Well, yes, in response to the claim that this is mainly due to the influence of western theology, the article clearly shows that there is an indisputable Tradition within the Greek and the Eastern Churches itself regarding the Panagia's perfect sinlessness; and this, perhaps, is established by nothing so much as the testimony of Patriarchs known to be anti-Latin and who therefore would never have asserted it unless it were already considered sound doctrine within their own local Tradition. As the article notes,
1. "George Scholarios (+1456), the last Patriarch of the Byzantine Empire, has also left us a homily on the Dormition and an explicit affirmation of the Immaculate Conception. He says that Mary was “all pure from the first moment of her existence” (gegne theion euthus). (6) It is rather strange that the most precise Greek affirmation of the Immaculate Conception should come from the most anti-Latin, the most “Protestantizing” of the patriarchs of Constantinople, Cyril Lukaris (+1638). He too gave a sermon on the Dormition of Our Lady. He said that Mary “was wholly sanctified from the very first moment of her conception (ole egiasmene en aute te sullepsei) when her body was formed and when her soul was united to her body”; and further on he writes: “As for the Panaghia, who is there who does not know that she is pure and immaculate, that she was a spotless instrument, sanctified in her conception and her birth, as befits one who is to contain the One whom nothing can contain?”
Archbishop St. Proclus of Constantinople had said over a millenia ago, [Homily 1:3 in PG 65:683B]: "As He formed her without any stain of her own, so He proceeded from her contracting no stain" See http://catholicpatristics.blogspot.in/2009/03/immaculate-conception.html
Jesus and Mary alone were stainless and sinless from the moment of their conception.
2. It's not true that everyone is immaculately conceived after Adam's fall - Original sin is taught in the synod of orange, "Canon 2 (529 A.D) If anyone asserts that Adam's sin affected him alone and not his descendants also, or at least if he declares that it is only the death of the body which is the punishment for sin, and not also that sin, which is the death of the soul, passed through one man to the whole human race, he does injustice to God and contradicts the Apostle" and it means simply that we are born deprived of indwelling grace until we are born again in Baptism. http://www.ewtn.com/library/Councils/Orange.htm
Original sin, says St. Thomas Aquinas, is formally, the privation of sanctifying grace. Original sin is very clear in early Councils.
"Council of Carthage, Canon 2 (418 A.D) Likewise it seemed good that whosoever denies that infants newly from their mother’s wombs should be baptized, or says that baptism is for remission of sins, but that they derive from Adam no original sin, which needs to be removed by the laver of regeneration, from whence the conclusion follows, that in them the form of baptism for the remission of sins, is to be understood as false and not true, let him be anathema. For no otherwise can be understood what the Apostle says, “By one man sin is come into the world, and death through sin, and so death passed upon all men in that all have sinned,” than the Catholic Church everywhere diffused has always understood it. http://www.earlychurchtexts.com/public/carthage_canons_on_sin_and_grace.htm