LAUSR

Renal involvement in plasma cell dyscrasia has been widely described, including Monoclonal Gammopathy of Renal significance (MGRS). Chronic kidney disease (CKD) in hematological disorders carries major implications for management, prognosis and the potential for progressive renal injury and ESRD. Specific monthly Kidney-Hemopathy Consultation has been created in 2017 in the department of Nephrology. The aimed of this was to describe the clinical, biological and histological characteristics of patients with hematological disorders and CKD. From 01/05/2017 to 31/12/2019 adults with hematological disorders and CKD (eGFR<60ml/min and/or proteinuria or hematuria) were prospectively included. Fifty-six patients (27 men) were enrolled: Multiple Myeloma (n=30), MGUS (n=11), Lymphoma (n=5), Acute Leukemia (n=4), LMC (n=2), 1 LLC (n=2), Cryoglobulinemia (n=1), Refractory Anemia with Excess blasts (n=1), Bone marrow aplasia (n=1). This nephrology consultation was the first for 22 patients (39%), referred by a hematologist in 38 cases (68%). Renal injury was confirmed after the hematologic diagnosis in 34 patients (61%) and precedes the diagnosis of plasma cell dyscrasia for 8 patients (14%). The median eGFR was 54.1ml/min/1.73m (128-4): CKD stage II (n=16), stage III (n=28), stage IV (n=7) and stage V (n=2). Proteinuria was >0.5g/day for 22 (39.3%) patients including a Bence-Jones proteinuria for 15 patients (27%). Acute Kidney Injury (AKI) was confirmed in 34 patients (63%) and 8 (24%) requiring acute dialysis. Histologic diagnostic of kidney injury was confirmed for 21 patients (38%): 16 kidney biopsies and 5 AL renal amyloidosis confirmed by salivary glands or abdominal fat biopsy. MGRS was confirmed in 34 patients (61%): Cast nephropathy (n=10;29%), AL amyloidosis (n=7;20%); C3 nephropathy (n=3; 9%), Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits (n=3), Light Chain Proximal Tubulopathy (n=3), Randall-type monoclonal immunoglobulin deposition disease (n=2, 6%), 1 Minimal Change Disease (n=1; 3%), Glomerulonephritis with Organized Microtubular Monoclonal Ig Deposits (n=1) and exclusive tumoral renal infiltration (n=1). Associated tumoral infiltration or crystalline podocytopathy was confirmed in 2 and 1 biopsy respectively. Glomerular MGRS was highly suspected for 2 patients, even if no biopsy was performed. MGRS was excluded for 22 patients (39%): AKI due to antibiotics or sepsis (n=8; 36%), hypovolemia (n=4; 18%) or hypercalcemia (n=3; 14%); 2 renal artery stenosis due to tyrosine kinase inhibitors (n=2; 9%), nephroangiosclerosis (n=1), lithiasis (n=1), CKD post- nephrectomy CKD (n=1), and immunoallergic nephritis (n=1). Hematological treatment was initiated in 54 patients (96%). All patients with MGRS were treated, whom 17 (50%) completely or partially in the Nephrology department. Proteasome inhibitors, alkylant agents and IMIDs were the main molecule used in first line therapy (56%, 23% and 12% respectively). Eleven patients (20%) had stem cell transplantation. After a median follow up of 16 months (38-0), complete or very good partial hematologic response was obtained in 48 patients (89%); whom 30 with MGRS (88%). Median eGFR was 45ml/min/1.73m (142-4): CKD stage II (n=18), stage III (n=23) and stage IV (n=9). Only 1/3 CKD stade V patient needed chronic replacement therapy. Eight patients died (14%): 4 uncontrolled hematologic disease (50%) and 3 septic complications (38%). Very closed collaboration between Nephrology and Hematology Department in our Center contributes to improve early management of patients with hematological disorders associated with CKD, and probably their survey. Hemato-Nephrology is a viable and emergent specialty.