find common lines between multiple files

i have 4 files which are like

       file A
       >TCONS_00000867
       >TCONS_00001442
       >TCONS_00001447
       >TCONS_00001528
       >TCONS_00001529
       >TCONS_00001668
       >TCONS_00001921

       file b
       >TCONS_00001528
       >TCONS_00001529
       >TCONS_00001668
       >TCONS_00001921
       >TCONS_00001922
       >TCONS_00001924

       file c
       >TCONS_00001529
       >TCONS_00001668
       >TCONS_00001921
       >TCONS_00001922
       >TCONS_00001924
       >TCONS_00001956
       >TCONS_00002048

       file d
       >TCONS_00001922
       >TCONS_00001924
       >TCONS_00001956
       >TCONS_00002048

all files contain more than 2000 lines and sorted for first column.

i want to find common lines in all files. i tried awk and grep and comm but not working