Protein Z polymorphisms associated with vaso-occlusive crisis in young sickle cell disease patients.

We investigated the association of protein Z (PZ) promoter (rs3024718, rs3024719, and rs3024731) and intron (rs3024735; G79A) SNPs with sickle cell disease (SCD) vaso-occlusive crisis (VOC). Study subjects included 239 SCD patients with VOC and 138 pain-free SCD control patients. PZ genotyping was done by allelic discrimination (real-time PCR) assays. The minor allele frequency of rs3024718 (P=0.03), rs3024719 (P=0.02), rs3024731 (P<0.001), and rs3024735 (P<0.001) were higher in VOC patients than control SCD patients. Significant differences in the distribution of rs3024731 (P=0.028) and rs3024735 (P=0.045) genotypes were seen between VOC and steady-state SCD patients. This association remained significant after adjusting for gender, HbS, and HbF. Four-locus (rs3024718/rs3024719/rs3024731/rs3024735) PZ haplotypes analysis demonstrated increased frequency of GAAA (P=0.024), AGAA (P=0.011), and GGTG (P=0.002), and reduced frequency of AGTG haplotype (P=0.001) in VOC than in steady-state control patients, thereby conferring disease susceptibility and protective nature to these haplotypes, respectively. Of these, only AGTG (P(c)=0.001) and GGTG (P(c)=0.018) remained significant after applying the Bonferroni correction. In conclusion, specific PZ variants and haplotypes are significantly associated with SCD VOC.

Anti-annexin V IgG and IgM antibodies in sickle cell disease patients with vaso-occlusive crisis.

Vaso-occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell anemia (SCA) patients; however, its mechanisms are poorly understood. In view of their prothrombotic nature, we hypothesized that SCA-associated VOC may be due to the presence of anti-annexin V antibodies. Anti-annexin V antibodies were measured with ELISA in 177 VOC and 81 steady-state SCA patients. Anti-annexin V IgM and IgG concentrations were significantly higher in VOC patients than in steady-state patients and were associated with elevated VOC risk. After categorizing anti-annexin V antibodies, the adjusted odds ratio increased as the percentile value increased. Monovariate logistic regression analysis demonstrated a positive dose-effect relationship for anti-annexin V IgM with VOC, with increased VOC risk seen with increased antibody titers. Multivariate logistic regression analyses confirmed the association of anti-annexin V IgM, more so than IgG, as an independent VOC risk factor. Anti-annexin V IgG antibodies correlated positively with VOC type and negatively with HbF and age of VOC onset, while anti-annexin V IgM correlated positively with VOC type, duration, frequency, site, pain severity, hospitalization, and medication, and negatively with age of VOC onset and HbS levels. High levels of anti-annexin V IgM antibodies constitute a risk factor for VOC in SCA patients.

The relation of C-reactive protein to vasoocclusive crisis in children with sickle cell disease.

In view of evidence linking sickle cell anemia (SCA) with chronic inflammation, and given the role of high sensitivity C-reactive protein (hs-CRP) as inflammatory mediator, we hypothesized that SCA vasoocclusive crisis (VOC) is associated with heightened hs-CRP levels. Study subjects comprised 104 SCA patients who experienced VOC event during the study period (VOC group), and 40 SCA patients who did not develop VOC for at least 9 months prior to blood collection (Steady-state group). hs-CRP determination was done by latex-enhanced nephelometry. Higher hs-CRP levels were seen in VOC [median(range)=31.3(1.14-363.0)] than steady-state [median(range)=5(0.16-185.0)] groups (P<0.001), with enrichment in high hs-CRP percentiles in VOC cases, which translated into step-wise increased VOC risk. Receiver-operating characteristic (ROC) analysis was employed in assessing the usefulness of hs-CRP as predictor of the frequency and severity of VOC. Spearman's correlation coefficient between hs-CRP and VOC was 0.65 (P<0.001) among unselected patients (0.71 in males and 0.59 in females). hs-CRP area under ROC curves was 0.90 (95% CI=0.85-0.94) among unselected patients, 0.94 (95% CI=0.89-0.98) for males, and 0.85 (95% CI=0.77-0.93) for females. Logistic regression analysis confirmed the positive association of increased hs-CRP levels with VOC, which correlated positively with VOC frequency (P<0.001), type (P<0.001), pain (P<0.001), and need for hospitalization (P=0.024). These data support strong association of increased hs-CRP levels with VOC, which impacts VOC-related parameters, and support a role for hs-CRP in VOC follow-up.

