Association of CD22 gene polymorphism with susceptibility to limited cutaneous systemic sclerosis

Activating and inhibitory signal transducers, CD19 and CD22, have been substantially implicated both in human systemic sclerosis (SSc) and tight-skin mouse, a model for SSc. We previously showed that a single nucleotide polymorphism (SNP) in CD19 promoter region was significantly associated with increased CD19 expression level and with susceptibility to SSc. In the present study, we examined whether CD22 polymorphisms were associated with susceptibility to SSc. CD22 variations were genotyped in 126 Japanese patients with SSc [47 diffuse cutaneous SSc and 79 limited cutaneous SSc (lcSSc)] and 93 unrelated healthy controls. At the c.2304C > A SNP coding for a synonymous substitution in exon 13, A/A genotype was observed in six patients with SSc (4.8 %) but none in the controls (P=0.040). All six patients with A/A genotype belonged to the lcSSc subgroup (7.6%, P=0.008 vs controls). Surface expression level of CD22 tended to be lower in B cells from the patients with A/A genotype (n=5) as compared with C/A (n=7) or C/C (n=14) genotype (17% decrease, P=0.0032). Taken together with our previous observation on CD19 polymorphism, intrinsic difference in the expression level of CD19 and CD22 was suggested to play a causative role in a proportion of patients with lcSSc.

A compass that points to lupus: genetic studies on type I interferon pathway

It was more than 20 years ago that patients with systemic lupus erythematosus (SLE) were first reported to display elevated serum levels of type I interferon (IFN). Since then, extensive studies revealed a crucial role for type I IFN in SLE pathogenesis. The current model proposes that small increase of type I IFN production by plasmacytoid dendritic cells (pDCs) is sufficient to induce unabated activation of immature peripheral DCs. IFN-matured DCs select and activate autoreactive T cells and B cells, rather than deleting them, resulting in peripheral tolerance breakdown, a characteristic feature of SLE. Furthermore, immune complexes provide an amplification loop to pDCs for further IFN production. In the past 5 years, high-throughput technologies such as expression profiling and single-nucleotide polymorphism (SNP) typing established the role of altered type I IFN system in SLE, and a detailed picture of its molecular mechanisms is beginning to emerge. In this review, we discuss two major lines of genetics studies on type I IFN pathway related to human SLE: (1) expression profiling of IFN-responsive genes and (2) disease-associated SNPs of IFN-related genes, especially IRF5 (IFN-regulatory factor 5). Lastly, we discuss how such genetic alterations in type I IFN pathway fit in the current model of SLE pathogenesis.

Differential association of HLA-DRB1 alleles in Japanese patients with early rheumatoid arthritis in relationship to autoantibodies to cyclic citrullinated peptide

OBJECTIVE

To evaluate the role of HLA-DRB1 genotypes and antibodies to cyclic citrullinated peptides (anti-CCP antibodies) in the development and radiographic progression of Japanese patients with rheumatoid arthritis (RA).

METHODS

One hundred and ten patients with early RA (88 female, 22 male) who visited our clinic within 1 year of symptom onset were examined for anti-CCP antibody levels and HLA-DRB1 genotypes. HLA-DRB1 genotypes were also determined in 265 healthy controls. Radiographic progression over a 2-year interval was evaluated using the Larsen's method in 66 patients.

RESULTS

Among the 110 patients with early RA, 82 patients (74.5%) were anti-CCP positive. Carrier frequency of HLA-DRB1*0405 was significantly increased in RA patients with anti-CCP antibodies compared with controls and RA patients without anti-CCP antibodies (odds ratio [OR] 3.4, 95% confidence interval [95% CI] 2.0-5.7 and OR 3.3, 95% CI 1.3-8.6, respectively). Carriership of one or two SE alleles was significantly associated with production of anti-CCP antibodies (OR 2.7, 95% CI 1.1-6.7 and OR 9.3, 95% CI 1.1-78.2, respectively). On the other hand, allele frequency of HLA-DRB1*0901 was significantly increased in RA patients without anti-CCP antibodies compared with controls and RA patients with anti-CCP antibodies (OR 2.2, 95% CI 1.1-4.1 and OR 3.0, 95% CI 1.4-6.4, respectively).

CONCLUSION

In Japanese patients with RA, HLA-DRB1 SE alleles are associated with production of anti-CCP antibodies and HLA-DRB1 alleles appear to be differently associated with early RA depending on anti-CCP positivity as in Caucasian patients with RA.

