Pemphigus Linked to SLE, but Not RA

Two poster abstracts presented at the 2020 American Academy of Dermatology Virtual Meeting Experience investigated the potential associations between pemphigus and rheumatoid arthritis and systemic lupus erythematosus.^1,2

“Pemphigus defines a group of IgG-mediated autoimmune conditions targeting the squamous epithelium of skin and oral mucosa manifesting as intraepidermal blisters and erosions, which can be severely debilitating,” the authors said. Due to the etiology and chronicity of pemphigus disorders, several investigations into its associations with other autoimmune conditions have been conducted, including systemic lupus erythematosus and rheumatoid arthritis, they added.

In both poster studies, the researchers performed separate systemic reviews and meta-analyses to assess the association between pemphigus and systemic lupus erythematosus and rheumatoid arthritis. They calculated the odds ratio (OR) using random effects model to consider baseline study heterogeneity as assessed with I2 statistics.^1,2

Rheumatoid Arthritis¹

Of the 6 studies included in the meta-analysis, the researchers found no significant association between pemphigus and rheumatoid arthritis (OR 1.52; 95% CI, 0.70-3.34, p=0.24), with heterogeneity (I²=67%).
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“Our results differ to prior studies that suggests pemphigus may belong in the same autoimmune disease cluster with rheumatoid arthritis,” they concluded in their first poster. Our study suggests their underlying autoimmune mechanisms may differ between pemphigus and rheumatoid arthritis.”

SLE²

Of the 4 studies included in the meta-analysis, they found a statistically significant association between pemphigus and SLE (OR 2.16; 95% CI, 1.95-4.25, p=0.03). with heterogeneity (I²=50%).

“Clinicians caring for patients with pemphigus should be aware of this association given its underlying epidemiological, serological, and possible genetic foundation,” the researchers noted in their second poster. “Further research is required to elucidate the molecular basis of this association.”

Reference

1. Phan K, Smith SD. Association between pemphigus and rheumatoid arthritis: Systemic review and meta-analysis. Abstract presented at: 2020 American Academy of Dermatology Virtual Meeting Experience; Jun 12-14, 2020.

2. Phan K, Smith SD. Association between pemphigus and systemic lupus erythematosus: A systemic review and meta-analysis. Abstract presented at: 2020 American Academy of Dermatology Virtual Meeting Experience; Jun 12-14, 2020.