Agammaglobulinemia with normal B-cell numbers in a patient lacking Bob1

In B cells, Bob1 is a transcriptional coactivator that confers octamer-dependent specificity to the transcription factors Oct-1 and Oct-2.1 P-FR1 had normal B-cell numbers but disturbed B-cell differentiation, with decreased class-switched memory cells and a relative increase in atypical-memory cells (IgG+ or IgA+ CD27– [Fig 1, D and E]). [...]Bob1 can directly regulate expression of B-cell receptor (BCR) signaling molecules by interacting with octamer motifs in their promoter regions, as described for CD79β.2 Low CD79β may contribute to low BCR and CD79α expression, as shown in B-cell lines.3 Additionally, interaction with Bob1 has been reported to control the stability of Syk.4 Also, BAFF-R expression and CD22 expression were reduced in P-FR1 B cells. [...]activated P-FR1–derived B cells failed to upregulate CD86 (see Fig E3, A in the Online Repository at www.jacionline.org).