Inmunodeficiencia común variable: caracterización clínica e inmunológica de pacientes e identificación de subgrupos homogéneos con base en la tipificación de subpoblaciones de linfocitos B / Common variable immunodeficiency: Clinical and immunological characterization of patients and homogeneous subgroup definition by means of B lymphocyte subpopulation typing

Introducción. La inmunodeficiencia común variable es un síndrome heterogéneo caracterizado por infecciones recurrentes, hipogammaglobulinemia y producción deficiente de anticuerpos específicos. Las anormalidades en subpoblaciones de linfocitos en sangre periférica, particularmente de linfocitos B, permiten la clasificación de los pacientes en grupos homogéneos. Objetivo. Caracterizar clínica e inmunológicamente los linfocitos B y tipificar sus subpoblaciones en doce pacientes colombianos con inmunodeficiencia común variable, para clasificarlos en grupos homogéneos. Materiales y métodos. Se revisaron las historias clínicas de los pacientes y se evaluaron las inmunoglobulinas séricas, la proliferación de linfocitos y la hipersensibilidad retardada, así como las subpoblaciones de linfocitos y de linfocitos B mediante citometría de flujo. Resultados. Todos los pacientes presentaron infecciones respiratorias o gastrointestinales recurrentes y, algunos, infecciones en otros sistemas. Además, todos presentaban disminución de la IgG, en tanto que la IgA y la IgM fueron bajas en nueve y diez pacientes, respectivamente. En todos hubo disminución de la proliferación de linfocitos inducida por mitógenos, pero fue normal frente a antígenos específicos. La tipificación de subpoblaciones reveló valores elevados de linfocitos T en tres pacientes; siete presentaron disminución en la relación CD4+/CD8+ y, cuatro, linfocitos NK bajos. El conteo de linfocitos B fue normal en once pacientes, ocho de los cuales presentaron linfocitos B de memoria bajos, en tanto que cuatro presentaron aumento de linfocitos B de transición o de linfocitos B CD21 low . Conclusión. La tipificación de subpoblaciones de linfocitos solo permitió asignar a 11 de los pacientes a grupos homogéneos según los esquemas de clasificación internacionales, lo que indica la necesidad de agregar más criterios hasta lograr una clasificación ideal. Este estudio permitirá establecer mejores seguimientos médicos para pacientes con inmunodeficiencia común variable en grupos con alto riesgo de desarrollar complicaciones clínicas.

Introduction: Common variable immunodeficiency is a heterogeneous syndrome characterized by recurrent infections, hypogammaglobulinemia and defective production of specific antibodies. Abnormalities in peripheral blood lymphocyte subpopulations, in particular of B lymphocytes, allow the classification of patients into homogeneous groups. Objective: To perform a clinical and immunological characterization and to evaluate lymphocyte subpopulations of twelve Colombian patients with common variable immunodeficiency in order to define homogeneous groups. Materials and methods: We reviewed medical records and evaluated serum immunoglobulins (Ig), lymphoproliferation, delayed hypersensitivity and used flow cytometry to quantify peripheral blood total lymphocyte and B cell populations. Results: All patients had recurrent respiratory and/or gastrointestinal infections, while some also had infections affecting other systems. All patients had abnormally low serum IgG levels, while IgA and IgM levels were reduced in nine and ten patients, respectively. Lymphoproliferation to mitogen was lower in patients than in healthy controls but lymphoproliferation to specific antigen was normal in all. Flow cytometry revealed high numbers of T cells in three patients, while seven had a low CD4+/CD8+ ratio and four had reduced NK cells . Eleven patients had normal B cell counts, and eight of them also showed decreased memory B lymphocytes, and four had increased transitional or CD21 low B lymphocytes. Conclusion: Lymphocyte typing allowed assigning all but one patient to homogeneous groups according to international classification schemes, indicating the necessity of including more criteria until an ideal classification is achieved. This study will lead to a better medical monitoring of common variable immunodeficiency patients in groups at high risk of developing clinical complications.

Impaired number and function of lymphocytes in patients with common variable immunodeficiency: a consequence of activation-induced cell death / Alteração do número e da função de linfócitos em pacientes com imunodeficiência comum variável: uma consequência da morte celular induzida por alteração

Introduction: Common variable immunodeficiency (CVID) is an immunological disorder characterized by defective antibody production. Objectives: To study lymphocytes number, surface activation molecules, cell markers, lymphoproliferative response, cytokine production, and cell death. Methods: A study was led on thirty four patients with CVID selected from the Division of Clinical Immunology and Allergies of the Faculty of Medicine of São Paulo University (FMUSP), Brazil. Peripheral mononuclear blood cells (PBMC) of CVID patients and healthy individuals were evaluated in regard to the expression of cell surface markers, activation molecules, lymphoproliferative response, cytokine synthesis and apoptosis. Results: CVID patients showed decrease in T and B lymphocyte counts, CD25, CD69, CD40L, and CD70 expression, and low synthesis levels of IL-4 and IL-5. Furthermore, their lymphocytes were more susceptible to apoptosis following activation. Conclusion: The higher susceptibility to apoptosis following activation may also be responsible for the decrease in the expression of activation molecules and CD40L, in cytokine synthesis, and in levels of circulating T and B cells.

Introdução: A imunodeficiência comum variável (CVID) é uma enfermidade imune caracterizada pela produção deficiente de anticorpos. Objetivo: Avaliar o número de linfócitos, moléculas de ativação, resposta linfoproliferativa, produção de citocinas e morte celular. Métodos: Foram selecionados 34 pacientes com CVID na Divisão de Imunologia Clínica e Alergia da Faculdade de Medicina da Universidade de São Paulo (FMUSP), Brasil. Células mononucleares obtidas a partir de sangue periférico (PBMC) foram isoladas para avaliação de marcadores de superfície celular, moléculas de ativação, resposta linfoproliferativa, quantificação de citocinas e apoptose. Resultados: Os pacientes analisados apresentaram diminuição na contagem de linfócitos T e B, expressão de CD25, CD69, CD40L, CD70, e baixa produção de IL-4 e IL-5. Os linfócitos se apresentaram mais suscetíveis à apoptose pós-ativação. Conclusão: A maior susceptibilidade à apoptose pós-ativação pode ser responsável pela diminuição na expressão de moléculas de ativação e CD40L, síntese de citocinas e linfócitos T e B circulantes.