CHRONIC COLD AGGLUTININ DISEASE OF THE IDIOPATHIC TYPE IS A PREMALIGNANT OR LOW-GRADE MALIGNANT LYMPHOPROLIFERATIVE DISEASE

We investigated the clinical, pathological, and immunological features of ''idiopathic'' cold agglutinin disease (CAD) in a population-based study. Fourteen patients were studied, giving a prevalence of about 1 4 per million with a mean age of 75 years. Haemolysis was present in a ll cases, but only eight patients had clinical symptoms of peripheral haemagglutination. Serum electrophoresis, immunofixation, morphologica l bone marrow evaluation, and flow cytometric immunophenotyping were u sed to detect any monoclonal lymphoproliferative disorder. Flow cytome try seemed to be a sensitive way to demonstrate a clonal B-cell prolif eration. Some evidence of clonality was found in 13 patients, and a cl onal lymphoproliferative disease was documented by flow cytometry or b iopsy in 10 out of 11 patients. We conclude that CAD is a symptom-prod ucing monoclonal lymphoproliferative disorder in nearly all patients.