A meta-analysis by Pillinger et al. showed a reduced variability of IL-1β, IL-4, IL-6, IL-8 and TNF-α levels in FEP compared to the control group, which, along with the unimodality of the distributions, could suggest the absence of an immune subgroup of patients and the prevalence of cytokine dysregulation in patients with schizophrenia [37]. This evidence concerns the gene IL1B and schizophrenia.