Ongoing Receptor Editing in Peripheral Blood B Cells of EOPA-JIA Patients

[Guest guest]

Title:

Ongoing Receptor Editing in Peripheral Blood B Cells of EOPA-JIA Patients

Category:

12. Pediatric rheumatology — pathogenesis and genetics

Author(s):

Hermann J. Girschick, Henner Morbach, Claudius Faber. University of Würzburg, Würzburg, Germany

Presentation Number:

765

Poster Board Number:

67

Purpose: Since antinuclear antibodies are diagnostic in Early-onset pauciarticular arthritis, one can assume a participation of B cells.

Methods: Using flow cytometry we compared the distribution of B cell subpopulations in the peripheral blood of EOPA patients (n=21) and age matched controls (n=15). By single cell sorting and PCR we analysed the rearrangement of the Vkappa immunoglobulin locus and the expression of recombination activating genes 1 and 2 (RAG+) in individual B cells. RAG expression is normally found in developing B cells in the bone marrow enabling V(D)J-recombination of immunoglobulin genes.

Results: Peripheral blood B cells of EOPA contained a significantly higher number of naïve IgD+ B cells compared to healthy controls (77.3 v. 71.1%). The percentage of auto/polyreactive CD5+ B cells (B1) tended to be higher in EOPA (55.1 v. 45.8%). There was no difference in the distribution of CD27+ memory B cells (16.2 v. 16.5%).

The Vkappa immunoglobulin genes O12, L6 and A27 were rearrangend most frequently. O12 and L6 were used significantly more often in IgD+ EOPA B cells than in healthy controls. Jkappa4 usage was higher in EOPA B cells.

Up to 18% of peripheral blood EOPA B cells expressed RAG 1 and 2. This frequency was higher in IgD+ than in IgD- B cells. There was no difference between CD5+ and CD5- B cells. However, significantly higher frequencies were only found in some EOPA when compared to normals.

conclusions: Increased expression of RAG 1 and 2 in some patients might enable peripheral blood B cells to alter their B cells receptor. Receptor editing in peripheral blood B cells might lead to an uncontrolled change in the immunoglobulin repertoire.

OASIS - Online Abstract Submission and Invitation System™ ©1996-2005, Coe-Truman Technologies, Inc.