Complement activation: an atypical presentation of an atypical syndrome.

A 42-year-old Hispanic female and long-distance runner was seen for evaluation of fatigue. Her physical examination showed petechiae and ecchymoses in upper extremities, abdominal distension and bilateral ankle oedema. Laboratory workup revealed anaemia, thrombocytopenia, hypoalbuminemia and proteinuria of 1.4 g/24 hours. No schistocytes were found on peripheral blood smear. CT of her abdomen revealed diffuse small lymphadenopathy and hepatomegaly. Bone marrow biopsy demonstrated normal trilineage hematopoiesis with no hemophagocytosis. The patient was started on oral prednisone with no improvement and was subsequently admitted to the hospital for pulsed steroids, intravenous immunoglobulin and rituximab. Her proteinuria became nephrotic range, and a renal biopsy revealed features of thrombotic microangiopathy limited to the glomerular capillaries. ADAMTS13 was low which is >10% of normal, and a diagnosis of atypical haemolytic-uraemic syndrome (aHUS) was made. Eculizumab was started with prompt response. Whole exome sequencing demonstrated mutation in SPTA1, which has been associated with red blood cell membrane diseases but has not been described in patients with aHUS.

Primary thyroid lymphoma presenting as dermatomyositis: a first case and review of the literature.

A 55-year-old woman presented with a 3-week history of weakness. On examination, she had a heliotrope rash, V-neck and shawl signs. There was symmetric proximal muscle weakness, and 2/5 strength in upper and lower extremities. Laboratory values showed CK 5836, CRP 14.9, erythrocyte sedimentation rate 49, lactate dehydrogenase 633, negative antinuclear antibodies and anti-Jo1 antibodies. Muscle biopsy and immunohistochemistry findings were consistent with dermatomyositis. Treatment with high-dose steroids, cyclophosphamide and intravenous immunoglobulin (IVIG) was started, without improvement of symptoms. She was found to have cold agglutinins with a cold screen titre of 1:256,256. Work up for malignancy ensued. Positron emission tomography-computed tomography (PET-CT) showed increased uptake in the thyroid. Fine-needle thyroid biopsy with flow cytometry studies revealed atypical lymphocytes consistent with diffuse large B-cell lymphoma. The patient underwent R-CHOP therapy, with remarkable improvement of her symptoms. Dermatomyositis associated with primary thyroid lymphoma has not been previously reported. This case reinforces the importance of cancer screening in dermatomyositis patients.

Circulating follicular helper-like T cells in systemic lupus erythematosus: association with disease activity.

OBJECTIVE: To assess circulating follicular helper T (Tfh)-like CD4+ T cells in patients with systemic lupus erythematosus (SLE) and determine their relationship to disease activity. METHODS: Blood samples from patients with SLE, as well as blood samples from patients with Behçet's disease (BD) and healthy individuals as controls, were analyzed. In all samples, circulating Tfh-like cells were enumerated by flow cytometry, using, as markers, expression of CXCR5, inducible T cell costimulator (ICOS), and programmed death 1 (PD-1) protein, as well as secretion of interleukin-21 (IL-21). The frequency of circulating Tfh-like cells was compared to that of circulating plasmablasts (CD19+IgD-CD38+). In addition, the possible association of circulating Tfh-like cells with the SLE Disease Activity Index (SLEDAI) was evaluated. RESULTS: The subset of circulating Tfh-like T cells, identified as CXCR5(high) ICOS(high) PD-1(high) , was expanded in the blood of SLE patients compared to controls. Circulating Tfh-like cells were found to produce IL-21 and had lower expression of CCR7 as compared to that in circulating CXCR5(high) central memory T cells, thereby enabling their distinction. Expression of PD-1, but not ICOS or CXCR5, was significantly elevated in circulating Tfh-like cells from SLE patients compared to controls. PD-1 expression among CXCR5(high) circulating Tfh-like cells correlated with the SLEDAI, frequency of circulating plasmablasts, and anti-double-stranded DNA antibody positivity, but not with disease duration or past organ injury; rather, this cell profile appeared to be a reflection of current active disease. CONCLUSION: Circulating Tfh-like cells are associated with disease activity in SLE, suggesting that their presence indicates abnormal homeostasis of T cell-B cell collaboration, with a causal relationship that is central to disease pathogenesis. These findings also suggest that circulating Tfh-like cells provide a surrogate for aberrant germinal center activity in SLE, and that their PD-1 expression offers a tool for measuring disease activity and monitoring the response to therapies.