Increased regulatory T cells in acute lymphoblastic leukemia patients

Introduction: Regulation in adaptive immune response balances a fine line that prevents instigation of self-damage or fall into unresponsiveness permitting abnormal cell growth. Mechanisms that keep this balance in check include regulatory T cells (Tregs). Tregs consist of a small but heterogeneous population which may be identified by the phenotype, CD3+CD4+CD25+CD127-. Role of Tregs in pathogenesis of cancers is thus far supported by evidence of increased Tregs in various cancers and may contribute to poorer prognosis. Tregs may also be important in acute leukemias. Objective: A review of the literature on Tregs in acute leukemias was conducted and Tregs were determined in B-cell acute lymphoblastic leukemias (ALLs). Results: Studies on Tregs in B-cell ALL are few and controversial. We observed a significantly increased percentage of Tregs (mean ± SD, 9.72 ± 3.79% vs. 7.05 ± 1.74%; P = 0.047) in the bone marrow/peripheral blood of ALL (n = 17) compared to peripheral blood of normal controls (n = 35). A positive trend between Tregs and age (R = 0.474, P = 0.055, n = 17) implicates this factor of poor prognosis in B-cell ALL. Discussion: Tregs in cancer are particularly significant in immunotherapy. The manipulation of the immune system to treat cancer has for a long time ignored regulatory mechanisms inducible or in place. In lymphoma studies tumor-specific mechanisms that are unlike conventional methods in the induction of Tregs have been hypothesized. In addition, tumor-infiltrating Tregs may present different profiles from peripheral blood pictures. Tregs will continue to be dissected to reveal their mysteries and their impact on clinical significance

Expression of killer cell immunoglobulin-like receptors (KIR) in sex-associated malignancies

Introduction: Sex shapes immune response with possible consequence on tumor immune escape. Acute lymphoblastic leukemia (ALL) predominates in males while ovarian cancer (OC) occurs in females. NK cells essential for tumor killing may have male preponderance. Association of sex, NK cell activity and malignancies is unclear. We hypothesize that sex differentially affects KIR expressions in sex-biased cancers. Method: Expression of inhibitory (KIR2DL1-5 and KIR3DL1-3) and activating (KIR2DS1-2 and 4-5 and KIR3DS1) genes in B-, T-cell ALL, OC and normal controls were determined by reverse-transcription polymerase-chain-reaction. Result: All normal males (but not females) expressed the framework genes and generally maintained haplotype A, except KIR3DL1. Normal females expressed more activating KIRs. Frequencies of KIR2DL1, 2DL4 and 2DS2 were significantly reduced among ovarian cancer patients. Sex difference in frequencies of KIR expression was not detected in ALL as majority were undetectable except framework gene KIR3DL2, was more frequent among T-ALL. Conclusion: Cancers may be associated with reduced KIR expression and influence of sex requires investigation