Abstracts (complete list) - Wissenschaft Online

Nadine Voelxen, Sylvia Gutenberger, Hans-Hartmut Peter, Hermann Eibel, Klaus
Warnatz
Defective activation of B cells in persistent polyclonal B cell
lymphocytosis (PPBL)?
Persistent polyclonal B cell lymphocytosis (PPBL) is a disorder which mainly affects
female smokers in their 4.-6. decade. The origin of this polyclonal lymphocytosis of
atypical B cells often associated with a polyclonal rise of serum IgM is not understood.
We therefore examined B cells of 6 PPBL patients (all female, age: 35-63 years)
phenotypically by FACS as well as by activation in vitro.
The characterization of the B cell subpopulations showed a polyclonal expansion of CD27
+IgD+IgM+ memory type B cells up to 88.8% of CD19+ B cells (normal range: 7.8 –
36%) as well as an increased number of CD21low B cells up to 30% of CD19+ B cells
(normal range: 1.1-6.9%). There were no aberrations within the T cell compartment
detectable.
Functional analysis revealed a reduced proliferation especially after stimulation with anti-
CD40, a decreased expression of CD86 on the surface of cells(17.98-70.43% with a
mean of 37,91% compared to 53.54-73.76% with a mean of 62,59% in healthy donor),
as well as enhanced apoptosis revealed by staining for annexin (21.69-55.81% with a
mean of 39,76% versus 5.82-19.68% with a mean of 15,43% in healthy donor),
despite an expansion of these cells in vivo.
Based on our findings we currently investigate early and late signalling events
downstream of CD40 and the B cell receptor in isolated B cells via western blotting and
FACS to identify potential defects in these pathways.