P2RX7 and schizophrenia: Antibodies have also allowed the development of an immunoassay (Cusabio, Houston, TX, USA) to quantify circulating, soluble P2X7 [63], which may have diagnostic potential in sepsis [64], Mycoplasma pneumoniae pneumonia [65], acute myocardial infarction [66], COVID-19 [67], and epilepsy [68], but not schizophrenia [69].