Role of APRIL (TNFSF13) polymorphisms in the susceptibility to systemic lupus erythematosus in Japanese

OBJECTIVES

A polymorphism of APRIL, c.199G > A (Gly67Arg), has been reported to be associated with systemic lupus erythematosus (SLE) in Japanese. To identify the causative polymorphism, we screened for polymorphisms of APRIL as well as TWEAK (TNFSF12), a closely located gene that generates a fusion protein TWE-PRIL by intergenic splicing. Association of APRIL and TWEAK with rheumatoid arthritis (RA) was examined in parallel.

METHODS

Polymorphisms were screened by direct sequencing. Association was analysed by case-control analysis using 266 SLE, 298 RA and 208 healthy individuals. Allele-specific difference in the mRNA level was examined using RNA difference plot analysis. Serum APRIL level was measured by ELISA.

RESULTS

The protective effect of APRIL c.199A/A homozygotes in SLE was replicated (odds ratio 0.50, 95% confidence interval 0.30-0.83, P = 0.0073; pooled P = 0.0001, Pcorr = 0.007). In addition, association of c.287A > G (Asn96Ser, P = 0.0064, allele frequency) and c.*263C > T (3' untranslated region, P = 0.025, allele frequency) was detected. c.199G-c.287A (67Gly-96Asn) haplotype was found to confer risk for SLE, while c.199A-c.287G (67Arg-96Ser) was protective. Association of TWEAK was observed neither for SLE nor RA. APRIL mRNA was increased in SLE-associated c.*263T allele. In addition, serum APRIL was undetectable in all six healthy controls homozygous for the protective c.199A-c.287G haplotype (P = 0.015).

CONCLUSIONS

In addition to replicating the protective role of APRIL c.199A/A, two additional SNPs in APRIL were found to be associated with SLE. Presence of a protective haplotype and a risk haplotype was demonstrated. The mechanism of association was suggested to be altered expression at the protein and mRNA levels.

Diversity of Human Immune System Multigene Families and its Implication in the Genetic Background of Rheumatic Diseases

A large number of molecules in the immune system are encoded by multigene families. These genes are rich in pairs of activating and inhibitory receptors that share the same ligands, thereby playing a crucial role in immunoregulation. Furthermore, multigene families tend to be highly polymorphic. Thus, multigene families are strong candidates for containing genes that enhance susceptibility to immune system-related diseases. Here, we review studies from our group, as well as other investigators, on three multigene families that belong to the immunoglobulin (Ig) - like receptor superfamily: Fcgamma receptor (FCGR), killer cell Ig-like receptor (KIR) and leukocyte Ig-like receptor (LILR) families. FCGR genes have been implicated in susceptibility to systemic lupus erythematosus (SLE). In FCGR2B encoding an inhibitory receptor expressed in B cells, monocytes and dendritic cells, a polymorphism within the transmembrane region, Ile232Thr, was identified and found to be associated with susceptibility to SLE in three Asian populations. Functional analyses revealed that SLE-associated FcgammaRIIb-232Thr was less efficient in entering the membrane lipid raft, and exhibited reduced inhibitory potential against B cell receptor signaling. Although the frequency of this polymorphism was low in Caucasians, another polymorphism within the promoter region was reported to be associated with SLE. KIR/HLA combinations have been shown to be associated with various autoimmune and infectious diseases. Recently, LILR families have also been found to be highly polymorphic, and association with several diseases has been identified. These results emphasize the role of multigene families in the diversity of human immune response and susceptibility to diseases.

Role of B cell inhibitory receptor polymorphisms in systemic lupus erythematosus: a negative times a negative makes a positive

