Comparative immunophenotypic features of EBV-positive and EBV-negative atypical lymphocytosis

Phage display sequencing reveals that genetic, environmental, and intrinsic factors influence variation of human antibody epitope repertoire

Phage-displayed immunoprecipitation sequencing (PhIP-seq) has enabled high-throughput profiling of human antibody repertoires. However, a comprehensive overview of environmental and genetic determinants shaping human adaptive immunity is lacking. In this study, we investigated the effects of genetic, environmental, and intrinsic factors on the variation in human antibody repertoires. We characterized serological antibody repertoires against 344,000 peptides using PhIP-seq libraries from a wide range of microbial and environmental antigens in 1,443 participants from a population cohort. We detected individual-specificity, temporal consistency, and co-housing similarities in antibody repertoires. Genetic analyses showed the involvement of the HLA, IGHV, and FUT2 gene regions in antibody-bound peptide reactivity. Furthermore, we uncovered associations between phenotypic factors (including age, cell counts, sex, smoking behavior, and allergies, among others) and particular antibody-bound peptides. Our results indicate that human antibody epitope repertoires are shaped by both genetics and environmental exposures and highlight specific signatures of distinct phenotypes and genotypes.

The fine-needle aspiration cytology and clinical findings of Kikuchi-Fujimoto disease in pediatric patients: a retrospective clinical study

BACKGROUND

Histological evaluation of lymph node is crucial for the definitive diagnosis of Kikuchi-Fujimoto disease (KFD). However, lymph node biopsy under local anesthesia is often difficult in pediatric patients.

OBJECTIVES

We evaluated cytological findings for pediatric patients with prolonged cervical lymphadenitis clinically suggestive of KFD and investigated the clinical characteristics of patients diagnosed with KFD by fine-needle aspiration cytology (FNAC).

METHODS

This retrospective clinical study included 58 Japanese pediatric patients with cervical lymphadenitis who underwent FNAC.

RESULTS

Cytological diagnosis was KFD for 22 and suspicion of KFD for 11 patients. The remaining 25 patients were diagnosed with non-specific lymphadenitis (NSL). Tenderness was independently associated with a higher frequency of both KFD in narrow and broad senses, compared with NSL (p = .009; p = .038). The percentage of patients who underwent FNAC within 28 days from symptom onset tended to be higher among patients with KFD in a narrow sense than those with NSL (p = .052).

CONCLUSION

This study indicated that the period from symptom onset to FNAC (<28 days) and the symptom of tenderness were associated with the cytological diagnosis of KFD.

Absolute lymphocyte count proliferation kinetics after CAR T-cell infusion impact response and relapse

CD19-directed chimeric antigen receptor (CAR) T cells show characteristic proliferation kinetics after infusion that correlate with response. Clearance of circulating disease, B-cell aplasia (BCA), and cytokine release syndrome (CRS) are used to observe CAR T-cell function, given the lack of commercial CAR T-cell measurement assays. We investigated the utility of common hematology laboratory parameters in 166 patients with B-cell acute lymphoblastic leukemia (B-ALL) who were treated with CAR T-cell therapy targeting CD19. CAR T-cell infusion was followed by disappearance of circulating blasts in 86% of patients at a median of 6 days. After a lag phase, there was a rapid expansion in absolute lymphocyte count (ALC) in the second week that coincided with the appearance of atypical lymphocytes. The expansion phase was followed by a contraction phase with a concomitant decrease in atypical lymphocytes. In vitro CAR T-cell studies showed similar kinetics and morphological changes. Peak ALC and overall expansion was greater in sustained responders compared with that in nonresponders. Patients with early loss of BCA and those with eventual CD19+ minimal residual disease/relapse showed lower overall lymphocyte expansion compared with the controls. Pleomorphic lymphocytosis was noted in the cerebrospinal fluid at post-CAR time points. We conclude that lymphocyte counts and differential can also be used to evaluate CAR T-cell expansion after infusion, along with BCA and CRS. This is the first report to characterize the morphology of CAR T cells and determine the utility of lymphocyte kinetics.

