Background: In RA synovitis, ZAP-70 positive B cells seem to correlate with the inflammatory activity and be associated with increased survival. Objectives: To assess ZAP-70 protein expression in PB B cells at baseline and after treatment with rituximab (RTX) in a cohort of RA patients during a 24 months follow-up and to evaluate it as biomarker of clinical response. Methods: Twenty-eight RA patients (mean age 56.8±11.9 years; mean disease duration 12.7±9.6 years) with active disease despite treatment with DMARDs or TNF-α blockers received a first course of Rituximab 1 g i.v. two weeks apart. Disease activity was assessed at baseline and every three months according to the EULAR criteria. Clinical, immunological and laboratory data were included in the set of disease evaluation. Cytofluorimetric analysis of B cell subsets at baseline and 6, 12 and 24 months after treatment was performed using surface markers (CD45, CD3, CD56, CD19, IgD, CD38, CD27, CD5, CD23) and intracellular ZAP-70 (1). Retreatment was performed when DAS increased by 0.6. Results: Patients at baseline had active disease with mean DAS 4.1±1.6, and mean HAQ 1.39±0.94. The percentage of peripheral CD19+ cells decreased from the baseline value of 7,5±4.0% to 3.0±6.4% at T6, 1.8±2.0% at T12 and 2.7±3.8% at T24 (p<0.001). The recovery of B cells in PB was characterized by the appearance of immature cells coupled with a reduction of memory cells as shown by the increasing values of Bm2+Bm2'/eBm5+Bm5 ratio from baseline 1.9±2.1 to 8.3±9.4 at T6 (p<0.001), 6.8±7.7 at T12 (p=0.02), 7.5±7.3 at T24 (p=0.01). This finding was confirmed by the reduction of percentage of un-switched memory B cells CD27+IgD+ from 8.7±7.5 at baseline to 2.3±1.9 at T6, 3.2±3.2 at T12 and 3.1±3.8 at T24 (p<0.001). Also, double negative cells percentage CD27-IgD- showed a significant reduction at T6, T12 and T24 compared with baseline (13.2±5.2% at T0 vs 6.6±4.9% at T6, and 7.9±6.6% at T12, and 10.6±17.4% at T24, (p<0.01). Recovery phase was featured by a significant increase of CD19+ZAP-70+% cells from 4.1±4.5% at T0 to 10.9±12.0% at T6, 10.4±8.1% at T12 and 16.0±15.1% at T24 (p<0.01). A significant difference of baseline values of CD19+ZAP-70+% was evident for patients who exhibited a good response at T6 compared with those who did not (0.57±0.44% vs 6.2±4.9%, p=0.001). Conclusions: Pretreatment percentage of CD19+ZAP-70+ cells appears to be predictive of a poor response to BCDT at T6. Naïve activated and Zap-70+ B cells are the main feature of recovery. References:[span] 1. Tolusso B., et al. Clin Immunol 2009
CD19+ZAP70+ B cells value at baseline predicts response at T6 to BCDT (B cell depletion therapy). Recovery is mainly characterized by the appearance of naïve activated B cells and ZAP-70 positive B cells
Gremese E;
2011-01-01
Abstract
Background: In RA synovitis, ZAP-70 positive B cells seem to correlate with the inflammatory activity and be associated with increased survival. Objectives: To assess ZAP-70 protein expression in PB B cells at baseline and after treatment with rituximab (RTX) in a cohort of RA patients during a 24 months follow-up and to evaluate it as biomarker of clinical response. Methods: Twenty-eight RA patients (mean age 56.8±11.9 years; mean disease duration 12.7±9.6 years) with active disease despite treatment with DMARDs or TNF-α blockers received a first course of Rituximab 1 g i.v. two weeks apart. Disease activity was assessed at baseline and every three months according to the EULAR criteria. Clinical, immunological and laboratory data were included in the set of disease evaluation. Cytofluorimetric analysis of B cell subsets at baseline and 6, 12 and 24 months after treatment was performed using surface markers (CD45, CD3, CD56, CD19, IgD, CD38, CD27, CD5, CD23) and intracellular ZAP-70 (1). Retreatment was performed when DAS increased by 0.6. Results: Patients at baseline had active disease with mean DAS 4.1±1.6, and mean HAQ 1.39±0.94. The percentage of peripheral CD19+ cells decreased from the baseline value of 7,5±4.0% to 3.0±6.4% at T6, 1.8±2.0% at T12 and 2.7±3.8% at T24 (p<0.001). The recovery of B cells in PB was characterized by the appearance of immature cells coupled with a reduction of memory cells as shown by the increasing values of Bm2+Bm2'/eBm5+Bm5 ratio from baseline 1.9±2.1 to 8.3±9.4 at T6 (p<0.001), 6.8±7.7 at T12 (p=0.02), 7.5±7.3 at T24 (p=0.01). This finding was confirmed by the reduction of percentage of un-switched memory B cells CD27+IgD+ from 8.7±7.5 at baseline to 2.3±1.9 at T6, 3.2±3.2 at T12 and 3.1±3.8 at T24 (p<0.001). Also, double negative cells percentage CD27-IgD- showed a significant reduction at T6, T12 and T24 compared with baseline (13.2±5.2% at T0 vs 6.6±4.9% at T6, and 7.9±6.6% at T12, and 10.6±17.4% at T24, (p<0.01). Recovery phase was featured by a significant increase of CD19+ZAP-70+% cells from 4.1±4.5% at T0 to 10.9±12.0% at T6, 10.4±8.1% at T12 and 16.0±15.1% at T24 (p<0.01). A significant difference of baseline values of CD19+ZAP-70+% was evident for patients who exhibited a good response at T6 compared with those who did not (0.57±0.44% vs 6.2±4.9%, p=0.001). Conclusions: Pretreatment percentage of CD19+ZAP-70+ cells appears to be predictive of a poor response to BCDT at T6. Naïve activated and Zap-70+ B cells are the main feature of recovery. References:[span] 1. Tolusso B., et al. Clin Immunol 2009I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
