Autoimmune Haemolytic Anaemia Due to Cold Antibodies in a Renal Cancer Patient

Autoimmune haemolytic anaemia (AIHA) is an acquired disorder in which antibodies are produced against self-erythrocyte antigens. We distinguish those produced by cold antibodies (IgM), which may be associated with lymphoproliferative syndromes, infectious diseases, other autoimmune phenomena, as well as drugs or solid tumours. We report a case of AIHA due to cold antibodies as a paraneoplastic syndrome (PNS) in a patient with metastatic renal carcinoma. A 67-year-old man with newly diagnosed stage IV renal carcinoma with hepatic, bone, and lymph node involvement was consulted for abdominal pain. Laboratory tests showed grade 4 anaemia (4.5 g/dL), with positive direct Coombs' test C3bC3d and agglutinated red blood cells in the blood smear. AIHA by cold antibodies was labelled as PNS in the context of the patient; therefore, blood transfusion as well as treatment of the underlying disease with tyrosine kinase inhibitors (sunitinib) were initiated, with subsequent clinical and analytical improvement. AIHA due to cold antibodies is a well-known PNS in lymphoproliferative disorders, although association with solid tumours, such as Kaposi's sarcoma and non-small-cell lung cancer have also been described in a small percentage. However, there are few reported cases of AIHA due to cold antibodies associated with renal carcinoma. Management with corticosteroids and immunosuppressors is effective in the majority of cases, but treatment of the underlying disease is critical.