Effect of CD38 on B-cell function and its role in the diagnosis and treatment of B-cell-related diseases

CD38 is a multifunctional receptor and enzyme present on the surface of B lymphocytes, which can induce B lymphocytes proliferation and apoptosis by crosslinking related cytokines to affect the function of B cells, thus affecting immune regulation in humans and promoting tumorigenesis. The level of CD38 expression in B cells has become an important factor in the clinical diagnosis, treatment, and prognosis of malignant tumors and other related diseases. Therefore, studying the relationship between CD38 expression on the surface of B cells and the occurrence of the disease is of great significance for elucidating its association with disease pathogenesis and the clinical targeted therapy. In this paper, we review the effects of CD38 on B-cell activation, proliferation, and differentiation, and elaborate the functional role and mechanism of CD38 expression on B cells. We also summarize the relationship between the level of CD38 expression on the surface of B cells and the diagnosis, treatment, and prognosis of various diseases, as well as the potential use of targeted CD38 treatment for related diseases. This will provide an important theoretical basis for the scientific research and clinical diagnosis and treatment of B-cell-related diseases.

A Cross Sectional Study on T Cells and Subsets in Chronic Lymphocytic Leukemia and their Association with Clinical Phenotype

T cells in B chronic lymphocytic leukaemia (CLL) have been reported to show qualitative and quantitative alterations, thereby regulating the antitumor immune response. We evaluated the absolute count, percentages of T cells and subsets and their association with disease parameters in Indian patients. 45 treatment naïve CLL cases and 10 healthy controls were evaluated for CD3 + Tcells, CD4 + T cells, CD8 + T cells percentage by flowcytometry. The absolute counts were obtained by multiplication with absolute lymphocyte counts obtained on cell counter. The clinical characteristics (age, sex, Rai stage, B symptoms, CD38 expression) were analysed for any association with alteration of these cells (percentages, absolute counts, ratio with monoclonal B cell count) and CD4: CD8 ratio. The mean absolute count of CD3 + T cell, CD4 + T cell and CD8 + T cells was significantly higher (p < 0.05) in CLL patients as compared to healthy controls. CD4:CD8 ratio was variable (normal, increased and decreased). The mean CD8 + T cells count was higher in advanced disease stage, and CD38 positive cases (p > 0.05). Younger CLL patients (< 55 years) had greater increase in CD8 + T cells (p > 0.05). Significant alterations in T cells and their subsets were observed in CLL. A trend towards advanced stage, CD38 expression, presentation an early age was seen with increase in CD8 + T cell counts.

STUDY THE EFFECTS OF IONIZING RADIATION ON THE LEVEL OF CHROMOSOME INSTABILITY IN HUMAN SOMATIC CELLS DURING THE DEVELOPMENT OF TUMOR-INDUCED BYSTANDER EFFECT

OBJECTIVE

to determine the impact of the irradiated in vitro blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) on the level of chromosomal instability in peripheral blood lymphocytes (PBL) from healthy persons during the development of tumor-induced bystander effect.

MATERIALS AND METHODS

Separate and joint cultivation of PBL from healthy persons (cells-bystanders) together withblood cells from CLL patients irradiated in vitro at the G0 stage of the mitotic cycle by γ-quanta 137Cs in a dose of0.5 Gy 137Cs (cells-inductors) was used. For joint cultivation our own model system for co-cultivation of PBL fromindividuals of different sex, designed by us to investigate the bystander effects at the cytogenetic level was used.Traditional cytogenetic analysis of uniformly painted chromosomes with group karyotyping was performed. The frequency of chromosome aberrations in cells-inductors and cells-bystanders as the markers of chromosome instability were determined.

RESULTS

Found that at co-cultivation of PBL from healthy individuals with irradiated blood cells from CLL patientsthe middle group frequency of chromosome aberrations in the bystander cells (5.18 ± 0.51 per 100 metaphases,p < 0.001) was statistically significant higher than its background level determined at a separate cultivaton (1.52± 0.30 per 100 metaphases), and at co-cultivation with non-irradiated blood cells from CLL patients (3.31 ± 0.50 per100 metaphases, p < 0.01).

