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Objective The survival advantage of females over males is lost in dialysis patients in many countries. Japanese female hemodialysis patients, however, have a survival advantage over their male counterparts. This study explored causes of death that contribute to sex differences in all-cause mortality in Japanese dialysis patients. Methods Data from the Japanese Society for Dialysis Therapy registry and National Vital Statistics from 2017 and 2018 were used. Standardized mortality ratios, male-to-female mortality rate ratios, and age-adjusted differences between sexes were calculated for all-cause, cardiovascular, and non-cardiovascular mortality, as well as cause-specific mortality, in dialysis patients and the general population. Results During the 2-year study period, 41,006 and 21,254 deaths occurred in 417,740 and 225,292 patient-years in male and female dialysis patients, respectively. The age-standardized all-cause mortality ratio was 1.21 (95% confidence interval, 1.20-1.23) for male patients compared to female patients. The male-to-female mortality rate ratio for cardiovascular disease was about 1.4 in younger age categories but closer to 1.0 in older age categories. Conversely, the ratio for non-cardiovascular disease was about 1.3 in older age categories but closer to 1.0 in younger age categories. Death from infectious disease, malignancy, and heart failure contributed to 38.4%, 22.7%, and 12.1%, respectively, of the male-to-female difference in all-cause mortality of dialysis patients. Conclusion Low cardiovascular mortality in younger age categories and low non-cardiovascular mortality in older age categories contributed to the survival advantage of female Japanese dialysis patients. Infectious disease was the greatest contributor to sex differences in all-cause mortality.

Objective Treatment of elderly patients with rheumatoid arthritis (RA) has been controversial because they often have serious comorbidities and cannot use methotrexate (MTX). In Japan, golimumab (GLM) 100 mg without MTX is approved. We investigated the effectiveness and safety of GLM in elderly patients with RA. Methods The GLM survival rate was evaluated using the Kaplan-Meier method. Disease activities, laboratory findings, and treatments were evaluated. Patients We enrolled 168 patients with RA in our hospital. Using age ≥75 years old to identify elderly patients, younger (n=111) and elderly (n=57) groups were established. Elderly patients were divided into 2 groups according to the MTX treatment status (with, n=27; without, n=25). Results The GLM survival rates were 80.8% and 82.3% in elderly and younger patients, respectively (p=0.762). At 52 weeks, the Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR) was improved in elderly patients (4.26 vs. 3.31, p0.001); the Health Assessment Questionnaire Disability Index (HAQ-DI) was unchanged (1.12 vs. 0.88, p=0.694). When elderly patients were compared according to the MTX treatment status, the DAS28-ESR had improved in both groups (with MTX: 3.82 vs. 2.68, p0.001; without MTX: 4.76 vs. 4.25, p=0.026); however, the HAQ-DI had not. The GLM survival rates at 52 weeks were 85% and 76% in patients with and without MTX, respectively. Conclusion In elderly patients with RA, GLM was effective, regardless of MTX treatment status, but it did not affect the HAQ-DI. GLM survival rates were comparable between elderly and younger patients. GLM may be a suitable option for elderly patients with RA who cannot use MTX.

Background The relationship between obesity and risk of death in chronic kidney disease (CKD) patients remains controversial. In addition, no clear evidence has been accumulated regarding whether or not exercise improves mortality in CKD patients. Materials and Methods The original cohort was based on a Japanese general population of 685,889 people from 40 to 74 years old who had undergone annual specific health checkups. The number of all-cause deaths during follow-up (mean, 4.7 years) in this study was 1,490. Information on walking and exercise habits was obtained by questionnaires. The study population was divided into 4 categories by the combination of CKD and obesity [body mass index (BMI) ≥25.0 kg/m

Objective Results from previous studies on the dose-dependent effect of adhering to multiple lifestyle factors on all-cause mortality in patients with chronic kidney disease (CKD) are inconsistent, despite the reported dose-dependent effect in the general population. This study aimed to examine whether CKD modifies the dose-dependent effect of adhering to multiple lifestyle factors on mortality. Methods This population-based prospective cohort study targeted 262,011 men and women aged 40-74 years at baseline. Of these, 18.5% had CKD, which was defined as GFR

