Transitional B cells and CD21low in patients with ataxia-telangiectasia

Methods Blood samples were obtained from 18 AT patients and 15 age-sex-matched controls (C). This study was approved by the Medical Ethic Committee of the Federal University of Sao Paulo. Total numbers of T, B, and NK cells were enumerated from whole blood samples using TruCount Tubes. Peripheral blood mononuclear cells (PBMC) were cryopreserved, thawed and stained with conjugated monoclonal antibodies: antiCD19-PerCP anti-CD3-APCCy7, anti-CD24-PE, antiCD21-APC, anti-CD38-PECy7. Five-color flow cytometric immunophenotyping was performed on a BD LSRFortessa (BD Biosciences), and data were analyzed with FlowJo software (TreeStar, Stanford University, CA). Transitional B cells were characterized as CD3 CD19CD24CD38, and CD21low B cells as CD3 CD19CD21CD38. Statistical analysis was performed with SPSS 20.0 and STATA 12, and a significance threshold of <0.05 was used.