Background/Purpose:  Macrophage Activation Syndrome, also known as acquired Hemophagocytic Lymphohistiocytosis in adults, is an immune-mediated systemic inflammatory state. It is associated with multisystem organ failure and high mortality. Diagnostic criteria are extrapolated from children with primary Hemophagocytic Lymphohistiocytosis as there is a paucity of literature on adults. Additionally, most recent evidence is reported from non-U.S. populations. These gaps in the literature may contribute to under-recognition and under-diagnosis of adults in the U.S. Study objectives were to characterize the demographic, clinical, and biopsy features of adult Macrophage Activation Syndrome or acquired Hemophagocytic Lymphohistiocytosis at a single American academic medical center; along with treatments, outcomes, and possible predictive factors in the outcomes.

Methods: The study center’s Electronic Health Record was queried for adult patients in the inpatient or outpatient setting between 1/1/2010-8/30/2015 with ICD-9 codes for hyperferritinemia, adult-onset Still’s disease, Macrophage Activation Syndrome, Hemophagocytic Lymphohistiocytosis, or combinations of these. This produced 42 patients. A chart review was performed to confirm diagnosis and patients with only hyperferritinemia or adult-onset Still’s disease were excluded. Patients without primary data or reliable report thereof for the first presentation of the disease were also excluded. A detailed chart review followed.

Results:  Thirteen patients met criteria during the study period. As compared to the global literature, the majority of patients with Macrophage Activation Syndrome or acquired Hemophagocytic Lymphohistiocytosis were male at our center and more often autoimmune-triggered as opposed to viral infection-associated. Ten patients (77%) had biopsy findings or elevated biomarkers for Macrophage Activation Syndrome or acquired Hemophagocytic Lymphohistiocytosis, though soluble IL-2 receptor and CD25 were more commonly positive than bone marrow aspirate. Although cardiopulmonary compromise requiring ICU-level care was common, normal renal function was often maintained. Combination immunosuppressive therapy with anakinra was the most common treatment. Importantly, ten of the eleven patients (91%) whose index encounter was at the medical center survived to discharge.

Conclusion:  This study reviewed data for adult patients from an American population that is under-represented in the literature. Patient demographics and key clinical features differ from globally observed trends. This may reflect characteristics innate to the study center or the limitations of using EHR-captured data retrospectively. Molecular and biochemical markers can provide a diagnosis when pathognomonic hemophagocytes are not seen in the bone marrow or lymph organs. Combination immunosuppressive therapy remains important but survivorship is difficult to predict without standardization of treatment regimens.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/macrophage-activation-syndrome-or-acquired-hemophagocytic-lymphohistiocytosis-in-adults-demographics-clinical-characteristics-and-survivorship-in-an-american-academic-medical-center/