This paper describes a single 62‑year‑old woman who had a rare blood cancer called chronic neutrophilic leukemia that appeared together with a protein abnormality (monoclonal IgA kappa). The authors suggest the two conditions might come from the same early cell or that the protein problem could trigger the leukemia.

A 62-year-old woman with chronic neutrophilic leukemia (CNL) is described. She presented in February 1988 for evaluation of leukocytosis of 3 years' duration with no complaint. Physical examination was normal. The leukocyte count was 20,100/microliters with 70% segmented neutrophils and 12% band forms. A myelogram showed marked myeloid hyperplasia and plasmacytosis (5.9%). Neutrophil alkaline phosphatase score, serum lysozyme and vitamin B12 levels were elevated. Cytogenetic analysis of the marrow aspirate showed normal karyotype, with no Philadelphia chromosome. Total serum protein (TP) was 7.5 g/dl with increased beta-globulin (23.5%), identified as monoclonal IgA kappa (3.3 g/dl) on immunoelectrophoresis. No activity of G-CSF was detected in the serum. A retrospective study revealed that the beta-globulin level was normal (6.3%, TP 6.9 g/dl) in 1980 and that it was slightly increased (11.6%, TP 7.0 g/dl) without leukocytosis (5,900/microliter) in 1981. In 1985, when leukocytosis obviously existed (9,900/microliter), the percentage of beta-globulin was increased to 17.5% (TP 7.2 g/dl). The possibility that monoclonal gammopathy preceded the leukocytosis must be admitted. On the basis of our observation, it is assumed that CNL and monoclonal gammopathy may be blood dyscrasias derived from a common precursor cell or that the immunological abnormality associated with monoclonal gammopathy may be implicated in the development of CNL.