[Eculizumab for the treatment of atypical hemolytic uremic syndrome: case report and revision of the literature]. / Uso do eculizumab na síndrome hemolítica urêmica atípica: relato de caso e revisão da literatura.

SHU atypical (aHUS), that is, not associated with Escherichia coli Shiga toxinproducing, is seen in 5 to 10% of cases of Hemolytic Uremic Syndrome (HUS), and can occur at any age and may be sporadic or familial. The prognosis in these cases is reserved, with high mortality and morbidity in the acute phase of the disease, and about 50% of cases can develop chronic kidney disease. The increased knowledge of the pathogenesis of aHUS (overactivation of the alternative pathway of complement), was accompanied by the appearance of a drug, eculizumab, which acts as an inhibitor of membrane attack complex. Our goal is to report a case of infant with aHUS with excellent clinical and laboratory response with the use of eculizumab. 14 month old infant, previously healthy, male, presented anemia and thrombocytopenia at 12 months of age. He was treated with corticosteroids and forwarded to our service for high blood pressure. However, the scans showed nephrotic proteinuria with renal involvement and hypoalbuminemia with direct Coombs negative. He developed anemia, thrombocytopenia, worsening of renal function and hypertension. Renal biopsy showed thrombotic microangiopathy (TMA). On the non-hemolytic anemia, thrombocytopenia and acute renal failure with histological substrate MAT, was diagnosed of aHUS. The patient received eculizumab excellent clinical and laboratory response. This case shows the importance of early diagnosis and treatment of the aHUS. Eculizumab is effective and keeps long-term remission, avoiding invasive measures such as plasmapheresis, which resolves only part of the picture.

Uso do eculizumab na síndrome hemolítica urêmica atípica: relato de caso e revisão da literatura / Eculizumab for the treatment of atypical hemolytic uremic syndrome: case report and revision of the literature

Síndrome Hemolítico Urêmica atípica (SHUa), isto é, não associada à Escherichia coli, produtora de Shiga toxina, é vista em 5% a 10% dos casos de Síndrome Hemolítico Urêmica (SHU), podendo ocorrer em qualquer idade e ser esporádica ou familiar. O prognóstico nestes casos é reservado, com alta mortalidade e morbidade na fase aguda da doença, e cerca de 50% dos casos podem evoluir para doença renal crônica terminal. O aumento do conhecimento da patôgenese da SHUa (hiperativação da via alternativa do complemento) foi acompanhado pelo surgimento de uma droga, eculizumab, a qual age como inibidor da via final do complemento. Nosso objetivo é relatar um caso de lactente com SHUa que apresentou excelente resposta clínica e laboratorial com o uso de eculizumab. Lactente, 14 meses de idade, sexo masculino, previamente hígido, apresentou quadro de anemia e plaquetopenia aos 12 meses de idade. Foi tratado com corticoterapia e encaminhado ao nosso serviço por hipertensão arterial. Entretanto, os exames demonstraram acometimento renal com proteinúria nefrótica e hipoalbuminemia, com Coombs direto negativo. Evoluiu com anemia, plaquetopenia, piora de função renal e hipertensão. Realizada biópsia renal que mostrou microangiopatia trombótica (MAT). Diante do quadro de anemia não hemolítica, plaquetopenia e insuficiência renal aguda com substrato histológico de MAT, foi feito diagnóstico de SHUa. O paciente recebeu eculizumab, com excelente resposta clínico-laboratorial. Este caso denota a importância de diagnóstico e tratamento precoces nesta entidade grave que é a SHUa. Eculizumab é eficaz e mantém remissão a longo prazo, evitando medidas invasivas como a plasmaferese, a qual resolve apenas parcialmente o quadro.

SHU atypical (aHUS), that is, not associated with Escherichia coli Shiga toxinproducing, is seen in 5 to 10% of cases of Hemolytic Uremic Syndrome (HUS), and can occur at any age and may be sporadic or familial. The prognosis in these cases is reserved, with high mortality and morbidity in the acute phase of the disease, and about 50% of cases can develop chronic kidney disease. The increased knowledge of the pathogenesis of aHUS (overactivation of the alternative pathway of complement), was accompanied by the appearance of a drug, eculizumab, which acts as an inhibitor of membrane attack complex. Our goal is to report a case of infant with aHUS with excellent clinical and laboratory response with the use of eculizumab. 14 month old infant, previously healthy, male, presented anemia and thrombocytopenia at 12 months of age. He was treated with corticosteroids and forwarded to our service for high blood pressure. However, the scans showed nephrotic proteinuria with renal involvement and hypoalbuminemia with direct Coombs negative. He developed anemia, thrombocytopenia, worsening of renal function and hypertension. Renal biopsy showed thrombotic microangiopathy (TMA). On the non-hemolytic anemia, thrombocytopenia and acute renal failure with histological substrate MAT, was diagnosed of aHUS. The patient received eculizumab excellent clinical and laboratory response. This case shows the importance of early diagnosis and treatment of the aHUS. Eculizumab is effective and keeps long-term remission, avoiding invasive measures such as plasmapheresis, which resolves only part of the picture.

Mycoplasma arthritidis superantigen (MAM)-induced macrophage nitric oxide release is MHC class II restricted, interferongamma dependent, and toll-like receptor 4 independent.

Mycoplasma arthritidis causes arthritis in rodents that resembles human rheumatoid arthritis. It produces a superantigen (MAM) that stimulates production of cytokines by making a bridge between lymphocyte T-cell receptor with the appropriate Vbeta chain, and H-2 1-Ealpha MHC class II molecules. Here we studied MAM-induced nitric oxide (NO) production in mouse peritoneal macrophages and found that it was: (1) time and concentration dependent, (2) possibly derived from inducible NOS synthase since it was reduced significantly by amino guanidine pretreatment, (3) restricted to H-2(K) (C3H/HePas and C3H/HeJ) and H-2(d) strains (BALB/c), (4) independent of TLR4 signaling since the coisogenic strains C3H/HePas and C3H/HeJ (TLR4 deficient) produced similar levels of NO following MAM stimulation, (5) potentiated by lipopolysaccharide, and (6) dependent on the presence of nonadherent peritoneal cells. Neutralization of interferon-gamma (IFNgamma in the peritoneal cell cultures with monoclonal antibodies abolished MAM-induced NO production. Addition of rIFNgamma to the adherent cells substituted the nonadherent cells for MAM-induced NO production. A macrophage cell line, J774A.1 (H-2(d)), also produced NO upon MAM stimulation but only when BALB/c spleen lymphocytes were added. Thus, in murine macrophages, MAM induces NO production that is dependent on signaling through MHC class II molecules and IFNgamma but independent of TLR4 expression.