ADAMTS5 is a biomarker for prediction of response to infliximab in patients with rheumatoid arthritis.

OBJECTIVE: To identify a biomarker for prediction of the response to infliximab (IFX) in patients with rheumatoid arthritis (RA), we focused on a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) that seems to play a key role in aggrecan degradation in cartilage. METHODS: Seventy-three randomly selected patients with active RA were treated with IFX. Peripheral blood samples were collected at baseline and ADAMTS5 messenger RNA (mRNA) was quantified using real-time polymerase chain reaction. RESULTS: Baseline ADAMTS5 mRNA levels in the good responder group were significantly lower (1.84 +/- 1.56; p = 0.0408) than those in the moderate and nonresponder groups (2.54 +/- 1.70) at 38 weeks of treatment with IFX. The 28-joint count Disease Activity Score (DAS28) at 38 weeks of treatment was significantly lower in the low ADAMTS5 group (2.30 +/- 1.28; p = 0.0038) than in the high ADAMTS5 group (3.90 +/- 1.61). The percentage reduction of the DAS28 was significantly higher in the low ADAMTS5 group (52.5% +/- 28.8%; p = 0.0156) than in the high ADAMTS5 group (29.4% +/- 27.2%). Further, the Delta Health Assessment Questionnaire (DeltaHAQ) score, an estimate of the improvement in the HAQ score, at 38 weeks of treatment was significantly higher in the low ADAMTS5 group (1.18 +/- 0.60; p = 0.0102) than in the high ADAMTS5 group (0.21 +/- 0.78). The positive predictive value of a low baseline ADAMTS5 level for predicting good response and remission (DAS28 < 2.6 at 38 weeks) was 90.0% and 70.0%, respectively. CONCLUSION: The baseline ADAMTS5 mRNA level is a candidate biomarker for prediction of the response to IFX in patients with RA.

Conservative sequences in 3'UTR of TCRzeta mRNA regulate TCRzeta in SLE T cells.

We have demonstrated that T-cell receptor zeta (zeta) mRNA with a 562-bp deleted alternatively spliced 3'-untranslated region (3'UTR) observed in T cells of patients with systemic lupus erythematosus (SLE) can lead to a reduction in zeta and TCR/CD3 (J. Immunol., 2003 & 2005). To determine the region in zeta mRNA 3'UTR for the regulation of zeta, zeta mRNA with 3'UTR truncations ligated into pDON-AI was used to infect murine T-cell hybridoma MA5.8 cells, which do not contain zeta. As a Western blot analysis demonstrated the importance of the regions from +871 to +950, containing conservative sequence 1 (CS1), and +1070 to +1136, containing CS2, for the production of zeta, we constructed MA5.8 mutants carrying zeta mRNA 3'UTR with deletions of these regions (DeltaCS1 and DeltaCS2 mutants). Western blot and FACS analyses showed significant reduction in the cell surface zeta and TCR/CD3 in both these mutants, and IL-2 production was decreased, compared with MA5.8 cells transfected with wild-type zeta mRNA. Furthermore, real-time PCR demonstrated the instability of zeta mRNA with 3'UTR deletions in these MA5.8 mutants. In conclusion, CS1 and CS2 may be responsible for the regulation of zeta and TCR/CD3 through the stability of zeta mRNA in SLE T cells.