CONCLUSIONS

Co-cultivation of in vitro irradiated blood cells from CLL patients with PBL from healthy persons leadsto an increase in the level of chromosome instability in the bystander cells due to synergism between tumor-inducedand radiation-induced bystander effects.

Disease Flare During Temporary Interruption of Ibrutinib Therapy in Patients with Chronic Lymphocytic Leukemia

BACKGROUND

Approximately 25% of patients with chronic lymphocytic leukemia (CLL) experience a flare of disease following ibrutinib discontinuation. A critical question is whether this phenomenon may also occur when ibrutinib is temporarily held. This study aimed to determine the frequency and characteristics of disease flares in this setting and assess risk factors and clinical outcomes.

MATERIALS AND METHODS

We identified all patients with CLL seen at Mayo Clinic between October 2012 and March 2019 who received ibrutinib. Temporary interruptions in treatment and associated clinical findings were ascertained.

RESULTS

Among the 372 patients identified, 143 (38%) had at least one temporary interruption (median 1 hold, range 1-7 holds) in treatment. The median duration of interruption was 8 days (range 1-59 days) and the most common indication was periprocedural. Among the 143 patients with ≥1 hold, an associated disease flare was seen in 35 (25%) patients: mild (constitutional symptoms only) in 21 patients and severe (constitutional symptoms with exam/radiographic findings or laboratory changes) in 14 patients. Disease flare resolved with resuming ibrutinib in all patients. Predictive factors of disease flare included progressive disease at time of hold and ≥ 24 months of ibrutinib exposure. The occurrence of disease flare with an ibrutinib hold was associated with shorter event-free survival (hazard ratio 2.3; 95% confidence interval 1.3-4.1; p = .007) but not overall survival.

CONCLUSION

Temporary interruptions in ibrutinib treatment of patients with CLL are common, and one quarter of patients who held ibrutinib in this study experienced a disease flare. Resolution with resuming ibrutinib underscores the importance of awareness of this phenomenon for optimal management.

IMPLICATIONS FOR PRACTICE

Ibrutinib is a very effective treatment for chronic lymphocytic leukemia (CLL) but needs to be taken continuously. Side effects, such as increased bleeding risk with procedures, require temporary interruptions in this continuous treatment. Rapid CLL progression following ibrutinib discontinuation has been increasingly recognized. This study demonstrates that similar flares in disease signs or symptoms may occur during ibrutinib holds as well. Importantly, management with restarting ibrutinib led to quick clinical improvement. Awareness of this phenomenon among clinicians is critical to avoid associated patient morbidity and premature cessation of effective treatment with ibrutinib if the flare is misidentified as true progression of disease.

The relationship between oxidative stress and cytogenetic abnormalities in B-cell chronic lymphocytic leukemia

BACKGROUND

Prospective data on the value of oxidative stress in the pathogenesis of B-CLL are limited, and data on the relationship between oxidative stress and the presence of cytogenetic abnormalities (CA) in this pathology are almost absent. In the present study, we evaluated the serum levels of oxidative stress biomarkers [conjugated dienes (CD), malondialdehyde (MDA), and nitrite levels] and antioxidant biomarkers [ceruloplasmin (CP) level and glutathione peroxidase (GPx) activity] in B-CLL and investigated the relationship between these biomarkers and the presence of CA.

MATERIAL AND METHODS

A total of 64 B-CLL patients were grouped with respect to the Rai stages of the disease, then to the mutated/unmutated status of IGHV genes as well as to the presence/absence of CA. The type and frequency of CA in the B-CLL cells were determined by fluorescence in situ hybridization. Control group included 30 healthy volunteers. The CD, MDA, and nitrite levels as well as the GPx activity were evaluated spectrophotometrically; the CP level was evaluated turbidimetrically.

RESULTS

Compared to control, the B-CLL patients had increased CD, MDA, and nitrite levels as well as increased CP level and decreased GPx activity, which was observed at all Rai stages of the disease. CA were identified in 47 patients: del(13q14.3) as a single CA occurred in 18 patients, del(11q22.3) in 5 patients, del(17p13.1) in 4 patients, tri 12 in 5 patients, and multiple CA occurred in 15 patients. Compared to patients without CA, isolated del(17p13.1) was associated with higher CD and MDA levels while multiple CA with elevated CD levels only. The nitrite and CP levels and the activity of GPx in patients with CA were close to those in patients with normal FISH. The odds of harboring CA increased by a factor of 1.88 (p = 0.004) for every one unit increase in serum CD level (μmol/L), as assessed by binomial logistic regression.