Objective To evaluate the effectiveness and drug retention rate of golimumab (GLM) for long-term use in daily practice for patients with rheumatoid arthritis (RA). Methods Patients with RA who started GLM therapy with a minimum follow-up period of 52 weeks were included. The patients were divided into a biologic-naive group and switch group. The disease activity score (DAS) 28-erythrocyte sedimentation rate (ESR) (DAS28-ESR), grip power, and Japanese version of the health assessment questionnaire (J-HAQ) score were assessed. In addition, the treatment continuation rate was evaluated at the final follow-up. Patients Sixty-five patients (58 women and 7 men; median [range] age, 69 [61-74] years; median [range] disease duration, 9 [5-16] years) were included. Twenty-eight patients were biologic-naive (naive group), and 37 were switched to biologics (switch group). Results The median (range) follow-up period was 134 (58-162) weeks. The DAS28-ESR improved from a median (range) of 4.31 (3.52-5.25) to 2.65 (2.28-3.77) in the naive group and from 4.27 (3.19-4.89) to 2.89 (2.49-3.88) in the switch group. The grip power improved in both groups (p

A 48-year-old woman with a 9-year-history of anorexia nervosa (AN) was admitted complaining of generalized bone pain. Blood tests showed hypocalcemia and hyperphosphatasemia, and a radiological survey revealed multiple rib fractures, suggesting complication with osteomalacia. Two years earlier, she had undergone subtotal colectomy for colon cancer. Her serum 25-hydroxy vitamin D concentration was below the detectable level. In addition to a poor nutritional intake and insufficient sun exposure, malabsorption of fat-soluble substances in the intestine and phosphate loss from the kidneys might have contributed to the development of her osteomalacia.

Objective In Japan, the Specific Health Check and Guidance (Tokutei-Kenshin) program was started in 2008 to decrease the social burden related to metabolic syndrome (MetS). However, so far this program has not been found to have any impact on the mortality rate. Methods The subjects consisted of individuals who participated in the Tokutei-Kenshin in seven districts between 2008 and 2015. Using a National database of death certificates, we identified those who might have died and then further confirmed such deaths with the collaboration of the regional National Health Insurance agency and public health nurses. The diagnosis of MetS was made according to the Japanese criteria. The causes of death were classified by ICD-10. Mortality risk was evaluated after adjusting for age, sex, smoking, alcohol intake and past medical history such as stroke, heart disease and kidney disease. Results Among the total of 664,926 subjects, we identified 8,051 fatal cases by the end of 2015. The crude death rate was 1.6% for those with MetS, 1.3% for those with preliminary metabolic syndrome, and 1.1% those without MetS. In MetS, the adjusted hazard ratio (95% confidence interval) was 1.08 (1.02-1.15) for all-cause and 1.39 (1.22-1.58) for cardiovascular disease mortality when the reference was for those without MetS. Conclusion The death rate was found to be significantly higher among the participants with MetS.

Objective The earlobe crease, a wrinkle extending from the tragus to the outer border of the earlobe, is a well-known surrogate marker for a high risk of cardiovascular disease. However, information is lacking about its association with cardiovascular events among hemodialysis patients, who already have an increased risk of cardiovascular disease. We tested the hypothesis that earlobe creases are independently associated with the risk of cardiovascular events among Japanese hemodialysis patients. Methods This prospective cohort study followed 247 adult hemodialysis patients with no history of cardiovascular disease for 4 years. The presence of earlobe creases was defined by two researchers using photos of patients' earlobes on both sides while blinded to one another's assessments and clinical data. The primary outcome was defined as the first fatal or nonfatal cardiovascular event (myocardial infarction, ischemic or hemorrhagic stroke, or peripheral vascular disease requiring aortic or peripheral vascular bypass surgery or below- or above-the-knee amputation). A Fine-Gray competing risks regression model was used to examine the association between earlobe creases and cardiovascular events. Results During the 4-year follow-up period, 43 patients suffered cardiovascular events. After the competing risk of non-cardiovascular death was accounted for, patients with earlobe creases had an increased cumulative incidence of cardiovascular events compared to those without earlobe creases (subhazard ratio =2.04, 95% confidence interval: 1.09 to 3.82). This association was no longer significant after adjusting for age. Conclusion Earlobe creases were not independently associated with cardiovascular events among Japanese hemodialysis patients, suggesting that these marks are simply indicative of advanced age.