B lymphocytes play a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). Here, we will review our studies on the role of polymorphisms of two genes coding for B cell inhibitory receptors, FCGR2B and CD72. In FCGR2B, a single nucleotide polymorphism leading to a nonsynonymous substitution, Ile232Thr, within the transmembrane domain was identified, and a significant association of the 232Thr/Thr genotype with SLE was observed in Japanese, Thai and Chinese populations, while this allele was found to be rare in Caucasians. On the other hand, the association of FCGR2B promoter polymorphism with SLE in Caucasians has been reported by two independent groups, but this allele was not found to be present in Japanese. These observations demonstrate that the association of FCGR2B polymorphisms with SLE is common to multiple populations, but the alleles associated with SLE depend upon the genetic background of each population. Functional analyses using a human B cell line lacking endogenous FcgammaRIIb revealed that SLE-associated 232Thr allele product was partially excluded from membrane lipid rafts under resting conditions and after coligation with B cell receptor, and was significantly less potent at inhibiting B cell activation. Two haplotypes were identified in CD72, one of which was associated with increased production of an alternative splicing isoform that substantially alters the extracellular region of CD72. Interestingly, the presence of the haplotype significantly decreased the risk of SLE conferred by FCGR2B-232Thr in an epistatic manner. These observations emphasize the need to understand human immune system diversity if we are to improve our understanding of the pathogenesis of autoimmune diseases.

Diagnosis of Bone Metastasis in Men with Prostate Cancer by Measurement of Serum ICTP in Combination with Alkali Phosphatase and Prostate-specific Antigen

AIMS

Carboxy-terminal telopeptide of type I collagen (ICTP) is a parameter of bone absorption, and has recently been introduced to monitor bone metastases. The aim of this retrospective study was to investigate the potential of ICTP as a candidate serum marker of bone metastasis in prostate cancer.

MATERIALS AND METHODS

Serum markers in 155 men pathologically diagnosed with prostate cancer were measured. The serum levels of ICTP, prostate-specific antigen (PSA), and alkali phosphatase (ALP) were compared to assess the extent of disease (EOD) scores from bone scans and then analysed statistically.

RESULTS

The serum ICTP levels were not well correlated with the EOD scores in the total group of men, men newly diagnosed with prostate cancer, or men previously diagnosed with prostate cancer who were followed up. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ICTP (cut-off value, 5.0 ng/ ml) of the men newly diagnosed with prostate cancer were 78.6%, 88.0%, 78.6%, and 88.0%, respectively. In these men, the specificity and PPV of ALP (cut-off value, 335 IU/l) were 100%, whereas the sensitivity and NPV of PSA (cut-off value, 40 ng/ml) were 100% in this study. The serum levels of ICTP in the men with low ALP (< 335 IU/l) and high PSA (> or = 40 ng/ ml) clearly separated the men with or without bone metastasis, as judged by bone scans.

CONCLUSION

We found that the ICTP is not a superior serum marker for bone metastases compared with ALP or PSA. Our study suggests, however, that the ICTP measurement is useful in a certain subset of men with the combination of PSA and ALP in distinguishing men with bone metastasis from those without.

Identification of expressed genes characterizing long-term survival in malignant glioma patients

Better understanding of the underlying biology of malignant gliomas is critical for the development of early detection strategies and new therapeutics. This study aimed to define genes associated with survival. We investigated whether genes coupled with a class prediction model could be used to define subgroups of high-grade gliomas in a more objective manner than standard pathology. RNAs from 29 malignant gliomas were analysed using Agilent microarrays. We identified 21 genes whose expression was most strongly and consistently related to patient survival based on univariate proportional hazards models. In six out of 10 genes, changes in gene expression were validated by quantitative real-time PCR. After adjusting for clinical covariates based on a multivariate analysis, we finally obtained a statistical significance level for DDR1 (discoidin domain receptor family, member 1), DYRK3 (dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 3) and KSP37 (Ksp37 protein). In independent samples, it was confirmed that DDR1 protein expression was also correlated to the prognosis of glioma patients detected by immunohistochemical staining. Furthermore, we analysed the efficacy of the short interfering RNA (siRNA)-mediated inhibition of DDR1 mRNA synthesis in glioma cell lines. Cell proliferation and invasion were significantly suppressed by siRNA against DDR1. Thus, DDR1 can be a novel molecular target of therapy as well as an important predictive marker for survival in patients with glioma. Our method was effective at classifying high-grade gliomas objectively, and provided a more accurate predictor of prognosis than histological grading.

Association of killer cell immunoglobulin-like receptor genotypes with microscopic polyangiitis

OBJECTIVE

Genetic background and infection have been implicated in the etiology of microscopic polyangiitis (MPA). Killer cell immunoglobulin-like receptors (KIRs) are a diverse family of activating and inhibitory receptors expressed on natural killer (NK) cells and T cells, the genes of which show extreme polymorphism. Some KIRs bind to HLA class I subgroups, and genetic interactions between KIR genes and their ligand HLA have been shown to be associated with several autoimmune and viral diseases. In this study, we examined possible associations of the presence or absence of KIR loci with a genetic predisposition to MPA.

