Method to identify subjects at higher risk to develop an autoimmune disease based on genetic and/or phenotypic screening for epistatic variants in DDX39B (RS2523506) and IL7R (RS6897932)

An assay comprising:

• measuring an interaction between DDX39B rs2523506 and IL7R rs6897932 by:
• obtaining a biological sample from a subject suspected of having an autoimmune disease;
• and
• detecting in the biological sample an amount of a soluble Interleukin-7 receptor (sIL7R) and an amount of an RNA Helicase DDX39B, whereby higher expression of sIL7R and lower expression of DDX39B identifies the subject from which the biological sample was obtained as having an increased risk of developing an autoimmune disease, when compared to a human subject not having an autoimmune disease.

A method of selecting for treatment a subject with an autoimmune disease caused by decreased levels of RNA Helicase DDX39B, increased levels of soluble interleukin-7 receptor (sIL7R), or both, comprising:

• obtaining a biological sample;
• detecting or measuring a level of expression of RNA Helicase DDX39B, sIL7R, or both in the biological sample, wherein a patient is selected for treatment if a higher secretion of sIL7R is detected, a decrease in the expression or activity of RNA Helicase DDX39B, or both;
• and
• selecting a treatment for the subject that has decreased levels of RNA Helicase DDX39B, increased levels of Sil7R, or both when compared to a sample from a human subject not having an autoimmune disease and increased expression of sIL7R.