Detection and outcome of occult leptomeningeal disease in diffuse large B-cell lymphoma and Burkitt lymphoma.

The benefit of intrathecal therapy and systemic rituximab on the outcome of diffuse large B-cell lymphoma at risk of central nervous system disease is controversial. Furthermore, the effect of intrathecal treatment and rituximab in diffuse large B-cell and Burkitt lymphoma with occult leptomeningeal disease detected by flow cytometry at diagnosis is unknown. Untreated diffuse large B-cell (n=246) and Burkitt (n=80) lymphoma at clinical risk of central nervous system disease and having had pre-treatment cerebrospinal fluid were analyzed by flow cytometry and cytology. Spinal fluid involvement was detected by flow cytometry alone (occult) in 33 (13%) diffuse large B-cell and 9 (11%) Burkitt lymphoma patients, and detected by cytology in 11 (4.5%) and 5 (6%) patients, respectively. Diffuse large B-cell lymphoma with occult spinal fluid involvement had poorer survival (P=0.0001) and freedom from central nervous system relapse (P<0.0001) compared to negative cases. Burkitt lymphoma with occult spinal fluid involvement had an inferior freedom from central nervous system relapse (P=0.026) but not survival. The amount of intrathecal chemotherapy was quantitatively associated with survival in diffuse large B-cell lymphoma with (P=0.02) and without (P=0.001) occult spinal fluid involvement. However, progression of systemic disease and not control of central nervous system disease was the principal cause of treatment failure. In diffuse large B-cell lymphoma, systemic rituximab was associated with improved freedom from central nervous system relapse (P=0.003) but not with survival. Our results suggest that patients at risk of central nervous system disease should be evaluated by flow cytometry and that intrathecal prophylaxis/therapy is beneficial.

Reduced numbers of naïve CD4 + T cells and an altered CD4/CD8 balance in depressed common variable immune deficiency (CVID) patients. Is thymosin-α1 a possible treatment?

In the 1990's the macrophage-T-cell-theory of depression was posed stating that low grade inflammation and an abnormal T cell system destabilize the development and function of the emotional brain in such a way, that individuals become ultrasensitive to stress. Recently we gathered evidence that indeed higher frequencies of CD4+ memory T cells, lower frequencies of naive CD4 + T cells, higher frequencies of CD8 + T cells (the latter two in part elicited by Cytomegalovirus, CMV, infection) are a characteristic of Major Depressive Disorder (MDD). In MDD patients with a history of childhood trauma and severe depression monocytes are inflammatory activated. Low grade inflammation and T cell system defects have also been reported in patients with Common Variable Immune Deficiency (CVID) (next to antibody production defects). CVID patients show a higher prevalence of mild depression. The aim of this study was to determine T cell frequencies and monocyte inflammatory activation in CVID patients with and without depression. This study confirms that CVID patients have CMV independent decreases in the frequency of naïve CD4 + T cells and it de novo shows a CMV dependent increase in the expression of inflammatory genes in monocytes. CVID patients with depression are additionally characterized by a CMV independent increase in the frequency of naïve CD8 + T cells, while lacking monocyte inflammatory activation. In conclusion, depressed CVID patients have T cell abnormalities comparable to that of patients with regular MDD. These abnormalities are presently targeted by thymosin α1 in an open-label proof of concept trial.

Immune monitoring with iTAg MHC Tetramers for prediction of recurrent or persistent cytomegalovirus infection or disease in allogeneic hematopoietic stem cell transplant recipients: a prospective multicenter study.

Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality in hematopoietic stem cell transplant recipients despite the introduction of posttransplantation viral monitoring and preemptive antiviral therapy. We evaluated the use of HLA class I tetramers in monitoring CMV-specific T-cell recovery to predict patients at risk for CMV-related complications. This prospective multicenter clinical trial obtained nearly 1400 tetramer/allele results in more than 800 biweekly blood samples from 83 patients monitored for 1 year after transplantation. Major HLA types were included (A*0101, A*0201, B*0702, B*0801, B*3501). iTAg MHC Tetramers (Beckman Coulter) were used to enumerate CMV-specific CD8(+) T cells by flow cytometry using a single-platform absolute counting method. Assay variability was 8% or less and results were available within 3 hours. Delayed recovery of CMV-specific T cells (< 7 cells/µL in all blood samples during the first 65 days after transplantation) was found to be a significant risk factor for CMV-related complications; these patients were more likely to develop recurrent or persistent CMV infection (relative risk 2.6, CI 1.2-5.8, P = .01) than patients showing rapid recovery, which was associated with protection from CMV-related complications (P = .004). CMV tetramer-based immune monitoring, in conjunction with virologic monitoring, can be an important new tool to assess risk of CMV-related complications and to guide preemptive therapeutic choices.

