**1. Introduction**

In recent years, the way in which researchers' results, discoveries, and knowledge have been disseminated has changed significantly. The advancement of Internet technology has enabled the rise of social media platforms such as Facebook, Twitter, Reddit, and others to serve as channels where people interact, share opinions, and debate. These forums create communities where people establish relationships and interactions among themselves.

These online communities can influence and can be influenced by other online communities. This spread of influence plays a major role in the spreading of information, some of which may affect people's offline behavior [1].

Content produced on social media can spread quickly throughout these communities, triggering rumors and cascading effects that can deeply influence political decisions, economic choices, social well-being, perceptions, and beliefs [2].

The use of social media text analysis and social network detection is not new in the public health field. Many studies have investigated the areas of forecasting clinical surveillance [3,4] and misinformation within and across health communities [5]. These studies contain considerable evidence suggesting that technology has been useful in the health domain, generating considerable awareness on social media, and helping people who live in remote areas [6] or who have little access to treatment [7].

Most of these studies have focused on epidemic and infectious diseases, while in the field of chronic diseases e fforts have been mainly devoted to well-known diseases like diabetes or cardiovascular disease [8]. To our knowledge, little e ffort has been made to investigate the online communities' dynamics around rare and complex rheumatic diseases, such as systemic lupus erythematosus (SLE), which is a chronic autoimmune disease whose managemen<sup>t</sup> is still challenging due to the variety and complexity of the symptoms. These challenges greatly impact SLE patients' quality of life and social activities [9]. Additionally, SLE also faces significant and complex unmet needs that must be dealt with [10], such as diagnostic delay and high burden of therapy [11], which puts pressure on healthcare costs.

Despite this lack of deep investigation of the social media interaction phenomenon for this complex rheumatic disease, patient associations, healthcare communities, blog pages, and patients are active on social media in order to seek information and increase awareness among the general public. In most cases, patients use these channels for emotional and peer health support [12,13], often searching for new treatments or healthcare decision suggestions [14].
