The current role of interferon in hairy cell leukaemia: clinical and molecular aspects.

We investigated the current role of interferon-alpha (IFNα) in hairy cell leukaemia (HCL) in a retrospective analysis of patients with HCL. A cohort of 74 patients with HCL was divided in to three groups: (A) patients aged >65 years with first-line treatment; (B) patients with comorbidities with first-line treatment; (C) patients who were purine analogues resistant. In total, 94% achieved a response, with a complete response rate of 24%. After a median (range) follow-up of 60 (7-236) months, 55 patients (78%) are still responding. The 5-year progression-free survival was 95%, 68%, and 96% in groups A, B and C respectively. A proportion of patients were monitored through their B-Raf proto-oncogene, serine/threonine kinase (BRAF)-V600E status. IFNα remains a possible option in select patients with HCL, where minimal residual disease negativity is achievable.

Prognostic Value of Baseline Serum Lactate Dehydrogenase Level in Patients With Hairy Cell Leukemia.

BACKGROUND: Hairy cell leukemia is a rare B-cell lymphoproliferative disorder. It has an indolent course with relapse and remission periods. The aim of this study was to investigate the clinical characteristics and risk factors affecting the outcome of patients with hairy cell leukemia. PATIENTS AND METHODS: The retrospective data of 65 patients were evaluated according to initial hematologic and biochemical parameters, response rates, progression-free survival, and overall survival. Factors effecting response and survival rates were analyzed. RESULTS: The median follow-up duration was 62.8 months (range, 5.7-229.3 months). The result of the analysis showed that the patients with relapse/progressive disease had higher lactate dehydrogenase (LDH) levels at the time of diagnosis than patients without relapse/progression (median [range], 243 [137-540] vs. 179 [99-334] U/L, P = .01). Patients with LDH ≥ 200.5 IU at the time of diagnosis were demonstrated to have a shorter progression-free survival than those with LDH < 200.5 IU (P = .010). CONCLUSION: Serum LDH level is significantly associated with relapse/progression in hairy cell leukemia patients. Patients with higher LDH levels at diagnosis should be monitored closely even if they experience complete remission.

A novel approach to assess domain specificity of anti-drug antibodies to moxetumomab pasudotox, an immunotoxin with two functional domains.

Biologics are potentially immunogenic and can elicit immune response. Complex biologics, such as bispecific antibodies or multi-domain molecules can induce anti-drug antibodies (ADA) with specificity to different domains. Domain specific ADAs may differently affect drug efficacy and safety, and thus, characterization of ADA domain specificity has become a regulatory expectation for multi-domain biologics. Unlike well-established methods for screening, confirmation, titer and neutralizing ADA detection, characterization of ADA domain specificity is an emerging field. The conventional approach for determination of ADA domain specificity is a competitive inhibition with domain-containing molecules. When developing a conventional domain specificity assay for moxetumomab pasudotox, a recombinant anti-CD22 immunotoxin, comprised of two functional domains (CD22-binding fragment and truncated Pseudomonas exotoxin A (PE38), we encountered a bioanalytical challenge. The method was able to detect immunodominant anti-PE38 (ADA-PE) but generated false negative results for low abundant CD22-binding domain ADA (ADA-BD) in a polyclonal sample. Troubleshooting experiments using control samples with varying levels of each ADA subtype demonstrated that a major factor for successful ADA identification was the ratio of the ADA signals contributed by each ADA subtype. To overcome this unique bioanalytical challenge, we developed a novel approach, which ensures detection of a domain-specific ADA subtype regardless of its relative level in a polyclonal ADA sample by evaluating signal inhibition by a respective domain-containing molecule at the condition when signals from all other ADAs are fully blocked. The method has been used for characterization of ADA domain specificity in moxetumomab pasudotox clinical trials, including study 1053, the pivotal Phase III study in hairy cell leukemia patients. It allowed for successful detection of ADA-BD in the presence of immunodominant ADA-PE, enabling accurate determination of domain specificity for moxetumomab pasudotox. The results demonstrated that the method was superior than the conventional approach. The method could be applied broadly to other biologics with two or more domains when there is a need to detect a minor ADA subtype in polyclonal samples.

Decreased Activity of Blood Acid Sphingomyelinase in the Course of Multiple Myeloma.

Acid sphingomyelinase (aSMase) is involved in the generation of metabolites that function as part of the sphingolipid signaling pathway. It catalyzes the breakdown of sphingomyelin into ceramide, a bioactive lipid that, among other roles, is involved in regulation of apoptosis. Dry drop blood test (DBS) and colorimetric 2-step enzymatic assay were used to assess the activity of human blood aSMase, beta-galactosidase, and beta-glucosidase, these enzymes are lysosomal hydrolases that catalyze the degradation of related sphingolipids, of sphingolipid signaling molecules. Blood was collected from a group of healthy volunteers and patients that were diagnosed with multiple myeloma (MM) in various stages of the disease. Additionally, activity of those enzymes in patients diagnosed with other hematological cancers was also assessed. We found that aSMase activity in the blood of patients with MM (at the time of diagnosis) was 305.43 pmol/spot*20 h, and this value was significantly lower (p < 0.030) compared to the healthy group 441.88 pmol/spot*20 h. Our collected data suggest a possible role of aSMase in pathogenesis of MM development.

