OP0112 THE EVER-LARGEST ASIAN GWAS FOR SYSTEMIC SCLEROSIS AND TRANS-POPULATION META-ANALYSIS IDENTIFIED SEVEN NOVEL LOCI AND A CANDIDATE CAUSAL SNP IN A CIS-REGULATORY ELEMENT OF THE FCGR REGION

Background

Genome-wide association studies (GWASs) have identified 29 disease-associated single nucleotide polymorphisms (SNPs) for systemic sclerosis (SSc) in non-human leukocyte antigen (HLA) regions (1-7). While these GWASs have clarified genetic architectures of SSc, study subjects were mainly Caucasians limiting application of the findings to Asians.

Objectives

The study was conducted to identify novel causal variants for SSc specific to Japanese subjects as well as those shared with European population. We also aimed to clarify mechanistic effects of the variants on pathogenesis of SSc.

Methods

A total of 114,108 subjects comprising 1,499 cases and 112,609 controls were enrolled in the two-staged study leading to the ever-largest Asian GWAS for SSc. After applying a strict quality control both for genotype and samples, imputation was conducted using the reference panel of the phase 3v5 1,000 genome project data combined with a high-depth whole-genome sequence data of 3,256 Japanese subjects. We conducted logistic regression analyses and also combined the Japanese GWAS results with those of Europeans (6) by an inverse-variance fixed-effect model. Polygenicity and enrichment of functional annotations were evaluated by linkage disequilibrium score regression (LDSC), Haploreg and IMPACT programs. We also constructed polygenic risk score (PRS) to predict SSc development.

Results

We identified three (FCRLA-FCGR, TNFAIP3, PLD4) and four (EOMES, ESR1, SLC12A5, TPI1P2) novel loci in Japanese GWAS and a trans-population meta-analysis, respectively. One of Japanese novel risk SNPs, rs6697139, located within FCGR gene clusters had a strong effect size (OR 2.05, P=4.9×10-11). We also found the complete LD variant, rs10917688, was positioned in cis-regulatory element and binding motif for an immunomodulatory transcription factor IRF8 in B cells, another genome-wide significant locus in our trans-ethnic meta-analysis and the previous European GWAS. Notably, the association of risk allele of rs10917688 was significant only in the presence of the risk allele of the IRF8. Intriguingly, rs10917688 was annotated as one enhancer-related histone marks, H3K4me1, in B cells, implying that FCGR gene(s) in B cells may play an important role in the pathogenesis of SSc. Furhtermore, significant heritability enrichment of active histone marks and a transcription factor C-Myc were found in B cells both in European and Japanese populations by LDSC and IMPACT, highlighting a possibility of a shared disease mechanism where abnormal B-cell activation may be one of the key drivers for the disease development. Finally, PRS using effects sizes of European GWAS moderately fit in the development of Japanese SSc (AUC 0.593), paving a path to personalized medicine for SSc.

Conclusion

Our study identified seven novel susceptibility loci in SSc. Downstream analyses highlighted a novel disease mechanism of SSc where an interactive role of FCGR gene(s) and IRF8 may accelerate the disease development and B cells may play a key role on the pathogenesis of SSc.

References

[1]F. C. Arnett et al. Ann Rheum Dis, 2010.

[2]T. R. Radstake et al. Nat Genet, 2010.

[3]Y. Allanore et al. PLoS Genet, 2011.

[4]O. Gorlova et al. PLoS Genet, 2011.

[5]C. Terao et al. Ann Rheum Dis, 2017.

[6]E. López-Isac et al. Nat Commun, 2019.

[7]W. Pu et al. J Invest Dermatol, 2021.

Disclosure of Interests

None declared

Detection of human papillomavirus type 56 in Bowen's disease involving the nail matrix

BACKGROUND

As Bowen's disease of the nail apparatus is quite rare, there have been only a few reports on the prevalence of human papillomavirus (HPV) infection in this condition.

OBJECTIVES

The purpose of this study was to clarify the association of HPV with this disease involving the nail apparatus.

METHODS

Five patients with Bowen's disease of the nail apparatus were investigated clinically, virologically and histologically. Total DNAs extracted from excised skin lesions were analysed using polymerase chain reaction (PCR) for the presence of HPV DNA and the amplified products were subjected to DNA sequence analyses. Histological localization of HPV DNA was examined by in situ hybridization.

RESULTS

In three of five patients, HPV was detected by PCR amplification, and subsequent sequence analyses of the PCR products showed the sequences of HPV type 56. A common clinical feature of the three HPV-positive patients was longitudinal melanonychia. In contrast, the two HPV-negative patients presented with a convex nail deformity and a periungual ulcerative lesion. In two of three positive cases, there was a silent point mutation in the L1 gene of each HPV. In the remaining one case, the nucleotide sequence was consistent with the consensus sequence of HPV 56. Sequence analyses of the E6 gene revealed the infection of different variants of HPV 56 among the three cases. The viral genomes were located in keratinocyte nuclei upon in situ hybridization.

CONCLUSIONS

HPV 56 may be involved in the carcinogenesis of Bowen's disease affecting the nail matrix with longitudinal pigmentation.

Safety and efficacy of sirolimus in kidney transplant patients and in patients with coronary artery disease undergoing angioplasty

We show the key results of our 4-year experience with sirolimus in kidney transplant patients and in nontransplanted patients undergoing coronary angioplasty.

