Characterization of CD4+ T cell-mediated cytotoxicity in patients with multiple myeloma.

Multiple myeloma (MM) is an incurable cancer characterized by the development of malignant plasma cells. The CD8 T cell-mediated cytotoxicity is considered a major player in antitumor immunity, but in MM patients, the CD8 T cells displayed senescence markers and were functionally impaired. To investigate whether cytotoxic CD4 T cells could act as a treatment alternative in MM, we examined the frequency and function of naturally occurring cytotoxic CD4 T cells in MM patients. The cytotoxic CD4 T cells were identified as granzyme-A, granzyme B-, and perforin-expressing CD4 T cells, and their frequencies were significantly upregulated in MM patients when compared with healthy controls. The frequencies of cytotoxic CD4 T cells in MM patients were not associated with the frequencies of cytotoxic CD8 T cells, but were negatively associated with disease severity. Interestingly, the expression levels of inhibitory molecules, including PD-1 and CTLA-4, were significantly lower in cytotoxic CD4 T cells than in cytotoxic CD8 T cells. When co-incubated with autologous CD38+CD138+ plasma cells, CD4 T cells were capable of eliminating plasma cells with varying degrees of efficacy. In MM patients, the frequency of circulating plasma cells was negatively correlated with the frequency of cytotoxic CD4 T cells. Therefore, CD4 T cell-mediated cytotoxicity existed naturally in MM patients and could potentially act as an option in antitumor therapies.

Effect of 393T>C polymorphism of GNAS1 gene on dobutamine response in Chinese healthy subjects.

The purpose of this study was to characterize the functional consequences of the 393T>C polymorphism of the GNAS1 gene in vivo. PCR-RFLP assays were used to identify GNAS1 and beta 1-adrenoceptor genotypes. The heart rate (HR), blood pressure, left ventricular fractional shortening (LVFS), and left ventricular ejection fraction (LVEF) were determined in different genotypes through a modified dobutamine stress echocardiography protocol. Our results showed that individuals with homozygous or heterozygous C393 had an increased cardiovascular agonistic response to dobutamine, and the increases from baseline in LVFS at the 3 dosage levels of dobutamine were 19.3% +/- 1.0% versus 32.0% +/- 2.9%, 36.7% +/- 3.1% versus 41.3% +/- 4.1%, and 51.7% +/- 3.3% versus 58.7% +/- 2.6% in T393 homozygotes and C393 homozygotes or heterozygotes, respectively (P = .026). Significant differences were also found between these 2 groups with the increases from baseline in LVEF (P = .007) and SBP (P = .048). In addition, there were significant differences in the increases from atopine in LVFS (P = .011), LVEF (P = .004), and SBP (P = .046) between the T393 homozygotes and C393 homozygotes or heterozygotes. The change of LVEF in C393 homozygous was higher than that in T393 homozygous at the dose of 40 microg/kg/min (28.9% +/- 4.0% vs 36.4% +/- 2.1%; 95% CI, 18.8%-38.9%; P = .046). These data suggested that the 393T>C polymorphism of GNAS1 was functionally relevant in vivo.

Effects of allicin on CYP2C19 and CYP3A4 activity in healthy volunteers with different CYP2C19 genotypes.

OBJECTIVE: To investigate the interaction between allicin and omeprazole and to observe the effects of allicin on CYP2C19 and CYP3A4 activity in healthy Chinese male volunteers with different CYP2C19 genotypes. METHODS: Eighteen subjects (six CYP2C19*1/CYP2C19*1, four CYP2C19*1/CYP2C19*2, two CYP2C19*1/ CYP2C19*3, and six CYP2C19*2/ CYP2C19*2) were enrolled in a two-phase randomized crossover trial. In each phase, all subjects received placebo or a 180 mg allicin capsule once daily for 14 consecutive days. The pharmacokinetics of omeprazole (20 mg orally on day 15) was determined for up to 12 h following administration by high-performance liquid chromatography. RESULTS: In carriers of the CYP2C19*1/CYP2C19*1 and CYP2C19*1/CYP2C19*2 or *3 genotype, allicin treatment increased the peak plasma concentration (C(max)) of omeprazole by 49.7 +/- 7.2 (p < 0.001) and 54.2 +/- 9.2% (p < 0.001), and increased the area under the plasma time-concentration curve (AUC(0-infinity)) of omeprazole by 48.1 +/- 9.0 (p = 0.001) and 73.6 +/- 26.7% (p < 0.001), respectively. The ratio of AUC(0-infinity) of 5-hydroxyomeprazole to omeprazole (a marker for CYP2C19 activity) decreased significantly (p < 0.001 and p = 0.001, respectively). However, no pharmacokinetic parameters were significantly changed by allicin in CYP2C19*2/CYP2C19*2. The C(max) and AUC(0-infinity) of omeprazole sulfone were unchanged in all three genotypes. CONCLUSIONS: Allicin reduced the metabolism of omeprazole by inhibiting CYP2C19 activity in individuals with the CYP2C19*1/CYP2C19*1 and CYP2C19*1/CYP2C19*2 or *3 genotypes, but not in those with the CYP2C19*2/ CYP2C19*2 genotype. Allicin did not significantly affect the activity of CYP3A4 in all subjects.

Effect of SLCO1B1 genetic polymorphism on the pharmacokinetics of nateglinide.

AIMS: Nateglinide is a meglitinide analogue with antidiabetic action. A recent study showed that SLCO1B1 (which codes the OATP1B1 gene, also known as OATP-C, OATP2) is a major determinant which markedly affects the pharmacokinetics of repaglinide. Our objective was to assess the association between single nucleotide polymorphisms (SNPs) of SLCO1B1 and the pharmacokinetics of nateglinide. METHODS: Seventeen healthy volunteers with different SLCO1B1 genotypes (11 with 521TT, four with 521TC and two with 521CC) were enrolled in this study. Each was given a single oral dose of 90 mg nateglinide. Plasma concentrations of nateglinide were measured up to 8 h by HPLC. RESULTS: The C(max) and AUC(0,infinity) of nateglinide were 83% (P = 0.002) and 82% (P = 0.001) higher in the SLCO1B1521TC subjects (n = 4), and 76% (P = 0.016) and 108% (P = 0.001) higher in the SLCO1B1521CC subjects (n = 2) than in the SLCO1B1521TT subjects (n = 11), respectively. The t(1/2) of nateglinide in SLCO1B1521CC subjects was 78% longer than that in 521TT subjects (P = 0.036). The difference in t(max) values among the three genotypic groups was not statistically significant. CONCLUSIONS: Our results suggest that OATP1B1-mediated hepatic uptake of nateglinide may be the prior step for its metabolism and elimination. SLCO1B1521T > C SNP might play an important role in the pharmacokinetics of nateglinide.