The severe form of COVID-19 share several clinical and laboratory features with four entities gathered under the term "hyperferritinemic syndromes" and including macrophage activation syndrome (MAS), adult-onset Still's disease (AOSD), catastrophic anti-phospholipid syndrome (CAPS) and septic shock. COVID-19 systemic inflammatory reaction and "hyperferritinemic syndromes" are all characterized by high serum ferritin and a lifethreatening hyper-inflammation sustained by a cytokines storm which eventually leads to multi-organ failure. In this review, we analyze the possible epidemiological and molecular mechanisms responsible for hyper-inflammation in patients with severe COVID-19 and we underline the similarities between this condition and "hyperferritinemic syndromes" which would allow considering severe COVID-19 as a fifth member of this spectrum of inflammatory conditions.

This study determined disease activity levels, PASS and MCII of ESSDAI and ESSPRI. These results will help designing future clinical trials in SS. For evaluating systemic complications, the proposal is to include patients with moderate activity (ESSDAI≥5) and define response to treatment as an improvement of ESSDAI at least three points. For addressing patient-reported outcomes, inclusion of patients with unsatisfactory symptom state (ESSPRI≥5) and defining response as an improvement of ESSPRI at least one point or 15% seems reasonable.

This study confirmed that the prevalence of the pSS high-risk subset for severe systemic manifestations is ∼15%. Serological markers might help in the early identification of patients who are candidates to receive more aggressive treatments.