IL-1<i>β</i>and IL-6 Are Highly Expressed in RF+IgE+ Systemic Lupus Erythematous Subtype

Abstract

<i>Background.</i> Systemic lupus erythematosus (SLE) is an autoimmune disease with great heterogeneity in pathogenesis and clinical symptoms. Rheumatoid factor (RF) is one key indicator for rheumatoid arthritis (RA) while immunoglobulin E (IgE) is associated with type I hypersensitivity. To better categorize SLE subtypes, we determined the dominant cytokines based on familial SLE patients. <i>Methods.</i> RF, IgE, and multiple cytokines (i.e., IL-1<i>β</i>, IL-6, IL-8, IL-10, IL-17, IFN-<i>γ</i>, IP-10, MCP-1, and MIP-1<i>β</i>) were measured in sera of familial SLE patients (<i>n</i> = 3), noninherited SLE patients (<i>n</i> = 108), and healthy controls (<i>n</i> = 80). <i>Results.</i> Three familial SLE patients and 5 noninherited SLE cases are with features of RF+IgE+. These RF+IgE+ SLE patients expressed significantly higher levels of IL-1<i>β</i> and IL-6 than the other SLE patients (<i>P</i> < 0.05). IL-6 correlated with both IgE and IL-1<i>β</i> levels in RF+IgE+ SLE patients (<i>r</i>² = 0.583, <i>P</i> = 0.027; <i>r</i>² = 0.847, <i>P</i> = 0.001), and IgE also correlated with IL-1<i>β</i> (<i>r</i>² = 0.567, <i>P</i> = 0.031). <i>Conclusion.</i> Both IL-1<i>β</i> and IL-6 are highly expressed cytokines in RF+IgE+ SLE subtype which may be related to the pathogenesis of this special SLE subtype and provide accurate treatment strategy by neutralizing IL-1<i>β</i> and IL-6.