Hemophagocytic lymphohistiocytosis in a patient with Goodpasture's syndrome: a rare clinical association.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening clinical syndrome. HLH can occur in the setting of an autoimmune disease, chronic immunosuppression, malignancy, and infection. We discuss a rare case of a young woman who was diagnosed with Goodpasture's syndrome that was most likely complicated by HLH. To the best of our knowledge, this is the first report of HLH in the setting of this rare autoimmune disease.

Case Report: A 31-year-old woman who was diagnosed with Goodpasture's syndrome 7 years prior presented with febrile neutropenia. She was initially receiving treatment with azathioprine and prednisone, which was subsequently switched to hydroxychloroquine. Over time, she had developed polyarthritis and was later diagnosed with MPO-ANCA-positive vasculitides. On this admission, her clinical status deteriorated from persistent pancytopenia. This was initially attributed to the immunosuppressive effect of hydroxychloroquine. A bone marrow biopsy was performed and revealed hypercellular bone marrow without any cytogenetic abnormalities. Due to a prolonged pancytopenia thought to be of autoimmune etiology, treatment with high-dose steroids was initiated. With the persistent febrile episodes, hepatosplenomegaly on examination, and laboratory workup that revealed hyperferritinemia and pancytopenia, HLH syndrome was suspected. A repeat bone marrow biopsy confirmed this diagnosis with the presence of hemophagocytosis, demonstrated by the presence of histiocytes engulfing erythroid cells. She also met 5 of 8 diagnostic criteria, which confirmed the diagnosis of HLH. The patient eventually died despite aggressive treatment with high-dose steroid therapy for her autoimmune disorder, as well intravenous antibiotics and supportive care for her underlying infections.

Conclusions: HLH is a syndrome marked by a hyper-inflammatory state aggravated by specific triggers. To make the diagnosis of HLH, at least 5 of the 8 criteria must be met. Treatment involves suppression of the overwhelming inflammatory response by the use of immunomodulators. The mortality rate can range from 50-90% due to delayed recognition and onset of treatment. Here, we present a rare case of Goodpasture's syndrome with overlap and pauci-immune vasculitis, which may have triggered the HLH. This correlation has not been described before in the literature.