analysed samples, leaving a need to electronically recombine these to increase dimensionality. Nearest-neighbour (NN) based imputation fulfils this need but can produce artificial subpopulations. Clustering-based NNs can reduce these, but requires prior domain knowledge to be able to parameterize the clustering, so is unsuited to discovery settings. RESULTS: We present flowBin, a parameterization-free method for combining multitube FCM data into a higher-dimensional form suitable for deep profiling and discovery. FlowBin allocates cells to bins defined by the common markers across tubes in a multitube experiment, then computes aggregate expression for each bin within each tube, to create a matrix of expression of all markers assayed in each tube. We show, using simulated multitube data, that flowType analysis of flowBin output reproduces the results of that same analysis on the original data for cell types of >10% abundance. We used flowBin in conjunction with classifiers to distinguish normal from cancerous cells. We used flowBin together with flowType and RchyOptimyx to profile the immunophenotypic landscape of NPM1-mutated acute myeloid leukemia, and present a series of novel cell types associated with that mutation.

Abnormalities of the lymphocyte subsets and their immunophenotype, and their prognostic significance in adult patients with hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a final common pathway resulting from diverse immune processes. Most of the current understanding of HLH is based on studies involving pediatric patients (pHLH). Adult HLH (aHLH) is distinct from pHLH, with less frequent genetic basis, higher frequency of chemo-resistance and a higher mortality. Immunological processes underlying aHLH are poorly understood. So far, no immunophenotypic abnormalities associated with aHLH have been described, and their etiopathologic and prognostic significance has not been explored. We reviewed all adult patients with bone marrow hemophagocytosis and identified 21 who fulfilled the criteria for HLH. We then analyzed abnormalities in their lymphocyte subsets and immunophenotype and tested association of these abnormalities with survival. Twenty of 21 patients showed abnormalities in either lymphocyte subsets and/or immunophenotype: 10 showed increased CD8+ cells and decreased CD4:CD8 ratio, 8 had decreased CD3+ cells, 3 each had increased CD56+ cells, increased CD7-/CD4+ cells, and increased CD3+/CD4-/CD8- (DN) cells, and one had increased CD3-/CD4+ cells. Six of 10 patients with increased numbers of CD8+ cells and decreased CD4:CD8 ratio are alive, compared to 2/11 with normal values (p = 0.0385). On the other hand, all 8 patients with decreased CD3+ cells are dead, compared to 8/13 with normal numbers (p = 0.0417). Those who survived were younger than those who did not (median, range: 29 years, 19-88, vs 62 years, 24-81; p = 0.0272). In conclusion, most aHLH patients show diverse abnormalities in either lymphocytes and/or immunophenotype. Young age, increased numbers of CD8+ cells or decreased CD4:CD8 ratio are favorably associated with survival, while a decreased number of CD3+ cells is adversely associated with survival in aHLH patients.

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

The significance of paroxysmal nocturnal haemoglobinuria (PNH(pos) ) 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 PNH(pos) , of whom 94% achieved at least a partial response (PR) to IST; 11/16 (69%) achieved complete response (CR). Only 2/6 (33%) PNH(neg) patients achieved PR. PNH(pos) patients were less likely to fail IST compared to PNH(neg) 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.

Frequency of and reasons for paroxysmal nocturnal haemoglobinuria screening in patients with unexplained anaemia.

Referral to hematology for anemia is common. In paroxysmal nocturnal hemoglobinuria (PNH), cells deficient in the glycosylphosphatidyl inositol (GPI) anchor are lysed by complement. Eculizumab improves overall survival and quality of life while reducing hemolysis, transfusion requirements, and thrombosis. We evaluated the frequency of screening for PNH in patients with unexplained anemia. Key clinical features, laboratory data, and investigations were recorded for patients referred for anemia since 2010, without a specific cause found. PNH testing was done by flow cytometry. 540 patients had: anemia not yet diagnosed (NYD, n=318 (including unexplained iron deficiency, n=92; DAT-negative hemolysis, n=9)); anemia of chronic disease, n=173; and pancytopenia NYD, n=49. 82.4% had LDH testing done; 85.0% total bilirubin; 78.7% reticulocyte counts; and 40.6% haptoglobin level; 131 (24.2%) had possible hemolysis. PNH testing was done in 56 (10.4%). Those screened for PNH were more likely to have: younger age (P=0.04); a history of thrombosis (P<0.001); undergone a BMBx (P<0.001); received RBC transfusions (P=0.0018); or evidence of DAT-negative hemolysis (P<0.001). In summary, PNH was tested for in a minority of patients with unexplained anemia (10.4%) despite potential indicators of hemolysis in 24.2%. Increased screening could identify patients who would benefit from treatment and should be considered.

Clinical applications of molecular haematology: flow cytometry in leukaemias and myelodysplastic syndromes.

Flow cytometry is semi-automated study of antigen profile of cells using the Scatchard principle of antigen-antibody binding and fluorochrome-based detection systems. Flow cytometric evaluation of cellular proteomics has become an integral part of the laboratory diagnosis and classification of haematopoietic neoplasms. Recent technical advances in lasers, monoclonal antibodies, fluorochromes, and computer-based color compensation algorithms have expanded the usefulness of flow cytometry. Detection of minimal residual disease by flow cytometry in leukaemias and lymphomas is incorporated in many treatment protocols. Finding of aberrant maturation pattern of granulocytes offers a sensitive screening tool for early diagnosis of myelodysplastic syndromes. Detailed proteomic analysis of leukemias is helping more precise prognostic and biological stratification.

