Objectives to study B-cell subsets dynamics in SLE patients receiving rituximab (RTX) therapy with following 6 months observation.
Methods The study included 16 SLE pts (1m/15f) with high (SLEDAI2K>10 - 13 pts.) and moderate (SLEDAI2K<10- 3 pts.) disease activity. Out of them 7 pts with lupus nephritis and 3 pts with neurolupus. RTX was administered to pts who failed to respond to glucocorticoids (GCs) and cytostatics (CTs). B-cells subsets were assessed before RTX administration (month 0), and at month 3 and month 6 of RTX therapy. RTX was administered at 500 to 2000 mg doses depending on disease activity. We investigated the absolute and relative number of CD19+ B cells, the total population of memory B cells (CD19+CD27+), “preswitch” (CD19+IgD+CD27+) and “postswitch” (CD19+IgD-CD27+) memory B cells, naive (CD19+IgD+CD27-) and transitional (CD19+IgD+CD10+CD38++CD27-) B cells, plasmablasts (CD19+CD38+++IgD-CD27+CD20-), short-lived plasma cells (CD19+CD38+), long-lived plasma cells (CD19+CD138+), and double-negative B-cells (CD19+CD27-IgD) were measured. All B cell subsets were analyzed by technique of multicolor flow cytofluorometry using panel of monoclonal antibodies to surface membrane markers of B-lymphocytes.
Results Following initiation of RTX SLE clinical and lab activity indices have decreased in all 16 pts by month 3 and month 6 of follow up (SLEDAI-2K 0 month –Me 15 [11;19], 3 month -Me 7 [3;10], 6 month –Me 5 [4;9], p<0.05), as well as decrease of absolute count CD19 B-cell subpopulation (0 month – Me 0,11 [0,0741; 0,2], 3 month - Me 0,0017 [0; 0,003], 6 month - Me 0,0045 [0,0005; 0,01], p<0.05). B-cell repopulation by 6 month in 11 out of 16 pts was due to “naive” B-cells Me 0,00085 [0; 0,008], double negative Me 0,001 [0; 0,0025] and “postswitch” memory B-cells Me 0,0013 [0,0001; 0,003]. SLE exacerbation by 6 month was documented in 5 pts, in 3 out of them B-cell repopulation occurred. A correlation between baseline high SLE activity before RTX infusions (SLEDAI-2K 5 pts – Me 20 [18;24], 11 pts. Me 12 [8;12]) and SLE exacerbation at 6 month after initiation of RTM therapy (p<0,05, r=0,54) was found.
Conclusions Decrease in clinical and lab SLE activity was documented in all 16 pts by 3 month after one course of RTM therapy. In 3 out of 5 exacerbated pts at 6 month B-cell repopulation was found, but without significant correlation with counts of B-cells subpopulations during the whole follow up period.
Disclosure of Interest None declared