Figure 6

Peripheral blood MPP number is elevated in SLE and migrate preferentially to the kidneys. (A) Gating strategy for obtaining human HSC and MPP cell populations from PBMC from healthy (n = 11) and SLE (n = 12) individuals. These representative graphs from a total of gated live cell population (7AAD, orange gate) was initially gated for CD34⁺CD38- progenitor pool (green gate), which was further examined for CD45RA⁻CD90⁺CD49f⁺ HSCs (light blue gate) and CD45RA⁻CD90⁻CD49f⁻ MPPs (purple gate). (B) X–Y graphs showing the percentage of HSCs and MPPs in PBMC-gated and CD34⁺CD38⁻-gated cell populations (and mean values). There are statistically more MPPs in the CD34⁺CD38⁻-gated cell populations that is linked to SLE flare and PGA > 1.5, at the time of sample collection (orange triangles, p < 0.03, Student’s T-test). No statistical difference in HSC percentage between SLE and Healthy PB (p = 0.35, Student’s T-test). M = male subjects. (C) Mice were sacrificed at 5 weeks and kidney-derived cells were subjected into immunostaining with antibodies against human-only surface markers for CD105 and PDGFRα, in order to assess human cell presence. Lympho-gates, granulo-gates and mono-gates represent different immune cell subpopulations and therefore examined separately, according to their FSC/SSC readout N = 4.