CONCLUSION

The results indicate that B-CLL patients experience increased oxidative stress and the relative deficiency of the antioxidant defense system. Increased CD level was independently associated with greater likelihood of harboring CA.

The applications of anti-CD20 antibodies to treat various B cells disorders

B-lymphocyte antigen CD20 (called CD20) is known as an activated-glycosylated phosphoprotein which is expressed on the surface of all B-cells. CD20 is involved in the regulation of trans-membrane Ca²⁺ conductance and also play critical roles in cell-cycle progression during human B cell proliferation and activation. The appearance of monoclonal antibody (mAb) technology provided an effective field for targeted therapy in treatment of a variety of diseases such as cancer, and autoimmune diseases. Anti-CD20 is one of important antibodies which could be employed in treatment of several diseases. Increasing evidences revealed that efficacy of different anti-CD20 antibodies is implicated by their function. Hence, evaluation of anti-CD20 antibodies function could provide and introduce new anti-CD20 based therapies. In the present study, we summarized several applications of anti-CD20 antibodies in various immune related disorders including B-CLL (B-cell chronic lymphocytic leukemia), rheumatoid arthritis (RA), multiple sclerosis (MS) and melanoma.

Albumin-to-Fibrinogen Ratio as an Independent Prognostic Parameter in Untreated Chronic Lymphocytic Leukemia: A Retrospective Study of 191 Cases

PURPOSE

Chronic lymphocytic leukemia (CLL) is one of the most frequent type of B-cell chronic lymphoproliferative disorders and chronic inflammation takes part in the development of CLL. However, there has been no valid immune biomarker to predict the prognosis of untreated CLL patients.

Materials and Methods

In this retrospective study, we analyzed the clinical correlations and prognostic value of albumin-to-fibrinogen ratio (AFR) detected at diagnosis in 191 CLL patients.

RESULTS

The cut-off value of AFR was 9.7 calculated by X-tile. Patients who were more than 65 years old were often accompanied by low level of AFR (p < 0.001). Survival analysis showed that patients with low level of AFR had shorter overall survival (OS) than patients with high level of AFR (p < 0.001). Multivariate analysis illustrated that AFR had a negative impact on OS (p=0.003) and was independent of parameters involved in CLL international prognostic index and other prognostic markers such as CD38 and ZAP-70.

CONCLUSION

These data provide a comprehensive view of AFR and shows that AFR at diagnosis is an adverse prognostic factor in untreated CLL patients.

Insect Bite-Like Reaction with Bullous Lesions Mimicking Bullous Pemphigoid in a Patient with Chronic Lymphocytic Leukemia

Patients with chronic lymphocytic leukemia (CLL) rarely exhibit an exaggerated insect bite-like reaction without a history of an arthropod bite. We report a case of an insect bite-like reaction in a 74-year old man with CLL. The patient presented with a 2-year history of recurrent itchy erythematous patches and blisters on the whole body. He had been diagnosed with CLL 2 years ago, and the skin lesions developed 1 month after remission. The result of a skin biopsy was consistent with insect bite. Immunohistochemical staining of the infiltrated cells showed positive reactions for CD3, CD5 and negative for CD20, CD23. Direct and indirect immunofluorescence revealed negative results. The patient was treated with oral prednisolone and dapsone, under the diagnosis of CLL-associated insect bite-like reaction, and showed marked improvement. Dermatologist should be aware of insect bite-like reaction associated with CLL as a distinct disease entity that is similar to insect bite or bullous pemphigoid.

The potential of venetoclax (ABT-199) in chronic lymphocytic leukemia

Venetoclax (VEN, ABT-199/GDC-0199) is an orally bioavailable BH3-mimetic that specifically inhibits the anti-apoptotic B-cell lymphoma/leukemia 2 (BCL2) protein. Although BCL2 overexpression is not genetically driven in chronic lymphocytic leukemia (CLL), it is nearly universal and represents a highly important and prevalent mechanism of apoptosis evasion, making it an attractive therapeutic target. This review summarizes the role of BCL2 in CLL pathogenesis, the development path targeting its inhibition prior to VEN, and the preclinical and clinical data regarding the effectiveness and safety of VEN. We further strive to contextualize VEN in the current CLL treatment landscape and discuss potential mechanisms of resistance.

