Mild and moderate Mannose Binding Lectin deficiency are associated with systemic lupus erythematosus and lupus nephritis in Brazilian patients / As deficiências leve e moderada de lectina ligadora de manose estão associadas ao lúpus eritematoso sistêmico e à nefrite lúpica em pacientes brasileiros

Abstract Objective The potential association of mannose binding lectin (MBL) deficiency and systemic lupus erythematosus (SLE) has been investigated in several studies, but results have been mixed. One explanation for the conflicting results could be differences in ethnic background of study subjects. In this study we investigated the association of MBL deficiency and SLE in a large cohort of Brazilian SLE patients and controls. Methods Serum MBL and Complement levels were determined for 286 Brazilian adult SLE patients and 301 healthy Brazilian adults as controls. MBL deficiency was classified as mild (<1000 and ≥500 µg/L), moderate (<500 and ≥100 µg/L) or severe (<100 µg/L). Results SLE patients presented higher frequency of mild and moderate MBL deficiency compared to controls. SLE patients with MBL deficiency presented higher frequency of lupus nephritis compared to those without MBL deficiency. MBL deficiency was not associated with any other clinical manifestation, use of immunosuppressant therapy, disease activity, disease severity serum or Complement levels. Conclusion This study shows that an association between MBL deficiency and SLE does exist in the Brazilian population. We also found an association between MBL deficiency and lupus nephritis. These findings support the hypothesis that MBL deficiency contributes to the development of SLE and lupus nephritis.

Resumo Objetivo Vários estudos já investigaram a potencial associação entre a deficiência de lectina de ligação a manose (LLM) e o lúpus eritematoso sistêmico (LES), mas os resultados obtidos são controversos. Uma explicação para esses resultados conflitantes poderia estar nas diferenças étnicas dos indivíduos estudados. Este estudo investigou a associação entre a deficiência de LLM e o LES em uma grande coorte de pacientes brasileiros com LES e controles. Métodos Determinaram-se os níveis séricos de LLM e complemento em 286 pacientes adultos brasileiros com LES e 301 adultos brasileiros saudáveis que atuaram como controles. A deficiência de LLM foi classificada como leve (< 1000 e ≥ 500 µg/L), moderada (< 500 e ≥ 100 µg/L) ou grave (< 100 µg/L). Resultados Os pacientes com LES apresentaram maior frequência de deficiências leve e moderada de LLM em relação aos controles. Os pacientes com LES com deficiência de LLM apresentaram maior frequência de nefrite lúpica em comparação com aqueles sem deficiência de LLM. A deficiência de LLM não esteve associada a qualquer outra manifestação clínica, uso de terapia imunossupressora, atividade da doença, gravidade da doença ou níveis séricos de complemento. Conclusão Este estudo mostra que há uma associação entre a deficiência de LLM e o LES na população brasileira. Encontrou-se também uma associação entre a deficiência de LLM e a nefrite lúpica. Esses resultados apoiam a hipótese de que a deficiência de LLM contribui para o desenvolvimento do LES e da nefrite lúpica.

Down-Syndrome associated with MBL-deficiency, IgG-deficiency, vasculitis and mutated prothrombin / Síndrome de Down asociado a deficiencia de lectina de unión a manosa, deficiencia de IgG, vasculitis y mutación de la protrombina: Informe de un caso

The association of Down syndrome with mannose-binding lectin (MBL)-deficiency, recurrent infections and vasculitis has not been reponed. We repon a 30 year-old female with Down-syndrome associated with MBL-deficiency with the genotype LXA/HYD, IgG-deficiency, recurrent uro-genital infections, cutaneous vasculitis, G20.210A prothrombin mutation, deep venous thrombosis, and pulmonary embolism. MBL-deficiency in combination with IgG deficiency might have favored the development of recurrent uro-genital infections. Immunodeficiency might be also involved in the pathogenesis of cutaneous vasculitis. Deep venous thrombosis and pulmonary embolism were attributed to the genetically determined prothrombotic state and intake of oral contraceptives.

