Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


The Lupus Africa to US Gradient RevisitedGenetic Versus Environmental Factors in Lupus.

Gilkeson1,  Gary S., Kamen4,  Diane L., Ruth3,  Natasha M., Meyer2,  Anna, Maggi5,  Darrius

Med Univ of South Carolina, Charleston, SC
MUSC
MUSC, Charleston, SC
MUSC PO Box 250637, Charleston, SC
West Africa Fistula Foundation

Background:

The Africa to US Lupus Gradient is a widely held belief that lupus is rare in west Africa while common in African Americans. This belief is based on limited assessments in Africa. If true, this gradient would provide novel insight into the genetic versus environmental causation of lupus. Assessing true lupus prevalence in west Africa is impossible at present, we therefore sought to assess prevalence of "autoimmunity", i.e. positive autoantibodies, in lupus unaffecteds.

Methods:

Two unique cohorts were utilized for this study: the Gullah population in South Carolina and comparator patients of the West Africa Fistula Foundation in Sierra Leone. Sierra Leone is the ancestral home of the Gullah. All individuals were screened by history and exam to exclude lupus and SLE in a family member. The cohorts are all female and matched for age. Serum was obtained and autoantibody prevalence, viral seropositivity and vitamin D levels tested to assess autoimmunity prevalence and potential environmental factors implicated in lupus. ANA was done by Hep2 IFA, ACL by ELISA, anti-DNA by Crithidia and ENA by Ochterlony. Viral seroconversion was tested by standard ELISAs.

Results:

A trend towards decreased ANA positivity that was not significant in the Sierra Leoneans was found (Table). A marked increase in APL positivity was found in the Sierra Leoneans, with no difference in antibodies against dsDNA, Sm, or RNP. Sierra Leoneans had significant increased seropositivity for EBV, CMV, HSV1 and HSV2. In addition there was a significant difference in serum 25OH vit D with a mean of 11ng/ml in the Gullah and 36ng/ml in the Sierra Leoneans. There was a trend towards lower vitamin D levels in the Sierra Leoneans who were ANA+ >1/120 (mean 32 for ANA+ and 37 for ANA-). There were only three Sierra Leoneans that were seronegative for CMV/EBV and they were ANA-.

Conclusions:

Overall, there is a trend towards higher ANA reactivity in the Gullah, while ACL positivity is markedly higher in the Africans, possibly related to infections. Thus, autoimmunity is not significantly less common in Africans; differences in the prevalence of clinical lupus remain to be determined. There is a significant difference in environmental factors implicated in lupus including viral seropositivity and vitamin D levels. Further studies are needed to assess the lupus gradient hypothesis and the potential role of environmental factors in disease development.

 SLEIGH Female Unrelated Controls (N = 122)Sierra Leone Females (N = 70)Age Adjusted p-value
ANA Positivity >=1:4035.2%28.5%NS
ANA Positivity >=1:12019.7%15.7%NS
ANA Titer >1:10003.3%4.2%NS
Cardiolipin IgG >204.9%37.1%<0.01
Cardiolipin IgM >200.0%10.0%<0.01
dsDNA or Sm positive0.0%0.0%NS
RNP positive0.8%0.0%NS
Ro (SSA) or La (SSB) positive0.0%2.8%NS

To cite this abstract, please use the following information:
Gilkeson, Gary S., Kamen, Diane L., Ruth, Natasha M., Meyer, Anna, Maggi, Darrius; The Lupus Africa to US Gradient RevisitedGenetic Versus Environmental Factors in Lupus. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :510
DOI: 10.1002/art.28279

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