METHODS

The presence or absence of 14 KIR loci was determined in 57 myeloperoxidase antineutrophil cytoplasmic antibody-positive Japanese subjects (43 patients with MPA and 239 healthy controls).

RESULTS

The carrier frequency of activating KIR2DS3 was significantly decreased among patients with MPA compared with healthy controls (4.7% versus 16.7%; P = 0.038, odds ratio [OR] 0.24, 95% confidence interval [95% CI] 0.06-0.94). When KIRs were analyzed in combination with their HLA ligands, the proportion of individuals carrying inhibitory KIR3DL1 and HLA-Bw4 but not activating receptor KIR3DS1, a combination presumed to be the most inhibitory of all KIR3DS1/3DL1/HLA-B combinations, was significantly increased in the MPA group compared with the control group (46.5% versus 27.0%; P = 0.014, OR 2.35, 95% CI 1.18-4.70). Furthermore, when subjects were classified according to KIR3DL1/3DS1/HLA-B and KIR2DL1/ HLA-C combinations, an increasing trend toward susceptibility was observed as combinations became more inhibitory.

CONCLUSION

The decreased activation potential of NK and/or T cells associated with KIR/HLA genotypes may predispose to MPA, possibly through insufficient resistance against infections.

Effects of down-regulating the Id genes in human colorectal cancer cells on early steps of haematogenous metastasis

Id genes (inhibitor of DNA binding/differentiation) play important roles in tumour growth. We have previously described crucial roles of Id gene over-expression in endothelial cells for tumour angiogenesis. Here, we have evaluated direct effects of Id gene down-regulation on tumour cells, namely on cell proliferation, motility, and adhesion to lung microvasculature during haematogenous metastasis. For this purpose, Id genes were stably down-regulated by RNA interference in human colorectal cancer cells. These cells showed delayed proliferation, inhibited motility and decreased expression of integrin alpha6 and consequently reduced adhesion to lung microvasculature in mice. Static adhesion assays and laminar flow assays revealed decreased laminin binding capacity of these cells, and blocking experiments confirmed that it could be attributed to decreased expression of integrin alpha6. The present results indicate important roles of Id genes in tumour cells during early steps of haematogenous metastasis and suggest dual effects from their therapeutic inhibition.

Targeting Id1 and Id3 inhibits peritoneal metastasis of gastric cancer

Inhibitor of DNA binding (Id) proteins are essential for cell differentiation, proliferation, migration, invasion and angiogenesis. Recently, they have been shown to correlate with less differentiated phenotypes, high malignant potential and poor clinical outcome in various kinds of tumors. In an attempt to develop new strategies for the treatment of peritoneal metastasis of gastric cancer, we prepared an Id1, 3 double-knockdown gastric cancer cell line, MKN45, by RNA interference and investigated its effects on the development of metastatic nodules in the peritoneal cavity. Both cell proliferation and migration capabilities were decreased in Id1, 3 double-knockdown cells, as was their ability to bind to laminin, which could be explained by the decreased expression of integrin alpha6. These are important steps in the metastatic process. In a mouse model, the number of peritoneal metastatic nodules formed by Id1, 3 double-knockdown cells was reduced compared to mock-transfected control cells, as was the size of individual tumors. In this study, we clearly demonstrated that Id1, 3 double-knockdown significantly impaired the ability of gastric cancer cells to form peritoneal metastasis. Id should be considered an ideal target for the treatment and prevention of gastric cancer, and RNA interference is an attractive and promising strategy to achieve it.

Chemistry and Biological Effects of Melanoidins and Glyceraldehyde-Derived Pyridinium as Advanced Glycation End Products

Blue pigments (blue-M1 and blue-M2) and red pigments (red-M1 and red-M2) were generated in a xylose-glycine reaction system. Blue-M2 was identified as an addition compound of di-xylulose-glycine to blue-M1 that involved two pyrrolopyrrole structures. We identified red pigments as isomers of addition compounds of xylulose-glycine to the condensed compound between pyrrolopyrrole-2-carbaldehyde and pyrrole-2-carbaldehyde. These pigments have polymerizing activity, suggesting that they are important Maillard reaction intermediates through the formation of melanoidins. Melanoidins induced IFN-gamma and IL-12 expression in spleen cells exposed to allergen and in macrophages, respectively. These findings suggest that melanoidins have a suppressive effect on allergic reaction as a novel physiological effect. On the other hand, we identified a glyceraldehyde-derived advanced glycation end product (AGE) formed from glyceraldehyde and N-acetylarginine as well as glyceraldehyde-derived pyridinium (GLAP) in physiological conditions. The AGE was identified as 5-methylimidazoline-4-one (MG-H1), which has been reported to be formed from arginine and methylglyoxal. GLAP, which induced reactive oxygen species (ROS) production in HL-60 cells, is supposed to be a toxic AGE, while MG-H1 is a nontoxic AGE.

