Sodium-glucose cotransporter 2 inhibition in primary and secondary glomerulonephritis

BACKGROUND

The role of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in the management glomerular/systemic autoimmune diseases with proteinuria in real-world clinical settings is unclear.

METHODS

This is a retrospective, observational, international cohort study. Adult patients with biopsy-proven glomerular diseases were included. The main outcome was the percentage reduction in 24-h proteinuria from SGLT2i initiation to 3, 6, 9 and 12 months. Secondary outcomes included percentage change in estimated glomerular filtration rate (eGFR), proteinuria reduction by type of disease and reduction of proteinuria ≥30% from SGLT2i initiation.

RESULTS

Four-hundred and ninety-three patients with a median age of 55 years and background therapy with renin-angiotensin system blockers were included. Proteinuria from baseline changed by -35%, -41%, -45% and -48% at 3, 6, 9 and 12 months after SGLT2i initiation, while eGFR changed by -6%, -3%, -8% and -10.5% at 3, 6, 9 and 12 months, respectively. Results were similar irrespective of the underlying disease. A correlation was found between body mass index (BMI) and percentage proteinuria reduction at last follow-up. By mixed-effects logistic regression model, serum albumin at SGLT2i initiation emerged as a predictor of ≥30% proteinuria reduction (odds ratio for albumin <3.5 g/dL, 0.53; 95% CI 0.30-0.91; P = .02). A slower eGFR decline was observed in patients achieving a ≥30% proteinuria reduction: -3.7 versus -5.3 mL/min/1.73 m2/year (P = .001). The overall tolerance to SGLT2i was good.

CONCLUSIONS

The use of SGLT2i was associated with a significant reduction of proteinuria. This percentage change is greater in patients with higher BMI. Higher serum albumin at SGLT2i onset is associated with higher probability of achieving a ≥30% proteinuria reduction.

Resistant Cytomegalovirus Infection After Renal Transplantation: Literature Review

BACKGROUND

Resistant cytomegalovirus (R-CMV) is an emerging problem in the renal transplantation population. The most frequent CMVs are high-resistance mutations (UL97 gene).

METHODS

We describe our experience in management of R-CMV after renal transplant at our center (2012-2016).

RESULTS

We encountered 3 cases of R-CMV infection after renal transplant (all primary infections). All 3 patients received induction therapy with corticosteroids, tacrolimus, and mycophenolate mofetil. The first patient (basiliximab induction, preemptive CMV) developed CMV replication on day +53, which responded poorly both to standard-dose valganciclovir (vGCV) and high-dose ganciclovir (GCV) (creatinine clearance [CrCl] >70 mL/min; vGCV 900 mg twice daily for 50 days and GCV 7.5 mg/kg twice daily for 8 days). Hematologic toxicity occurred. The R-CMV test was positive and foscarnet (FOS) was initiated (90 mg/kg twice daily for 21 days). The second patient presented CMV infection (day +30, thymoglobulin induction, CMV prophylaxis), which was not controlled with the high dose (CrCl 23 mL/min; GCV 3.5 mg/kg twice daily and vGCV 900 mg twice daily), resulting in severe neutropenia. R-CMV was detected and FOS initiated (FOS 50 mg/kg twice daily for 7 days and 50 mg/kg every 2 days for 13 days). The third patient's infection occurred on day +22 (basiliximab induction, preemptive CMV). Standard-dose vGCV was uneffective (CrCl >70 mL/min, vGCV 900 mg twice daily) and it did not respond to the high dose (GCV 7.5 mg/kg twice daily and vGCV 2700 mg/d). Moderate hematologic toxicity occurred. R-CMV was diagnosed and FOS treatment begun (FOS 70 mg/kg per day for 2 weeks).

CONCLUSIONS

Resistant CMV infection may be severe due to viral infection and side effects of high-dose antiviral treatment. We presented 3 cases requiring the use of FOS in the absence of response or toxic effects from the usual treatment, with an optimal sustained response (temporary in case 2) and without serious side effects.

Testing the Activity of Complement Convertases in Serum/Plasma for Diagnosis of C4NeF-Mediated C3 Glomerulonephritis

Autoantibodies termed C3-nephritic factor (C3NeF), which stabilize convertases of the alternative complement pathway, often stimulate autoinflammatory diseases. However, knowledge about analogous autoantibodies acting on the classical pathway (C4NeF) is limited to a few reports, which indicate association with kidney dysfunction, systemic lupus erythematous, and infections. C4NeF may appear independently from C3NeF, but the lack of a routine diagnostic method predisposes C4NeF for being an underestimated player in autoinflammatory episodes. We tested the activity of classical convertases directly in serum/plasma to screen samples from 13 patients with C3 glomerulopathies and identified one patient showing significantly prolonged half-life of these enzymes. Observed effect was reproduced by immunoglobulins purified from patient's plasma and additionally confirmed on classical convertase built from purified components. Isolated immunoglobulins protected classical convertases from both spontaneous and inhibitor-driven decay but not from C4b proteolysis. The patient had a decreased serum level of C3, elevated sC5b-9, and normal concentrations of factor B and C4. Neither C3NeF nor other autoantibodies directed against alternative pathway proteins (factor H, factor B, factor I, C3, and properdin) were found. Genetic analysis showed no mutations in C3, CFB, CFH, CFI, MCP, THBD, and DGKE genes. Renal biopsy revealed a membranoproliferative pattern with intense C3 deposits. Our results underline the importance of C4NeF as an independent pathogenic factor and a need for the implementation of routine examination of classical convertase activity. Proposed method may enable robust inspection of such atypical cases.