January 2000, Volume 9, Issue 1, Pages 68 – 71

Case report

Acquired C1q deficiency caused by monoclonal paraproteinaemia Margaret-Mary Gordon1, Norman Lucie2 & Duncan Porter3 1Centre for Rheumatic Diseases, Glasgow Royal Infirmary, Scotland, UK     2Department of Haematology, Gartnavel General Hospital, Glasgow, Scotland, UK     3Department of Rheumatology, Gartnavel General Hospital, Glasgow, Scotland, UK     Correspondence to: Dr. Margaret-Mary Gordon , Specialist Registrar in Rheumatology, Centre for Rheumatic Diseases, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, Scotland, UK. Tel: (+44) 141 211 4965; fax: (+44) 141 552 4862.

Keywords

acquired C1q deficiency;   paraproteinaemia;   lymphoma

Abstract

Acquired C1q deficiency secondary to anti C1q auto-antibodies may result in the hypocomplementaemic urticarial vasculitis syndrome and may also be seen in active systemic lupus erythematosus. Some patients with acquired C1 inhibitor deficiency are found to have an underlying malignancy, most commonly lymphoma. We report a case of a 40-year-old man presenting with a lupus-like illness with acquired C1q deficiency secondary to a monoclonal paraprotein in the presence of splenic lymphoma with villous lymphocytes. His clinical symptoms correlated with the presence of the paraprotein. Relapse coincided with a rise in the paraprotein and fall in C1q, C3 and C4. There was no improvement in his clinical condition following combination chemotherapy. He remains on oral prednisolone. Lupus (2000) 9, 68-71

Received 6 May 1999; Accepted 20 September 1999

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