IL6 and acquired immunodeficiency: 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.