The prognostic significance of surface dipeptidylpeptidase IV (CD26) expression in B-cell chronic lymphocytic leukemia

A number of factors related to B-cell chronic lymphocytic leukemia (B-CLL) patients' prognosis have been identified. However, still some factors better reflecting disease activity in individual cases are explored. The study aimed to evaluate prognostic significance of dipeptidylpeptidase IV/CD26 expression on B-CLL cells and its relationship with other well established prognostic factors. The study included 94 patients with newly diagnosed B-CLL and involved analysis of clinical, laboratory, flow-cytometry and cytogenetic data. Detailed analysis showed that CD26 expression on B-CLL cells correlates with Rai's clinical stage of the disease at diagnosis (p=0.034), β2-microglobulin concentration (p=0.012), lactic acid dehydrogenase activity (p=0.045) and absolute lymphocytes' count (p=0.027) in the blood. The multivariate analysis revealed that time to treatment (TTT) was significantly influenced by Rai clinical stage, LDH activity in blood and CD26 expression on B-CLL cell's. Moreover, in the multivariate analysis restricted to the group of patients with documented cytogenetic risk (n=36) CD26 expression, Rai clinical stage and cytogenetic profile remained their independent impact on TTT. The results of our study indicate that the CD26 expression should be incorporated in B-CLL patients risk assessment along with well known prognostic factors, since it seems to have a relationship with the tumor mass and influences TTT.

Humanized mouse G6 anti-idiotypic monoclonal antibody has therapeutic potential against IGHV1-69 germline gene-based B-CLL

In 10-20% of the cases of chronic lymphocytic leukemia of B-cell phenotype (B-CLL), the IGHV1-69 germline is utilized as VH gene of the B cell receptor (BCR). Mouse G6 (MuG6) is an anti-idiotypic monoclonal antibody discovered in a screen against rheumatoid factors (RFs) that binds with high affinity to an idiotope expressed on the 51p1 alleles of IGHV1-69 germline gene encoded antibodies (G6-id(+)). The finding that unmutated IGHV1-69 encoded BCRs are frequently expressed on B-CLL cells provides an opportunity for anti-idiotype monoclonal antibody immunotherapy. In this study, we first showed that MuG6 can deplete B cells encoding IGHV1-69 BCRs using a novel humanized GTL mouse model. Next, we humanized MuG6 and demonstrated that the humanized antibodies (HuG6s), especially HuG6.3, displayed ∼2-fold higher binding affinity for G6-id(+) antibody compared to the parental MuG6. Additional studies showed that HuG6.3 was able to kill G6-id(+) BCR expressing cells and patient B-CLL cells through antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Finally, both MuG6 and HuG6.3 mediate in vivo depletion of B-CLL cells in NSG mice. These data suggest that HuG6.3 may provide a new precision medicine to selectively kill IGHV1-69-encoding G6-id(+) B-CLL cells.

Polymorphisms in genes of the BAFF/APRIL system may constitute risk factors of B-CLL--a preliminary study on a Polish population

The association of single-nucleotide polymorphisms (SNPs) of B-cell activating factor (BAFF)/a proliferation-inducing ligand (APRIL) system with B-cell chronic lymphocytic leukemia (B-CLL) have been suggested, therefore, we investigated 20 SNPs of BAFF, APRIL, BAFF-R, transmembrane activator and calcium modulator and cyclophilin-ligand interactor (TACI), B-cell maturation antigen (BCMA) genes and the risk and outcome of B-CLL in 187 patients and 296 healthy subjects as well as ligand-receptor gene × gene interactions. Although the obtained P-values for all 20 SNPs did not reach statistical significance for this study (α = 0.003), the high value of the global chi-squared statistic (χ(2) df = 38  = 52.65; P = 0.0586), and obtained values of odds ratio indicate that rs9514828 (BAFF), rs3803800 (APRIL) and rs4985726 (TACI) may be associated with the risk of B-CLL. We observed that the B-CLL patients with the genotype rs9514828CT/rs11570136AA were diagnosed with the disease 12 years later than the whole group of patients in this study.

