1 - Solo kills, you get a solo kill score when self buffed and you kill someone without anyone else or any mob dealing dmg to him
2 - Team kills, you get a team kill if you have others buffs or someone else engages combat with the person who gets killed.
3 - losses, how many times you have been killed in PvP.
Wolfe
EDIT: Its silly to have all pvp ranking in one number that goes up or down dependig on how toy perform.