Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.

Circulating B Cells Subpopulations in Patients with Antiphospholip Syndrome.

Alvarez-Rodriguez1,  Lorena, Lopez-Hoyos1,  Marcos, Calvo-Alen2,  Jaime, del1,  Rafael Barrio, Pompei1,  Orlando, Martinez-Taboada3,  Victor M.

Hospital Universitario Marques de Valdecilla. IFIMAV, Santander, Spain
Hospital Sierrallana, Torrelavega, Spain,
Hospital Universitario Marques de Valdecilla-IFIMAV, Santander, Spain


Antiphospholipid syndrome (APS) is characterized by arterial and/or venous thrombosis and obstetrical complications together with the production of antiphospholipid autoantibodies. Its pathogenesis remains to be elucidated, but the production of autoantibodies suggests that B cells may have some role in APS. Our aim was to describe the peripheral blood frequency of B cells at different stages of maturation in APS.


Frequencies of B cells in peripheral blood of 25 APS patients and 11 SLE (without APS) were determined by flow cytometry. As controls, 12 age- and sex-matched healthy subjects (HC) were used. B cell subsets were identified with a combination of monoclonal antibodies (anti-CD5, -CD10, -CD19, -CD24, -CD27, -CD38, -CD138, -IgM and IgD) conjugated to different fluorochromes. Such a panel allowed us to identify the following B cell subsets: immature, naïve, double negative (DN), non-switched memory, switched memory and plasma cells.


A significant decrease of circulating immature (p=0.006) and naïve (p=0.003) cells in APS than in SLE patients was observed. However, non-switched (p=0.001) and switched memory (p=0.038) B cells from peripheral blood of APS patients were increased as compared with SLE. No differences in circulating DN and plasma cells were observed between both disorders. In addition, naïve B cells were higher in SLE patients than in HC whereas non-switched memory B cells were lower in SLE patients than in HC. No significant differences were found in B cells between HC and APS patients.


Circulating B cells at a more differentiated stage were higher in APS than in SLE, whereas immature B cells were higher in SLE than in APS. These data point for a higher ability of B cells from SLE to mature in the periphery and to broad the spectrum of autoantigens they are reactive against. However, our data are only from the peripheral blood compartment and lack confirmation in bone marrow and germinal centres.

The present work was supported by grants from Roche (Spain) and IFIMAV.

To cite this abstract, please use the following information:
Alvarez-Rodriguez, Lorena, Lopez-Hoyos, Marcos, Calvo-Alen, Jaime, del, Rafael Barrio, Pompei, Orlando, Martinez-Taboada, Victor M.; Circulating B Cells Subpopulations in Patients with Antiphospholip Syndrome. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :16

Abstract Supplement

Meeting Menu