Targeted PI3Kδ inhibition by the small molecule idelalisib as a novel therapy in indolent non-Hodgkin lymphoma

Indolent Non-Hodgkin Lymphomas (iNHL) are typically B-cell malignancies and are incurable with current standard approaches. Thus, there is a demand for novel agents specific for this group of disorders. In a phase II study published by Gopal et al. in the New England Journal of Medicine, idelalisib, a small molecule inhibitor of PI3Kδ that was FDA approved in July of 2014, was shown to be effective when combined with rituximab in patients who cannot tolerate chemotherapy and as last line therapy in patients with iNHL refractory to 2 prior systemic therapies. Idelalisib demonstrated tolerable diarrhea, fatigue, nausea, pyrexia, and cough. While this novel agent is a clinically significant addition to the iNHL arsenal, further research is needed to determine its most appropriate place in iNHL therapy.

Elevated expression of pleiotrophin in lymphocytic leukemia CD19+ B cells

Pleiotrophin (PTN) has been demonstrated to be strongly expressed in many fetal tissues, but seldom in healthy adult tissues. While PTN has been reported to be expressed in many types of tumors as well as at high serum concentrations in patients with many types of cancer, to date, there has been no report that PTN is expressed in leukemia, especially in lymphocytic leukemia. We isolated the CD19(+) subset of B cells from peripheral blood from healthy adults, B-cell acute lymphocytic leukemia (B-ALL) patients, and B-cell chronic lymphocytic leukemia (B-CLL) patients and examined these cells for PTN mRNA and protein expression. We used immunocytochemistry, western blotting, and enzyme-linked immunosorbent assay to show that PTN protein is highly expressed in CD19(+) B cells from B-ALL and B-CLL patients, but barely expressed in B cells from healthy adults. We also examined PTN expression at the nucleic acid level using reverse transcription polymerase chain reaction (RT-PCR) and northern blotting and detected a high levels of PTN transcripts in the CD19(+) B cells from both groups of leukemia patients, but very few in the CD19(+) B cells from the healthy controls. Interestingly, the quantity of the PTN transcripts correlated with the severity of disease. Moreover, suppression of PTN activity with an anti-PTN antibody promoted apoptosis of cells from leukemia patients and cell lines SMS-SB and JVM-2. This effect of the anti-PTN antibody suggests that PTN may be a new target for the treatment of lymphocytic leukemia.

Granulysin induces apoptotic cell death and cleavage of the autophagy regulator Atg5 in human hematological tumors

Granulysin is a protein present in the granules of human CTL and NK cells, with cytolytic activity against microbes and tumors. Previous work demonstrated that granulysin caused cell death through mitochondrial damage with release of AIF and cytochrome c. However, the molecular mechanism and, especially, the type of cell death were still not well defined. In the present work we show that granulysin-induced cell death is apoptotic, with phosphatidylserine exposure preceding membrane breakdown and with caspase 3 activation. Granulysin-induced apoptosis is prevented in Jurkat cells over-expressing Bcl-xL or Bcl2, or lacking Bak and Bax or Bim expression, suggesting a central role of the mitochondrial apoptotic pathway. This apoptotic process is initiated by intracellular Ca(2+) increase and mitochondrial ROS generation. We have tested granulysin against other hematological tumor cells such as multiple myeloma cell lines, and cells from B cell chronic lymphocytic leukemia (B-CLL) patients, finding different degrees of sensitivity. We also show that granulysin induces the cleavage of Atg5 in the complex formed with Atg12, without affecting autophagy. In conclusion, granulysin induces apoptosis on hematological tumor cells and on cells from B-CLL patients, opening the door to research on its use as a new anti-tumoral treatment.