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.

Intravascular lymphoma presenting with bone marrow involvement and leukemic phase.

We describe the case of a 62-year-old man with recent onset of constitutional symptoms and vague intellectual deficit. The blood showed pancytopenia with blastemia, and bone marrow confirmed an extensive "vacuolated blast-like cell" infiltrate. Initial diagnosis of, and treatment for Burkitt's leukemia/lymphoma was questioned when the "blasts" typed as CD5+ mature B-cells; however, it was revised to intravascular lymphoma (IVL) only after the sinusoidal pattern was confirmed by immunocytochemistry. Literature review indicated that blood and bone marrow involvement in IVL appears to be rare, but a systematic search for this involvement is often not carried out. CD5 expression has been increasingly reported in this disease. The actual frequency and the significance of this expression are still to be defined.

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).

Artifacts that may be present on a blood film.

Many artifacts or pseudoartifacts may be noted during the examination of a blood film. Artifactual results also may be generated by automated hematology analyzers, which in turn may be investigated by blood film examination. Some artifacts are misdiagnosed, and this in turn leads to inappropriate investigations or treatment. An awareness of the spectrum of spurious or artifactual results may help to prevent such an unfortunate occurrence.

Aberrant expression of CD13 identifies a subgroup of standard-risk adult acute lymphoblastic leukemia with inferior survival.

BACKGROUND: The standard-risk (SR) subgroup of acute lymphoblastic leukemia in adults (aALL) is a heterogeneous category, with a 20% to 40% relapse rate and a wide range of relapse-free survival (RFS) and overall survival (OS). There is a need to identify at the outset those patients with SR-aALL who are likely to have shorter RFS and OS, so they can be treated more aggressively. PATIENTS AND METHODS: Flow cytometric data of 81 patients with SR-aALL treated with a standardized protocol were retrospectively analyzed. Thirty-two patients (40%) relapsed; the median RFS and OS were 12.5 months (range, 1-136 months) and 30 months (range, 3-235 months), respectively. Twenty-six patients survived ≥ 48 months. RESULTS: Expression of myeloid antigen CD13, using the conventional ≥ 20% threshold and a lower ≥ 5% threshold, was seen in 17 (29%) of 59 and 29 (49%) of 59 patients, respectively, whereas dual expression of CD13 and CD33 was seen in 8 patients. CD13 positivity at ≥ 20% and ≥ 5% threshold was associated with a shorter RFS (P = .0158 and P < .0001, respectively) and OS (P = .0072 and P < .0001, respectively). Dual expression of CD13 (at ≥ 5% or ≥ 20% threshold) and CD33 was associated with inferior OS (P = .0038 and P = .0032, respectively) and RFS (P = .0705 and P = .2516, respectively). For ≥ 20% and ≥ 5% threshold of positivity, 16 of 42 and 28 of 42 who survived < 48 months were positive, compared with 1 of 17 and 1 of 17 who survived ≥ 48 months (P = .0133 and P < .0001, respectively). CONCLUSION: Aberrant expression of CD13 in ≥ 5% of blasts of patients with SR-aALL is an adverse prognostic factor, delineating a subgroup of patients with SR-aALL that should be considered for more aggressive treatment.

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

BACKGROUND: 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. METHODS: One hundred and nineteen cases tested for PNH by flow cytometry were included in the study. Both the total number of monocytes and the number of GPI-deficient monocytes gated with CD33 or CD64 were compared. The clustering pattern and any other unusual patterns were noted and investigated. RESULTS: CD64 staining showed more distinct separation of the monocyte cluster than did CD33 staining. The difference between the number of monocytes gated by CD33 and CD64 staining ranged from -26 to +32% (median 1.60%, average 1.69%). Six patients had GPI-deficient monocytes by both CD33- and CD64-based gating, ranging from 0.02 to 83.23%. There were no patients who showed GPI-deficient monocytes by one but not the other gating. The presence of blasts in patients with acute leukemia resulted in abnormal cluster patterns, both by CD33- and CD64-based gating. CONCLUSIONS: CD64-based gating showed more distinct clustering of monocytes than CD33-based gating, allowing for objective separation. The number of monocytes in total and GPI-deficient monocytes derived from both gating strategies was comparable.

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.

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.

Azathioprine-associated acute myeloid leukemia in a patient with Crohn's disease and thiopurine S-methyltransferase deficiency.

Immunosuppressive thiopurines like azathioprine, 6-mercaptopurine, and thioguanine are commonly used in inflammatory and neoplastic disorders. A subset of these patients are genetically slow metabolizers due to point-mutations in enzyme thiopurine S-methyltransferase (TPMT), and are at a higher risk of hematologic toxicity and leukemogenesis. We present such a patient who was a slow metabolizer for azathioprine, and developed a rapidly lethal form acute myeloid leukemia after relatively low dose exposure to the drug. There was prominent hemophagocytic activity in the bone marrow, and cytogenetic analysis showed a complex karyotype with monosomy 7, but no involvement of chromosome 8.