• Transplantation of marginal grafts, development or renal failure greater than RIFLE class 2, transfusion of more than 10 units of FFP, respiratory failure, MELD score greater than 23, transfusion of more than seven units of RBC and sepsis are predictors for increased length of stay in the ICU. Angiotensin-converting enzyme 2 autoantibodies: further evidence for a role of the renin-angiotensin system in inflammation Traditionally viewed as important in the regulation of blood pressure, the renin-angiotensin system - and specifically the angiotensin-converting enzyme (ACE)-angiotensin (Ang) II-AT(1 )receptor axis - may play a prominent role to promote inflammation and fibrosis. ACE2, a new component of the renin-angiotensin system, has emerged as a key enzyme that selectively degrades Ang II and generates Ang-(1-7), a bioactive peptide with anti-inflammatory and anti-fibrotic actions. Takahashi and colleagues demonstrate circulating titers of inhibitory autoantibodies against ACE2 in patients with systemic sclerosis. The current study reveals a potentially novel mechanism to attenuate the catalytic activity of ACE2, thereby promoting the actions of Ang II. In the present issue of Arthritis Research & Th erapy, Takahashi and colleagues assessed circulating levels of ACE2 in patients with connective tissue pathologies including pulmonary hypertension and persistent digital ischemia [1] . In comparison with normal controls, patients with overt vasculopathy expressed signifi cantly higher amounts of ACE2 protein in the circulation. Th ese patients, however, exhibited reduced ACE2 activity in serum and circulating autoantibodies against the enzyme. Th ere are few reports on the circulating levels of ACE2 in humans or experimental models, possibly refl ecting the diffi culty of obtaining a consistent measure ment of the enzymatic activity. Th e current study reveals a potentially novel mechanism to attenuate the catalytic activity of ACE2, thereby promoting the infl ammatory actions of Ang II.