Mindray BC-6800 haematological analyser: 3D-DIFF scattergram usefulness in infectious mononucleosis diagnosis

INTRODUCTION

3D-DIFF scattergram of the Mindray BC-6800 haematological analyser shows morphological abnormalities and lymphocyte cluster splitting related to the presence of reactive lymphocytes. This study aims to assess whether these cytographic changes are useful in detecting both activated and apoptotic lymphocytes, leading to an improvement in the laboratory diagnostic process of infectious mononucleosis.

METHODS

Two hundred three samples with modified shape and doubled lymphocyte cluster of DIFF scattergram (study group) were divided into two different subgroups: with and, respectively, without serological evidence of ongoing IM. Activated and apoptotic cells in peripheral blood were counted by light microscopy or gating in the instrumental dot plots. Values of apoptotic cells counted by microscopy were compared with those resulting from gating.

RESULTS

Samples with both shape change and doubled lymphocyte cluster had serological profiles according to the diagnosis of ongoing infectious mononucleosis. Blood smears review was positive for reactive lymphocytes in all 112 samples (100%). An underestimation of apoptotic cell count by light microscopy compared with the gating in the instrumental scatterplot was also observed (96 out of 112, 85.7%).

CONCLUSION

The additional lymphocyte cluster was significantly associated with activated and apoptotic lymphocytes in samples with serology suggesting ongoing infectious mononucleosis. Considering the significance of clue for infectious mononucleosis assigned to the apoptotic lymphocytes, a specific flag such as "apoptotic cells?" could be associate with the related cluster. Such a flag could be used for dedicated rules for smears review, thus increasing infectious mononucleosis detection in laboratories that do not usually practise instrumental cytograms observation.

Dynamic Distribution and Clinical Value of Peripheral Lymphocyte Subsets in Children with Infectious Mononucleosis

OBJECTIVE

To study the dynamic change of peripheral lymphocyte subsets and its clinical value in children with infectious mononucleosis (IM).

METHODS

Thirty-six pediatric patients with IM, 19 children with IM-like symptoms but lacking the serological pattern compatible with EB virus infection, and 33 healthy children were enrolled. The changes of peripheral lymphocyte subsets were detected by flow cytometry on admission and on the fifth day of antiviral treatment, respectively. Indicators of liver function and routine blood count were also detected. Besides, the receiver operating characteristic (ROC) curve and the correlation of related indicators was analyzed.

RESULTS

When IM patients were admitted, the frequency and absolute number of T, CD4^-CD8⁺T, and CD4⁺CD8⁺T (DPT) cells were significantly increased while B cells were decreased; the frequency of CD4⁺CD8^-T cells were decreased, but its absolute number did not change significantly; the frequency of NK cells decreased, but its absolute number increased. The absolute number of CD4^-CD8⁺T most significantly positively correlated with serum lactate dehydrogenase (LDH) concentration which could reflect the severity of IM patients. After short-term treatment with acyclovir, elevated lymphocytes decreased, but only DPT-cell frequency and NK-cell absolute number were recovering towards normal. The ROC curve suggested that the frequency of B cells has better diagnostic value for IM in pediatric patients compared to other lymphocyte subsets.

CONCLUSIONS

Peripheral lymphocyte subsets are closely related to the condition of children with IM, and each subset plays a relatively different role in the diagnosis and evaluation of IM.

T-cell prolymphocytic leukemia: Review of an entity and its differential diagnostic considerations

T-cell prolymphocytic leukemia (T-PLL) is a rare T-cell leukemia characterized in many patients by marked peripheral lymphocytosis, prominent splenomegaly, and skin lesions. The differential diagnosis is broad and includes other T-cell disorders presenting with similar clinical findings. This review addresses (a) the natural history, demographics, and genetic features of T-PLL; (b) clinical and pathologic differential diagnostic considerations; and (c) recent developments in the T-PLL literature relevant to laboratory professionals.

Clinical differentiation of infectious mononucleosis that is caused by Epstein-Barr virus or cytomegalovirus: A single-center case-control study in Japan

Introduction

Infectious mononucleosis (IM) is a common viral infection that typically causes fever, pharyngitis, and lymphadenopathy in young patients. The Epstein-Barr virus (EBV) is the most common cause of IM, followed by cytomegalovirus (CMV). Given that serological testing is associated with limitations regarding its accuracy, availability, and time to receive results, clinical differentiation based on symptoms, signs, and basic tests would be useful. We evaluated whether clinical findings could be used to differentiate EBV-IM from CMV-IM.

