Tracing B cell development in human germinal centres by molecular analysis of single cells picked from histological sections.

B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease

“…Although in classical GCs clonal relatedness between the Ki67 ϩ centroblasts and the Ki67 Ϫ centrocytes has been observed, 28 we found no clonal relatedness between Ki67 ϩ and Ki67 Ϫ cells with mutated rearrangements in 3 PTGCs analyzed. This is probably because most Ki67 Ϫ B cells represent naive mantle zone B cells and a major fraction of Ki67 Ϫ B cells with mutated V-region genes are memory B cells, hampering the identification of perhaps rare, but nevertheless existing, resting B cells belonging to clones defined by mutated Ki67 ϩ cells.…”

“…29 In 3 human lymph node GCs studied by micromanipulation and single-cell immunoglobulin gene PCR, only occasional unmutated GC B cells were observed. 28,30 One may speculate that the apparently increased frequency of GC founder cells is related to the disorganized structure of a PTGC, preventing some GC cells from receiving the appropriate signals to initiate somatic hypermutation and to undergo massive clonal expansion.…”

Lineage tree analysis of immunoglobulin variable-region gene mutations in autoimmune diseases: Chronic activation, normal selection

“…Mutational lineage trees of B cell clones from patients with MG, RA, SS, and MS [6,[16][17][18][19][20][21], and from normal human GCs [25][26], were created from published and unpublished IgV sequence data; we also used published lineage trees [12,10,14]. Each dataset contained IGV sequences from different IGV groups and patients (Table 1).…”

“…Sample trees are shown in Tree measurements of AI data sets were compared to those of trees from normal human samples of both Peripheral blood lymphocytes (PBL [8]) and germinal centers (GC [6,26]), revealing large variability between the data of the different groups, including between data sets of the same disease ( Figure 2). Despite this variability, in all but two sets [10,14] the trees were larger than in the normal control data sets, whether we look at the number of leaves L, i.e.…”

“…As an additional verification, we performed R:S mutation analysis [23][24][25][26][27][28][29] on our data, showing that the AI clones underwent positive antigen-mediated selection, at least as strong as that in normal clones (Supplementary Table 3). R:S analysis is known to give many false positive indications of selection [30][31].…”