Recovery of Renal Function and Late Withdrawal of Hemodialysis in IgD Multiple Myeloma: A Case Report

Introduction

IgD multiple myeloma (MM) is a rare subtype that often presents with advanced kidney impairment at diagnosis; survival benefits from renal recovery.^1,2 We report, to our knowledge, the first case of IgD-MM with such late hemodialysis (HD) withdrawal (1260 days after diagnosis) driven by progressive renal improvement.

Case Report

A 56-year-old patient presented with bilateral lumbosacral pain (day 0). He was normotensive. Laboratory tests showed creatinine at 2.6 mg/dL, calcium at 8.7 mg/dL, uric acid at 11.1 mg/dL, albumin at 2.7 g/dL, hemoglobin at 7.9 g/dL, β2-microglobulin level at 24.70 mg/L, normal lactate dehydrogenase level, protein/creatinine ratio of 4310 mg/g, and albumin/creatinine ratio of 152.9 mg/g. Urine culture and renal imaging were unremarkable.

Serum studies revealed a monoclonal IgD-λ component (4.93 g/dL), markedly elevated free λ light chains (LCs) (5800 mg/L), suppressed ĸ (15.9 mg/L), and a pathological ĸ/λ ratio (0.002). Additionally, 24-hour urinalysis confirmed albuminuria (175 mg) and proteinuria (5170 mg); urine immunofixation was positive for Bence-Jones λ. Bone marrow aspirate showed 49% atypical plasma cells; no p53 or del(17p) alterations were detected. MRI exhibited patchy marrow infiltration, lytic lesions (left humerus), and vertebral fractures. IgD λ-MM stage III-B, with ISS 3 was diagnosed. Treatment was initiated with a dexamethasone, bortezomib, and cyclophosphamide regimen for induction (day 4), followed by bortezomib and lenalidomide maintenance. Given rapid renal decline, extracorporeal clearance was started using a sequential high-cut-off and online hemodiafiltration protocol. A 64% reduction in serum light chains was achieved by day 16. After reaching minimal residual disease, urine output increased, and renal function progressively improved, despite signs of chronicity on imaging, finally allowing hemodialysis discontinuation by day 1260 [Figure 1]. At 9 months post-HD, eGFR was 13.8 mL/min/1.73m² with albuminuria 164.5 mg/g.

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Figure 1:

Response to chemotherapy, diuresis, and creatinine level to modify dialysis schedule. CFM: Cyclophosphamide DXT: Dexamethasone; HCO: High cut off; HDF: Hemodiafiltration online. EMIK2: Fresenius polysulfone 1.8m² and heat sterilization; FX 800 cordiax: Helixone plus 2m² and heat sterilization; MRD: Minimal residual disease; PR: Partial response. PO: Per os; SC: Subcutaneous.

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Discussion

A serum-free LC concentration >500 mg/L with proteinuria predominantly composed of monoclonal LCs supports the diagnosis of LC cast nephropathy (LCCN). LCNN is the leading cause of AKI in MM. It results from excessive free LC production, saturation of proximal tubular catabolism, and intratubular cast formation, ultimately causing interstitial fibrosis and progression to CKD.³ Although renal biopsy is diagnostically valuable, it is not essential for diagnosis or management. In this patient, no reversible precipitating factors such as hypercalcemia, dehydration, infection, or exposure to nonsteroidal anti-inflammatory drugs were identified.

A rapid, profound, and sustained reduction in LC concentration following chemotherapy is crucial for renal function recovery; a 60% decrease by day 21 correlates with renal function improvement in 80% of patients with LCCN.³ Bortezomib inhibits monoclonal LC production and may also reduce inflammation and fibrosis by blocking nuclear factor-κB activation.³ The role of high-cut-off HD remains controversial,⁴ while early autologous stem cell transplantation enables HD discontinuation in 24% of MM patients, albeit with a 17% mortality rate.⁵

HD withdrawal in IgD-MM has been rarely reported. In three women (aged 52, 57, and 45), it occurred 33, 43, and 660 days after HD initiation, respectively, following bortezomib-based induction.^6-8

Renal reserve and treatment response favor renal insufficiency reversal. Both were present in our relatively young patient without major comorbidities; age <65 has been linked to successful HD discontinuation in IgD-MM.⁶ In maintenance HD, careful ultrafiltration and nephrotoxin avoidance are key. Notably, cytogenetics does not influence renal injury in IgD-MM.²

This late recovery of renal function in IgD-MM highlights the need for a better understanding of its determinants and underscores the importance of coordinated hematology-nephrology care.