Depression, anxiety, and stress comorbidities in sickle cell anemia patients with vaso-occlusive crisis.

We investigated the association of sickle cell anemia (SCA) vaso-occlusive crisis (VOC) with depression, anxiety, and stress disorders among Bahraini patients and controls. This was a cross-sectional study that involved administering Depression Anxiety Stress Scales (DASS-21) consisting of structured depression, anxiety, and stress scales to SCA patients with (n=138) and without (n=105) VOC. Multinomial regression and correlation analysis were used in assessing the association of VOC with depression and/or anxiety and/or stress, after adjusting for other covariates. Significantly higher proportion of VOC patients was found among the severe-extremely severe anxiety (P<0.002) and stress (P=0.001) groups; the frequency of depressed patients was comparable between the 2 groups. Adjusting for age, sex, income, number of affected individuals per family, and HbS levels, mild-moderate (P=0.042; odds ratio=2.00; 95% confidence interval=1.03-3.91) and severe-extremely severe (P=0.004; odds ratio=4.43; 95% confidence interval=1.59-12.34) anxiety were independently associated with VOC. Both depression and stress were not associated with VOC after adjusting for these covariates. These results suggest a positive contribution of VOC to the increased rates of anxiety disorders among SCA patients, thereby recommending counseling SCA patients with repeated VOC for these psychologic comorbidities, in particular anxiety.

Human platelet alloantigens (HPA) 1, HPA2, HPA3, HPA4, and HPA5 polymorphisms in sickle cell anemia patients with vaso-occlusive crisis.

OBJECTIVES: Vaso-occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell anemia (SCA) patients. Insofar as polymorphism in human platelet alloantigen (HPA) exhibit a prothrombotic nature, we hypothesized that specific HPA polymorphic variants are associated with VOC. We investigated the distribution of HPA1, HPA2, HPA3, HPA4, and HPA5 alleles genotypes among VOC and non-VOC control SCA patients. PATIENTS/METHODS: This was a case-control study. Study subjects comprised SCA patients with (VOC group; n = 127) or without (Steady-state group; n = 130) VOC events. HPA genotyping was done by PCR-SSP. RESULTS: Significantly higher frequencies of HPA-2b, HPA-3b, and HPA-5b alleles, and marked enrichment of HPA-3b/3b, HPA-5a/5b, and HPA-5b/5b genotypes, were seen in VOC than in control SCA patients. Taking homozygous wild-type genotypes as reference, univariate analysis identified HPA-3a/3b, HPA-3b/3b, and HPA-5b/5b to be associated with VOC. Multivariate analysis confirmed the independent association of only HPA-3a/3b and HPA-3b/3b genotypes with VOC. HPA-3 genotypes were significantly correlated with VOC frequency, type, and medication, and requirement for hospitalization. While both HPA 3a/3b (P = 0.002; OR = 2.94; 95% CI = 1.49-5.77) and 3b/3b (P = 0.006; OR = 3.16; 95% CI = 1.40-7.17) genotypes were associated with need for hospitalization, only HPA-3b/3b was associated with VOC frequency, type (localized vs. generalized), and medication (narcotics vs. NSAIDs). CONCLUSION: This confirms the association of HPA polymorphisms with SCA VOC, of which HPA-3 appears to be independent genetic risk factors for SCA VOC.

HLA class II haplotypes distinctly associated with vaso-occlusion in children with sickle cell disease.

We investigated the association of HLA class II alleles and haplotypes with sickle cell anemia vaso-occlusive crisis (VOC). DRB1*100101 was positively associated, while DRB1*140101, DRB1*150101, and DQB1*060101 were negatively associated, with VOC. Both susceptible (DRB1*100101-DQB1*050101) and protective (DRB1*110101-DQB1*030101 and DRB1*150101-DQB1*060101) haplotypes were identified, indicating that HLA class II haplotypes influence VOC risk.

