Inborn errors of immunity illuminate mechanisms of human immunology and pave the road to precision medicine

Abstract

The Yellow Brick Road leads Dorothy through Oz to the Emerald City-a luminescent green metropolis where she hopes to meet the great and powerful Wizard. The Emerald City is the destination of Dorothy's journey, where desires become reality. Arguably, the "Emerald City" for most physician-scientists caring for patients with inborn errors of immunity (IEI) is to apply effective therapies that target the specific impaired cell type/pathway, while avoiding detrimental effects on the rest of the immune system and other tissues (Figure 1). That is, to use the right treatment, at the right time, for the right patient-precision medicine at its best. The journey to this Emerald City has always started with the patient's symptoms and history. However, the constellation of these clinical clues has significantly changed over time, making it more challenging to begin the odyssey down the yellow brick road. In 1952, Dr. Ogden Bruton started his journey with patients who had recurrent pneumonias.Along the road, he found that they lacked serum γ-globulins. He then discovered a causative single gene defect, inherited as a Mendelian trait with full penetrance. Finally, he arrived at the targeted destination of immunoglobulin replacement therapy. 1 Today, neither the starting point nor the road that follows are as straight and smooth.