A north-south worldwide gradient in systemic activity of primary Sjögren syndrome: increased severe disease in patients from southern countries

as printed: Danda, D

as printed: Quartuccio, Luca

as printed: Priori, Roberta

as printed: Kruize, Aike A

as printed: Kwok, S-K

as printed: Wahren-Herlenius, Marie

as printed: Praprotnik, Sonja

as printed: Sene, D

as printed: Bartoloni, Elena

as printed: Solans, R.

as printed: Rischmueller, Maureen

as printed: Mandl, T

as printed: Suzuki, Y

as printed: Isenberg, David A

as printed: Valim, V

as printed: Wiland, Piotr

as printed: Nordmark, Gunnel

as printed: Fraile, G

as printed: Bootsma, Hendrika

as printed: Giacomelli, R.

as printed: Devauchelle-Pensec, Valérie

as printed: Hofauer, Benedikt

as printed: Trevisani, Virginia Fernandes Moça

• Cairo University (EG)

as printed: Gheita, Tamer A

as printed: Atzeni, Fabiola