METHODS

Recipients of one-haplotype living-related kidney allografts were randomized to receive sirolimus (2 mg/d, n = 35) or azathioprine (2 mg/kg per day, n = 35). Recipients of fully mismatched living kidney allografts (n = 55) received sirolimus (2 mg/day). High-risk recipients of black ethnicity (n = 68) were randomized to target whole-blood trough sirolimus concentrations between 8 and 12 ng/mL or 15 to 20 ng/mL. All kidney transplant patients received cyclosporine and prednisone. Sirolimus/cyclosporine pharmacokinetic studies were performed in 40 patients receiving 2 mg (n = 20) or 5 mg (n = 20) of sirolimus 7 days after transplantation. In the coronary intervention study, 12 patients at high risk for in-stent restenosis received sirolimus for 28 days after angioplasty.

RESULTS

The incidence of biopsy-confirmed acute rejection was 11.4% in recipients of one-haplotype living-related kidney allografts, 16.4% in recipients of fully mismatched living kidney allografts, and 15% (8 to 12 ng/mL) and 4% (15 to 20 ng/mL) in high-risk recipients of black ethnicity. Cyclosporine exposure was higher after morning administration compared to evening administration. There were poor correlations between sirolimus and cyclosporine exposures. The 4-month follow-up angiography revealed no restenosis (stenosis diameter > 50%), a late loss of 0.56 +/- 0.40 mm, and a loss index of 0.33 +/- 0.30. The follow-up 3D-intravascular ultrasound restudy showed an in-stent relative volumetric obstruction of 9.9 +/- 5.5%. Sirolimus in highly effective in preventing kidney allograft acute rejection and in-stent coronary restenosis.

Expression and cellular distribution of cytosolic phospholipase A2 in the rat ovary

Cellular expression of cytosolic phospholipase A2 (cPLA2) was investigated in the rat ovary in different endocrine states. Its mRNA expression was detected by RT-PCR. The immunohistochemistry identified an intense signal for cPLA2 in oocytes. Granulosa and thecal cells in growing follicles were negative, but turned positive during the periovulatory period, whereas those in atretic follicles were highly immunoreactive. The immunoreactive signal was modest in newly formed corpora lutea (CL) but intensified in functionally and morphologically regressing CL. These results show a broad but specific distribution of cPLA2 in ovarian cell types, and suggest its role in ovulation, CL regulation and apoptotic processes.

Cytologic diagnosis of signet-ring cell carcinoma of the breast

OBJECTIVE

To examine the cytologic features of signet-ring cell carcinoma (SRCC), defined as carcinoma dominated by signet-ring cells, of the breast and to discuss problems that occur in cytodiagnosis.

STUDY DESIGN

Five cases of SRCC of the breast were examined cytopathologically. Signet-ring cells were subclassified into intracytoplasmic lumina (ICL) type and non-ICL type. ICL type had large ICL containing mucin. Non-ICL-type cells had wide, amorphous cytoplasm diffusely dispersed with mucin.

RESULTS

In cases 1 and 2, fine needle aspiration biopsy (FNAB) revealed many signet-ring cells (non-ICL type), suggesting SRCC. Histologic diagnoses were ductal SRCC containing many signet-ring cells (non-ICL type). In cases 3 and 4, signet-ring cells (ICL type) were found sporadically among carcinoma cells without signet-ring features. Signet-ring cells were not regarded as the major component of the cells; thus, the cytologic diagnoses were lobular carcinoma, not otherwise specified. Pathologic diagnoses were lobular SRCC. Signet-ring cells were mostly ICL type. In case 5, most carcinoma cells on the smears showed signet-ring features (non-ICL type), suggesting SRCC. The histologic diagnosis was lobular SRCC, and signet-ring cells were mostly non-ICL type.

CONCLUSION

Ductal SRCC yielded more cellular smears as compared with lobular SRCC; therefore, cytologic diagnosis was easier in the former.

[Detection of antinuclear antibodies and their significance as disease markers]

The improvement of the quality control in the detection of fluorescent antinuclear antibodies (FANA) have decreased the differences among institutions. However, the positive lower or upper reference limit and the criteria for the determination vary among laboratories. By examining 725 sera from children and 227 sera from healthy adults, we proposed the titers of 160-320 for children and 80-160 for adults as the positive lower limits. The higher positive incidence in the children's sera might be due to some abnormality in the ANA production or the higher sensitivity of the reagents used. The clinical significances of the anti-U1RNP antibody and anticentromere antibody (ACA) in ANA have been described. The anti-U1RNP antibody, present in only MCTD and related disorders, might play some role in the development of Raynaud's phenomenon and symptoms in a case of neonatal lupus erythematosus. ACA was detected in sera not only of CREST syndrome patients but also of PBC patients. The functions and molecular structures of nuclear antigens have recently been extensively investigated. However, the pathogenetic significance of most of the ANA and the mechanism of their production have not been clarified yet.

Rapid, sensitive detection of myoglobulinemia by improved counterimmunoelectrophoresis in cases of acute myocardial infarction

A counterimmunoelectrophoresis technique for detection of serum myoglobin (Mb) was improved using non-ionic polymer dextran. Precipitin lines were graded according to their strength, which was ascertained by radioimmunoassay data. By this method, serum Mb in concentrations of 500 ng./ml. before stain and of 200 ng./ml. after stain were detected. Electrophoretic time was 60 minutes. Among 32 cases of acute myocardial infarction (AMI) whose blood samples were collected within 24 hours after disease onset, precipitin lines were detected in 25 cases (78%) before stain and 31 cases (97%) after stain. Considering the early peak concentration time (approximately 10 hours) of serum Mb after AMI onset, diagnosis becomes more rapid and exact with this method, especially in severe cases.