Long-term azathioprine therapy in two children with steroid-dependent minimal-change nephrotic syndrome

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.

Mizoribine Pulse Therapy for a Pediatric Patient with Steroid-Resistant Nephrotic Syndrome

A 12-year-old Japanese boy was referred to our hospital with a 2-month history of persistent proteinuria. Despite urinary protein excretion in the nephrotic range, associated with hypoproteinemia, the patient did not complain of any disability. A percutaneous renal biopsy revealed minor glomerular abnormalities, without any evidence of immune complex deposition. Therapy with prednisolone (60 mg/day) was initiated, and while the proteinuria decreased after 4-week therapy, elevated urinary protein excretion persisted thereafter, at 1-2 g/day. Because of the steroid-resistant proteinuria, mizoribine (MZR), was started at 150 mg/day (3 mg/kg), administered as a single daily dose an immunosuppressive agent, in combination with prednisolone. Although there was some fluctuation in the urinary protein excretion, heavy proteinuria persisted for the next 4 weeks. The peak blood level of MZR was 0.9 microg/ml. Since we have previously reported the efficacy and safety of oral MZR pulse therapy, which is associated with higher peak serum MZR levels than conventional MZR therapy in selected patients with lupus nephritis, we adopted MZR pulse therapy for this patient, after obtaining informed consent. MZR was started at the daily dose of 300 mg (6 mg/kg), administered as a single dose before breakfast, twice a week (on Monday and Thursday). The peak blood level of MZR then increased to 1.29 microg/ml. Thereafter, despite a gradual reduction of the concomitantly administered prednisolone dose, the urinary protein excretion decreased rapidly to around 0.3 g/day and remained at this level thereafter. No adverse effects of MZR were observed. Based on these clinical observations, we suggest that oral MZR pulse therapy may be the treatment of choice in selected patients of steroid-resistant nephrotic syndrome, in addition to those of lupus nephritis.

Single-dose daily administration of cyclosporin A for relapsing nephrotic syndrome

Cyclosporin A (CsA) has been reported to be effective as a steroid-sparing agent in frequently relapsing nephrotic syndrome (FRNS). However, low efficacy has sometimes been observed in selected patients with steroid-dependent FRNS. We speculated that a low peak level of CsA in the blood might be the cause, and conducted a prospective pilot study on such steroid-dependent FRNS patients to examine whether single-dose daily administration of CsA would yield a sufficient peak blood level, and therefore a satisfactory steroid-sparing effect. Five children with steroid-dependent FRNS, aged 7-16 years, were enrolled in the study. All had been treated with prednisolone combined with twice daily CsA ( T), which was subsequently replaced with the single-dose daily administration protocol ( S), because of a poor steroid-sparing effect. Although the mean daily CsA dosage with the S protocol was significantly lower than with the T protocol ( S 2.4+/-1.1 mg/kg per day vs. T 3.6+/-0.8 mg/kg per day, P<0.05), the mean peak blood level tended to be higher with the S protocol than the T protocol ( S 764+/-122 ng/ml vs. T 358+/-250 ng/ml, P=0.1797) without mean trough blood level elevation. As a result, the minimum dose of prednisolone required for maintenance of clinical remission tended to be lower with the S than the T protocol ( S 0.4+/-0.2 mg/kg on alternate days vs. T 0.6+/-0.4 mg/kg on alternate days, P=0.0656). No evidence of CsA nephrotoxicity was observed in a repeat renal biopsy performed 9 months after commencement of the S protocol in one patient. These clinical observations, although on a small number of patients and preliminary, suggest that single-dose daily administration of CsA might be an attractive protocol in selected patients with steroid-dependent FRNS in whom CsA administration by the conventional protocol is associated with a poor steroid-sparing effect.