RESUMO
CD40 ligand deficiency (CD40L), currently classified as an inborn error of immunity affecting cellular and humoral immunity, prevalently emerges in boys within the first two years of life. It manifests itself as a decrease in serum IgG, IgA and IgE, with normal or high IgM, defects in T cell proliferation, and decrease in soluble CD40L. These accompany sinopulmonary and/or gastrointestinal infections, and there may be infections caused by pyogenic bacteria, opportunistic infections, autoimmune diseases, and neoplasms. Mild and moderate cases of this deficiency may respond well to prophylactic antibiotic therapy or to human immunoglobulin replacement therapy, in addition to the early treatment of infections. Severe cases can be treated with hematopoietic stem cell transplantation, which allows the healing of such patients, rather than sequelae and a poor progression. Thus, its differential diagnosis with other inborn errors of immunity is essential, especially CD40 deficiency and variable common immunodeficiency; the reason why we have proposed the present literature review.
Assuntos
Ligante de CD40/deficiência , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/diagnóstico , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/terapia , Humanos , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/imunologia , MasculinoRESUMO
INTRODUCTION: CD40 ligand (CD40L) deficiency or X-linked Hyper-IgM syndrome is a severe primary immunodeficiency caused by mutations in the CD40L gene. Despite currently available treatments, CD40L-deficient patients remain susceptible to life-threatening infections and have poor long term survival. Areas covered: Here, we discuss clinical and immunological characteristics of CD40L deficiency as well as current therapeutic strategies used for patient management. This review highlights that beyond B cell defects, patients' susceptibility to opportunistic pathogens might be due to impaired T cell and innate immune responses. In this context, we discuss how better knowledge of CD40L function and regulation may result in the development of new treatments. Expert opinion: Despite the introduction of hematopoietic stem-cell transplantation, immunoglobulin replacement, granulocyte colony-stimulating factor (G-CSF) administration, and prophylactic antibiotic therapies, life-threatening infections still cause high morbidity and mortality among CD40L-deficient patients. The reasons for this inadequate response to current therapies remains poorly understood, but recent reports suggest the involvement of CD40L-CD40 interaction in early stages of the innate immune system ontogeny. The development of novel gene therapeutic approaches and the use of redirected immunotherapies represent alternative treatment methods that could offer reduced morbidity and mortality rates for patients with CD40L deficiency.
Assuntos
Ligante de CD40/deficiência , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Transplante de Células-Tronco Hematopoéticas , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1 , Mutação , Aloenxertos , Animais , Antígenos CD40/genética , Antígenos CD40/imunologia , Ligante de CD40/imunologia , Intervalo Livre de Doença , Terapia Genética , Humanos , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/genética , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/imunologia , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/mortalidade , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/terapia , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , Taxa de SobrevidaRESUMO
Individuals with X-HIGM syndrome fail to express functional CD40 ligand; consequently they cannot mount effective protective antibody responses against pathogenic bacteria. We evaluated, compared, and characterized the humoral immune response of wild type (WT) and C57-CD40L deficient (C57-CD40L(-/-)) mice infected with Citrobacter rodentium. Basal serum isotype levels were similar for IgM and IgG3 among mice, while total IgG and IgG2b concentrations were significantly lower in C57-CD40L(-/-) mice compared with WT. Essentially IgG1 and IgG2c levels were detectable only in WT mice. C57-CD40L(-/-) animals, orally inoculated with 2 × 10(9) CFU, presented several clinical manifestations since the second week of infection and eventually died. In contrast at this time point no clinical manifestations were observed among C57-CD40L(-/-) mice infected with 1 × 10(7) CFU. Infection was subclinical in WT mice inoculated with either bacterial dose. The serum samples from infected mice (1 × 10(7) CFU), collected at day 14 after infection, had similar C. rodentium-specific IgM titres. Although C57-CD40L(-/-) animals had lower IgG and IgG2b titres than WT mice, C57-CD40L(-/-) mice sera displayed complement-mediated bactericidal activity against C. rodentium. C. rodentium-infected C57-CD40L(-/-) mice are capable of producing antibodies that are protective. C57-CD40L(-/-) mouse is a useful surrogate model of X-HIGM syndrome for studying immune responses elicited against pathogens.
Assuntos
Antígenos CD40/biossíntese , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/imunologia , Imunidade Humoral/genética , Imunoglobulina M/imunologia , Animais , Antígenos CD40/imunologia , Citrobacter rodentium/patogenicidade , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/genética , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/patologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Ligantes , Camundongos , Camundongos KnockoutRESUMO
BACKGROUND: Patients with X-linked hyper-IgM syndrome (X-HIGM) due to CD40 ligand (CD40L) mutations are susceptible to fungal pathogens; however, the underlying susceptibility mechanisms remain poorly understood. OBJECTIVE: To determine whether monocyte-derived dendritic cells (DCs) from patients with X-HIGM exhibit normal responses to fungal pathogens. METHODS: DCs from patients and controls were evaluated for the expression of costimulatory (CD80 and CD86) and MHC class II molecules and for their ability to produce IL-12 and IL-10 in response to Candida albicans and Paracoccidioides brasiliensis. We also evaluated the ability of C albicans- and P brasiliensis-pulsed mature DCs to induce autologous T-cell proliferation, generation of T helper (T(H)) 17 cells, and production of IFN-γ, TGF-ß, IL-4, IL-5, and IL-17. RESULTS: Immature DCs from patients with X-HIGM showed reduced expression of CD80, CD86, and HLA-DR, which could be reversed by exogenous trimeric soluble CD40L. Most important, mature DCs from patients with X-HIGM differentiated by coculturing DCs with fungi secreted minimal amounts of IL-12 but substantial amounts of IL-10 compared with mature DCs from normal individuals. Coculture of mature DCs from X-HIGM patients with autologous T cells led to low IFN-γ production, whereas IL-4 and IL-5 production was increased. T-cell proliferation and IL-17 secretion were normal. Finally, in vitro incubation with soluble CD40L reversed the decreased IL-12 production and the skewed T(H)2 pattern response. CONCLUSION: Absence of CD40L during monocyte/DC differentiation leads to functional DC abnormalities, which may contribute to the susceptibility to fungal infections in patients with X-HIGM.