[Epidemiology of monoclonal gammopathy in a general hospital and a university internal medicine department].

PURPOSE: Monoclonal gammopathy are common in the general population. We describe biological features and etiology of monoclonal gammopathy diagnosed during more than a ten year period in the Internal Medicine Department of Rennes University Hospital and in all the medical departments of General Hospital of Blois.

METHODS

Patients were identified by immunofixation registry of Biochemistry Laboratories in both hospital (from 1990 in Rennes and from 1980 in Blois).

RESULTS

Internal Medicine Department of Rennes University Hospital: 1051 monoclonal gammapathies were identified: 514 men and 537 women. Median age was 71. Isotypes repartition was: IgG 42.8% (450 cases), IgM 31.9% (335), IgA 8.9% (94) biclonal gammopathy 9.8% (103). Sixty-nine monoclonal light chains (6.6%) were identified. Median concentration of monoclonal protein was 14 g/l (1.8-104.4). All department of General Hospital of Blois: 1282 monoclonal gammapathies were identified: 700 men and 582 women. Median age was 79. Isotypes repartition was: IgG 59.7% (765 cases), IgM 27.5% (329), IgA 11.8% (151). Thirty-four monoclonal light chains (2.7%) were identified. Median concentration of monoclonal protein was 5.6 g/l (0.5-96.6). Most frequent diagnosis were: monoclonal gammopathy of undetermined significance or MGUS (77.6% in Blois and 64.1% in Rennes), multiple myeloma (11.9% and 12.7%), Waldenström's macroglobulinemia (4.4% and 8.7%).

CONCLUSION

Monoclonal gammopathy are common in clinical practice. MGUS account for more than 60% of monoclonal gammopathy. Given their frequency, diagnostic and follow-up strategies must be costless and simple.