medRxiv preprint doi: https://doi.org/10.1101/2020.10.12.20210344; this version posted October 14, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. The alternative complement pathway is activated in protoporphyria patients during sun exposure. Francesca Granata1*; Lorena Duca1; Valentina Brancaleoni1; Silvia Fustinoni2-3; Giacomo De Luca1; Irene Motta1-4; Giovanna Graziadei1; Elena Di Pierro1 1 Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, U.O.C. Medicina Generale, Milano, Italy 2 EPIGET - Epidemiology, Epigenetics, and Toxicology Lab, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy 3 Environmental and Industrial Toxicology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, Italy 4 Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy *Corresponding author: Francesca Granata, MSc Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico Via F. Sforza 3520122 Milan, Italy Email:
[email protected] Tel: +39 0255033363 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.10.12.20210344; this version posted October 14, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. ABSTRACT The homeostasis of tissues in chronic disease is an important function of the alternative pathway (AP) of the complement system (CS).