[Analysis of HLA-Cw, KIR2D genetic variations in 2 Chinese populations].

OBJECTIVE: To explore the genetic variations of HLA-Cw and 5 KIR2D loci in 2 Chinese Han populations residing at Southern and Northern mainland China, respectively, and to investigate the HLA-Cw polymorphism of a Mongolian Chinese population. METHODS: HLA-Cw genotyping was performed in a total of 293 healthy individuals including 1 Southern Han population living in Hunan Province (n=112), 1 Northern Han population (n=98) and 1 Mongolian Chinese population(n=83) in the Inner Mongolia Autonomous Region, using polymerase chain reaction-sequence specific primer(PCR-SSP) technique. Dimorphism at residue 80 of domain in the HLA-Cw molecule was examined by an additional set of PCR-SSP reactions. PCR-SSP was also used to detect the presence or absence of inhibitory KIR2DL1/2DL2/2DL3 loci and activating KIR2DS1/2DS2 loci for the 2 Han populations. RESULTS: The main findings were: (1) Very significant frequency difference in the HLA-Cw alleles and dimorphism at codon 80 was detected between Hunan Han and Northern Han population, and between Hunan Han and Mongolian population (P < 0.001),while there was no such difference between the 2 Northern Chinese populations (P> 0.05); (2) There was no significant difference in frequencies of either the 5 individual KIR2D genes or the genotype distributions between the 2 Han populations (P> 0.05); (3) Asn(80)ls/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- predominated in both Han populations (45/112, 29/98), followed by Asn(80)/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1+/2DS2- (18/112,16/98) and Asn(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2-(11/112,17/98). Among the 12 types of HLA-Cw codon 80 and KIR2D combinations, only Lys(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- showed marginally significant frequency difference between the 2 Han populations(1/112 vs 8/98; Fisheros P was 0.0134). CONCLUSION: Our study provided the polymorphism data of HLA-Cw gene for 3 Chinese populations with different geographic and/or ethnic background, we further analyzed the distribution of 5 KIR2D receptor genes in 2 Han populations. Our data suggest that in spite of HLA-Cw heterogeneity, remarkable similarities may exist between the Southern and Northern Chinese Han populations at the combinational level of HLA-Cw and KIR2D, which are characterized by preponderant inhibitory signal pathways.

Plasma S-100B protein in Chinese patients with schizophrenia: comparison with healthy controls and effect of antipsychotics treatment.

PURPOSE: To examine the possibility that structural damage to the brain may play a role in the pathogenesis of schizophrenia by measuring the level of plasma S-100B, a calcium-binding protein found predominantly in the cytosol of glial cells. METHOD: Fifty-seven Chinese psychiatric inpatients who met DSM-IV diagnosis of schizophrenia and 60 healthy controls were enrolled in the study. Patients were assessed with the Positive and Negative Symptoms Scale (PANSS) at admission and at 12 weeks after treatment. Plasma samples were collected from patients and controls and S-100B protein was assayed using ELISA. RESULTS: (1) 29 of 57 patients (50.9%) showed increased S-100B level compared to the mean level of 60 healthy controls (p<0.005) vs. only 1 of 60 (1.67%) controls. The S-100B levels of unmedicated (0.119+/-0.059microg/L) and medicated patients (0.117+/-.0.057microg/L) were significantly higher than controls (0.067+/-0.022microg/L, both p<0.001), and S-100B levels of unmedicated patients were higher than those of medicated patients (p=0.024); (2) at admission, S-100B level was positively correlated with total score of PANSS (r=0.269, p=0.043), especially with negative subscore of PANSS (r=0.306, p=0.021), but the correlation was no longer present after patients were treated by anti-psychotic agents. CONCLUSION: The S-100B levels of patients with schizophrenia are significantly higher than that of healthy controls, and the S-100B level is associated with severity of psychopathology, particularly negative symptoms, indicating that patients with schizophrenia may suffer structural damage to central nervous system. The concentration of S-100B may also be associated with treatment progress.

[Polymorphism of short tandem repeat of exon 5 of MHC class-I chain related gene A and association with nasopharyngeal carcinoma in a southern Chinese population].

