Variability of anticardiolipin antibody isotype distribution in 3 geographic populations of patients with systemic lupus erythematosus.
OBJECTIVE
To investigate the prevalence of anticardiolipin antibodies (aCL) and isotype distribution and their clinical associations with the features of the antiphospholipid syndrome (APS) in 3 different ethnic groups of patients with systemic lupus erythematosus (SLE).


METHODS
The study population consisted of 152 African-American, 136 Afro-Caribbean (Jamaican), and 163 Hispanic (Colombian) unselected patients with SLE. Serum samples were studied for the prevalence of aCL and isotype distribution. All aCL measurements were performed in the same laboratory by ELISA.


RESULTS
Positive results for 1 of the 3 aCL isotypes were found in 42 African-Americans (28%), 28 Afro-Caribbeans (21%), and 43 Hispanics (26%). IgG aCL was the dominant isotype in Hispanic and African-American patients, while IgA was the dominant isotype in Afro-Caribbeans. Of note, IgA aCL was found in all Afro-Caribbean patients who were aCL positive, while only 3 patients in this group had IgG aCL and 2 had IgM aCL. Clinical features of the APS were found to correlate better in Hispanics than in African-Americans and Afro-Caribbean patients with aCL isotypes.


CONCLUSIONS
Our data suggest the existence of ethnic differences in the prevalence and isotype distribution of aCL as well as in their clinical relevance in patients with SLE. Further studies of the role of genetic and/or environmental factors in the observed differences are required.
Molina
J F
JF
Department of Medicine, Louisiana State University Medical Center (LSUMCI), New Orleans 70112-2822, USA.
Gutierrez-Ureña
S
S
Molina
J
J
Uribe
O
O
Richards
S
S
De Ceulaer
C
C
Garcia
C
C
Wilson
W A
WA
Gharavi
A E
AE
Espinoza
L R
LR
D000293:Adolescent; D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000032:analysis*; D016736:Antiphospholipid Syndrome / Q000208:ethnology / Q000276:immunology / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003105:Colombia / Q000208:ethnology; D004797:Enzyme-Linked Immunosorbent Assay; D005006:Ethnicity; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007132:Immunoglobulin Isotypes / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis; D007563:Jamaica / Q000208:ethnology; D008180:Lupus Erythematosus, Systemic / Q000208:ethnology* / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014481:United States / Q000208:ethnology
D017153:Antibodies, Anticardiolipin; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M