Background Macrophage activation syndrome (MAS) is a potentially deadly complication that can occur in the course of an autoimmune disease such as systemic lupus erythematosus (SLE), especially in pediatric patients.

The MAS complicating SLE is considered as a part of acquired hemophagocytic lymphohistiocytic syndrome (HLH). Clinically and laboratory abnormalities include fever, pancytopenia, hepatosplenomegaly, liver dysfunction, CNS involvement and coagulopathy, confirming the diagnosis the presence of hemophagocitosys in bone marrow. Although it is considered that his association with SLE is rare, it is probably under diagnosed.

Objectives To describe the spectrum of clinical and laboratory features, treatment and outcome of patients with MAS associated with SLE assessed in a Rheumatology Unit.

Methods Data were collected, retrospectively, from patient with SAM associated with SLE, confirmed by bone marrow biopsy, admitted to our hospital between January 2009 and October 2014. Were collected demographic data, clinical and laboratory features, details regarding the presence on any infectious disease, treatment for MAS, concomitant medication and outcome of MAS.

Results 5 cases were identified, 80% women with a mean age at diagnosis of SLE of 28 years (range: 18-45). The time to development of MAS was variable; in one case it was the initial presentation, while in others it appeared at 6 months, 7, 11 and 31 years, respectively after de SLE diagnosis. There was a history of recent antibiotic treatment in all cases, introduction of new drugs in 3 of them (ibuprofen, azathioprine and rituximab, respectively) and previous bacterial infection in 2 cases. The clinical manifestations: constitutional symptoms with fever (5/5), hepatomegaly (4/5), splenomegaly (4/5), hemorrhagic manifestations (4/5), CNS involvement (3/5) abdominal pain (1/5) and diarrhea (1/5). All patients had pancytopenia, hypertransaminasemia, elevated LDH and ferritin, and hypertriglyceridemia, increased pancreatic enzymes, coagulopathy in 4/5 and 2/5had hyponatremia, but no low fibrinogen was found. All patients received pulse of methylprednisolone and 4 of them cyclosporine, with favorable response in 3 cases. A refractory case was treated with etoposide and another one with i.v. cyclophosphamide with the torpid evolution. The patient died after an infectious complication.

Conclusions The MAS can appear early or after several years of evolution of SLE, in most cases with one or more identifiable triggers. In our series, all patients met criteria for diagnosis according to HLH-2014 protocol. We want to highlight the pancreatic alteration in most of the cases, one of the patient initially was diagnosed as having lupus pancreatitis. MAS-related mortality is quite high (40%), so it is necessary an early diagnosis and an aggressive treatment.

Disclosure of Interest None declared