ab1904

Anti-b2 glycoprotein I and anticardiolipin antibodies in leptospirosis, syphilis and Kala-azar

M. Santiago¹, R. Martinelli², A. Ko^3,6, E.A. Reis³, R.D. Fontes⁴, E.G. Nascimento⁵, S. Pierangeli⁷, R. Espinola⁷, A. Gharavi⁷

¹Escola Bahiana de Medicina e Saúde Pœblica/Hospital Santa Izabel, ²Faculdade de Medicina da UFBa, ³Centro de Pesquisas Gonçalo Moniz, Fundação Osvaldo Cruz, ⁴COAS/DST/SESAB, and ⁵PIEJ/SESAB, Salvador, Bahia, Brazil; ⁶Weill Medical College, Cornell University, New York, NY; ⁷Morehouse School of Medicine, Atlanta, Georgia, USA.

ABSTRACT
Objective
Reports have shown that anticardiolipin (aCL) antibodies present in patients with autoimmune diseases are dependent on the cofactor b2 glycoprotein I (b2 GPI), as opposed to aCL antibodies seen in infectious diseases such as syphilis, HIV, hepatitis C, etc. The assay for anti-b2GPI antibodies has been reported to be more specific for antiphospholipid syndrome (APS). However, the prevalence of these antibodies in diseases such as leishmaniasis and leptospirosis remains unknown. The aim of the present study was determine the prevalence of antibodies to cardiolipin and to b2GPI in patients with different infectious diseases, including leptospirosis, syphilis and leishmaniasis.

Methods
Samples from patients with Kala-azar (visceral leishmaniasis), syphilis or leptospirosis were tested for IgG and IgM anticardiolipin and IgG anti-b2GPI antibodies by ELISA.

Results
In patients with Kala-azar the prevalence of IgG aCL, IgM aCL and anti-b2GPI was 6% (2/30), 3% (1/30) and 53% (16/30), respectively. In syphilis the prevalence was 18% (14/74), 13% (10/74) and 10% (8/70), respectively. In leptospirosis the frequency of these antibodies was 23% (9/39), 10% (4/39) and 17% (6/34), respectively. There was no statistical correlation between aCL and anti-b2GPI antibodies in these diseases.

Discussion
This study clearly shows a significant prevalence of anti-b2GPI antibodies in leptospirosis and leishmaniasis and syphilis. This indicates that the assay for anti-b2GPI antibodies should be thoroughly validated before it is introduced as a definitive tool for the diagnosis of APS, testing a larger number of sera from patients with a wider range of clinical conditions.

Key words
Antiphospholipid antibodies, anticardiolipin antibodies, anti-b2 glycoprotein I, syphilis, leptospirosis, Kala-azar.

Support for this project was provided by the Brazilian National Research Council (grants 52.1229/98-7) and FINEP 419 608 6200.

Please address correspondence to: Mittermayer Santiago, MD, Hospital Santa Izabel, Praça Almeida Couto, Nazaré Salvador, Bahia, Brazil CEP 40000-000.
E-mail: mitter@svn.com.br