OBJECTIVE: To explore the association between the short tandem repeat polymorphism of exon 5 of MICA gene (MICA-STR) and nasopharyngeal carcinoma (NPC) in a southern Chinese population. METHODS: One hundred and twenty-seven consecutive NPC patients and 112 randomly selected normal controls residing in southern China mainland were analyzed for MICA-STR allelic variation and MICA gene deletion by fluorescent polymerase chain reaction-gene scanning and polymerase chain reaction-sequence specific priming. RESULTS: MICA*A9 was observed at significantly higher frequency in the NPC patient group than in the control group (relative risk = 2.524, P = 0.001,Pc = 0.006); whereas MICA*A5.1 was present at significantly lower frequency in the NPC patient group than in the control group (RR = 0.418, P = 0.0004, Pc = 0.0026). Further analysis revealed that MICA*A9 was over-represented in male NPC patients, compared with male controls (RR = 3.23, P = 0.00095, Pc = 0.006); whereas MICA*A5.1 was present at significantly lower frequency in male NPC patients, compared with male controls (RR = 0.372, P = 0.0007, Pc = 0.004). None of the MICA-STR variants showed statistically significant frequency difference between female NPC patients and female controls (Pc > 0.05). CONCLUSION: MICA-STR polymorphism is associated with NPC, and MICA*A9 is a genetic susceptibility marker of male individuals for NPC in a southern Chinese population.

[Association study on HLA-DP and -DQ allelic polymorphisms and nasopharyngeal carcinoma in the Han nationality in Hunan province].

OBJECTIVE: To investigate whether the polymorphisms of HLA-DPA1,DPB1,DQA1 and DQB1 alleles were associated with nasopharyngeal carcinoma(NPC). METHODS: Eighty-seven NPC patients and 91 normal controls of Han nationality in Hunan province were genotyped for HLA-DPA1, HLA-DPB1,HLA-DQA1 and HLA-DQB1 by PCR/SSO technique. RESULTS: The frequencies of allelic gene DPA1*0201, DPB1*1901 and DQA1*0201 were lower, and of DPB1*0402, DQA1*0101 were higher in patients than in controls; the frequencies of haplotype DPA1*0201-DPB1*1401 and DQA1*0201-DQB1*0201 in patients were lower than those in controls; however, the values of P are not significant after Bonferroni correction(Pc>0.05). CONCLUSION: No significant association between the HLA-DP and HLA-DQ loci and NPC in Han nationality in Hunan province was confirmed.

Gender-specific associations between MICA-STR and nasopharyngeal carcinoma in a southern Chinese Han population.

Previous studies have identified several HLA-B specificities that are associated with nasopharyngeal carcinoma (NPC) in populations of Chinese descent, in particular HLA-B35, -B38, -B46, and -B58. Perhaps except for HLA-B46, other associations cannot be simply accounted for by the linkage disequilibrium between HLA-A and B loci. The human major histocompatibility complex (MHC) class I chain-related gene A (MICA) maps 46 kb centromeric to HLA-B and is highly polymorphic; it encodes a stress-inducible protein which functions as a ligand for the NKG2D/DAP10 complex to activate natural killer (NK) cells, gammadelta T cells, and CD8(+) T cells. We postulated MICA gene as a susceptibility factor for nasopharyngeal carcinoma, an Epstein-Barr virus-associated malignancy. In this study, 218 unrelated patients newly diagnosed with NPC and 196 randomly selected healthy controls from southern China mainland were analyzed for the short tandem repeat polymorphism of exon 5 of MICA gene (MICA-STR) and MICA gene deletion, using fluorescent polymerase chain reaction-gene scanning (PCR/size-sequencing) and polymerase chain reaction-sequence-specific priming (PCR/SSP) technology. MICA*A9 was present at significantly increased frequency in the patient group (P (C)=0.0001002, OR=2.528, 95% CI=1.636-3.907), whereas the frequency of MICA*A5.1 was significantly decreased (P (C)=0.006, OR=0.594, 95% CI=0.437-0.806). Gender-based stratification revealed a significant increase of MICA*A9 frequency (P (C)=0.000072, OR=3.255, 95% CI=1.855-5.709) and a significant decrease of MICA*A5.1 frequency (P (C)=0.000737, OR=0.486, 95% CI=0.337-0.702) in male patients with NPC (N=166), compared with male normal controls (N=120). A significant interaction between MICA*A9 and gender was observed ([see text]=41.58, P=0.0001). Statistics also revealed heterogeneity of effects among MICA*A5.1/MICA*A9-bearing phenotypes and a dose-dependent effect of MICA*A5.1 and MICA*A9 on NPC risk in male subgroup. This constitutes the first demonstration of a gender-specific association between MICA-STR polymorphism and NPC, which could largely be attributable to the underlying gender-related mechanisms that modulate MICA gene expression. The results provide strong supporting evidence suggesting that MICA*A9 may be a genetic risk factor for NPC in male individuals in this population. The potential interaction between MICA and other non-HLA host factors and environmental exposures remains to be further studied.