Renal involvement in cystic fibrosis: diseases spectrum and clinical relevance

Abstract

Background and objectives: Clinically relevant kidney involvement is uncommonly described in adult patients with cystic fibrosis (CF). We sought to report on a series of patients with CF and kidney biopsy-documented renal involvement.

Design, setting, participants, & measurements: A retrospective study was undertaken in two referral centers for adult patients with CF in Paris, France. Patients who had undergone a biopsy of native kidneys between 1992 and 2008 were identified, and their medical records were reviewed.

Results: We identified 13 adult patients with CF and renal disease. Proteinuria was present in all but two cases and was associated with progressive renal impairment in four patients (median serum creatinine 85 micromol/L; range 53 to 144 micromol/L). Renal biopsy disclosed a heterogeneous spectrum of nephropathies including AA amyloidosis (n = 3), diabetic glomerulopathy (n = 3), FSGS (n = 2), minimal-change disease (n = 1), postinfectious glomerulonephritis (n = 1), IgA nephropathy related to Henoch-Schönlein purpura (n = 1), membranous nephropathy (n = 1), and chronic interstitial nephropathy (n = 1). Chronic renal failure occurred in five patients, and one patient reached ESRD.

Conclusions: Although rare, clinically significant renal disease may arise in young adult patients with CF. Given the wide spectrum of diseases that may be encountered, definite diagnosis by kidney biopsy is mandatory to optimize clinical treatment of these complex patients, particularly in the perspective of organ transplantation.

Figure 1.

(A through D) Patient 5. (A) Light microscopy (Masson's trichrome). Massive amyloidosis with destruction of glomeruli. (B) Light microscopy (Congo red staining). Deposits are stained by Congo red. (C) Immunofluorescence study (anti-serum amyloid A antibody staining). Massive glomerular (*) as well as interstitial amyloid deposits are revealed. (D) Light microscopy (Wright technique). Congo red staining disappears after treatment by permanganate potassium. (E) Patient 12. Light microscopy (Masson's trichrome). Relatively mild glomerular amyloid deposits (#). (F) Patient 11. (F) Light microscopy (Jones staining). Nodular accumulation of mesangial matrix (&) and presence of aneurysmal dilations of the glomerular capillaries (¶). Magnifications: ×100 in A through E; ×250 in F.