A 56-year-old man was referred to our facility after developing edema in his right leg. Enhanced computed tomography (CT) revealed a periarterial soft tissue mass surrounding the right iliac artery compressing the iliac vein. His elevated serum IgG4 level indicated IgG4-related disease (IgG4-RD). Both a percutaneous and surgical biopsy of this periarterial lesion proved challenging and were not pursued. A prostate biopsy, however, finally provided a histological diagnosis of IgG4-RD. Oral steroid therapy successfully resolved his leg edema and periarterial lesion. This case illustrates the usefulness of an alternative prostate biopsy for the histological diagnosis of IgG4-RD when approaching the primary affected lesion is difficult.

A 68-year-old man with type 2 diabetes mellitus and chronic hepatitis B infection was referred to the nephrology department before planned surgery for hepatocellular carcinoma. He had been receiving low-dose adefovir dipivoxil (ADV) for 11 years. Laboratory findings revealed impaired re-absorption in the proximal renal tubules. He had been diagnosed with diabetic kidney disease and osteomalacia due to vitamin D deficiency; thus, ADV was not discontinued until he was referred to us. In this case, concomitant diabetes mellitus and vitamin D deficiency might have prevented the early diagnosis of ADV-induced Fanconi syndrome.

Legionella pneumonia is occasionally accompanied by renal complications; however, the cause of this remains unknown. We herein report a 70-year-old Japanese man with Legionella pneumonia who presented with hyponatremia, hypophosphatemia, and hypouricemia. The levels of urinary β2-microglobulin and N-acetyl-β-D-glucosaminidase were remarkably high, indicating severe renal tubular damage. The presence of glycosuria and aminoaciduria as well as increased fractional excretion of uric acid and decreased tubular reabsorption of phosphate indicated that the patient's condition was complicated with Fanconi syndrome. After antimicrobial therapy, the electrolyte abnormalities and renal tubular damage were completely resolved.

Objective Evidence suggests that the eating rate is positively associated with the body weight and blood pressure. Furthermore, people who are overweight or obese tend to have higher salt intakes than those of normal weight. To investigate whether or not the eating rate is also associated with the salt intake, a cross-sectional study was conducted using health examination survey data collected in 2014 from 7,941 residents of Sado City, Niigata, Japan. Methods The eating rates were evaluated using a questionnaire; 11.7% of participants rated themselves as slow eaters, 65.6% as normal eaters, and 22.7% as fast eaters. The salt intake was estimated from sodium and creatinine spot urine measurements using Tanaka's formula. Associations with eating rate were evaluated using multivariate linear regression analyses, with normal eaters as the reference (set at 0). Results Self-reported eating rates were positively associated with the salt intake after adjustment for age and sex [β coefficient (95% confidence interval) for slow -0.51 (-0.67, -0.35); fast 0.18 (0.05, 0.30) ]. Further adjustment for the body mass index showed that slower eaters had lower salt intakes than normal eaters, but there was no marked difference in the salt intake between normal and fast eaters. The association between slower eating and a lower salt intake persisted after further adjustment for comorbidities [slow -0.33 (-0.49, -0.18) ]. Conclusion Our results suggest that reducing eating rates may be an effective strategy for reducing dietary salt intake as well as preventing obesity.

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder that generally occurs in children and predominantly affects the long bones with marginal sclerosis. We herein report two cases of adult-onset CRMO involving the tibial diaphysis bilaterally, accompanied by polyarthritis. Magnetic resonance imaging (MRI) showed both tibial osteomyelitis and high intensity of the extensive lower leg muscles. Anti-interleukin-6 therapy with tocilizumab (TCZ) effectively controlled symptoms and inflammatory markers in both patients. High intensity of the lower leg muscles detected by MRI also improved. These cases demonstrate that CRMO should be included in the differential diagnosis of adult patients with bone pain, inflammation, and high intensity of the muscles detected by MRI. TCZ may therefore be an effective therapy for muscle inflammation of CRMO.

