The TLR3/IFN-β/RIG-I/CCL5 signalling pathway may mediate immune and inflammatory responses against viral infection in mesangial cells, suggesting the role of this pathway in the aggravation of glomerulonephritis due to viral infection.

Background: The optimal long-term treatment for lupus nephritis (LN) in pubertal patients remains to be determined. Tacrolimus (Tac) inhibits T cell activation, and is therefore expected to be effective in patients with LN. However, little has been published about the long-term efficacy and safety of Tac-based immunosuppressive treatment of young patients with LN in daily clinical practice. Methods: Nineteen consecutive patients with biopsy-proven LN were recruited for an open-label, prospective, long-term Tac-based treatment regimen. Tac was administered once daily at a dose of 3 mg as induction- or reinduction-maintenance treatment. Four patients (21%) with new-onset LN received mizoribine at a dose of 150 mg once daily in addition to Tac. Treatment outcomes were defined by the European Consensus Lupus Activity Measurement (ECLAM) index, urinary protein/creatinine ratio (Up/cr), serum creatinine and serological lupus markers (complement C3, complement hemolytic activity, CH₅₀, and anti-dsDNA antibody titer). Data on these parameters were collected prospectively. The median follow-up was 42 months. Results: Baseline characteristics of the patients were as follows: mean age, 18 years; Up/cr, 0.89 ± 1.17; serum C3, 68.1 ± 23.2 mg/dl (normal, 79–152 mg/dl); serum CH₅₀, 26.4 ± 10.5 U/ml (normal, 23–46 U/ml); serum anti-dsDNA antibody titer, 69.3 ± 67.5 IU/ml (normal, <12.0 IU/ml); serum creatinine, 0.55 ± 0.18 mg/dl, and ECLAM index, 4.6 ± 1.9. Despite gradually tapering the dose of concomitantly administered prednisolone, a marked improvement compared with baseline values was observed in all outcome measures as early as 3 months after the initiation of treatment, and the favorable changes persisted throughout the treatment period in most of the patients. Sustained improvements in the outcome measures compared with the baseline values were confirmed after a mean of 42 months of treatment: ECLAM index, 1.1 ± 1.1; serum CH₅₀, 36.0 ± 12.8 U/ml, anti-dsDNA antibody titer, 22.5 ± 26.5 IU/ml (all p < 0.01); Up/cr ratio, 0.35 ± 0.58, and serum C3 level, 79.7 ± 17.6 mg/dl (both p < 0.05). Serum creatinine level remained within the normal range in all the study participants. Complete response was achieved in 12 patients (63%), and a partial response was achieved in 5 patients (26%). The remaining 2 patients showed no response. No serious adverse effects were observed. Conclusion: The data suggest that long-term, relatively low-dose Tac-based immunosuppressive treatment is beneficial and has low cytotoxicity, and therefore represents an attractive option for the treatment of young patients with LN in daily clinical practice. Further studies involving a larger number of patients are needed to confirm these results.

The objective of the current work is to report the preliminary experience with tacrolimus (TL) administered as a single-dose daily for maintenance therapy of young patients with pediatric-onset, long-standing systemic lupus erythematosus (SLE). Six consecutive patients with long-standing SLE were recruited for a 6-month open-label trial of single-dose-daily administration of tacrolimus (3 mg/day) without dose up of concomitantly administered prednisolone (PDN). TL treatment was started at the time of the most recent flares. Data on the clinical and serologic lupus activity were collected prospectively. The baseline characteristics of the patients were: mean age, 20 years; urinary protein/creatinine ratio, 1.22 +/- 1.94; serum C3 level, 70.8 +/- 21.2 (normal, 79-152 mg/dL); serum complement hemolytic activity (CH50), 22.2 +/- 10.3 (normal, 23-46 U/mL); serum anti-dsDNA antibody titer, 60.4 +/- 71.7 IU/mL (normal, < 12.0 IU/mL); serum creatinine, 0.55 +/- 0.11 mg/dL; European Consensus Lupus Activity Measurement (ECLAM) index, 5.2 +/- 2.6. Despite the gradual tapering of the PDN dose, marked improvement as compared with the baseline values was observed in the ECLAM index examined at one and three months and serological parameters examined at three months after the start of treatment. After a 6-months' therapy, complete response was achieved in all of the patients (serum CH50 value, 27.7 +/- 8.3 U/mL; serum anti-dsDNA antibody titer, 28.4 +/- 27.9 U/mL and the ECLAM index, 1.2 +/- 1.2 (P < 0.05), respectively), except in one patient who showed WHO class V lupus nephritis. No serious adverse effects were observed. These data suggest that TL, even when administered as a single-daily dose, is effective and safe for selected young patients with pediatric-onset, long-standing SLE. However, further studies on a larger number of patients are needed to confirm these results.