Role of Fc gamma receptor IIb polymorphism in the genetic background of systemic lupus erythematosus: insights from Asia

FCGR2B codes for an inhibitory receptor expressed in B cells and monocytes. Polymorphisms of Fcgr2b in mice have been shown to be associated with autoimmune diseases including systemic lupus erythematosus (SLE) and targeted disruption of Fcgr2b renders mice susceptible to induced or spontaneous autoimmunity, depending on the genetic background. Polymorphism screening of FCGR2B has been hampered by the complexity and extreme homology among FCGR family members. We established a specific genotyping system, detected a SNP that changes position 232 amino acid in the transmembrane region from Ile to Thr and found a significant association of 232Thr with SLE in the Japanese, Thai and Chinese populations. In contrast, promoter polymorphism of FCGR2B, but not Ile232Thr, was shown to be associated with SLE in Caucasians. Linkage disequilibrium was observed among FCGR2A, 2B, 3A and 3B genes with varying degrees, but in the Asian populations, each of FCGR2B, 3A and 3B genes was suggested to contribute to the susceptibility to SLE. These results indicate that FCGR2B is a susceptibility gene to SLE in the context of a genetic background, both in humans and mice.

Association of HLA-DRB1*0901-DQB1*0303 haplotype with microscopic polyangiitis in Japanese

Microscopic polyangiitis (MPA) is a rare and severe form of systemic necrotizing vasculitis associated with myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibody (ANCA). We previously reported significant association of HLA-DRB1*0901 with MPA. To define the susceptibility loci within the HLA region, we determined the genotypes of HLA-DQB1, DPB1, B and C in 50 patients with MPA and 77 unrelated Japanese controls. In addition to HLA-DRB1*0901, significant association of DQB1*0303 (allele carrier frequencies 50% in MPA, 29.9% in controls, odds ratio 2.35, P = 0.017) was detected. These alleles were in strong linkage disequilibrium (D' = 0.95, r2 = 0.82). Increased frequency was also observed for DPB1*0201, B*15111 and Cw*0303, which was at least partly accounted for by linkage disequilibrium with DRB1*0901 and DQB1*0303. These results indicate that DRB1*0901-DQB1*0303 haplotype represents the primary genetic risk for MPA within the HLA region in Japanese, and provides the basis that future functional studies on the role of HLA in MPA should target DR9, DQ9 and DR53 proteins encoded by this haplotype.

The influence of mycophenolate mofetil versus azathioprine and mycophenolic acid pharmacokinetics on the incidence of acute rejection and infectious complications after renal transplantation

PURPOSE

The present retrospective study investigated the influence of mycophenolate mofetil (MMF) instead of azathioprine (AZA) as part of tacrolimus-based immunosuppression. Mycophenolic acid (MPA) pharmacokinetic (PK) parameters were used for associations with the incidence of acute rejection (AR) episodes and infectious complications after renal transplantation.

METHODS

The 66 consecutive renal transplant recipients reported herein excluded ABO-incompatible transplants or cytomegalovirus (CMV)-seronegative recipients. The immunosuppressive regimen consisted of tacrolimus, steroids, and AZA 1-2 mg/kg/d in 22 patients (between February 1998 and December 2000) or MMF 2 g/d in 44 patients (since January 2001). CMV infection was defined as positive CMV-antigenemia. MPA PK was studied on day 28 after transplantation in 21 recipients.

RESULTS

AR occurred in 13.6% of patients in the MMF group compared with 18.2% in the AZA group. The viral infection (CMV, varicella zoster virus, adenovirus hemorrhagic cystitis, and malignancy related to Epstein-Barr [EB] virus) rate was 22.7% in the MMF group and 0% in the AZA group (P = .015). There were no bacterial or fungal infections observed in the 2 groups. MMF dose per body weight was significantly lower among patients with AR than those without AR (25.1 vs 35.6 mg/kg; P = .026). There were no differences in MPA PK parameters between patients with and without viral infections.

