title: Differential expression of BAFF and its receptors in discoid lupus erythematosus patients.
abstract: BACKGROUND
  B-cell activating factor of the TNF family (BAFF) promotes the maturation and survival of B cells. Because BAFF levels are elevated in systemic lupus erythematosus (SLE) patients, BAFF has been the target of emerging therapies for SLE, such as belimumab. Levels of BAFF and its receptors in discoid lupus erythematosus (DLE) patients are unknown.
  
  
  OBJECTIVE
  To compare skin and blood mRNA and protein levels of BAFF and its receptors BAFF-R, TACI, and BCMA in DLE subjects with (DLE+/SLE+ (N=28)) and without SLE (DLE+/SLE- (N=35)), psoriasis subjects (N=11), and normal subjects (N=42).
  
  
  METHODS
  We used quantitative real-time PCR to measure blood and skin BAFF, BAFF-R, TACI, and BCMA mRNA, sandwich ELISAs to measure sera BAFF, and immunohistochemistry to evaluate BAFF and BAFF-R skin protein expression.
  
  
  RESULTS
  BAFF mRNA and protein levels were highest in DLE+/SLE+blood, followed by DLE+/SLE-, psoriasis, and normal blood. BAFF protein also correlated with anti-nuclear antibodies, and autoantibodies against double-stranded DNA, single-stranded DNA, and ribonucleoprotein, and Systemic Lupus Erythematosus Disease Activity Index scores in DLE patients. While showing no difference between DLE+/SLE+ and DLE+/SLE- skin, BAFF and its receptors mRNA were up-regulated in DLE skin vs. normal and psoriasis skin. DLE skin had higher percentages of BAFF-R⁺ inflammatory cells, likely T cells and macrophages, than psoriasis and normal skin.
  
  
  CONCLUSIONS
  BAFF may be a serologic marker of systemic disease in DLE patients. BAFF and its receptors are elevated in DLE skin, suggesting that targeted therapies against these proteins could treat refractory DLE patients.
authors: University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA. Electronic address: ben.chong@utsouthwestern.edu.
authors: Benjamin F
authors: BF
authors: Chong
authors: University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA.
authors: Lin-Chiang
authors: LC
authors: Tseng
authors: University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA.
authors: Andrew
authors: A
authors: Kim
authors: ProPath, Dallas, TX, USA.
authors: Rodney T
authors: RT
authors: Miller
authors: University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA.
authors: Kim B
authors: KB
authors: Yancey
authors: University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA; ProPath, Dallas, TX, USA.
authors: Gregory A
authors: GA
authors: Hosler
mesh_terms: D000328:Adult; D000368:Aged; D053264:B-Cell Activating Factor / Q000032:analysis* / Q000097:blood / Q000235:genetics; D053265:B-Cell Activation Factor Receptor / Q000032:analysis* / Q000097:blood / Q000235:genetics; D005260:Female; D006801:Humans; D008179:Lupus Erythematosus, Discoid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D012867:Skin / Q000737:chemistry / Q000378:metabolism
chemical_list: D053264:B-Cell Activating Factor; D053265:B-Cell Activation Factor Receptor; D012333:RNA, Messenger; C505719:TNFSF13B protein, human
keywords: BAFF; BAFF-R; Discoid lupus erythematosus; Macrophage; Systemic lupus erythematosus; T cell