No Evidence for Circulating Retina Specific Autoreactive T-cells in Latent Tuberculosis-associated Uveitis and Sarcoid Uveitis.

Purpose: To detect circulating retina-specific autoreactive CD4+ T-cells and antiretinal antibodies (ARA) in latent tuberculosis (TB)-associated uveitis or sarcoid uveitis patients.Methods: The presence of crude retinal extract (RE) autoreactive CD4+ T-cells was determined by a highly sensitive flowcytometric-based technique examining co-expression of CD25 and CD134 (OX40) on RE stimulated PBMC. The presence of ARA in available matched serum samples was assessed by indirect immunofluorescence.Results: No autoreactive CD4+ T-cells against RE could be detected in either latent TB-associated uveitis or sarcoid uveitis patients, while ARA were detected in the serum of the majority (5/6) of latent TB-associated uveitis and all (3/3) sarcoid uveitis patients.Conclusion: Even with the use of this highly sensitive flowcytometric technique circulating retina-specific autoreactive CD4+ T-cells could not be detected. In contrast, ARA were detected in the majority of patients indicating an adaptive humoral immune response toward retinal antigens had occurred.

Immunophenotypic measurable residual disease (MRD) in acute myeloid leukemia: Is multicentric MRD assessment feasible?

Flow-cytometric detection of now termed measurable residual disease (MRD) in acute myeloid leukemia (AML) has proven to have an independent prognostic impact. In a previous multicenter study we developed protocols to accurately define leukemia-associated immunophenotypes (LAIPs) at diagnosis. It has, however, not been demonstrated whether the use of the defined LAIPs in the same multicenter setting results in a high concordance between centers in MRD assessment. In the present paper we evaluated whether interpretation of list-mode data (LMD) files, obtained from MRD assessment of previously determined LAIPs during and after treatment, could reliably be performed in a multicenter setting. The percentage of MRD positive cells was simultaneously determined in totally 173 LMD files from 77 AML patients by six participating centers. The quantitative concordance between the six participating centers was meanly 84%, with slight variation of 75%-89%. In addition our data showed that the type and number of LAIPs were of influence on the performance outcome. The highest concordance was observed for LAIPs with cross-lineage expression, followed by LAIPs with an asynchronous antigen expression. Our results imply that immunophenotypic MRD assessment in AML will only be feasible when fully standardized methods are used for reliable multicenter assessment.

Analytical performance of a standardized single-platform MHC tetramer assay for the identification and enumeration of CMV-specific CD8+ T lymphocytes.

Major histocompatibility complex (MHC) multimers that identify antigen-specific T cells, coupled with flow cytometry, have made a major impact on immunological research. HLA Class I multimers detect T cells directed against viral, tumor, and transplantation antigens with exquisite sensitivity. This technique has become an important standard for the quantification of a T cell immune response. The utility of this method in multicenter studies, however, is dependant on reproducibility between laboratories. As part of a clinical study using a standardized two-tube three-color single-platform method, we monitored and characterized performance across multiple sites using tetramers against the T cell receptors (TCR) specific for MHC Class I, A*0101--VTEHDTLLY, A*0201--NLVPMVATV and B*0702--TPRVTGGGAM CMV peptides. We studied the analytical performance of this method, focusing on reducing background, maximizing signal intensity, and ensuring that sufficient cells are enumerated to provide meaningful statistics. Inter and intra-assay performance were assessed, which included inherent variability introduced by shipping, type of flow cytometer used, protocol adherence, and analytical interpretation across a range of multiple sample levels and specificities under routine laboratory testing conditions. Using the described protocol, it is possible to obtain intra- and interlab CV's of <20%, with a functional sensitivity for absolute tetramer counts of 1 cell/microL and 0.2% tetramer+ percent for A*0101, A*0201, and B*0702 alleles. The standardized single-platform MHC tetramer assay is simple, rapid, reproducible, and useful for assessing CMV-specific T cells, and will allow for reasonable comparisons of clinical evaluations across multiple centers at clinically relevant thresholds (2.0-10.0 cells/microL).

Report of the European Myeloma Network on multiparametric flow cytometry in multiple myeloma and related disorders.

The European Myeloma Network (EMN) organized two flow cytometry workshops. The first aimed to identify specific indications for flow cytometry in patients with monoclonal gammopathies, and consensus technical approaches through a questionnaire-based review of current practice in participating laboratories. The second aimed to resolve outstanding technical issues and develop a consensus approach to analysis of plasma cells. The primary clinical applications identified were: differential diagnosis of neoplastic plasma cell disorders from reactive plasmacytosis; identifying risk of progression in patients with MGUS and detecting minimal residual disease. A range of technical recommendations were identified, including: 1) CD38, CD138 and CD45 should all be included in at least one tube for plasma cell identification and enumeration. The primary gate should be based on CD38 vs. CD138 expression; 2) after treatment, clonality assessment is only likely to be informative when combined with immunophenotype to detect abnormal cells. Flow cytometry is suitable for demonstrating a stringent complete remission; 3) for detection of abnormal plasma cells, a minimal panel should include CD19 and CD56. A preferred panel would also include CD20, CD117, CD28 and CD27; 4) discrepancies between the percentage of plasma cells detected by flow cytometry and morphology are primarily related to sample quality and it is, therefore, important to determine that marrow elements are present in follow-up samples, particularly normal plasma cells in MRD negative cases.

