Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Deficient Ubiquitin Ligase Casitas B-Lineage Lymphoma b Expression and Abnormal Peripheral Tolerance in CD4 T Cells From Systemic Lupus Erythematosus Patients.

Gomez-Martin,  Diana, Ibarra-Sanchez,  Maria , Cruz-Ruiz,  Jose, Romo-Tena,  Jorge, Esparza-Lopez,  Jose, Diaz-Zamudio,  Mariana, Alcocer-Varela,  Jorge

Background/Purpose:

A resistant to anergy phenotype has been evidenced in T cells from SLE patients. This might be related to intrinsic defects associated to abnormalities in the anergy induced genetic program, particularly ubiquitin ligases such as Casitas B-lineage lymphoma b (Cbl-b), which have not been fully addressed in SLE. The aim of this study was to analyze the expression of Cbl-b in CD4+ T cells from SLE patients upon anergy induction and the associated proliferative and effector response.

Methods:

Twenty patients with SLE (11 in clinical remission and 9 with active untreated disease) and 20 healthy controls were included. PBMC were isolated and CD4+ T cells were negatively selected. Four experimental conditions were defined as followed: ex vivo, activation (anti-CD3 +anti-CD28), anergy (ionomycin) and rest. Cellular proliferation was addressed by CFSE dilution method. Cbl-b expression was assessed by real time PCR and western blot. Cytokine production was measured in the supernatants from cell cultures by luminometry. Surface expression of activation and costimulatory molecules were analyzed by flow cytometry. Mean and standard deviation or median and interquartilar range were used for descriptive statistics. Comparison between groups was made by means of Student's T test and Mann Whitney test.

Results:

Upon anergy induction, Cbl-b normalized mRNA (0.21 vs 0.47, p= 0.015) and protein expression (0.73 vs 0.90, p=0.038) in CD4+ cells from SLE patients was decreased in comparison to controls. No differences were found between active and remission patients. CD4+ cells from SLE patients shown multiple abnormalities regarding the proliferative response, particularly, resistance to anergy was evidenced by a decreased anergy index in patients vs controls (237 vs 558, p<0.05), as well as higher IL-2 production (43.4 vs 17.1 pg/mL) after ionomycin treatment. Moreover, the proliferative response to activation protocol was lower for SLE patients vs controls. Among SLE patients, after anergy induction, the synthesis of pro-inflammatory cytokines was diminished in comparison to activation protocol, being this difference significant only for IFN-' (130.30 pg/mL vs 23.72 pg/mL, p<0.05).After ionomycin treatment, a dichotomy between suppressive cytokines was displayed, as IL-4 production was increased and IL-10 was decreased in SLE patients vs controls (IL-4: 33 vs 24.2 pg/mL; IL-10: 159.5 vs 1166.7 pg/mL). In terms of activation surface markers, after anergy induction, increased expression of CD69 (20.1 vs 2.1, p<0.001), CD83 (30.7 vs 10.1, p=0.001) and CD40L (33.6 vs 15.1, p<0.001) was found in SLE patients vs healthy controls.

Conclusion:

CD4+ T cells from SLE patients display a vast array of abnormalities regarding proliferative and effector responses to activation and anergy induction. Our data suggest that resistance to anergy in CD4+ cells from SLE patients, without regarding disease activity, is related to decreased Cbl-b expression as well as overexpression of activation and costimulatory molecules. These might be related to persistent proliferation of autoreactive T cells even under the absence of appropriate costimulation.

To cite this abstract, please use the following information:
Gomez-Martin, Diana, Ibarra-Sanchez, Maria , Cruz-Ruiz, Jose, Romo-Tena, Jorge, Esparza-Lopez, Jose, Diaz-Zamudio, Mariana, et al; Deficient Ubiquitin Ligase Casitas B-Lineage Lymphoma b Expression and Abnormal Peripheral Tolerance in CD4 T Cells From Systemic Lupus Erythematosus Patients. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :854
DOI:

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