INTRODUCTION
Since December 2019, cases of severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) infection leading to a novel disease called
COVID-19 were initially identified in China. SARS-CoV-2 infection causes
respiratory symptoms that range from mild forms of presentation to more
serious ones that can risk patients’ lives, causing pneumonia, and
damage to other organs, particularly the immune and blood system
[1-3]. This disease has rapidly expanded to multiple countries
leading to a pandemic situation in March 2020 now affecting 5.595.091
individuals worldwide, with a global mortality of 350.547 deaths on May
27th. Today, the situation is dramatic in some European countries, such
as Spain with 236.259 cases and 27.117 deaths, being the
2nd country in the world with higher COVID-19
mortality per capita, following Belgium [4]. This official mortality
numbers only reflect the casualties occurring in the hospitals, not in
nursing homes or at home, and considering the low availability of
accurate COVID-19 diagnostic tests, the current situation in Spain could
unfortunately be worse. Furthermore, some patients are asymptomatic
[5, 6] and the current prevalence reflects a possible underdiagnosis
of the infection that has facilitated the disease expansion. This,
together with the massive social and political activities that were
promoted in Spain in early March in spite of the well-known previous
recommendations of the WHO could influence this rapid progression.
Severe cases of the disease represent about 15% of COVID-19 patients
[7] and require their hospitalization. Given the progressive spread
of the pandemic in relation to the available health resources, it is
essential to find new equally effective treatments, especially when
evidence indicates that a rapid shortage of some of the existing
treatments’ stock may occur. Therefore, there is an urgent need to find
novel treatments in the early stages of COVID-19 to prevent the
progression to severe forms of the disease. Evidence suggests that the
hyperactivation of the immune response is of paramount relevance in
COVID-19 progression. The accumulated knowledge about the
pathophysiology of this disease reveals a crucial involvement of
different molecules of the main inflammatory pathways, including
interleukins 1, 6 and 8 (IL-1, IL-6, IL-8) and tumour necrosis factor
alpha (TNFα). Currently, drugs inhibiting some of these pathways are
used in the routine management of COVID-19, although results from
clinical trials are still required to corroborate their effectiveness
[8]. Clear examples are anti-IL-6 compounds for patients with severe
forms of COVID-19 [9-11] and hydroxychloroquine, widely used and
highly questioned that has been now withdrawn from the clinical trials
due to the serious adverse effects [12-13].
Immunomodulated inflammatory diseases (IMIDs) are a group of unrelated
and highly diverse conditions, such as rheumatoid arthritis and
psoriasis, that share a common pathogenesis pathway, i.e., an immune
dysregulation leading to an imbalance in inflammatory cytokines.
Treatments to relieve IMIDs symptoms share similar mechanisms of action
and are namely disease modifying antirheumatic drugs (DMARDs),
subdivided into two main subgroups: synthetic and biological. Biological
DMARDs (bDMARDs) are monoclonal antibodies that have a much higher
affinity and selectivity for the targeted protein than synthetic DMARDs
(sDMARDs). Patients with an autoimmune disease might be at higher risk
of developing severe infections, as these medications are
immunosuppressants [14]. In that context, the Rheumatology,
Dermatology and Gastroenterology services of Hospital del Mar began to
follow-up more closely on their patients and, surprisingly, they
reported less COVID-19 symptoms than expected. Considering the role of
the immune system in COVID-19 progression and that these
immunomodulatory treatments are not associated with worse COVID-19
outcomes [15] we hypothesize that specific compounds used in IMIDs
treatment could provide therapeutic benefits in early stages of
COVID-19.