Methods

In this single-center retrospective case-control study, we evaluated >14-year-old patients with serologically confirmed EBV-IM or CMV-IM during 2006–2017. We compared the patients’ symptoms, physical findings, blood counts, and serum biomarkers to create three regression models: model 1 (symptoms and signs), model 2 (model 1 plus sonographic hepatosplenomegaly and blood counts), and model 3 (model 2 plus hepatobiliary biomarkers).

Results

Among the 122 patients (72.6%) with EBV-IM and 46 patients (27.4%) with CMV-IM, the median age was 25 years and 82 patients (48.8%) were male. The median age was 10 years older in the CMV-IM group (p < 0.001) and the median interval from onset to visit was 5 days longer in the CMV-IM group (p < 0.001). Logistic regression revealed that EBV-IM was predicted by younger age, short onset-to-visit interval, lymphadenopathy, tonsillar white coat, hepatosplenomegaly, atypical lymphocytosis, and elevations of lactate dehydrogenase and gamma-glutamyl transferase. All regression models had areas under the curve of >0.9.

Conclusion

History and physical findings, especially when used with atypical lymphocytosis and sonographic hepatosplenomegaly, can help physicians differentiate EBV-IM from CMV-IM.

Prognostic factors and importance of recognition of adult croup

OBJECTIVES

Croup, or laryngotracheobronchitis, is a common disease in childhood. On the other hand, to our knowledge, there are only 14 cases in six English literatures describing adult croup (AC). The clinical features of AC have not been well known.

METHODS

We conducted a retrospective analysis of medical records of 18 patients with AC during the period from 2008 to 2016.

RESULTS

None of the 18 patients required an urgent airway intervention. Univariate analysis indicated that the duration of symptoms was significantly longer in patients with cough (p < .01) and younger patients (age < 60, p = .037). The duration of subglottic edema was significantly longer in female (p = .035), patients with high levels of CRP (≥1 mg/dL, p = .049), and patients with cough symptom (p = .035).

CONCLUSIONS

Female, young age (<60 years), the symptom of cough, and high levels of CRP should be recognized as signs of prolonged AC. It is important to confirm the diagnosis of AC by laryngoscopic examination, which also help to avoid airway intervention.

Current views and advances on Paediatric Virology: An update for paediatric trainees

Paediatric Virology is a bold new scientific field, which combines Paediatrics with Virology, Epidemiology, Molecular Medicine, Evidence-based Medicine, Clinical Governance, Quality Improvement, Pharmacology and Immunology. The Workshop on Paediatric Virology, which took place on Saturday October 10, 2015 in Athens, Greece, provided an overview of recent views and advances on viral infections occurring in neonates and children. It was included in the official programme of the 20th World Congress on Advances in Oncology and the 18th International Symposium on Molecular Medicine, which attracted over 500 delegates from the five continents. During the Workshop, the topics covered included the challenges of vaccine implementation against human papillomaviruses in countries under financial crisis, strategies for eradicating poliomyelitis and its 60th vaccine anniversary, as well as the debate on the association between autism and vaccination against measles, mumps and rubella. Among the non-vaccine related topics, emphasis was given to viral infections in prematurely born infants and their long-term outcomes, new paediatric intensive care management options for bronchiolitis related to respiratory syncytial virus, the clinical implications of hepatitis B virus and cytomegalovirus genotyping, the Ebola virus threat and preparedness in Paediatric Emergency Departments, oral, oropharynx, laryngeal, nasal and ocular viral infections and Merkel cell polyomavirus as a novel emerging virus of infancy and childhood. In this review, we provide selected presentations and reports discussed at the Workshop.

