Table 1

Baseline demographics

Patients	Pat 1	Pat 2	Pat 3	Pat 4	Pat 5	Pat 6	Pat 7	Pat 8	Pat 9	Pat 10	Pat 11	Pat 12	Pat 13	Pat 14	Pat 15
Sex (0=male/1=female)	0	1	0	0	1	1	1	0	1	1	1	1	0	0	1
Age at MS diagnosis (in years)	20	21	31	23	39	34	21	36	34	31	29	21	30	30	32
Age at PML diagnosis (in years)	32	32	40	33	46	38	30	52	45	46	34	41	43	36	41
MS duration (in years)	15	11	10	11	9	4	12	20	13	16	7	24	14	8	10
MS duration until escalation natalizumab (in years)	9	5	5	6	4	2	7	15	9	12	3	18	10	4	6
Duration natalizumab treatment (in months)	34	64	50	43	31	25	32	13	26	39	25	30	31	37	36
Number of natalizumab infusions (n)	34	62	51	40	30	27	30	14	24	40	26	29	32	38	37
Prior immunosuppressive agents (0=n/1=y)	0	0	0	0	0	0	1	1	0	0	0	0	0	0	0
Azathioprine (0=n/1=y)	0	0	0	0	0	0	0	1	0	0	0	0	0	0	0
Mitoxantrone (0=n/1=y))	0	0	0	0	0	0	1	0	0	0	0	0	0	0	0
MS-Therapie prä-PML
Interferonß-1b Betaferon (0=n/1=y)	1	0	1	0	0	0	0	0	0	1	1	0	1	0	1
Interferonß-1a (Rebif) (0=n/ 1=y)	0	1	0	1	1	1	0	1	1	0	0	0	1	0	0
Interferonß-1a (Avonex) (0=n/1=y)	1	1	0	0	0	0	0	1	0	0	0	1	0	1	0
Glatiramer acetate (0=n/1=y)	0	1	0	0	0	0	1	0	0	0	0	0	0	1	0
Immunglobulines (0=n/1=y)	0	0	0	0	0	0	0	0	0	0	0	1	0	0	0
Anti-JCV-Ab (0=neg/1=pos/2=unknown)	1	1	2	2	2	1	1	2	1	1	2	1	2	2	1

MS, multiple sclerosis; n, no; neg, negative, PML, progressive multifocal leukoencephalopathy; pos, positive; y, yes.