(A) Experimental design: After 1 DSS cycle (1.5%), lipodystrophic or WT mice were transplanted with 500–600 mg adipose tissue from WT or leptin-deficient ob/ob donors by mini-laparotomy before undergoing another 2 cycles of DSS. Image on right shows vascularized transplanted fat 1 month after surgery. (B) Weight change of transplanted fat tissue relative to baseline. (C) Plasma leptin levels (n = 4–9). (D) Representative images of H&E- stained colon sections from transplanted versus nontransplanted DSS-treated animals. Scale bars: 100 μm. (E) Box-and-whisker plots summarizing the histologic inflammation score of fat-transplanted and nontransplanted animals. Data shown were pooled from 2 independent transplantation experiments (bold symbols) and additional control data points derived from nontransplantation DSS experiments (light gray) shown in Figure 3 (n = 4–18). (F) Liver weights of transplanted WT and Pparg^fl/fl Adipoq-Cre mice (n = 4–18; data were pooled from 5 experiments). (G) Representative FACS plots showing IFN-γ and IL-17A production in colonic CD4⁺ T cells. UNSTIM., unstimulated. (H) Box-and-whisker plots summarizing absolute numbers of IFN-γ– and IL-17A–producing CD4⁺ T cells normalized to WT mice (n = 4–18; data were pooled from 5 experiments). Statistical differences were calculated by 1-way ANOVA with Šídák’s correction. Each point represents 1 mouse; boxes range from the 25th-75th percentiles. Whisker plots show the minimum (smallest) and maximum (largest) values while the line in the box indicates the median. (I) Experimental setup and representative FACS plots showing IFN-γ– and IL-17A–producing CD4⁺ T cells in peripheral blood of a patient with AGLCD before and 4 days after daily recombinant leptin substitution. transpl., transplantation. Data indicate the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 1-way ANOVA with Tukey’s multiple comparisons test for B, C, E, F, and H.