Quantitative peripheral blood perturbations of γδ T cells in human disease and their clinical implications

Human γδ T cells, which play innate and adaptive, protective as well as destructive, roles in the immune response, were discovered in 1986, but the clinical significance of alterations of the levels of these cells in the peripheral blood in human diseases has not been comprehensively reviewed. Here, we review patterns of easily measurable changes of this subset of T cells in peripheral blood from relevant publications in PubMed and their correlations with specific disease categories, specific diagnoses within disease categories, and prognostic outcomes. These collective data suggest that enumeration of γδ T cells and their subsets in the peripheral blood of patients could be a useful tool to evaluate diagnosis and prognosis in the clinical setting.

Immunophenotypic profile in acute infectious mononucleosis mimicking malignant lymphoproliferative disorder: a case report and review of literature

Infectious mononucleosis is characterized by an intensive lymphoproliferation with atypical forms which sometimes resemble with acute leukemia or malignant lymphoproliferative diseases. Flow cytometric analysis of lymphocytes shows a typical phenotype but unawareness of it may lead to misdiagnosis of malignant lymphoproliferative diseases. Herewith we present an immunophenotypic profile in a case of acute infectious mononucleosis and review of literature.

A practical approach to the flow cytometric detection and diagnosis of T-cell lymphoproliferative disorders

The flow cytometric analysis of T-cell malignancies is difficult due to the heterogeneity of T-cells and the lack of convenient methods to detect T-cell clonality. Neoplastic T-cells are most often detected by their altered level of surface antigen expression, and detection requires an extensive knowledge of the phenotype of normal T-lymphocytes. This review focuses on the methods to distinguish malignant T-cells from their normal counterparts and the phenotypic features of the T-cell lymphoproliferative disorders.

CD7(-) T cells are late memory cells generated from CD7(+) T cells

CD7(-) T cells constitute a distinct subset within the CD4(+) and CD8(+) T cell populations; their developmental and functional relationship to the majority of CD7(+) T cells, however, remained so far unresolved. We here elucidate that CD7(-) cells represent aging T cells in late memory cell development characterized by a high activation threshold, low effector capacities, and high sensitivity to activation-induced cell death (AICD). In this regard, CD7(-) T cells highly express killer cell lectin-like receptor G1 (KLRG-1), harbor telomeres of shorter lengths, a decreased telomerase expression per cell, and less amounts of T cell receptor rearrangement excision circles (TRECs) compared to CD7(+) cells. CD7(-) T cells are generated in vitro from naive CD7(+) T cells upon repetitive TCR/CD28 engagement, a process that is unidirectional and requires multiple cell divisions. Consequently, clonal expansions of CD7(-) T cells in vivo are less frequent than of CD7(+) T cells, the former can be traced back to those of CD7(+) T cells.

2006 Bethesda International Consensus recommendations on the flow cytometric immunophenotypic analysis of hematolymphoid neoplasia: medical indications

The clinical indications for diagnostic flow cytometry studies are an evolving consensus, as the knowledge of antigenic definition of hematolymphoid malignancies and the prognostic significance of antigen expression evolves. Additionally the standard of care is not routinely communicated to practicing clinicians and diagnostic services, especially as may relate to new technologies. Accordingly there is often uncertainty on the part of clinicians, payers of medical services, diagnostic physicians and scientists as to the appropriate use of diagnostic flow cytometry. In an attempt to communicate contemporary diagnostic utility of immunophenotypic flow cytometry in the diagnosis and follow-up of patients with hematolymphoid malignancies, the Clinical Cytometry Society organized a two day meeting of international experts in this area to reach a consensus as to this diagnostic tool. This report summarizes the appropriate use of diagnostic flow cytometry as determined by unanimous approval of these experienced practitioners.

Unusual expression of CD94 on CD8+ TCR-alpha beta T cells in infectious mononucleosis

Infectious mononucleosis, caused by primary Epstein-Barr virus (EBV) infection, is usually a benign, self-limited lymphoproliferative disorder. We report a case of a 21-year-old woman who presented with fever, sore throat, severe neutropenia, and absolute lymphocytosis with atypical lymphocytes. In situ hybridization for EBV-encoded small RNA performed on the marrow aspirate clot specimen demonstrated scattered positive cells. EBV serology was compatible with primary infection. Flow cytometry immunophenotypic studies performed on aspirate material revealed a profoundly expanded population of CD8+ T-cell receptor (TCR)-alphabeta T cells with uniform expression of CD94. No evidence of a monoclonal T-cell population was found as assessed by V(beta) use with flow cytometry and by TCR gamma-chain gene rearrangement using a polymerase chain reaction method. Uniform expression of CD94 in an exuberant reactive proliferation of CD8+ TCR-alphabeta T cells in infectious mononucleosis has not been reported previously, and combined with atypical morphology might be misinterpreted as a malignant neoplasm.

