Researchers found two genetic variants on the interleukin-1 beta (IL-1β) gene that predispose patients from India with systemic lupus erythematosus (SLE) to develop kidney and hematological disease symptoms.
The population-based study, “Predisposition of IL-1β (-511 C/T) polymorphism to renal and hematologic disorders in Indian SLE patients,” was published in the journal Gene.
In addition to genetic environmental factors, genetics are an important factor contributing to lupus development and progression. Variations on the genetic sequence of pro-inflammatory proteins or other immune mediators, for example, have been shown to modulate the immune response in lupus, which ultimately affects disease outcomes.
The pro-inflammatory protein IL-1β is known to be involved in lupus. Two specific modification in its genetic sequence – -511 C/T and +3954 C/T – have been linked to increased IL-1β protein levels and disease progression in Asian patients.
A research team led by Anita Nadkarni, PhD, senior researcher at the National Institute of Immunohaematology at the Indian Council of Medical Research, evaluated the impact of those IL-1β genetic variants in a group of Indian lupus patients. A total of 200 patients and 201 healthy volunteers (used as controls) were included in the study.
Lupus patients had significantly higher amounts of the IL-1β protein than the controls. Those with renal and hematological symptoms of the disease had the highest levels of the protein.
To understand why patients had higher levels of the protein, the team examined the IL-1β gene, looking for certain variants. Due to DNA modifications, some variants produce more protein than others.
The team found that lupus patients were nearly twice as likely to have the +3954 C/T variant, while the -511 C/T was found equally in both groups.
However, -511 CC was 2.9 times more likely to be found in lupus nephritis patients compared to lupus patients without that kidney condition. Also, the prevalence of the -511 C version of the gene was 60 percent higher in lupus patients with renal and hematological manifestations.
The researchers concluded that the two IL-1β gene variants were risk factors for disease susceptibility in an Indian lupus population.
“IL-1β gene polymorphisms appear to confer susceptibility to the disease in Indian SLE patients,” the team wrote.