High-Dimensional Analysis of Type 2 Lymphocyte Dynamics During Mepolizumab or Dupilumab Treatment in Severe Asthma

Although the type 2 biologics mepolizumab and dupilumab show clinical efficacy in severe asthma, their influence on circulating lymphocytes is largely unknown. Here, we studied their impact on type 2 lymphocytes in severe asthma.

We performed high-parameter flow cytometry analysis of peripheral blood mononuclear cells from 40 patients with severe asthma before, and after 4 and 12 months of mepolizumab (n = 33) or dupilumab (n = 7) treatment, focusing on type 2 lymphocytes. Additionally, we performed single-cell RNA sequencing (scRNA-seq) (n = 3) and stimulation experiments of type 2 lymphocytes (n = 3) to explore transcriptional and functional changes associated with mepolizumab treatment.

Mepolizumab treatment increased circulating type 2 innate lymphoid cell (ILC2), type 2 T helper (Th2) and type 2 cytotoxic (Tc2) cell frequencies, skewing ILC2 towards a CD117^low signature with high CD62L expression, and Th2/Tc2 cells towards a CD45RA^-CD62L⁺ central memory phenotype. Dupilumab-treated patients also showed increased frequencies of total ILC2 and CD117^low ILC2. Mepolizumab treatment reduced the expression of tissue homing receptors CXCR4 in ILC2, and GPR183 in ILC2, Th2, and Tc2 cells while enhancing their type 2 cytokine producing capability in response to alarmins.

Mepolizumab increases the frequencies of circulating ILC2, Th2, and Tc2 cells, with reduced tissue homing receptor expression but increased type 2 cytokine production potential. This reveals a potentially new mechanism for how mepolizumab reduces airway inflammation by re-directing trafficking of inflammatory type 2 lymphocytes away from airway-homing, with implications for the possibility of achieving biologics-free remission in asthma.