Epstein-Barr virus reactivation in a patient treated with anti-thymocyte globulin for severe aplastic anemia

Epstein-Barr virus (EBV) infection and reactivation is an increasing complication in immune deficient patients, particularly after allogeneic hematopoietic stem cell transplantation (HSCT). Therapy with anti-thymocyte globulin (ATG) is associated with higher incidence of EBV-related disease in HSCT patients, but this risk is not documented in patients receiving ATG for severe aplastic anemia (SAA). We describe the case of a patient who developed an EBV infection, with the clinical features of an infectious mononucleosis, after immune suppression with cyclosporine and two courses of ATG for SAA.

Clonally rearranged T-cell receptor beta chain genes in HTLV-I carriers with abnormal, non-flower-like, lymphocytes

BACKGROUND

The diagnosis of Adult T-cell leukemia/lymphoma ATLL subtypes in human T-lymphotropic virus type I (HTLV-I) carriers based in morphology and immunophenotype of lymphocytes can be challenger. We propose that polymerase chain reaction (PCR) amplification of the rearranged TCR gene in HTLV-I healthy carriers would be a convenient method for establishing the nature of the circulating T lymphocytes in asymptomatic HTLV-I carriers, presenting only mild and inconclusive signals of deviation from normality.

METHODS

Using PCR, we analyzed the genetic recombination pattern of the T-cell beta-chain receptor gene (TCR-beta) in order to identify clonal expansion of peripheral blood T lymphocytes in 17 HTLV-I-positive healthy carriers and in nine normal HTLV-I-negative blood donors. To evaluate the performance of PCR in detection of clonality, we also analyzed 18 patients with post-thymic/mature T-cell malignancies presenting circulating abnormal lymphocytes.

RESULTS

Seven of the 17 HTLV-I positive individuals presented circulating abnormal lymphocytes; monoclonal or oligoclonal expansion of T-cells was detected in five of the 17 HTLV-I-positive individuals, all of them presenting abnormal lymphocytes. Clonal expansion was not detected in any of the negative controls or in any of the 12 remaining healthy carriers. All patients in the positive control group tested positive by PCR and Southern blots. Southern blots were negative for all 17 healthy carriers.

CONCLUSIONS

PCR amplification of segments of rearranged TCR-beta is reliable for allowing early detection of small populations of clonal T cells in blood samples from asymptomatic HTLV-I carriers, providing an additional alert in the follow-up of carriers with abnormal circulating lymphocytes.

Inverse relationship between the ratio of ICAM-1 expressing lymphocytes and serum TGF-β1 concentrations in acute rheumatic fever

Autoimmunity in acute rheumatic fever (ARF) is triggered by group-A beta hemolytic streptococci (GAS). Although most of the recent work has focused on the major impact of lymphocytes, the exact immunopathogenesis is still unresolved. Regulation of self-tolerance in response to GAS has been investigated in various animal experiments. This study aimed to associate the ratio of lymphocytes bearing adhesion/costimulatory molecules, Bcl-2/CD95 and serum TGF-beta1 concentrations with clinical stages of ARF. Thirty-five patients were assigned according to the clinical stages. Bcl-2 expression on CD19+ and CD3+ lymphocytes was similar within patient groups and controls. CD62p expression was higher in patients with carditis. The ratio of ICAM-1 bearing lymphocytes was significantly different between patient groups and controls and was increased through acute to remission stages longitudinally. In contrast, a gradual and significant decrease in TGF-beta1 concentrations was observed longitudinally from acute to chronic stages. A positive correlation has been documented between ICAM-1+ lymphocyte ratios and Fas+ cytotoxic T cell ratios supported by a prominent increase in CD95+ T cells. These data draw our attention to the role of ICAM-1, Fas and TGF-beta1 in ARF pathogenesis through the perspective of self-tolerance in a clinical setting.