CONCLUSIONS

Patients treated with MMF required less treatment for AR, however, there were no significant differences. MMF dose per body weight may play an important role in the occurrence of AR. Although virus infections occurred in recipients treated with MMF, MPA PK did not influence the infectious complications after renal transplantation.

Impact of CYP3A5 and MDR1(ABCB1) C3435T polymorphisms on the pharmacokinetics of tacrolimus in renal transplant recipients

OBJECTIVE

The objective of this study was to assess the influence of CYP3A5 and MDR1 genetic polymorphisms on tacrolimus pharmacokinetics in Japanese renal transplant recipients.

METHOD

The pharmacokinetic parameters of tacrolimus were calculated in steady-state on day 28 after transplantation. Polymerase chain reaction-restriction fragment length polymorphism and direct sequence methods were used for CYP3A5 and MDR1 polymorphisms, respectively.

RESULTS

The dose-adjusted area under the concentration-time curve (AUC0-12) was significantly lower among CYP3A5*1 carriers than those bearing CYP3A5*3/*3. (0.570 +/- 0.105 vs 0.865 +/- 0.343 ng.h/mL per mg/kg, P = .00322). The daily tacrolimus dose per body weight was significantly higher in CYP3A5*1 carriers than those of CYP3A5*3/*3 carriers (0.271 +/- 0.110 vs 0.150 +/- 0.056 mg/kg, P = .00016). In this study, a distinction was made between carriers of CYP3A5*1/*1+*1/*3 and CYP3A5*3/*3 to investigate the influence of the MDR1 C3435T mutation on tacrolimus pharmacokinetics. The MDR1 C3435T polymorphisms did not affect any tacrolimus pharmacokinetic parameter in either group.

CONCLUSIONS

Renal transplant recipients who were CYP3A5*1 carriers required a higher dose of tacrolimus than CYP3A5*3/*3, indicating a significantly lower dose-adjusted AUC0-12 of tacrolimus. In contrast, MDR1 C3435T polymorphism was not an important factor in tacrolimus pharmacokinetics.

FcγRIIB Ile232Thr transmembrane polymorphism associated with human systemic lupus erythematosus decreases affinity to lipid rafts and attenuates inhibitory effects on B cell receptor signaling

The B cell inhibitory receptor FcgammaRIIB plays crucial roles in the maintenance of self-tolerance. We have identified a polymorphism FCGR2B c.695T>C that results in the non-conservative replacement of 232Ile at the transmembrane helix to Thr and demonstrated the association of the polymorphism with susceptibility to systemic lupus erythematosus (SLE) in Asians. In this study, we examined the impact of FCGR2B c.695T>C on the functional properties of FcgammaRIIB by expressing each allele product in a human B cell line ST486 lacking endogenous FcgammaRIIB. FcgammaRIIB 232Thr was found to be significantly less potent than wild-type 232Ile in inhibiting B cell receptor (BCR)-mediated phosphatidylinositol-3,4,5-trisphosphate accumulation, Akt and PLCgamma2 activation and calcium mobilization, and to display decreased levels of tyrosine phosphorylation and SH2-containing 5'-inositolphosphate phosphatase recruitment compared with 232Ile after IgG Fc-mediated coligation with BCR. Notably, a quantitative analysis of the subcellular distribution of FcgammaRIIB using 125I-labeled anti-FcgammaRIIB revealed that FcgammaRIIB 232Thr is less effectively distributed to detergent-insoluble lipid rafts than 232Ile, findings in accordance with the importance of the transmembrane amino acid residues, in particular large hydrophobic amino acids including Ile, in the association of membrane proteins with lipid rafts. Given the crucial roles of lipid rafts in integrating BCR signaling, decreased association of FcgammaRIIB 232Thr could contribute to its impaired inhibitory potential. Collectively, the present findings indicate that the Ile232Thr substitution affects the localization and function of FcgammaRIIB and that the molecular mechanism may link the polymorphism and susceptibility to SLE.

