This category, termed “phenocopies of primary immunodeficiencies (PIDs),” includes acquired immunodeficiency due to certain anti-cytokine AAbs, notably to interferon gamma (IFNγ), interleukin-6 (IL-6), interleukin-17 (IL-17), interleukin-22 (IL-22), and Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) that result in phenotypes similar to those that occur due to pathogenic variants in genes encoding either these specific cytokines, their receptors or molecules mediating cytokine signal transduction. The gene discussed is IL6; the disease is inborn error of immunity.