Selective elimination of mutated monocytes from mutation-positive and mosaic patients. (A) Trypan blue exclusion assay of purified monocytes. Purified monocytes were incubated with or without cLPS (10 ng/mL) and dead cells were counted. Values represent the means (± SD) of 3 mutation-positive patients. *P less than .01 compared with LPS (-) counterparts. (B) Representative intracellular IL-1β staining of PBMCs from patient 7 or healthy controls after incubation with or without cLPS (10 ng/mL) for 24 hours. Numbers in each rectangle are the percentages of total cells. (C) PBMCs from patient 7 were cultured with or without cLPS (10 ng/mL) for 24 hours. CD14-positive and -negative cells were sorted, and DNA was extracted and sequenced for analysis of CIAS1. Chromatograms of the CIAS1 gene at nucleotide position 1709 (black or white arrowhead) from each population of cells are shown. Note that the overlapping “G” peak (black arrowhead) disappeared from LPS-treated CD14-positive cells. The data are representative of 3 independent experiments. (D) CIAS1-mutated monocytes from a mosaic patient were enriched in the dying cell population. Left panel: flow cytometry data of PBMCs from patient 7 stimulated with cLPS for 2 hours. Right panel: chromatograms of the CIAS1 gene at position 1709 (arrowhead), and frequency of the mutant allele as determined by subcloning from each population. The data are representative of 3 independent experiments.