Table 6. Mutations and polymorphisms in samples genotyped under LPV/r treatment.

		Samples failing LPV/r as first PI n = 114						Samples failing LPV/r as second or higher PI n = 126						p
		B n = 22		C n = 67		nonBC n = 25		B n = 21		C n = 89		non-BC n = 13		LPV/r first PI			LPV/r second or higher PI			First vs. second or higher
Samples revealing major PI mutations		0		7 (10%)		1 (4%)		10 (47.6%)		40 (44.9%)		8 (61.5%)		B vs. C	B vs. non-BC	C vs. non-BC	B vs. C	B vs. non-BC	C vs. non-BC	B	C	non-BC
PI Mutations		No	%	No	%	No	%	No	%	No	%	No	%
I	L10F/I/V	2	9	8	12	6	24	11	52	36	40	6	46							0.003	<0.00001
	G16E	0	0	9	13	2	8	0	0	8	9	0	0	0.1
	K20R/I/M/T	3	14	15	22	9	36	3	14	38	43	7	54		0.1		0.02	0.02			0.01
	L24I	0	0	0	0	0	0	1	5	3	3	3	23						0.03			0.03
	L33F	0	0	0	0	0	0	2	10	8	9	2	15								0.01
	M36I	4	18	64	96	22	88	8	38	88	99	10	77	<0.00001	<0.00001		<0.00001	0.04	0.006
	K43T	0	0	0	0	0	0	0	0	1	1	0	0
	M46I/L	0	0	4	6	1	4	6	29	23	26	3	23							0.009	0.001	0.1
	I47A/V	0	0	0	0	0	0	0	0	2	2	0	0
	G48V/M	0	0	0	0	0	0	1	5	1	1	2	15						0.04
	I50V/L	0	0	0	0	0	0	0	0	2	2	1	8
	F53L	0	0	0	0	0	0	1	5	1	1	2	15						0.04
	I54A/V	0	0	4	6	1	4	6	29	28	31	6	46							0.009	<0.00001	0.004
	Q58E	0	0	0	0	0	0	0	0	3	3	1	8
	L63P	12	55	23	34	11	44	16	76	37	42	10	77				0.007	0.01	0.03	0.1		0.09
	A71V	3	14	2	3	1	4	6	29	15	17	3	23	0.09							0.008	0.1
	G73A/C/S/T	0	0	1	1	0	0	2	10	2	2	1	8
	T74P/S	0	0	7	10	1	4	0	0	26	29	0	0		0.002		0.003		0.04		0.005
	L76V	0	0	1	1	0	0	1	5	7	8	2	15								0.1	0.1
	V82A/C/S	0	0	6	9	1	4	3	14	26	29	6	46		0.002			0.06		0.1	0.002	0.004
	I84V	0	0	0	0	0	0	4	19	4	4	2	15	0.04			0.07			<0.05	0.1	0.1
	L89V	0	0	1	1	0	0	0	0	3	3	0	0
	L90M	0	0	1	1	0	0	6	29	18	20	1	8							0.009	<0.00001
II	V11I	0	0	1	1	0	0	1	5	1	1	0	0
	I13V	4	18	2	3	11	44	8	38	10	11	3	23	0.03	0.07	<0.00001	0.006				0.07
	L23I	0	0	0	0	0	0	0	0	2	2	1	8
	D30N	0	0	0	0	0	0	0	0	1	1	0	0
	D60E	0	0	5	7	3	12	3	14	3	3	4	31				0.08		0.005	0.1
	I62V	14	64	5	7	4	16	9	43	13	15	4	31	<0.00001	0.001		0.01
	H69K/Q/R/N	2	9	67	100	20	80	5	24	89	100	7	54	<0.00001	<0.00001	0.001	<0.00001		<0.00001			0.1
	V77I	7	32	2	3	1	4	7	33	1	1	3	23	0.001	0.02		<0.00001		0.006			0.1
	N83D	0	0	0	0	0	0	0	0	1	1	0	0
	I85V	0	0	1	1	0	0	0	0	5	6	0	0
	N88D/S	0	0	0	0	0	0	2	10	4	4	0	0								0.1
	I93L	6	27	67	100	12	48	10	48	87	98	5	38	<0.00001	<0.00001	<0.00001	<0.00001		<0.00001
III	T12S	0	0	13	19	1	4	2	10	22	25	0	0	0.03	0.01				0.08
	I15V	2	9	29	43	3	12	2	10	57	64	4	31	0.004	<0.00001	0.006	<0.00001		0.03		0.01
	L19I/K/M/T/V	1	5	18	27	2	8	3	14	30	34	3	23	0.03	0.01	0.09	0.1
	E35D	10	45	6	9	15	60	4	19	16	18	6	46	<0.0001	0.01	<0.0001			0.03	0.1
	S37N	4	18	29	43	9	36	6	29	51	57	8	62	0.04			0.03	0.08			0.1
	R41K	3	14	64	96	21	84	4	19	85	96	8	62	<0.00001	<0.00001	0.08	<0.00001	0.03	0.001

Samples from 237 patients under LPV/r treatment were analyzed. The last available sample from each patient was used. Mutations were divided into three groups according to: I - amino-acids that appear in at least one algorithm for LPV/r resistance (reviewed in [39]); II - other amino-acids known to be involved in resistance to PI; III - amino-acids that are not known to be involved in resistance to PI for which a statistically significant difference between subtypes was found. Amino acids that appear in all four algorithms are shown in bold type and those that appear in 3 different algorithms in italics. For mutation that are significantly different between subtypes the most prevalent variant is shown in bold type. In order to emphasize significant differences only p values smaller than 0.1 were noted. Mutations V32I, E34Q (Group I) and E35G (Group II) did not appear at all and were taken out from the table.

B – subtype B; C – subtype C; LPV/r – Lopinavir/ritonavir; non-BC– subtypes other than B or C; PI – protease Inhibitor.