Adhesion molecules expression in CLL: Potential impact on clinical and hematological parameters

Siglec-6 as a therapeutic target for cell migration and adhesion in chronic lymphocytic leukemia

Siglec-6 is a lectin receptor with restricted expression in the placenta, mast cells and memory B-cells. Although Siglec-6 is expressed in patients with chronic lymphocytic leukemia (CLL), its pathophysiological role has not been elucidated. We describe here a role for Siglec-6 in migration and adhesion of CLL B cells to CLL- bone marrow stromal cells (BMSCs) in vitro and compromised migration to bone marrow and spleen in vivo. Mass spectrometry analysis revealed interaction of Siglec-6 with DOCK8, a guanine nucleotide exchange factor. Stimulation of MEC1-002 CLL cells with a Siglec-6 ligand, sTn, results in Cdc42 activation, WASP protein recruitment and F-actin polymerization, which are all associated with cell migration. Therapeutically, a Siglec-6/CD3-bispecific T-cell-recruiting antibody (T-biAb) improves overall survival in an immunocompetent mouse model and eliminates CLL cells in a patient derived xenograft model. Our findings thus reveal a migratory role for Siglec-6 in CLL, which can be therapeutically targeted using a Siglec-6 specific T-biAb.

Evaluation of immunophenotypic markers and clinico-hematological profile in chronic lymphocytic leukemia: implications for prognosis

Objective

Chronic lymphocytic leukemia (CLL) is an adult leukemia presented with clonal accumulation of lymphocytes. Immunophenotypic changes can be effective in predicting clinical course, the survival of patients, and determining first-line treatment. This is a study of the association between immunophenotypic markers with complete blood cell count (CBC) values and clinical parameters.

Results

Peripheral blood samples were collected from 35 newly diagnosed CLL patients. The expression of immunophenotypic markers and CBC were evaluated. Platelet counts and hemoglobin concentration had a significant, inverse association with Rai staging, modified Rai staging, Binet staging systems (all p < 0.001 in both parameters), and splenomegaly (p = 0.001 and 0.007, respectively). The platelet/lymphocyte ratio (PLR) had a significant, inverse association with Rai staging (p = 0.014), modified Rai staging (p = 0.024), Binet staging systems (p = 0.027), and splenomegaly (p = 0.033). However, CD38, CD25, and double-positive CD56/CD117 expression, group 3 of innate lymphocyte cells (ILC3s), had no significant association with clinical parameters. In regression analysis, that ILC3s has an inverse correlation with neutrophil/lymphocyte ratio (r = −0.340, p = 0.046). Given that there is an inverse association between PLR and advanced clinical stages, it seems that PLR may have prognostic value in CLL.

CD markers variations in chronic lymphocytic leukemia: New insights into prognosis

Chronic lymphocytic leukemia (CLL) is one of the most commonly occurring adult leukemias that is associated with clonal accumulation of mature apoptosis-resistant B-cells in bone marrow, peripheral blood, and specific tissues. Different pathogenesis factors can contribute to the aggression of the clinical course in this disease. Cytogenetic abnormalities and surface biomarkers of neoplastic CLL cells can be effective in the outcome of CLL, and the examination of changing CD markers expressions in the progression of CLL can be related to the prognosis of this disease. Changing expression levels of CD markers on lymphocytes and other cells in CLL patients can play a role in the aggressive clinical outcomes such as organomegaly, immunodeficiency, and advanced disease stages through their interaction with CLL microenvironment. Given the involvement of CD markers in the pathogenesis of CLL, it can be stated that recognizing the expression changes of CD markers in the cells involved in CLL can be a proper approach to evaluate prognosis among these patients.

Oral cholera vaccination promotes homing of IgA+ memory B cells to the large intestine and the respiratory tract

Oral cholera vaccination is used to induce immune responses in the intestines to protect against cholera infection. However, oral vaccination may also affect immune responses in other mucosal tissues. To study this, tissue-specific homing potential and kinetics of B-cell responses were characterized after oral cholera vaccination. Healthy adult volunteers received two doses of Dukoral® and blood, saliva, nasal wash, and fecal samples were collected over time to detect vaccine-specific antibodies. Additionally, homing potential of lymphocytes to small intestine, colon, airways, skin, and periphery was measured by expression of Integrin β1 and β7, CCR9, CCR10, CCR7, and CLA. After vaccination, antibody responses to cholera toxin B (CTB) and Dukoral® were detected in serum and nasal wash. CTB-specific memory B cells in peripheral blood and tissue homing profiles of memory B cells peaked at day 18. IgA⁺ memory B cells expressed markers that enable homing to the airways and colon, while IgA^- memory B cells primarily expressed small-intestine-homing markers. These data show that oral cholera vaccination has a differential effect on immune responses in various mucosal sites, including the respiratory tract.