La asociación de síndrome de Down con deficiencia de lectina de unión a manosa, infecciones recurrentes y vasculitis no ha sido informada. Presentamos una mujer de 30 años de edad con síndrome de Down asociado a deficiencia de lectina de unión a mañosa, con el genotipo LXA/HYD, deficiencia de IgG, infecciones urogenitales recurrentes, vasculitis cutánea, mutación de protrombina G20.210A, trombosis venosa profunda y embolia pulmonar. La deficiencia de lectina de unión a manosa combinada con la deficiencia de IgG puede haber favorecido las infecciones urogenitales recurrentes. La inmunodeficiencia puede también tener relación con la patogenia de la vasculitis cutánea. La trombosis venosa profunda y la embolia pulmonar pueden deberse al estado protrombótico derivado de la mutación de protrombina y el uso de contraceptivos orales.

Disease associations of mannose-binding lectin & potential of replacement therapy.

Mannose-binding lectin (MBL) is an important component of the immune defence able to bind to repeating mannose based structural patterns typical of microbial surface (bacteria, viruses, fungi, parasites) leading to opsonization and phagocytosis, and activation of the complement pathway resulting in lysis of the pathogen. MBL thus plays a very important role in the first line of host immune response. MBL deficiency has been implicated in susceptibility and modulating the severity in viral, bacterial, fungal, and protozoan infections. High MBL levels, on the contrary might be helpful to intracellular organisms, which take the advantage of C3 opsonization and C3 receptor on monocytes/macrophages to enter their host. MBL replacement therapy to help patients with MBL deficiency has undergone phase I clinical trials. Phase II and III trials and production of recombinant MBL for replacement therapy are currently underway.

IgA deficiency: clinical correlates with IgG subclass and mannan-binding lectin deficiencies

OBJECTIVE: To characterize an IgA deficient population in terms of the incidence of IgG subclass and mannose-binding lectin (MBL) deficiencies and the type and severity of infections and other associated disorders. BACKGROUND: Selective IgA deficiency is probably the commonest of the primary immunodeficiency disorders and although it may lead to an increased risk for respiratory and gastrointestinal infections and associated to various autoimmune diseases, it may also be asymptomatic. Several studies have suggested the need of a concomitant defect in order for manifestation of its symptoms. METHODS: A total of 27 patients fulfilling the diagnostic criteria of selective IgA deficiency were evaluated for IgG subclass and MBL deficiencies after a thorough medical history, physical examination and pertinent evaluation for concomitant medical conditions. RESULTS: The overall incidence of IgG subclass deficiency found in the IgA deficient group was 18.5. MBL deficiency was found to be 3.7. These frequencies may have been influenced by the age group evaluated and the size of the population studied. Severe infections were more common in patients with combined deficiencies, either IgA and any of the IgG subclasses or IgA and MBL deficiency. Atopy was widely represented in the patients studied. CONCLUSIONS: The observed relationship between combined deficiencies Ig A, IgG subclasses and MBL and the increased representation of severe infections needs to be corroborated in a larger sample of patients with an inclusion of pediatric patients.

Avaliação do gene estrutural da proteína de ligação à lectina (MBL) e sua relação com a transmissão materno-fetal do HIV / Mannan-binding lecting (MBL) and its correlation with maternal-to-child HIV transmission

Avaliou-se a expressão do gene mbl2 em 79 crianças e suas mães HIV positivas com o objetivo de avaliar a sua influência na transmissão vertical. Os pacientes divididos em dois grupos: crianças HIV positivas e suas mães (n=18) e crianças HIV negativas e suas mães (n=61) foram avaliados pelo CH50 e AP50 (ensaios hemolíticos), dosagem e avaliação funcional da MBL, ativação da cascata terminal do complemento (ELISA) e o gene mbl2 (PCR). Os resultados não mostraram diferença significante entre os níveis séricos, atividade funcional e o gene da MBL entre os grupos, excluindo a sua influência sobre a transmissão materno-fetal do HIV. Apoio: FAPESP e DAAD / It was evaluated the mbl2 gene expression in 79 children and their HIV positive mothers with the aim to evaluate its influence on mother-to-child HIV. The patients were divided in two groups: HIV positive children and their mothers (n=18) and HIV negative children and their mothers (n=61) were evaluated by CH50 and AP50 (hemolytic assays); levels and functional MBL and terminal complement cascade (ELISA) and mbl2 gene (PCR). The results didn’t show significant difference amons serum levels, functional activities and MBL gene between the groups, excluding the influence in the mother-to child HIV transmission...