Genetic Predisposition

LE is a multifactorial systemic disease. A genetic background has been suggested by familial aggregation and twin studies (Shai et al. 1999). Several studies have found human leukocyte antigen (HLA) associations in DLE with the A1, B7, B8, DR2, and DR3 haplotypes (Fowler et al. 1985, Knop et al. 1990, Millard et al. 1977). However, other studies have not confirmed these findings (Bielsa et al. 1991, Tongio et al. 1982). In SCLE, associations to HLA A1, B8, DR2, DR3, DQ2, and DRw52 are described (Callen and Klein 1988, Herrereo et al. 1988, Johansson-Stephansson et al. 1989, Provost et al. 1988, Sontheimer et al. 1981). It has been suggested that the HLA-DR antigen associations of SCLE relate more to the anti-Ro/SSA antibody response than to the specific SCLE lesions (Watson et al. 1991). Patients with CLE who generate anti-Ro/SSA antibodies show immunogenetic association with the HLA A1, B8, DRB1*0301 extended haplotype (Meyer et al. 1985, Watson et al. 1991) and a significant negative association with DRB*04 (Stephens et al. 1991). SCLE has also been independently associated with the rare tumor necrosis factor 308A allele, part of the same A1, B8, DRB*0301 extended haplotype (Werth et al. 2000, Wilson et al. 1993).

Genetic deficiencies (e. g., homozygous deficiency of C2, C3, C4, and C5) and C1-esterase inhibitor deficiency have been found in association with SCLE and DLE (Asghar et al. 1991, Meyer et al. 1985, Partanen et al. 1988, Perkins et al. 1994, Provost et al. 1983). Deficiencies in early components of the complement system are significantly associated with LE (Schur 1978, Sullivan 1998). The prevalence of homozygous

Association with tumors:

Clinical presentation: Autoantibodies: Photosensitivity: Drugs and hormones:

Genetic predisposition: Race and sex:

HLA associations, complement deficiencies

Annular erythema as Asian counterpart of SCLE, female predominance

Systemic involvement

ANA titer (>1:320), anti-Ro/SSA antibodies

Family or personal history of PLE

Thiazides, calcium channel blockers, angiotensin-convert ing enzyme inhibitors, estrogens and others

Skin tumors on DLE scars, internal tumors in SCLE

C4A deficiency is approximately 10 times higher in patients with LE than in controls (Howard et al. 1986, Petri et al. 1993). Interestingly, patients with LE associated with complement C2 and C4 deficiencies are said to have a better prognosis than individuals with LE without inherited complement deficiencies (Petri et al. 1993, Ratnoff et al. 1996, Sullivan 1998). Cutaneous and articular involvement is prominent, but pleuropericardial, neurologic, and renal involvement is absent or mild. The prevalence of anti-Ro/SSA antibodies is reported to be much higher than in non-C2-defi-cient patients with LE (Meyer et al. 1985, Provost et al. 1983). Comparison between LE patients with C2 deficiency and a large cohort of unselected patients revealed that photosensitivity, SCLE lesions, and anti-Ro/SSA antibodies are more frequent among C2-deficient patients (Lipsker et al. 2000).

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