ABSTRACT
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. CONCLUSION: 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.
Subject(s)
Antibodies, Anticardiolipin/analysis , Immunoglobulin Isotypes/analysis , Lupus Erythematosus, Systemic/ethnology , Lupus Erythematosus, Systemic/immunology , Adolescent , Adult , Aged , Antiphospholipid Syndrome/ethnology , Antiphospholipid Syndrome/immunology , Antiphospholipid Syndrome/pathology , Child , Child, Preschool , Colombia/ethnology , Enzyme-Linked Immunosorbent Assay , Ethnicity , Female , Humans , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Jamaica/ethnology , Lupus Erythematosus, Systemic/pathology , Male , Middle Aged , United States/ethnologyABSTRACT
Monocytes, synovial fluid (SF) and synovial membrane (SM) macrophages from patients with rheumatoid arthritis (RA) were maintained in short-term tissue culture for up to 10 days, and the synthesis of C4, C2, C3, C5, factor B(B), D, properdin (P), C3b inactivator (C3bINA) and beta 1H globulin studied. Functionally active C2, B, D, P, C3bINA and beta 1H were synthesized by the cells in each type of culture. C4, C3 and C5 could be detected, but were functionally inactive. RA monocytes synthesized more C2 than monocytes from patients with degenerative joint disease (DJD) (P < 0.001). Similar studies revealed that SF macrophages synthesized more C3 than SM macrophages (P < 0.001) which in turn produced more C2 than monocytes (P < 0.001). Other experiments showed that SF macrophages synthesized more of each component than the other cell types. SM macrophages made more C2 than B than RA and DJD monocytes, but synthesized only small quantities of P, D and beta 1H. RA monocytes synthesized more of each component than DJD monocytes. The results of these studies show that (1) in RA, complement components can be synthesized locally in the inflamed joints, and (2) local factors in the joints probably stimulate complement synthesis.
