B-cell subsets in patients with transient hypogammaglobulinemia of infancy, partial IgA deficiency, and selective IgM deficiency.

BACKGROUND: The pathogenesis of some primary humoral immunodeficiencies, such as transient hypogammaglobulinemia of infancy (THI) and immunoglobulin (Ig) A deficiency, remains unknown and can render diagnosis problematic. OBJECTIVE: In the present study, we used flow cytometry to analyze peripheral blood B-cell subsets in patients with THI and unclassified hypogammaglobulinemia (UCH), partial IgA deficiency, and selective IgM deficiency. METHODS: The study population comprised 41 patients with hypogammaglobulinemia (THI, 18; UCH, 23), 16 patients with partial IgA deficiency, and 16 patients with selective IgM deficiency who were admitted to Ankara University Department of Pediatric Immunology-Allergy between January 2010 and April 2011, as well as 29 healthy controls. B-cell subsets were examined according to the EUROclass classification. RESULTS: Age at diagnosis in the hypogammaglobulinemia group ranged between-14 months and 13 years (median, 26 months). Naive B-cell percentages were significantly higher and activated B-cell values lower in the THI patients than in the UCH patients and age-matched healthy controls. Nonswitched (IgM+CD27+IgD+) memory B-cell values were found to be significantly lower in patients with selective IgM deficiency than in healthy controls. No significant differences in B-cell subsets were found in patients with partial IgA deficiency. CONCLUSIONS: Previous reports show that reduced class-switched memory B cell values are associated with CVID, THI, and selective IgA deficiency. Our findings did not support these reports. Furthermore, we observed that naive B cell values were higher in patients with THI. A maturation defect could play a role in the pathogenesis of THI.

B-Cell Subsets in Patients With Transient Hypogammaglobulinemia of Infancy, Partial IgA Deficiency, and Selective IgM Deficiency

Antecedentes: La patogénesis de algunas inmunodeficiencias primarias tales como la hipogammaglobulinemia transitoria de la infancia (THI), el déficit de IgA permanece desconocida y a veces es motivo de un problema en su diagnóstico. Objetivos: El motivo de este estudio fue analizar mediante citometría de flujo, las subclases de células B en sangre periférica en pacientes con THI junto con hipogammaglobulinemias no clasificadas (UCH), deficiencias parciales de IgA y deficiencias selectivas de IgM. Métodos: Se incluyeron 41 pacientes con hipogammaglobulinemia (THI: 18 y UCH: 23 pacientes), 16 con déficit parcial de IgA, 16 con deficiencia selectiva de IgM y 29 controles sanos admitidos en Ankara University, Departamento de Pediatría e Inmunología -Alergia. Se examinaron las subclases de células B de acuerdo con la clasificación Euroclass. Los pacientes fueron vistos entre enero de 2010 y abril de 2011. Resultados: En el grupo de hipogammaglobulinemia, la edad en el diagnóstico se encontraba en un rango entre 14 meses y 13 años (Med: 26 meses). Las células B naive se encontraban significativamente elevadas y las células B activadas disminuidas en el grupo THI respecto al grupo UCH y los controles sanos. Las células B memoria (IgM+ CD27+ IgD+) se encontraban significativamente disminuidas en pacientes con diagnóstico de déficit selectivo de IgM. En la deficiencia parcial de IgA no se encontraron diferencias en las subclases de células B. Conclusiones: Nuestros resultados no confirman resultados previos de una reducción de células B memoria relacionada con CVID, THI y selectiva deficiencia de IgA. Encontramos un aumento de células B naive en pacientes con hipogammaglobulinemia transitoria, sugiriendo un defecto de maduración que puede jugar un papel en la patogénesis de esta enfermedad (AU)

Background: The pathogenesis of some primary humoral immunodeficiencies, such as transient hypogammaglobulinemia of infancy (THI) and immunoglobulin (Ig) A deficiency, remains unknown and can render diagnosis problematic. Objective: In the present study, we used flow cytometry to analyze peripheral blood B-cell subsets in patients with THI and unclassified hypogammaglobulinemia (UCH), partial IgA deficiency, and selective IgM deficiency. Methods: The study population comprised 41 patients with hypogammaglobulinemia (THI, 18; UCH, 23), 16 patients with partial IgA deficiency, and 16 patients with selective IgM deficiency who were admitted to Ankara University Department of Pediatric Immunology- Allergy between January 2010 and April 2011, as well as 29 healthy controls. B-cell subsets were examined according to the EUROclass classification. Results: Age at diagnosis in the hypogammaglobulinemia group ranged between 14 months and 13 years (median, 26 months). Naïve B-cell percentages were significantly higher and activated B-cell values lower in the THI patients than in the UCH patients and age-matched healthy controls. Nonswitched (IgM+CD27+IgD+) memory B-cell values were found to be significantly lower in patients with selective IgM deficiency than in healthy controls. No significant differences in B-cell subsets were found in patients with partial IgA deficiency. Conclusions: Previous reports show that reduced class-switched memory B cell values are associated with CVID, THI, and selective IgA deficiency. Our findings did not support these reports. Furthermore, we observed that naive B cell values were higher in patients with THI. A maturation defect could play a role in the pathogenesis of THI (AU)