Clinical manifestations and expression of CD18 to guide the diagnosis of leukocyte adhesion deficiency type 1

Background: Leukocyte adhesion deficiency type 1 (LAD-1) is an inborn error of immunity characterized by a defect in leukocyte trafficking. Methods: Patients with clinical suspicion of LAD-1 were referred to our institution. Complete blood count and flow cytometric analysis, to identify the expression of CD18, CD11b, and the lymphocyte population phenotyping, were performed, and statistical analysis was completed. Results: We report clinical manifestations and immunological findings of six Mexican patients diagnosed with LAD-1. The diagnosis was based on typical clinical presentation, combined with laboratory demonstration of leukocytosis, and significant reduction or near absence of CD18 and its associated molecules CD11a, CD11b, and CD11c on leukocytes. We found atypical manifestations, not described in other countries, such as early-onset autoimmunity or infections caused by certain microorganisms. Conclusions: Patients with LAD-1 may present with atypical manifestations, making flow cytometry an indispensable tool to confirm the diagnosis. We present the first report of LAD-1 patients in a Latin American country (AU)

La citometría de flujo como auxiliar en el diagnóstico de las inmunodeficiencias primarias humorales / Flow-cytometry as an auxiliary in the diagnosis of primary humoral immunodeficiencies

Resumen Antecedentes: Las deficiencias de anticuerpos abarcan un amplio espectro de patologías y constituyen aproximadamente 50 % de las inmunodeficiencias primarias; con la citometría es posible evaluar el estado inmunológico de forma rápida, efectiva y a bajo costo. Objetivo: Evaluar mediante citometría de flujo, las células de pacientes con tres tipos de inmunodeficiencias primarias humorales. Método: Mediante citometría de flujo se analizaron muestras de sangre de pacientes y sujetos sanos con distintos anticuerpos monoclonales. Resultados: Mediante diversas tinciones se demostró disminución severa de linfocitos B en pacientes con agammaglobulinemia ligada al cromosoma X, la falta de expresión de CD154 en pacientes con síndrome de hiperinmunoglobulina M y heterogeneidad de subpoblaciones de linfocitos B en pacientes con inmunodeficiencia común variable. Conclusión: Con la citometría de flujo es posible realizar el diagnóstico temprano de inmunodeficiencias primarias con un nivel de confianza elevado y, en muchos casos, identificar los genes implicados.

Abstract Background: Antibody deficiencies encompass a wide spectrum of pathologies and constitute approximately 50 % of primary immunodeficiencies; with cytometry, it is possible to evaluate the immune status rapidly, effectively and at low cost. Objective: To assess, by means of flow cytometry, the cells of patients with three types of primary humoral immunodeficiencies. Method: Using flow cytometry, blood samples from patients and healthy subjects were analyzed with different monoclonal antibodies. Results: Using various stains, a severe decrease in B lymphocytes was shown in patients with X-linked agammaglobulinemia, as well as a lack of CD154 expression in patients with hyper-immunoglobulin M syndrome, and heterogeneity of B lymphocyte subpopulations in patients with common variable immunodeficiency. Conclusion: Flow cytometry enables early diagnosis of primary immunodeficiencies with a high level of confidence and, in many cases, identification of the genes involved.