PBMC proliferative kinetics to Nm but not influenza antigens are delayed in patients with XLA. PBMCs from XLA and healthy control patients were stimulated with Nm OMVs (H44/76, TR4, TR10, PorA⁻, LpxA⁻; 1 μg/mL) or influenza antigens (90 ng/mL). Proliferation was assessed by tritiated-thymidine (³HTdR) incorporation during days 3 to 9 of culture. Results are expressed as the mean number of triplicate corrected counts per minute (ccpm). The standard error of the mean cell counts was always less than 10% of the mean value shown. Data are representative of 10 separate experiments, control n = 3 and includes all XLA patients n = 7.