Table 3.

Effect of CD19+ B-cell count and other covariables on antibody titer values. Results of linear regression model (§).

Variables	All Observations		Observations with Positive Antibody Titer
	Estimate	p-Value
Intercept	2.86	0.088	4.58	0.068
Log (CD19 count) L	0.43	0.001	0.39	0.008
Time since first vaccination (days)	0.049	0.008	0.022	0.21
Age at vaccination (years)	−0.047	0.027	−0.045	0.03
Insufficiently controlled disease	−1.18	0.024	−0.50	0.47

§ linear regression model: log(antibody titer + 1) = α + β₁ log(CD19 count) + β₂ time since vaccination + β₃ age + ε.