RESUMO
BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE: We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS: Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.
Assuntos
Linfócitos B/imunologia , Diferenciação Celular/imunologia , Imunodeficiência de Variável Comum/imunologia , Endotoxemia/imunologia , Deficiência de IgA/imunologia , Linfócitos T Reguladores/imunologia , Adolescente , Adulto , Linfócitos B/patologia , Criança , Pré-Escolar , Imunodeficiência de Variável Comum/patologia , Endotoxemia/patologia , Feminino , Humanos , Deficiência de IgA/patologia , Masculino , Pessoa de Meia-Idade , Linfócitos T Reguladores/patologiaRESUMO
A doença por depósito linear de imunoglobulina A (IgA) é um processo mucocutâneo crônico, raro e de origem auto-imune, caracterizado por depósitos lineares do anticorpo ao longo da membrana basal da pele e mucosas. O estudo da enfermidade é de grande importância, visto que a mesma é de complexo diagnóstico e tratamento, além de sua etiopatogenia não estar ainda definida. O presente artigo teve por objetivo revisar a literatura referente à doença da IgA linear, abordando suas características clínicas, diagnóstico diferencial e alternativas de tratamento
Assuntos
Masculino , Feminino , Criança , Adulto , Deficiência de IgA/diagnóstico , Deficiência de IgA/patologia , Doenças Autoimunes/diagnóstico , Imunoglobulina A Secretora/imunologia , Imunoglobulina A Secretora , Imunofluorescência/métodos , Membrana Basal/imunologia , Membrana Basal/lesõesRESUMO
We report a 1-year-old boy with an extensive cutaneous vascular malformation, oculocutaneous pigmentation, and severe neurologic abnormalities from birth, as well as a selective IgA deficiency. Ultrastructural study demonstrated prominent endothelial cells in the luminal of the blood vessels. The diagnosis of phacomatosis pigmentovascularis type IIb seemed appropriate for this patient.