Chronic natural killer cell lymphocytosis is associated with elevated cytotoxic activity of natural killer cells

The authors describe a 16-year-old girl who has suffered from chronic natural killer cell lymphocytosis (CNKL) for 12 years. From age 4 years, she has shown a persistent lymphadenopathy and lymphocytosis. Clinically, she developed allergic skin involvement, thrombocytopenia, and peripheral polyneuropathy. Annual flow cytometry analyses of lymphocyte subsets revealed persistently elevated NK cell levels (55-75% of the lymphocyte fraction and 0.7-10 x 10(3) NK cells per microliter of blood). Furthermore, IgE serum concentrations were markedly increased. Based on CD16, CD161, and CD94 surface antigen expression, the NK cell population was characterized as mature NK cells. Functional analysis of these cells showed a 2-fold increase of intrinsic cytotoxic activity toward K-562 cells compared with NK cells from healthy controls. The authors present a clinical case of rare CNKL. The patient's NK cells possess significantly increased cytotoxic activity. These findings are discussed in context with elevated IgE concentrations.

Polyclonal B-cell lymphocytosis mimicking malignant lymphoma in a newborn

We describe a 17-day-old newborn with fever and peripheral blood lymphocytosis. The circulating lymphocytes were large with lobulated and nucleolated nuclei. Their immature and uniform appearance raised the possibility of malignant lymphoma in the leukemic phase. Immunophenotypic study, however, showed that the lymphocytes were CD19(+) B cells with expression of both kappa and lambda light chains. Molecular biology study confirmed a polyclonal nature of the immunoglobulin heavy-chain gene. Cytogenetic analysis showed a normal karyotype, and viral cultures and serologic studies yielded negative results. The polyclonal lymphocytosis was self-limiting and disappeared within a month.

Murine CD45+CD86+ cells isolated from para-aortic lymph nodes in an abortion-prone model

The present study aims to address whether the analysis of CD45+CD86+ cells isolated from para-aortic lymph nodes (pLNs) is valuable in assessment of the status of local immunity at the murine feto-maternal interface. CBA/J x DBA/2 mice, virgin CBA/J mice, and CBA/J x BALB/c mice were used as an abortion-prone model (group A), nonpregnant controls (group N), and fertile controls (group F), respectively. The percentage of CD45+CD86+ cells in the CD45+ cell group (CD45+CD86+ percentage for short) and the absolute number of these cells were determined by means of flow cytometry (FCM), using mononuclear cells isolated from pLNs collected 5.5, 9.5, and 13.5 days post-coitum (dpc), respectively, and mononuclear cells isolated from placentas 13.5 dpc. To clarify the identity of these CD86+ cells, FCM was also performed with CD3, CD19, and DX5 as specific markers for murine T-cells, B-cells, and NK cells, respectively. Both resorption rate and absolute number of resorptions were significantly higher in group A (29.3%, 1.8+/-1.0) than in group F (4.8%, 0.3+/-0.5, P<0.001, respectively). Similarly, both cell percentage and absolute number of CD45+CD86+ cells in pLNs collected 13.5 dpc were significantly higher in group A than in group F (27.5+/-14.0% versus 12.3+/-7.1%, and 1362+/-687 versus 615+/-353, P=0.001, respectively). The CD45+CD86+ percentage was around 7.5% in nonpregnant CBA/J mice, similar to the 10.6% in CBA/JxDBA/2 mice 5.5 dpc, but had increased dramatically, to 23.9%, by 9.5 dpc (P<0.001 versus nonpregnant mice and P=0.002 versus CBA/JxDBA/2 mice 5.5 dpc), and remained at a higher level (27.5%) until 13.5 dpc. However, this trend was not observed in group F during pregnancy. The increased CD45+CD86+ percentage at day 9.5 of gestation, when resorption begins, may support the assumption that CD45+CD86+ cells play a role in the course of embryo resorption. Lymphocyte phenotypic analysis in the lymph nodes that drain the pregnant uterus may be helpful to assess the status of local immunity at the feto-maternal interface.