Immunophenotypic characterization of normal peripheral blood B lymphocyte by flow cytometry: reference for diagnosis of chronic B cell leukemia/lymphoma.

To establish reference values of various immunophenotypic markers in B lymphocyte population in healthy Chinese adults and build background information for accurate interpretation of B cell immunophenotyping data in clinical practice, peripheral blood from 41 healthy adults were collected separately into test tubes containing EDTA-K(2) and stored in room temperature no more than 24 hours before analysis. Whole blood lysis technique and multiparameter flow cytometry were applied to immunophenotype B cells gated on CD19/SSC dot-plot. The results showed that CD22, CD20, CD62L, CD40, CD24, CD79b, CD79a, and FMC-7 were almost positive in the circulating B cell population, whereas CD11a, CD80, CD103, CD10, CD40L, CD54, CD95L, CD86, and CD95 were almost negative in the peripheral blood B lymphocytes. CD18, CD44, CD23, CD5, CD11c and CD43 were positive in different B cell subpopulations. 78% of B cells were IgD positive and ratio kappa/lambda was 1.26. The significance of all these markers in the differential diagnosis of lymphoproliferative diseases was discussed. The conclusion is that it is necessary to consider the qualitative and quantitative levels of expression of various markers in normal B cell population in order to accurately interpret the pathological immunophenotypic data in clinical practice. It is also important to note the immunotypic differences of B cells between Chinese and Western populations.