Table 7

Summary of four articles on connections to Africa in African-Americans with lupus

Author, yearNObjectiveResultsConclusionsLevel of evidence
Fraser et al, 200073 18To define the haplotypes with C4A-deleted alleles in African-AmericansHaplotypes HLA-DRB1p1503, HLA-B53, B44031 or B18 and HLA-DRB1p0301 and HLA-B53 and B8 were observed in conjunction with C4A gene deletions.This is the first study to define the HLA haplotypes bearing C4A gene deletions in populations of sub-Saharan African ancestryIII
Gilkeson et al, 201155184To define whether a lupus gradient exists between African-Americans and AfricansThe prevalence of serum antinuclear antibodies in the two cohorts was comparable, though there was a significantly increased prevalence of antiphospholipid and anti-Sm antibodies in the Sierra Leone cohort. Seropositivity for common viral infections was significantly higher in women from Sierra Leone, while serum 25-OH vitamin D levels were drastically lower in the Gullah population.While the prevalence of autoimmunity is similar in the two populations, there are significant environmental differences that may impact progression to autoimmune diseaseIII
Kamen et al, 200874
Lodolce et al, 201075
To define the genetic and environmental factors contributing to SLE in the Gullah population
To examine two non-synonymous coding polymorphisms in the deubiquitinating domain of TNFAIP3: F127C, which is in high-linkage disequilibrium with reported SLE-risk variants, and A125 V, which has not been previously studied
The severity of lupus in the Gullah population was similar to that in other African-American populations, whereas skin disease and familial disease prevalence were increased in the Gullah.
Authors discovered a new African-derived risk haplotype that is separate from previously reported risk variants (OR 1.6, p=0.006), along with a rare protective haplotype defined by A125V (OR 0.31, p=0.027).
Findings suggest that there is an increased genetic influence on overall disease in this cohort compared with that in other African-American cohorts, which confirms the unique nature of this cohort
This is the first report of an association between TNFAIP3 polymorphisms and autoimmunity in African-Americans
  • SLE, systemic lupus erythematosus.