B lymphocyte alterations accompany abatacept resistance in new-onset type 1 diabetes
Peter S. Linsley, Carla J. Greenbaum, Cate Speake, S. Alice Long, Matthew J. Dufort
Peter S. Linsley, Carla J. Greenbaum, Cate Speake, S. Alice Long, Matthew J. Dufort
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Research Article Therapeutics

B lymphocyte alterations accompany abatacept resistance in new-onset type 1 diabetes

Abstract

Costimulatory interactions control T cell activation at sites of activated antigen-presenting cells, including B cells. Blockade of the CD28/CD80/CD86 costimulatory axis with CTLA4Ig (abatacept) is widely used to treat certain autoimmune diseases. While transiently effective in subjects with new-onset type 1 diabetes (T1D), abatacept did not induce long-lasting immune tolerance. To elucidate mechanisms limiting immune tolerance in T1D, we performed unbiased analysis of whole blood transcriptomes and targeted measurements of cell subset levels in subjects from a clinical trial of abatacept in new-onset T1D. We showed that individual subjects displayed age-related immune phenotypes (“immunotypes”) at baseline, characterized by elevated levels of B cells or neutrophils, that accompanied rapid or slow progression, respectively, in both abatacept- and placebo-treated groups. A more pronounced immunotype was exhibited by a subset of subjects showing poor response (resistance) to abatacept. This resistance immunotype was characterized by a transient increase in activated B cells (one of the cell types that binds abatacept), reprogrammed costimulatory ligand gene expression, and reduced inhibition of anti-insulin antibodies. Our findings identify immunotypes in T1D subjects that are linked to the rate of disease progression, both in placebo- and abatacept-treated subjects. Furthermore, our results suggest therapeutic approaches to restore immune tolerance in T1D.

Authors

Peter S. Linsley, Carla J. Greenbaum, Cate Speake, S. Alice Long, Matthew J. Dufort

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Figure 4

Flow cytometry shows that B cells and neutrophils were elevated in abatacept-treated NR and R subjects, respectively.

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Flow cytometry shows that B cells and neutrophils were elevated in abata...
Percentages of the indicated cell subsets determined by flow cytometry for abatacept-treated subjects were normalized by Z scores (value – mean of values for each subset)/(SD of values for each subset) and were plotted versus time of visit (x axis). The vertical dotted lines denote the day of the last dose of abatacept (day 700). Comparisons between groups were determined using a mixed-effects linear model with the lmer R package: value ~ visit + group + visit:group + (1 | id). This model contained fixed-effect terms for visit (days) and group; an interaction term for visit and group (i.e., changes in group over time); and a random effect for subject (id). P values determined by linear modeling and are shown as P values for group/P value for visit/group interaction. (A) Cell populations determined from side versus forward light scattering. Values represent viable cells determined by 7AAD dye exclusion. Mean numbers before normalization: granulocytes, 50%; lymphocytes, 43%; and monocytes, 5%. There were n = 6–17 R and n = 21–48 NR subjects at each visit. (B) Cell populations determined using immunofluorescence. Mean numbers before normalization: B cells (lymph/CD14–/CD3–/CD19+), 16%; T cells (lymph/CD14–/CD3+/CD19–), 75%; and monocytes (mono/CD3–CD19–/CD14+), 74%. There were n = 14–19 R and n = 39–46 NR subjects at each visit. This figure is representative of 2 flow cytometry experiments that had similar results. *****P < 1 × 10–5; **P < 1 × 10–2; *P ≥ 1 × 10–2 and < 0.05.