Extensive polymorphisms of LILRB1 (ILT2, LIR1) and their association with HLA-DRB1 shared epitope negative rheumatoid arthritis

Leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1/LIR1/ILT2) is an inhibitory receptor broadly expressed on leukocytes and recognizes HLA-class I and human cytomegalovirus UL18. LILRB1 is encoded within the leukocyte receptor complex on 19q13.4, previously implicated to be a susceptibility region to systemic lupus erythematosus (SLE). In this study, we screened for polymorphisms of LILRB1 and examined their association with SLE and rheumatoid arthritis (RA). In the 5' portion of LILRB1, three haplotypes containing four non-synonymous substitutions within the ligand-binding domains and two single nucleotide polymorphisms within the promoter region were identified and designated as PE01-03. In the 3' portion, two haplotypes (CY01, 02) containing a non-synonymous substitution of the cytoplasmic region were identified. CY01 and 02 did not co-segregate with PE01-03. Significant association with susceptibility to SLE or RA was not observed; however, among the subjects not carrying RA-associated HLA-DRB1 shared epitope (SE), LILRB1.PE01/01 diplotype was significantly associated with RA (odds ratio 2.05, P = 0.019 and Pc = 0.038). Gross difference was not observed in the crystal structures, thermostabilities and binding affinities to HLA-class I ligands among LILRB1.PE01-03 haplotype products; however, surface expression of LILRB1 was significantly decreased in lymphocytes and monocytes from the carriers of PE01 haplotype. These findings demonstrated that LILRB1 is highly polymorphic and is associated with susceptibility to RA in HLA-DRB1 SE negative subjects, possibly by insufficient inhibitory signaling in leukocytes. In addition, these observations suggested that the polymorphisms of LILR family members may be substantially involved in the diversity of human immune responses.

Incidence and Risk Factors of Clinical Characteristics, Tacrolimus Pharmacokinetics, and Related Genomic Polymorphisms for Posttransplant Diabetes Mellitus in the Early Stage of Renal Transplant Recipients

PURPOSE

Posttransplant diabetes mellitus (PTDM) is an important complication in a tacrolimus (TAC)-based immunosuppressive regimen. The present study investigated the incidence, clinical risk factors, TAC pharmacokinetics (PK), and genomic polymorphisms related to TAC-PK or diabetes mellitus (DM) under the TAC-based immunosuppressive protocol.

PATIENTS AND METHODS

Seventy-one nondiabetic renal allograft recipients transplanted from February 1998 to March 2004 were studied. Patients with over 6.5 mg/dL of hemoglobin A1c on sequential blood samples or requiring insulin or oral antidiabetic agents around 6 months after transplantation were diagnosed as having PTDM.

RESULTS

Six months after transplantation, 10 recipients (14.1%) developed PTDM. The positive risk factors were age (P = .003) and body mass index (P = .035). There were no significant differences in gender distribution, pretransplant dialysis period, dialysis modality, acute rejection rate, total steroid doses, TAC-PK, or its related genomic polymorphisms between the two groups. In the DM-related polymorphisms, the frequency of PTDM was significant higher in patients with the VDR TaqI tt or Tt genotype than in those with the TT genotype (P = .013). After a multivariate analysis, age over 50 years (P = .007, odds ratio 8.92) and the presence of VDR TaqI t allele (P = .043, odds ratio 6.71) were correlated with the development of PTDM.

CONCLUSION

The incidence of PTDM in our series was 14.1%. Age over 50 years was a risk factor. The presence of VDR TaqI t allele might be a risk for PTDM. An association between TAC-PK and development of PTDM was not observed.

Effect of hypercapnia on arterial hypotension after induction of anaesthesia

We evaluated the effectiveness of intentional hypercapnia against hypotension after induction of anaesthesia with thiopental and isoflurane (TI) or propofol (P). For each group, 24 patients were anaesthetized with thiopental 4 mg kg(-1) (TI) or propofol 2 mg kg(-1) (P) for tracheal intubation and then lightly anaesthetized with isoflurane at 0.6% end-expiratory concentration (TI) or by 6 mg kg(-1) h(-1) infusion of propofol (P). In both anaesthesia groups, patients were randomly assigned to either normocapnia (end-tidal CO(2) = 35 mmHg) or hypercapnia (end-tidal CO(2) = 45 mmHg), which were achieved through adjusting the tidal volume. Systolic arterial pressure (SAP) 15 min after intubation was compared with the preanaesthetic baseline value. Under normocapnia, both TI and P induced a comparable, statistically significant suppression of SAP by approximately 20 mmHg from baseline. Hypercapnia prevented the decrease in SAP in TI but not in P. No patient in the TI-hypercapnia group experienced SAP below 100 mmHg, unlike those in the other groups. In conclusion, mild hypercapnia was effective in the prevention of hypotension in patients receiving thiopental followed by 0.6% end-expiratory isoflurane, but not in patients receiving 6 mg kg(-1) h(-1) propofol.

