Effect of mizoribine on serum IgE concentration in patients with IgA nephropathy

Association between decreased kidney function and endotoxin receptor CD14 C-159T polymorphism among Japanese health check-up examinees

BACKGROUND

A recently identified promoter polymorphism of the endotoxin receptor (CD14 C-159T) was shown to be associated with atherosclerotic diseases such as myocardial infarction. This study was conducted to determine whether this polymorphism is associated with decreased kidney function.

METHODS

A total of 281 male and 522 female health check-up examinees, aged 39-88 years, were genotyped for CD14 C-159T. The glomerular filtration rate (GFR) was estimated by the Modification of Diet in Renal Disease (MDRD) Study equation. Estimated GFR (eGFR) and the proportion of subjects with mildly decreased eGFR (eGFR under 90 mL/min/1.73 m(2)) were compared among the genotypes.

RESULTS

Subjects carrying the T allele showed decreased age- and sex-adjusted eGFR compared with those with CC genotype (101+/-22 vs. 105+/-23 mL/min/1.73 m(2); mean+/-SD, p = 0.012). The proportion of subjects with mildly decreased eGFR was higher in T allele carriers (34.2% for TT+CT and 26.3% for CC genotype, p = 0.041), but not statistically significant when adjusted for age and sex (odds ratio [OR] 1.41, 95% CI 0.97-2.05, p = 0.076). In subjects under 65 years, T allele carriers had a significantly increased risk for mildly decreased eGFR (27.1% for TT+CT and 18.0% for CC; age- and sex-adjusted OR 1.82, 95% CI 1.06-3.12, p = 0.030).

CONCLUSION

CD14-159T allele was associated with decreased eGFR compared with CC genotype, and with a higher prevalence of mildly decreased eGFR in younger subjects under 65.

Mizoribine treatment for childhood IgA nephropathy

BACKGROUND

There is currently no established therapy for childhood IgA nephropathy (IgAN). Mizoribine, a newly developed immunosuppressive agent characterized as a safe and well-tolerated drug, has been widely used in diverse conditions. Our preliminary study demonstrated that mizoribine could reduce the amount of proteinuria in children with IgAN. The present study was conducted to confirm this finding.

METHODS

Ten children with IgAN (median age 13.5 years) of moderate histological severity were enrolled. None of them had been previously treated by immunosuppressants. Mizoribine was administered orally for a median period of 20.5 months. We compared the urinary protein excretion expressed as the ratio of urinary protein to urinary creatinine (UP/UC) and the hematuria evaluated as the level of occult blood by dip-stick (OB score). Renal histology was also examined in three patients using paired biopsy specimens obtained both before and after treatment. We performed blood examinations regularly to monitor the toxicity and plasma concentration of mizoribine.

RESULTS

The median observation period was 44.5 months, consisting of a median 13.0 months before therapy, 20.5 months during therapy and 12.0 months after therapy. Significant reductions in both UP/UC and OB score were induced by mizoribine (P < 0.05). Renal mesangial proliferation was also improved. Plasma peak levels of mizoribine varied from 0.30 microg/mL to 1.23 microg/mL and were not associated with its effectiveness. No adverse effects were observed during the therapy, although a slight decrease in leukocyte count was noted.

CONCLUSION

Mizoribine can be an alternative drug for childhood IgAN with moderate severity because it results in a significant reduction of proteinuria and hematuria with histological improvement and causes far fewer complications compared to the conventional immunosuppressants.