This function was further elaborated by Chen S, wherein the combined utilization of dupilumab in the form of an add-on treatment maintained disease control in individuals with refractory pemphigus vulgaris and pulmonary TB.[69] It was previously reported that there was a considerable variation in individuals with TB and healthy subjects concerning IL-4 production, as the diseased individuals depicted a Th2 immune response mode, while TB-positive healthy people showed a Th1 mode in vitro.[70] Surcel et al[71] observed a similar phenomenon. The gene discussed is IL4; the disease is tuberculosis.