Immune reconstitution 20 years after treatment with alemtuzumab in a rheumatoid arthritis cohort: implications for lymphocyte depleting therapies

Table 7 Responses to vaccination in alemtuzumab (ALEM) and control cohorts (CON)against diphtheria, tetanus, polio virus (P1-P3), pneumococcal antigen and influenza

	Diphtheria toxoid		Tetanus Toxoid		Poliovirus
	Diphtheria toxoid		Tetanus Toxoid		P1		P2		P3		Pneumococcus antigen
	Alem (n = 6)	Controls (n = 4)	Alem (n = 6)	Con (n = 4)	Alem (n = 6)	Con (n = 4)	Alem (n = 6)	Con (n = 4)	Alem (n = 6)	Con (n = 4)	Alem (n = 7)	Con (n = 6)
Seroprotection rate, %	66	25	100	100	100	100	83.3	100	83.3	100	_
Seroconversion rate, %	33	25	66.7	50	50	100	16.6	100	83.3	100	_
% Satisfactory response	_										66	0
Influenza vaccine titres			A/Cal/7/09		A/Texas/50/12		B/Mass/02/12
Influenza vaccine titres			Alem	Con	Alem	Con	Alem	Con
Patients vaccinated at interview Alem n = 4 Controls, n = 3	GMT pre-vaccination		2.92	4.82	3.27	5.96	1.88	2.74
	GMT post-vaccination		3.42	5.16	3.53	6.17	1.98	2.61
	Seroconversion factor		1.16	1.07	1.08	1.03	1.05	0.85
	Seroprotection rate, %		50	66.7	50	100	25	33.3
	Seroconversion rate, %		25	0	0	0	0	0
Alem* n = 9 Controls* n = 8	Seroprotection rate, %		22	87.5	56	87.5	11	37.5

Tetanus and diphtheria seroprotection was achieved when respective IgG titres were >1.0 IU/ml and seroconversion was defined as new seroprotection. For polio subtypes (P1-P3) seroprotection was a neutralizing antibody titre of ≥1:8 and seroconversion a ≥ fourfold increase in titres. Satisfactory response for pneumococcal antigen was defined as a twofold or more increase from vaccination baseline in antibody concentrations in six or more of 12 pneumococcal serotypes (1, 3, 4, 5, 6B, 7 F, 9 V, 14, 19A, 19 F, 23 F and 18C). For influenza haemagglutination inhibition (HAI) titres >1:40 were defined as seroprotective and seroconversion was defined as rises from negative titres to values of =/>1:40 (or fourfold titre increase if values were above baseline). Seroconversion factor was defined as the fold increase in geometric mean HAI titres (GMT) post-vaccination (recommended ≥2) and seroconversion rate the percentage of vaccines with an increase in HAI titre ≥ fourfold following vaccination (recommended >30%). Seroprotection rate (for all) was defined as percentage of group achieving seroprotection. *Including patients who had influenza vaccine out with this study period

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