Neutropenia caused by hairy cell leukemia in a patient with myelofibrosis secondary to polycythemia vera: a case report.

BACKGROUND: Polycythemia vera is a myeloproliferative disease that sometimes evolves to myelofibrosis, causing splenomegaly and neutropenia. In this case report, we describe a patient with polycythemia vera and unexplained neutropenia who later turned out to also have hairy cell leukemia. CASE PRESENTATION: A middle-aged Caucasian man with polycythemia vera presented to our hospital with chronic mouth ulcers. Later he developed leukopenia and pancytopenia. Bone marrow biopsies showed fibrosis. Further morphological analyses of bone marrow and blood smears revealed probable transformation into acute myeloid leukemia. However, there were also cells indicating hairy cell leukemia. Morphological and immunohistochemical analyses later confirmed the presence of hairy cell leukemia in biopsies that had been present for 3 years. Treatment with cladribine temporarily reversed the patient's neutropenia. CONCLUSIONS: Hairy cell leukemia may mimic development to myelofibrosis in patients with polycythemia vera.

sIL2R ratio as early marker for response in hairy cell leukemia and the prognostic relevance of IL28B genotype to interferon-α therapy.

Interferon-α (IFNα) was the first effective drug therapy for hairy cell leukemia (HCL). Nowadays, it is used as an alternative treatment in selected patients. Due to unlimited treatment time, monitoring and early prediction of response are important. Moreover, IFNα is used in the therapy of chronic hepatitis C, where a single nucleotide polymorphism of interleukin-28B gene (IL28B) correlates with therapy response. The role of this polymorphism in therapy response of IFNα-treated patients with HCL is unknown. Thirty-seven HCL patients treated between 1978 and 2014 were included in this study. Treatment strategy and response parameters (blood cell counts, soluble interleukin-2 receptor (sIL2R), and bone marrow examination) have been assessed. Relative decrease of sIL2R was correlated with outcome parameters. Response parameters of IFNα-treated patients were correlated with IL28B polymorphism. Twenty-one patients were analyzed for the correlation of sIL2R ratio and outcome. After 1 and 3 months of therapy (IFNα or cladribine (CDA)), the median sIL2R level showed a relative decrease of 79 and 91%. These decreases significantly correlate with time to complete remission (CR, p = 0.029 and p = 0.018). Correlation analyses of IL28B genotype with outcome parameters are not significant. Six patients (16%) were diagnosed with secondary malignancies, and one death was registered (median follow-up time 14 years). IFNα is a safe, effective, and well-tolerated long-term treatment in HCL. Relative decreases of sIL2R levels correlate with time to CR and are useful as early predictor for response. There is no significant correlation between IL28B polymorphism and treatment response to IFNα. Graphical abstract.

Comparison of abnormal cell flagging of the hematology analyzers Sysmex XN and Sysmex XE-5000 in oncohematologic patients.

INTRODUCTION: Hematology analyzers should optimize flagging while minimizing false-negative results and unnecessary microscopic reviews. METHODS: We compared flagging performance of Sysmex XE-5000 and XN analyzers in oncohematologic patients. Differential counts were performed by Cellavision digital system (100 cells) and a hematologist (another 100 cells). RESULTS: First, we included 292 samples (86 with blasts): 28 acute lymphoblastic leukemia, 88 acute myeloid leukemia, 91 myelodysplastic syndromes, 45 chronic myeloproliferative neoplasms, and 40 chronic myelomonocytic leukemia. Sensitivity, specificity and efficiency to detect blasts were 59.3%, 88.3%, and 79.8% for XE-5000 analyzer and 70.9%, 91.3%, and 85.2% for the XN analyzer. Then, we included 111 lymphoid malignancies. In 55 CLL XE-5000 flagged for Abn Lympho/L_Blasts?, XN flagged for Abn Lympho?. In one-third of 19 samples with splenic marginal lymphoma, none of the analyzers flagged. In 5 Sézary syndrome cases, XE-5000 triggered the Abn Lympho/L_Blasts? flag while the flagging in XN was less consistent: Abn Lympho? Blasts? and Atypical Lympho?. In 5 hairy cell leukemias, both analyzers only flagged one sample. In 13 myelomas, XE-5000 generated Atypical Lympho? flag; XN triggered more variable flags. In other lymphoid malignancies, flags were variable. XN analyzer generates less samples with false basophilia. CONCLUSION: XN analyzer has improved blast detection in oncohematologic patients. Operators cannot rely on the blast flag alone but have to consider other flags and hemogram data. In lymphoproliferative disorders, XN analyzer yields less samples with pseudobasophilia. Both analyzers must improve flagging for hairy cell leukemia.

[The case of hairy cell leukosis in pediatrics].

According publications' data, hairy cell leukosis encounters in humans aged from 26 to 70 years and in males four times more often than in females. The disease is manifested by impotence, splenomegaly, and presence in blood and bone marrow clone of lymphoid cells with particular morphology, cytochemic markers and immune phenotype (sIg+, CD19+, CD20+, CD5-, CD10-, with marked expression of CD25+, CD103+). The presented clinical case of illness with hairy cell leucosis is the first one detected in pediatric practice in adolescent of 16 years old.