Modulation of type 1 diabetes susceptibility by tumor necrosis factor alpha -308 G/A and lymphotoxin alpha +249 A/G haplotypes and lack of linkage disequilibrium with predisposing DQB1-DRB1 haplotypes in Bahraini patients.

Tumor necrosis factor alpha (TNF-alpha) -308 G/A and lymphotoxin alpha (LTalpha) +249 A/G single-nucleotide polymorphisms were investigated in 228 type 1 diabetes mellitus (T1DM) patients and 240 controls. Only LTalpha +249G allele and +249G/+249G genotype frequencies were higher among patients, and no linkage disequilibrium was found between TNF-alpha/LTalpha alleles and susceptible/protective DRB1-DQB1 haplotypes. TNF-alpha/LTalpha T1DM-susceptible (-308G/+249G) and protective (-308G/+249A) haplotypes were identified.

Gene frequencies of human platelet alloantigens in Bahraini Arabs.

Human platelet antigens (HPA) are implicated in the pathophysiology of certain hematological disorders, and as varied distribution of HPA-1 alleles and genotypes were reported fordifferent countries and ethnic populations, we determined the distribution of HPA-1, -2, -3, -4, and -5 alleles, genotypes and haplotypes for 194 healthy Bahraini subjects by polymerase chain reaction with sequence specific primers. The distribution of the HPA polymorphisms was in Hardy-Weinberg equilibrium. Allele frequencies of 0.76 and 0.24 (HPA-1a and -1b), 0.77 and 0.23 (HPA-2a and -2b), 0.57 and 0.43 (HPA-3a and -3b), 0.93 and 0.07 (HPA-4a and -4b), and 0.86 and 0.13 (HPA-5a and -5b) were seen. With the exception of HPA-3a/a (30.4%), the frequencies of homozygous HPA-1a/a (56.8%), 2a/a (60.1%), 4a/a (87.2%), and 5a/a (75.7%) were higher than those of heterozygous (a/b) or homozygous (b/b) variants. Our results provide basic information for further studies of the HPA system polymorphism, which in turn will be instrumental in understanding and treating immune-mediated platelet disorders.

Contribution of selective HLA-DRB1/DQB1 alleles and haplotypes to the genetic susceptibility of type 1 diabetes among Lebanese and Bahraini Arabs.

CONTEXT: Human leukocyte antigen (HLA) class II genes contribute to the genetic susceptibility of type 1 diabetes (T1D), and both susceptible and protective alleles were implicated with its pathogenesis, which varies among various ethnic/racial groups. OBJECTIVE: This study investigated the heterogeneity in HLA class II haplotypes distribution among Bahraini and Lebanese T1D patients. DESIGN: This was a cross-sectional retrospective study. SETTING: The study was conducted at primary care private and public health centers. PATIENTS AND OTHER PARTICIPANTS: Subjects comprised 126 T1D patients and 126 healthy controls from Bahrain and 78 Lebanese T1D patients and 111 control subjects. INTERVENTION(S): There were no interventions. RESULTS: Although Lebanese and Bahraini patients share DRB1*030101, DQB1*0201 as susceptible and DRB1*100101 and DQB1*030101 as protective alleles, DRB1*040101 was an additional susceptible allele in Bahraini patients, and DRB1*130701 and DQB1*050101 were additional susceptible and protective alleles in Lebanese, respectively. DRB1*030101-DQB1*0201 was susceptible, whereas DRB1*070101-DQB1*0201 and DRB1*110101-DQB1*030101 were protective haplotypes in Bahraini and Lebanese. DRB1*040101-DQB1*0302 and DRB1*040101-DQB1*050101 displayed different associations: they were protective in Lebanese but susceptible or neutral among Bahrainis. Whereas the frequency of homozygous DRB1*03011-DQB1*0201 was higher in Bahraini and to a lesser extent Lebanese patients, homozygous DRB1*110101-DQB1*030101 was significantly more frequent in Lebanese but not Bahraini controls, whereas DRB1*030101-DQB1*0201/DRB1*040101-DQB1*0201 was the major genotype among Bahraini patients but not Lebanese subjects in whom it was present at very low frequencies. CONCLUSION: In view of these differences between Bahraini and Lebanese, this demonstrates that the contribution of HLA class II to the genetic susceptibility to T1D must be evaluated with regard to specific HLA haplotypes and also ethnic origin and racial background.