Immunosuppressive therapy in patients with IgA nephropathy

BACKGROUND

There is limited evidence to support cytotoxic therapy in patients with IgA nephropathy and renal insufficiency. We studied the effect of cytotoxic therapy in patients with IgA nephropathy and renal insufficiency, and evaluated possible predictors of response.

METHODS

Retrospective analysis of patients with IgA nephropathy who received immunosuppressive therapy. The primary outcome measure was progression of renal disease, defined as an increase in serum creatinine levels of ≥ 50% or development of end-stage renal disease.

RESULTS

From 1996 to 2008, 19 patients with biopsy-proven IgA nephropathy were treated with cytotoxic agents and prednisone because of renal insufficiency and÷ or severe proteinuria. Characteristics of patients at the start of therapy: age 42&plusmn;11 years, serum creatinine 208 (96-490) μmol÷l, estimated glomerular filtration rate (eGFR) 33 (12-65) ml÷min÷1.73 m2, and protein- creatinine ratio 3.8 (0.6-18.2) g÷10 mmol. Follow-up after initiation of therapy was 35 (7-133) months. Ten patients had progressive renal disease, whereas eGFR was stable in nine. Serum creatinine levels and proteinuria at the start of treatment were not significantly different between responders and non- responders. Proteinuria response at six months after start of therapy proved a good predictor: proteinuria decreased by ≥ 50% and÷or reached levels below 1 g÷day in 8÷9 responders. In contrast, proteinuria decreased by more than 50% and reached levels < 1 g÷day in only 3÷10 non-responders (p < 0.01).

CONCLUSION

Prolonged immunosuppressive therapy with cytotoxic agents and prednisone may benefit a subgroup of patients with progressive IgA nephropathy. A reduction of proteinuria ≥ 50% to levels below 1 g÷day within six months predicts a favourable long-term response.

Urinary excretion of low-molecular-weight proteins as prognostic markers in IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is characterised by high variability in clinical course and outcome. Accurate prediction of prognosis is needed to optimise treatment. Urinary alpha1-microglobulin and beta2-microglobulin are markers of tubulointerstitial injury and predict the risk of end-stage renal disease (ESRD) in idiopathic membranous nephropathy. We questioned the relevance of these markers in IgAN.

METHODS

We included patients with biopsy proven IgAN, who were evaluated for proteinuria in our centre between 1995 and 2007. Data were analysed using univariate and multivariate Cox regression for the outcome variables ESRD and progression (rise in serum creatinine of >50% or start of immunosuppressive therapy).

RESULTS

Seventy patients (71% men) were selected. Median age was 39 years, median serum creatinine 140 micromol/l, and median proteinuria 2.4 g/day. Median urinary alpha1-microglobulin excretion was 23.5 microg/min (range 3.5-275.3) and median urinary beta2-microglobulin excretion was 0.4 microg/min (range 0.1-62.1). Both alpha1m and beta2m correlated significantly with serum creatinine (r = 0.65, p<0.01 and r = 0.62, p<0.01) and total proteinuria (r = 0.35, p<0.01 and r = 0.28, p<0.05). During follow-up (median 75 months) 25 patients (36%) developed ESRD , and 46 patients (66%) showed progression. 19 patients (27%) were treated with immunosuppressive agents. In univariate analysis urinary alpha1- and beta2-microglobulin predicted ESRD and progression. In multivariate analysis only serum creatinine and urinary protein were independent predictors of both outcomes.

CONCLUSION

Urinary excretion of low molecular weight proteins did not offer an advantage over total proteinuria and serum creatinine in predicting prognosis in patients with IgAN.

Rituximab in minimal change nephropathy and focal segmental glomerulosclerosis: report of four cases and review of the literature

Minimal change nephropathy (MCNS) and focal segmental glomerulosclerosis (FSGS) are the main causes of the idiopathic nephrotic syndrome. MCNS usually responds to steroids and the long-term prognosis is generally good. However, some patients require prolonged treatment with immunosuppressive agents. FSGS generally follows a less favourable course: patients do not always respond to steroids and may progress to end-stage renal disease. Recurrence of FSGS after renal transplantation is frequently observed and may result in graft loss. Recently, anecdotal case reports have described long-term resolution of nephrotic syndrome due to MCNS or FSGS after treatment with rituximab. We present four patients with nephrotic syndrome due to MCNS, FSGS or recurrence of FS GS after kidney transplantation, who were treated with rituximab with variable success. A review of the recent literature suggests that anti-CD20 antibodies may be a promising therapy, especially for patients with MCNS or idiopathic FSGS. Controlled studies are required to determine the efficacy of rituximab and to define which patients will benefit.

Water in health and disease: new aspects of disturbances in water metabolism

Vasopressin is a critical regulator of water homeostasis. There are two major receptors for vasopressin: V1 and V2 receptors. Disturbances in water balance are commonly encountered in clinical practice and can be divided into disorders of urinary dilution and concentration. The major representatives of such disorders are diabetes insipidus and the syndrome of inappropriate secretion of antidiuretic hormone (SI ADH). Recent studies show that genetic forms of nephrogenic diabetes insipidus are due to mutations in the genes coding for the vasopressin V2 receptor (V2R) or aquaporin-2 (AQP2). Identification of the genes involved and analysis of the cellular fate of the V2R and AQP2 mutants are relevant for understanding the functioning of the V2R and AQP2 protein. These developments also have implications for future therapeutic options. The development of nonpeptide vasopressin receptor antagonists (VRAs) offers prospects for the treatment of euvolaemic (SI ADH) or hypervolaemic hyponatraemia (congestive heart failure or cirrhosis). Several nonpeptide VRAs are now in various stages of clinical trials. At present, only conivaptan is registered by the FD A for intravenous treatment of euvolaemic and hypervolaemic hyponatremia. A recent long-term study comparing tolvaptan with placebo in patients with chronic heart failure showed no reduction in risk of death and hospitalisation.