A phase I study of a new nucleoside analogue, OSI-7836, using two administration schedules in patients with advanced solid malignancies.

PURPOSE: To investigate the safety, tolerability, and pharmacokinetic profile of the novel nucleoside analogue OSI-7836 in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: OSI-7836 was initially given as a 60-minute i.v. infusion on day 1 every 21 days. In view of its dose-limiting toxicities, the administration time was amended to a 5-minute bolus, and subsequently, the schedule was amended to weekly for 4 weeks followed by a 2-week rest. Blood and urine samples were collected for pharmacokinetic studies. Analyses of cytokines and lymphocyte subsets were added later in the study to elucidate a mechanism for the severe fatigue and lymphocyte depletion observed in earlier patients. RESULTS: Thirty patients received a total of 61 treatment cycles. Fatigue was the main dose-limiting toxicity. Maximum-tolerated dose was defined as 300 mg/m2 in the 60-minute infusion, (three times per week) schedule; 400 mg/m2 in the 5-minute bolus infusion, (three times per week) schedule; and 100 mg/m2 in the weekly schedule. Other common toxicities were nausea, vomiting, rash, fever, and a flu-like syndrome. There were no clinically significant hematologic toxicities. Following the initial dose, OSI-7836 was eliminated from plasma with a median (range) elimination half-life of 48.3 minutes (22.6-64.8 minutes). Lymphocyte subset analysis showed a significant drop in B cell counts, which persisted to day 14 and beyond. Cytokine analysis showed significant elevations of interleukin-6 and interleukin-10 in all patients who received > or = 200 mg/m2 OSI-7836. Best response was disease stabilization in seven patients. CONCLUSION: OSI-7836 was associated with excessive fatigue, and despite changes in its schedule and duration of administration, we did not observe an improvement in its tolerability. Its potentially selective effect on B lymphocytes could be exploited in further studies in specific hematologic malignancies.

Fifteen years of external quality assessment in leukemia/lymphoma immunophenotyping in The Netherlands and Belgium: A way forward.

In 1985, external quality assurance was initiated in the Netherlands to reduce the between-laboratory variability of leukemia/lymphoma immunophenotyping and to improve diagnostic conclusions. This program consisted of regular distributions of test samples followed by biannual plenary participant meetings in which results were presented and discussed. A scoring system was developed in which the quality of results was rated by systematically reviewing the pre-analytical, analytical, and post-analytical assay stages using three scores, i.e., correct (A), minor fault (B), and major fault (C). Here, we report on 90 consecutive samples distributed to 40-61 participating laboratories between 1998 and 2012. Most samples contained >20% aberrant cells, mainly selected from mature lymphoid malignancies (B or T cell) and acute leukemias (myeloid or lymphoblastic). In 2002, minimally required monoclonal antibody (mAb) panels were introduced, whilst methodological guidelines for all three assay stages were implemented. Retrospectively, we divided the study into subsequent periods of 4 ("initial"), 4 ("learning"), and 7 years ("consolidation") to detect "learning effects." Uni- and multivariate models showed that analytical performance declined since 2002, but that post-analytical performance improved during the entire period. These results emphasized the need to improve technical aspects of the assay, and reflected improved interpretational skills of the participants. A strong effect of participant affiliation in all three assay stages was observed: laboratories in academic and large peripheral hospitals performed significantly better than those in small hospitals. © 2015 International Clinical Cytometry Society.

Use of TransFix™ cerebrospinal fluid storage tubes prevents cellular loss and enhances flow cytometric detection of malignant hematological cells after 18 hours of storage.

