#3276 LUPUS NEPHRITIS: THE INTERPLAY BETWEEN SENESCENT B AND NAÏVE T LYMPHOCYTES

Systemic Lupus Erythematosus (SLE) is characterized by a shift to senescent B cells, namely, switched memory (SM) (CD19+IgD-CD27+) and exhausted-double negative (DN) (CD19+IgD-CD27-) subtypes. The aim of this study was to evaluate the impact of T cell immunity in the distinct B cell - senescent pattern of SLE.

A wide range of senescent and exhaustion related lymphocyte surface molecules, including CD45RA, CCR7, CD31, CD28, CD57, on T cells and CD27 and IgD on B cells, was analyzed by flowcytometry and distinct naïve, active and senescent B and T lymphocyte subtypes were determined in 31 patients with inactive Lupus Nephritis (LP).

Comparison of SM and DN B cells with T cell subpopulations revealed significant correlation of naïve and “unexperienced” CD4 and CD8 compartment with SM and DN B cells. Indeed, the correlation appeared even stronger regarding SM B cells and Recent thymic emigrants (RTE) CD4CD31+ (r=0.575), CD4+ Central Memory (CM) (CD45RA-CCR7+) (r=0.546), CD4CD45RA+CD28+(r=0.556), CD4CD28+CD57- (r=0.621), CD4CD45+CD57- (r=0.544), CD4CD45-CD57- (r=0.65), CD8CD28+CD57- (r=0.596), CD8CD45-CD57- (r=0.556) while weak yet significant was their correlation with CD4 Naïve (CD45RA+CCR7+) (r=0.432), CD8CM(CD45RA-CCR7+) (r=0.474), RTE CD8CD31+ (r=0.461), CD8CD28+CD57+ (r=0.442). Less apparent was this phenomenon between DN B cells and CD4 CM (CD45RA-CCR7+) (r=0.381), CD4CD45RA+CD28+ (r=0.504), RTE CD4CD31+ (r=0.587), CD4CD28+CD57- (r=0.487), CD4CD28+CD57+ (r=0.491), CD4CD45+CD57- (r=0.419), CD4CD45-CD57- (r=0.397), CD8 Naive(CD45RA+CCR7+) (r=0.432), RTE CD8CD31+ (r=0.366), CD8CD28+CD57- (r=0.363), CD8CD28+CD57+ (r=0.483), CD8CD45-CD57- (r=0.444), CD8CD45-CD57+ (r=0.384).

The predominant shift to senescent/exhausted B lymphocytes in SLE and LN may have a direct impact on naïve CD4 and CD8 T lymphocyte subpopulations.