Rules-Based Medicine

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Interleukin-4 (IL-4)

Ultrasensitive Immunoassay


Rules-Based Medicine’s (RBM) has developed and manufactured an ultrasensitive immunoassay to interleukin-4 (IL-4) based on Simoa® bead technology. Being able to accurately quantitate sub-pg/mL levels of IL-4 in human serum and plasma is a valuable clinical research tool for pharmacodynamic analysis in autoimmune diseases.

IL-4 is a type II cytokine produced by CD4+ T-cell helper type 2 (TH2) cells, natural killer T cells, mast cells, eosinophils, basophils, and ILC2 (innate lymphocyte type two cells). IL-4 signals through the IL-4 receptors: type I is a heterodimer with γc and IL-4Ra and type II is a heterodimer with IL-4Ra d IL-13Ra1. IL-4 is a potent differentiator of naïve CD4+ T cells into the TH2 lineage, induces production of IL-5, drives IgE class production in B cells, induces mast cell activation and subsequent production of IL-13, promotes eosinophilic inflammation, and is involved in maturation of macrophages, fibroblasts, epithelial and endothelial cells. As such, IL-4 plays a critical role in induction of TH2 related diseases such as allergies (e.g. asthma, food allergies, atopic dermatitis), neurological diseases (e.g. multiple sclerosis), and periodontitis (through TH2 enhancement). Since IL-4 drives IL-5 and IL-13 production, blocking IL-4 may inhibit most TH2 responses. There are current anti-IL-4 therapies being investigated in multiple clinical trials: pasolizumab (humanized anti-IL4 monoclonal antibody), pitrakinra (a type II IL-4 receptor antagonist) and dupilumab (monoclonal antibody blocker of the type II IL-4 receptor).


Swiss-Prot Accession Number: P05112

Alternate names for this biomarker include:

B-cell stimulatory factor 1, BSF-1, Binetrakin, Lymphocyte stimulatory factor 1, Pitrakinra

Simoa™ Services
Biomarker LLOQ*
(Serum and Plasma)
(Undiluted Samples)
Volume Required
Serum or plasma Other fluids**
Interleukin 4 (IL-4) 0.012 pg/mL 0.006 pg/mL 150 µL 150 µL

* Lower limit of quantitation (LLOQ) represents the lowest amount of an analyte that can be quantitatively determined with acceptable precision. LLOQ is determined by performing 2-fold serial dilutions of Standard to be tested in triplicate over three runs. The percent coefficient of variation (CV) is calculated for each of the dilution replicates, and the LLOQ is determined as the concentration at which the CV is 30%.

** Cerebrospinal fluid, urine, tissue culture supernatants,  bronchoalveolar lavage, synovial fluid, tissue extracts, tears, skin washings, etc.

All assay services are performed in our CLIA-certified laboratory.
Intended for Research Use Only.