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Serum cystatin C and serum and urine NGAL in the kidney function assessment of patients with MGUS
Author(s) -
StelmachGoldys Agnieszka,
CzarkowskaPaczek Bozena,
WyczalkowskaTomasik Aleksandra,
Paczek Leszek
Publication year - 2015
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/ejh.12413
Subject(s) - renal function , cystatin c , medicine , albuminuria , creatinine , urine , lipocalin , monoclonal gammopathy of undetermined significance , gastroenterology , endocrinology , cystatin , immunology , monoclonal , monoclonal antibody , antibody
Objectives Monoclonal gammopathy of undetermined significance ( MGUS ) occurs without other symptoms, although monoclonal proteins can cause kidney injuries. Here, we assessed kidney function and identified the best follow‐up parameters in patients with MGUS without kidney damage symptoms. Methodology Forty‐six patients with MGUS were included in the study group. The control group ( CRT , n = 23) consisted of healthy subjects matched for age and sex. Serum cystatin C was determined using an immunonephelometric method, serum and urine neutrophil gelatinase‐associated lipocalin ( NGAL ) was measured with an immunoenzymatic method, and cathepsin B activity was determined fluorometrically. Results Serum cystatin C and urine NGAL were higher, and serum NGAL was lower in MGUS patients compared with CRT. Neither serum cystatin C, nor serum or urine NGAL, correlated with the biomarkers of MGUS. The serum activity of cathepsin B did not differ between groups and did not correlate with serum cystatin C. Serum cystatin C correlated with serum creatinine, while serum NGAL did not correlate with serum creatinine or cystatin C. The estimated glomerular filtration rates ( eGFR s) in MGUS were within normal range and correlated with serum cystatin C. The strongest correlation was observed for CKD‐EPI. Seven patients presented with albuminuria >30 mg/day. There was a correlation between albuminuria in this group and λ free light chains. Conclusions The kidney function in MGUS patients is impaired, although there are no clinical and standard laboratory test manifestations. Cystatin C and urine, but not serum, NGAL should be considered markers for kidney injury. CKD‐EPI is recommended for eGFR assessment.