Background: A novel purine synthesis inhibitor, mizoribine (MZR), with a similar activity to that of mycophenolate mofetil, was developed in Japan. We suspected that long-term oral MZR intermittent pulse therapy (MZR-P) might be more effective than the conventional daily MZR regimen due to the higher peak serum MZR levels that are achieved. Here, we examined the clinicopathologic efficacy of MZR-P treatment in 10 young patients with diffuse proliferative lupus nephritis (DPLN), including 3 patients who received MZR-P as their primary cytotoxic therapy. Methods: After their most recent renal flare-ups, all the patients were treated using MZR-P combined with oral prednisolone (PDN). MZR was administered as a single daily dose of 6–10 mg/kg per day (maximum dose of 500 mg) on 2 days of the week (Monday and Thursday) for at least 12 months or longer. The concomitantly administered PDN dose was gradually reduced. Results: The baseline characteristics of the patients were as follows: mean age 15 years; urinary protein/creatinine (Up/cr) ratio 1.57 ± 1.05 mg/mg; serum C3 level 50.3 ± 19.7 mg/dl; serum complement hemolytic activity (CH50) 18.1 ± 9.9 U/ml; serum anti-dsDNA antibody titer 177.5 ± 152.7 IU/ml; serum creatinine 0.6 ± 0.1 mg/dl, and European Consensus Lupus Activity Measurement (ECLAM) index 4.9 ± 2.6. Despite the gradual tapering of the PDN dose, marked improvements compared with the baseline values were observed at the last observation, mean interval of 29 months after the start of treatment: Up/cr ratio 0.19 ± 0.14; ECLAM index 1.3 ± 0.7 (p < 0.01); serum C3 level 76.5 ± 22.1 mg/dl; serum CH50 value 31.9 ± 8.7 U/ml, and anti-dsDNA antibody titer 34.2 ± 20.5 IU/ml (p < 0.05). The serum creatinine level remained within the normal range in all study participants. Post-treatment renal biopsies were performed in 5 of the patients; histology showed a marked attenuation of lesion progression. No serious adverse effects were observed. Conclusion: We believe that long-term MZR-P may prove to be a treatment of choice for young patients with DPLN. However, confirmation is needed as this preliminary study is limited by the small number of subjects, lack of controls, and its retrospective nature.

Interferon-gamma is a potent Th1-type cytokine and a key molecule in the pathogenesis of autoimmune diseases including lupus nephritis. Retinoic acid-inducible gene-I is a putative RNA helicase that plays an important role in immune and inflammatory reactions. We previously demonstrated the increased expression of the retinoic acid-inducible gene-I protein in the kidney tissue of patients with lupus nephritis, and the presence of a significant amount of retinoic acid-inducible gene-I mRNA in the urinary sediment of patients with this inflammatory renal disease. In the present study, interferon-gamma was found to induce the expression of retinoic acid-inducible gene-I in human mesangial cells in culture. Knockdown of retinoic acid-inducible gene-I inhibited the interferon-gamma-induced upregulation of interferon regulatory factor 7, a transcriptional factor involved in immune and inflammatory reactions. These findings suggest that retinoic acid-inducible gene-I produced by mesangial cells may be involved in the pathogenesis of lupus nephritis.