title: Monoclonal B-cell lymphocytosis in the population of Slovenian region of Lower Carniola.
abstract: BACKGROUND
  Monoclonal B-cell lymphocytosis (MBL) is a premalignant asymptomatic condition characterized by the presence of a small population of monoclonal B lymphocytes (less than 5 × 10(9) /L) in the venous blood of otherwise healthy individuals. Incidence of MBL is higher among first-degree relatives of patients with chronic lymphocytic leukemia (CLL) and also increases with age and among men. We compared the incidence of MBL found in the same environment in both an open general population and relatives of CLL patients.
  
  
  METHODS
  Samples were analyzed with 5-parameter flow cytometry using following monoclonal antibodies: kappa and lambda clonality, CD5, CD19, CD20. We analyzed 216 samples of patients in the Slovenian area of Lower Carniola aged 23-88 years. Fifty-four patients who came from families where CLL is present were compared by age and gender to 162 healthy individuals from the general population of the same region.
  
  
  RESULTS
  We found 10 cases of MBL (4.6%). In 9.4% of younger (≤ 50 years) first-degree relatives of CLL patients with immunophenotypic characteristics of atypical MBL, we observed a prevailingly normal κ to λ ratio. The difference in incidence of MBL cases between relatives and the general population decreases with age.
  
  
  CONCLUSIONS
  MBL in Slovenia can be coincidentally found with a similar frequency to previously studied populations of other parts of Europe. We found, however, a higher incidence of atypical MBL among first-degree relatives.
authors.affiliation: Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: P
authors.initials: P
authors.lastname: Bajuk
authors.affiliation: Department of Haematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: T
authors.initials: T
authors.lastname: Furlan
authors.affiliation: Department of Haematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: P
authors.initials: P
authors.lastname: Černelč
authors.affiliation: General Hospital Novo Mesto, Novo Mesto, Slovenija.
authors.forename: M
authors.initials: M
authors.lastname: Čeh
authors.affiliation: Department of Haematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: H
authors.initials: H
authors.lastname: Podgornik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000473:pathology; D002999:Clone Cells / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000453:epidemiology / Q000473:pathology*; D008218:Lymphocytosis / Q000453:epidemiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D017524:Slovenia / Q000453:epidemiology
keywords: Monoclonal B-cell lymphocytosis; chronic lymphocytic leukemia; flow cytometry