#2664 CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) PATIENTS WITH LYSOZYME NEPHROPATHY AND CMML RENAL INFILTRATION DISPLAY MARKERS OF SEVERE DISEASE

Chronic myelomonocytic leukemia (CMML) is a hematologic disorder which is an overlap syndrome between myelodysplastic syndromes, and myeloproliferative neoplasms, and can be associated with autoimmune and inflammatory diseases. The objective of this study was to describe kidney involvement in CMML patients, their treatments, and outcomes.

We conducted a French and American multicenter retrospective observational study in fifteen centers, identifying CMML patients with acute kidney injury (AKI), chronic kidney disease (CKD), and urine abnormalities.

Sixteen patients (males, n = 14, median age 76.5 [71.9-83]) developed a kidney disease 6 months [1.6-25.6] after the diagnosis of CMML. Median urinary protein to creatinine ratio was 2 g/g [1.3-3.4], and median serum creatinine was 2.26 mg/dL [1.46-2.68]. Fourteen patients (87.5%) underwent a kidney biopsy. The two main renal diagnoses were either a lysozyme nephropathy (n = 9, 56%), or a renal infiltration by the CMML (n = 6, 37.5%). Histological findings showed lesions of acute tubular injury with focal tubular epithelial necrosis (n = 4), a vacuolization of the epithelial cells of the proximal tubules (n = 7), and an inflammatory infiltrate with mostly mononuclear myeloid cells (n = 9). Ten patients received a new treatment following the CMML-associated kidney injury. The effect of CMML treatment on kidney injury could be assessed in 10 patients, and renal function evolution was heterogenous. After a median follow-up of 15 months [9.9-34.9], 4 patients had CKD stage 3, 4 CKD stage 4, 1 an end-stage kidney disease. Two patients evolved to an acute myeloid leukemia (AML), and 5 died. Compared with 116 CMML controls, patients who had a kidney involvement had a higher monocytes count (p<0.001), had more CMML-1 (p = 0.005), were more susceptible to develop an AML (p = 0.02), and were more eligible to receive a specific hematologic treatment, with hydroxyurea, or hypomethylating agents (p<0.001), but no survival difference was seen between the two groups (p = 0.6978).

In this largest published cohort of CMML patients with a kidney injury, the two most frequent renal complications were lysozyme-induced nephropathy, and renal infiltration by the CMML. The development of a kidney injury during CMML appears to worsen the patient prognosis.