Naloxone and flumazenil fail to antagonize the isoflurane-induced suppression of dorsal horn neurons in cats

Effects of naloxone and flumazenil on isoflurane activities were examined on dorsal horn neurons in cats. Isoflurane suppressed bradykinin-induced nociceptive responses in transected feline spinal cords. The bradykinin-induced neuronal firing rates were significantly suppressed by 60.0%, 35.3% and 32.2% at 10, 20 and 30 min after isoflurane administration, respectively. The 32.3% suppression on bradykinin-induced neuronal responses at 30 min after isoflurane administration was not reversed 5 min after administration of naloxone (36.4% suppression). The suppressive effects of isoflurane were not reversed by naloxone (0.2 mg.kg(-1), i.v.). Similarly, the benzodiazepine antagonist, flumazenil (0.2 mg.kg(-1), i.v.), did not affect the suppressive effects of isoflurane. Failure of naloxone and flumazenil to reverse the suppressive effects of isoflurane suggests that isoflurane interacts with neither opioid nor benzodiazepine receptors in producing its suppressive action on nociceptive responses in dorsal horn neurons of the feline spinal cord.

Evaluation of microsatellite markers in association studies: a search for an immune-related susceptibility gene in sarcoidosis

Association studies using linkage disequilibrium (LD) between candidate loci and nearby markers have been proposed to identify susceptibility genes for complex diseases. We analyzed polymorphisms of microsatellites (MSs) and LD patterns of the regions in which candidate genes related to the Th1 immune response have been annotated and attempted to identify a susceptibility gene for sarcoidosis in a marker-based association study. Nineteen MSs were identified in six Th1-related genes (IFNGR1, IFNGR2, IL12RB1, IL12RB2, STAT1 and STAT4) and then eight were further characterized as useful polymorphic markers. Most of these MSs showed LD with single nucleotide polymorphisms (SNPs) on both 5' and 3' ends of these candidate genes, in which r(2) values between at least one of the MS marker alleles and the SNPs were higher than 0.1. A significant association with one MS allele near STAT4 was shown and a cluster of SNPs in LD with the MS marker was associated with sarcoidosis. These results suggest that association studies using not only SNPs but also multi-allelic MS within or near candidate loci would be useful markers to search for a disease susceptibility gene, especially in populations with unknown LD structure.

Association of a functionalCD19 polymorphism with susceptibility to systemic sclerosis

OBJECTIVE

CD19 is overexpressed in B cells from patients with systemic sclerosis (SSc), and plays a crucial role not only for autoantibody production, but also for skin fibrosis in mouse models. We previously reported the association of a GT repeat polymorphism in the 3'-untranslated region (3'-UTR) of CD19 with human systemic lupus erythematosus. In this study, we examined whether CD19 polymorphisms are associated with genetic susceptibility to SSc.

METHODS

A case-control association study was performed for CD19 polymorphisms, -499G>T in the promoter region and a GT repeat polymorphism in the 3'-UTR, in 134 patients with SSc and 96 healthy individuals recruited at Kanazawa University. CD19 expression levels in the peripheral blood naive and memory B cells from SSc patients were examined by 2-color flow cytometry.

RESULTS

Carrier frequencies of the -499T allele in the promoter (odds ratio [OR] 2.18, 95% confidence interval [95% CI] 1.31-3.86, P = 0.003) and of the (GT)(14) allele in the 3'-UTR (OR 1.86, 95% CI 1.05-3.28, P = 0.03) were significantly increased in SSc patients compared with healthy controls. Association was particularly evident in patients with limited cutaneous SSc with anticentromere antibodies. These alleles were in linkage disequilibrium, but the -499T allele seemed to play a primary role. CD19 expression levels in peripheral blood B cells were significantly elevated in both naive (P = 0.0029) and memory (P = 0.0022) B cells from patients with SSc who had the -499T allele as compared with those without the -499T allele.

CONCLUSION

The CD19 -499G>T polymorphism is associated with higher CD19 expression in B cells, and with susceptibility to SSc.