Effects of Procainamide on CTLA-4 and CD28 Expression in Drug-Induced Lupus: A Research Protocol

Abstract

Introduction: Lupus erythematosus is a chronic autoimmune disease affecting over 5 million individuals worldwide, characterized by overactivation of B and T lymphocytes. Of these, 10% of patients are diagnosed with drug- induced lupus (DIL), which is caused by high doses of medications such as procainamide, with 20% of procainamide users developing DIL. CTLA-4 and CD28 receptors on T-cell surfaces bind to B7 proteins on antigen-presenting cells, halting and promoting T-cell activation, respectively. Studies indicate that certain lupus symptoms are linked to abnormal CTLA-4/CD28 expression, resulting in overreactive CD4+ T-cells. However, the exact nature of the relationship between CTLA-4 and lupus remains nonunanimous. Other studies show that procainamide alters DNA methylation⁷, while altered CTLA-4 methylation has been tied to autoimmune disorders. Thus, we hypothesize that procainamide leads to reduced CTLA-4 expression and/or increased CD28 expression, causing DIL symptoms.

Methods: We propose an in vivo experiment involving time-matched mouse models. CITE-seq analyses would be run on isolated T-cells from the splenic samples to obtain transcriptome and epitope data and to examine the expression of CTLA-4, CD28, and other potential genes of interest. To corroborate CITE-seq results, the T-cells would undergo immunohistochemical staining with primary and fluorescent antibodies that bind to CTLA-4/CD28.

Expected Results: Results are expected to indicate decreased CTLA-4 gene and protein expression, or increased CD28 gene and protein expression on the surface of procainamide-treated T-cells.

Discussion: If our analyses prove successful, potential next steps involve using gene editing technologies to screen, pinpoint, and correct the molecular mechanisms implicated in procainamide-induced DIL. Further analysis may also implicate additional or other genes of interest involved in the etiology of the disease.

Conclusion: This study is expected to provide insight into the effect of procainamide on molecular mechanisms involved in DIL. Further applications may involve adjunct therapies aimed at mitigating or preventing the development of DIL symptoms.