Morphology and expression status investigations of specific surface markers on B-cell chronic lymphocytic leukemia cells

The morphology of cells and expression status of specific surface markers [cluster of differentiation (CD)], such as CD5, CD19, CD20, CD38, and CD45, have long been considered as the essential indicators for the diagnosis and prognosis of B-cell chronic lymphocytic leukemia (B-CLL). Clinically, it is difficult to simultaneously obtain cell morphology and distribution of surface markers with flow cytometry, especially for some surrogate markers such as CD38. Here, as an alternative and complementary prognostic method, fluorescence microscopy and image processing method are introduced to directly visualize the cells from patients and to quantitatively determine the expression status of surface markers. In this study, the morphological parameters of B-CLL cells were measured to establish the correlation between the cellular morphology and the surface marker expression. It was clear that the CD38+ and CD38- B-CLL cells from the same CD38+ patients had hardly any size differences; however, an increase in perimeter was observed for CD38- patients. Moreover, the expression level of the receptors on the cell was independent of the cell size. There was no evidence showing that the expression intensities of CD19 and CD38 were related to each other for the CD38+ B-CLL cells. On the same cells, CD5 was more selectively expressed on the cell membrane; however, the expression patterns suggested that the cell membrane of CD38- B-CLL cells contained the least expression level of CD19.

Regulation of the MIR155 host gene in physiological and pathological processes

MicroRNAs (miRNAs), a family of small nonprotein-coding RNAs, play a critical role in posttranscriptional gene regulation by acting as adaptors for the miRNA-induced silencing complex to inhibit gene expression by targeting mRNAs for translational repression and/or cleavage. miR-155-5p and miR-155-3p are processed from the B-cell Integration Cluster (BIC) gene (now designated, MIR155 host gene or MIR155HG). MiR-155-5p is highly expressed in both activated B- and T-cells and in monocytes/macrophages. MiR-155-5p is one of the best characterized miRNAs and recent data indicate that miR-155-5p plays a critical role in various physiological and pathological processes such as hematopoietic lineage differentiation, immunity, inflammation, viral infections, cancer, cardiovascular disease, and Down syndrome. In this review we summarize the mechanisms by which MIR155HG expression can be regulated. Given that the pathologies mediated by miR-155-5p result from the over-expression of this miRNA it may be possible to therapeutically attenuate miR-155-5p levels in the treatment of several pathological processes.

The spectrum of use of rituximab in chronic lymphocytic leukemia

The monoclonal chimeric anti-CD20 antibody, rituximab, has considerably improved therapeutic outcome in B-cell chronic lymphocytic leukemia. Rituximab has limited clinical activity when used as a single agent. The combination of the monoclonal antibody with fludarabine-based regimens clearly demonstrated, in Phase II and randomized trials, an increase in clinical efficacy in previously untreated and pretreated patients. Furthermore the addition of rituximab enabled the eradication of minimal residual disease, which is correlated with the prognosis in a high proportion of patients. Although the combination of rituximab with fludarabine-based regimens increased myelosuppression and immunosuppression, incidence of infections did not increase. The benefit of adding rituximab to other purine analogs or other chemotherapeutic combination regimens has also been explored. Moreover there could be a role for achieving better quality of responses with the combination of different monoclonal antibodies, considering that they target different antigens and exert different mechanism of action. Although the role of rituximab as maintenance therapy in low grade non-Hodgkin's lymphomas has been determined, the benefit and optimal schedule in chronic lymphocytic leukemia are still under investigation. This review brings together knowledge of the pharmacokinetics, mechanism of action and clinical use of rituximab in chronic lymphocytic leukemia.

Analysis of HLA-G gene expression in B-lymphocytes from chronic lymphocytic leukemia patients

BACKGROUND

The human leukocyte antigen G (HLA-G) molecule exhibits limited tissue distribution, low polymorphism and alternative splicings that generate seven HLA-G isoforms. HLA-G exerts multiple immunoregulatory functions. Recent studies indicate an ectopic up-regulation in tumor cells that may favor their escape from anti-tumor immune responses. This study it is an effort to clarify the presence of HLA-G in B-cell chronic lymphocytic leukemia (B-CLL) patients.

METHODS

HLA-G mRNA expression was studied in a pilot study in circulating B-CLL and also healthy controls by reverse transcription (RT)-PCR using a set of pan-HLA-G primers.

RESULTS

RT-PCR was performed on B-cells from 74 B-CLL patients and 12 healthy controls. The data showed HLA-G gene expression in 20% of the B-CLL patients. No expression of HLA-G could be detected in the healthy control group.

CONCLUSION

These data suggest that HLA-G is expressed at the gene level in B cells from B-CLL patients but not in B cells from healthy controls. Further study is required to clarify the role of HLA-G as a regulatory factor that could affect immune response in B-CLL patients.