pnr 
a numeric vector patient number.
    
rcpage 
a numeric vector, age of recipient (years).
    
donage 
a numeric vector, age of donor (years).
    
type 
a numeric vector, type of leukaemia coded 1: AML, 2: ALL, 3: CML
      for acute myeloid, acute lymphatic, and chronic myeloid leukaemia.
    
preg 
a numeric vector code indicating whether donor has been pregnant. 0: no, 1: yes.
    
index 
a numeric vector  giving an index of mixed epidermal cell-lymphocyte
      reactions.
    
gvhd 
a numeric vector code, graft-versus-host disease, 0: no, 1: yes.
    
time 
a numeric vector, follow-up time
    
dead 
a numeric vector code, 0: no (censored), 1: yes