PRF1 and pertussis: At week 36, there was an inverse correlation between pertussis antibody levels and CD4+ T cell cluster 11 (HLA-DR+Ki67+), terminally differentiated clusters 6,7, and 9 (PD-1 + CD57+Perforin + ), and clusters 10 and 13 (CD38+CD39+), and also the CD8+ T cell cluster 7 (Proliferating EM: Ki67+CD45RA+CD27+CCR7-).