title: Grading of follicular lymphoma using flow cytometry.
abstract: BACKGROUND
  The treatment and prognosis of follicular lymphoma (FL) is dependant on the grade of the disease. In the World Health Organization classification of lymphoma, grading of FL into low grade (1 and 2) and high grade (3) is recommended. Grading of FL is possible in excision biopsy; histological grading is subjective and inconsistent. Grading is extremely difficult in needle core biopsies and fine needle aspirates. We attempted to grade FL using flow cytometry (FCM) and CD19/ forward scatter.
  
  
  METHODS
  Cases of FL seen in our institution and submitted for FCM were evaluated for the percentage of cells detected beyond the 500-channel mark (on a 1024 scale) on a CD19/forward scatter dot plot. We hypothesized that these cells most likely represent centroblasts and their percentage would reflect the grade of the disease. Histological grading of the lymphoma on the open biopsies constituted the reference for FL grade.
  
  
  RESULTS
  Thirty-six cases of FL, including 22 males and 14 females, ranging in age from 19 to 92 years (median, 42 years), were studied. There were 17 cases of low grade (grade 1; n=10 and grade 2; n=7) and 19 cases of high grade (grade 3) FL. The percentage of cells identified beyond the 500-channel mark on CD19/forward scatter dot plot ranged from 0.12% to 12.55% (median, 4.9%) in low grade (grade 1 and 2) whereas the percentage of those cells in high grade FL ranged from 6.22% to 51.95% (median, 21%; P=0.00001).
  
  
  CONCLUSIONS
  Our findings suggest that using a CD19/forward scatter dot plot can help identify centroblasts in FL making grading possible on FCM, especially in small biopsies and fine needle aspirates.
authors.affiliation: King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia. mourad@kfshrc.edu.sa
authors.forename: Walid A
authors.initials: WA
authors.lastname: Mourad
authors.forename: Faisal
authors.initials: F
authors.lastname: Rawas
authors.forename: Mohamed
authors.initials: M
authors.lastname: Shoukri
authors.forename: Abdelghani
authors.initials: A
authors.lastname: Tbakhi
authors.forename: Mohamed
authors.initials: M
authors.lastname: Al Omari
authors.forename: Asma
authors.initials: A
authors.lastname: Tulbah
authors.forename: Fouad
authors.initials: F
authors.lastname: Al Dayel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018941:Antigens, CD19; D001402:B-Lymphocytes; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008224:Lymphoma, Follicular / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged
chemical_list: D018941:Antigens, CD19