S100A8 and pachyonychia congenita: As such, the objective of this investigation was to conduct the first case-control study of PC in the United States to determine whether an association exists between H. pylori seropositivity and PC risk in males and females using 15 different multiplex serology antigens: GroEL (HP10), UreA (HP73), HP0231, NapA (HP243), HP0305, HpA (HP410), Cag delta (HP522), CagM (HP537), CagA, HyuA, Catalase (HP875), VacA, HcpC (HP1098), Cad (HP1104), and HP1564.