Flow cytometry is a sensitive method for detection of leptomeningeal localizations of hematological malignancies (LHM) in cerebrospinal fluid (CSF). Rapid processing of CSF is needed, as leukocyte numbers appear to decline quickly after lumbar puncture. The cell-stabilizing agent TransFix™ may enhance the detection of LHM in CSF by preventing cellular loss. To study the effects of TransFix on leukocyte numbers and the detection of LHM, we prospectively collected 99 CSF samples from patients with suspected or proven LHM in tubes with (i) TransFix; (ii) serum-containing medium; and (iii) no cell-stabilizing agents (native CSF). Presence of LHM and absolute leukocyte numbers were determined by flow cytometry after 30 minutes and 18 hours of storage. Leukocyte numbers in TransFix-stabilized CSF were higher than in the corresponding native samples at both time points (1.4× and 2.3× respectively, P < 0.0001 on each occasion). After 18 hours of storage, TransFix enhanced the detection of LHM in CSF. In all discordant paired observations (13/99, P = 0.005), the level of suspicion (classified as positive, suspicious, or negative) in CSF with TransFix was higher than in native CSF. We conclude that the use of TransFix-containing CSF storage tubes prevents cellular loss and enhances flow cytometric detection of LHM after 18 hours of storage.

High prognostic impact of flow cytometric minimal residual disease detection in acute myeloid leukemia: data from the HOVON/SAKK AML 42A study.

PURPOSE: Half the patients with acute myeloid leukemia (AML) who achieve complete remission (CR), ultimately relapse. Residual treatment-surviving leukemia is considered responsible for the outgrowth of AML. In many retrospective studies, detection of minimal residual disease (MRD) has been shown to enable identification of these poor-outcome patients by showing its independent prognostic impact. Most studies focus on molecular markers or analyze data in retrospect. This study establishes the value of immunophenotypically assessed MRD in the context of a multicenter clinical trial in adult AML with sample collection and analysis performed in a few specialized centers. PATIENTS AND METHODS: In adults (younger than age 60 years) with AML enrolled onto the Dutch-Belgian Hemato-Oncology Cooperative Group/Swiss Group for Clinical Cancer Research Acute Myeloid Leukemia 42A study, MRD was evaluated in bone marrow samples in CR (164 after induction cycle 1, 183 after cycle 2, 124 after consolidation therapy). RESULTS: After all courses of therapy, low MRD values distinguished patients with relatively favorable outcome from those with high relapse rate and adverse relapse-free and overall survival. In the whole patient group and in the subgroup with intermediate-risk cytogenetics, MRD was an independent prognostic factor. Multivariate analysis after cycle 2, when decisions about consolidation treatment have to be made, confirmed that high MRD values (> 0.1% of WBC) were associated with a higher risk of relapse after adjustment for consolidation treatment time-dependent covariate risk score and early or later CR. CONCLUSION: In future treatment studies, risk stratification should be based not only on risk estimation assessed at diagnosis but also on MRD as a therapy-dependent prognostic factor.

Implementation of flow cytometry in the diagnostic work-up of myelodysplastic syndromes in a multicenter approach: report from the Dutch Working Party on Flow Cytometry in MDS.

Flow cytometry (FC) is recognized as an important tool in the diagnosis of myelodysplastic syndromes (MDS) especially when standard criteria fail. A working group within the Dutch Society of Cytometry aimed to implement FC in the diagnostic work-up of MDS. Hereto, guidelines for data acquisition, analysis and interpretation were formulated. Based on discussions on analyses of list mode data files and fresh MDS bone marrow samples and recent literature, the guidelines were modified. Over the years (2005-2011), the concordance between the participating centers increased indicating that the proposed guidelines contributed to a more objective, standardized FC analysis, thereby ratifying the implementation of FC in MDS.

Monitoring cytomegalovirus IE-1 and pp65-specific CD4+ and CD8+ T-cell responses after allogeneic stem cell transplantation may identify patients at risk for recurrent CMV reactivations.

We studied the recovery of CMV-specific CD4+ and CD8+ T-cell immunity in 52 recipients of allogeneic stem cell transplantation (SCT). The proportions of IFN-gamma-producing CD4+ and CD8+ T cells upon in vitro activation using peptide pools representing the CMV pp65 and IE-1 proteins were assessed at multiple time points post SCT, and correlated with the occurrence of CMV reactivation. In a retrospective analysis, recurrent CMV reactivations occurred in 9 patients and were associated with low pp65-specific CD4+ T-cell and low IE-1-specific CD8(+) T-cell reactivities, whereas patients without detectable CMV reactivation (n = 30) or a single reactivation (n = 13) showed a better recovery of these immune responses. CD4+ T-cell responses to IE-1 were infrequent in most patients, whereas CD8+ T-cell responses to pp65 occurred frequently, but did not correlate with protection against (recurrent) reactivation. Prospectively, CMV-specific T-cell responses could be studied prior to 14 reactivation episodes in 8 patients. CD4+ T-cell responses to IE-1 and pp65 were positive in only 1 and 2 episodes, respectively. CD8+ T-cell responses against IE-1 were positive in 4, but against pp65 in 12 episodes, again showing that CD8+ T-cell reactivity against pp65 did not prevent CMV reactivation. Thus, monitoring of particular CMV-specific CD4+ and CD8+ T-cell responses after allogeneic SCT may identify patients at risk for recurrent CMV reactivations.