THE CELL-SURFACE ANTIGEN AND DNA CONTENT DISTRIBUTION OF LYMPH-NODES WITH REACTIVE HYPERPLASIA

Few studies have comprehensively examined the expression and distribut ion of cell surface antigens and DNA content in non-neoplastic, reacti ve lymph nodes. We have performed a flow cytometric immunophenotypic a nd DNA content analysis of 64 lymph nodes from 62 patients (23 male; 3 9 female; ages 21 months to 80 years) with typical reactive lymphoid h yperplasia as assessed by histology. CD45, a pan-leukocyte marker, was detected on virtually all cells (99 +/- 4%). AU pan-T-cell-associated antigens studied were expressed within a narrow range of average valu es (54-64%), and no loss of individual T-cell antigens was observed in any case. Intercase variation of fluorescence intensity for each anti gen was minimal. The mean CD4:CD8 ratio was 3.9 +/- 2.6, with only one case (HIV+) showing a marked CD4:CD8 inversion (0.4). The number of c ells coexpressing CD4 and CD8 was very low (3 +/- 3%), consistent with the mature phenotypic nature of the majority of T lymphocytes. B-cell s, as defined by CD19 and CD20 antibodies, accounted for 36 +/- 16% an d 43 +/- 18% of cells analyzed, respectively, and, like the pan-T-cell antigens, displayed minimal intercase variability in antigen expressi on. Cells coexpressing CD20 and CD5 were noted, although their frequen cy could not be calculated accurately. IgD- and IgM-bearing cells were both generally well-defined populations: 24 +/- 10% and 31 +/- 14%, r espectively. On the other hand, IgG- and IgA-bearing cells displayed b road fluorescence intensity, precluding an exact calculation of their frequencies. To avoid counting non-B-cells with nonspecifically bound immunoglobulin, kappa and lambda immunoglobulin Light chains were anal yzed on B-cells exclusively, selected by CD20 or CD19 antibodies. The values for kappa and lambda, expressed as percentages of CD20-positive cells, were 55 +/- 7% and 41 +/- 5%, respectively. Essentially identi cal results were obtained when kappa and lambda were analyzed on CD19- expressing cells. The mean kappa:lambda ratio was the same for CD20 an d CD19-selected cells (1.4 +/- 0.3). CD10 (CALLA) was observed on an a verage of 4 +/- 6% of all cells analyzed. The myeloid-associated antig ens CD13 and CD33 were found on less than 4% of cells. CD14, a monocyt e marker, and natural killer cell-associated markers CD16 and CD56 wer e each detected on a small fraction of cells. The stem cell-associated antigen CD34 was essentially absent (0 +/- 1%). CD11c, CD71, CD23, an d HLA-DR were expressed with variable intensity but did not label disc rete cell subpopulations. Ah cases were found to be diploid by DNA con tent analysis. Proliferative activity, as evidenced by S-phase fractio n determinations, was found to encompass a range of 0.2-14.0%, with a mean value of 3.0 +/- 2.8%. This extensive quantitative and qualitativ e description of the leukocyte surface marker distribution and DNA con tent of reactive lymph nodes should serve well as a reference for stud ies of neoplastic lymphoid processes.