title: Standardizing minimal residual disease by flow cytometry for precursor B lineage acute lymphoblastic leukemia in a developing country.
abstract: BACKGROUND
  In addition to standard risk criteria at diagnosis, minimal residual disease (MRD) following initiation of therapy is a well-recognized risk factor to predict relapse. Literature from developing countries addressing therapeutic or laboratory practices related to MRD, is largely lacking. In a first paper from India, we describe our experience in establishing a flow cytometry-based MRD assay for precursor B lineage ALL (BCP-ALL) with emphasis on the assay standardization and cost.
  
  
  METHODS
  Normal templates for B cell development were established in 10 control patients using CD45, CD11a, CD38, CD20, CD10, CD19, CD58, CD34, CD123, and CD22. BCP-ALL samples (n = 42) were characterized at diagnosis to identify a suitable marker for follow-up during mid (D+21) and end of induction (D+33). Both, multiparametric immunophenotyping and single marker detection of LAIP were used for data analysis.
  
  
  RESULTS
  In 95.2% of BCP-ALL at least two informative markers could be obtained when a minimum of four cocktail combinations were used. The combination CD20, CD10, CD45, and CD19 was the most useful (71.4%) followed by combinations containing CD38 (66.7%), CD22 (57.1%), CD11a (52.4%), and CD58 (33.3%). Using our approach, 60 and 47% of patients had detectable MRD at mid and end induction time points, respectively.
  
  
  CONCLUSIONS
  We have described a relatively cost effective MRD panel which is applicable to over 90% of patients. We hope that this data would encourage more centers in India and other resource constrained health delivery systems to develop MRD assays.
authors.affiliation: Department of Hematology, Christian Medical College, Vellore, Tamil Nadu, India. nvpatkar@gmail.com
authors.forename: Nikhil
authors.initials: N
authors.lastname: Patkar
authors.forename: Ansu Abu
authors.initials: AA
authors.lastname: Alex
authors.forename: Bargavi
authors.initials: B
authors.lastname: B
authors.forename: Rayaz
authors.initials: R
authors.lastname: Ahmed
authors.forename: Aby
authors.initials: A
authors.lastname: Abraham
authors.forename: Biju
authors.initials: B
authors.lastname: George
authors.forename: Auro
authors.initials: A
authors.lastname: Vishwabandya
authors.forename: Alok
authors.initials: A
authors.lastname: Srivastava
authors.forename: Vikram
authors.initials: V
authors.lastname: Mathews
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D001854:Bone Marrow Cells / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003365:Costs and Cost Analysis; D003906:Developing Countries; D005434:Flow Cytometry / Q000191:economics / Q000592:standards*; D006801:Humans; D016130:Immunophenotyping / Q000191:economics / Q000592:standards*; D007194:India; D007223:Infant; D008875:Middle Aged; D018365:Neoplasm, Residual; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000473:pathology; D011379:Prognosis; D012015:Reference Standards; D055815:Young Adult
chemical_list: D015703:Antigens, CD