Objective The administration of glucocorticoids usually causes a mild increase in fasting glucose levels and a greater dose-dependent increase in postprandial values in patients without pre-existing diabetes mellitus. Patients with persistent hyperglycemia due to glucocorticoid therapy sometimes require insulin therapy, which might result in increased weight gain and more episodes of hypoglycemia, some of which are severe. On the other hand, scant evidence is available on the efficacy of oral hypoglycemic agents in treating glucocorticoid-induced diabetes. In this study, we evaluated the efficacy of dipeptidyl peptidase (DPP)-4 inhibitors in patients with glucocorticoid-induced diabetes by continuous glucose monitoring (CGM). Methods We examined the glycemic profiles using CGM at baseline and 1-4 weeks after initiating DPP-4 inhibitor treatment in patients with newly developed glucocorticoid-induced diabetes. Results Eleven patients who had been diagnosed with kidney disease or other diseases with renal involvement were recruited for the present retrospective study. After starting DPP-4 inhibitors, the mean and standard deviation (SD) of the glucose level, and the mean amplitude of glycemic excursion (MAGE) were significantly improved in comparison to baseline. Furthermore, the area over the curve (AOC) for the glucose levels

Objective Our objective was to examine the safety and effects of therapy with biologics on the prognosis of rheumatoid arthritis (RA) patients with reactive amyloid A (AA) amyloidosis on hemodialysis (HD). Methods Twenty-eight patients with an established diagnosis of reactive AA amyloidosis participated in the study. The survival was calculated from the date of HD initiation until the time of death, or up to end of June 2015 for the patients who were still alive. HD initiation was according to the program of HD initiation for systemic amyloidosis patients associated with RA. Results Ten patients had been treated with biologics before HD initiation for a mean of 28.2 months (biologic group), while 18 had not (non-biologic group). HD was initiated in patients with similar characteristics except for the tender joint count, swollen joint count, and disease activity score (DAS)28-C-reactive protein (CRP). History of biologics showed that etanercept was frequently used for 8 patients as the first biologic. There was no significant difference in the mortality rate according to a Kaplan-Meier analysis (p=0.939) and or associated risk of death in an age-adjusted Cox proportional hazards model (p=0.758) between both groups. Infections were significantly more frequent causes of death in the biologic group than in the non-biologic group (p=0.021). However, treatment with biologics improved the DAS28-CRP score (p=0.004). Conclusion Under the limited conditions of AA amyloidosis treated with HD, the use of biologics might affect infection and thus may not improve the prognosis. Strict infection control is necessary for the use of biologics with HD to improve the prognosis.

Objective Rheumatoid arthritis (RA) is a chronic inflammatory disease accompanied by periarticular and systemic osteoporosis. Fibroblast growth factor 23 (FGF23), which is mainly produced by osteocytes, circulates to the kidneys and regulates bone metabolism. We herein assessed serum FGF23 and its relationship to inflammation and osteoporosis in patients with RA. Methods Sixty-one patients with RA were included. Serum concentrations of FGF23 were determined using a sandwich enzyme-linked immunosorbent assay. Results The mean (± standard deviation) serum FGF23 concentration was 34.9±9.2 (range, 21.0-61.0) pg/mL. The serum FGF23 level was significantly and positively correlated with the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels, disease activity score-28 based on the ESR (DAS-28 ESR) and DAS-28 CRP (r=0.261, p=0.044, r=0.280, p=0.029, r=0.409, p=0.001 and r=0.421, p=0.001, respectively). The serum matrix metalloproteinase-3 level was also significantly and positively correlated with the serum FGF23 level (r=0.331, p=0.015). Concentrations of type I collagen cross-linked N-telopeptide in the serum was significantly correlated with the serum FGF23 level (r=0.272, p=0.034). Neither the bone mineral density in the femoral neck nor lumbar was significantly correlated with the serum FGF23 level. Serum phosphate, calcium, 25-hydroxy vitamin D, and intact parathyroid hormone were not related to the serum FGF23 level. Conclusion In patients with RA, serum FGF23 is correlated with inflammation, the disease activity of RA, and bone absorption markers. Serum FGF23 may be associated with abnormal bone absorption related to RA inflammation. Further studies are necessary to clarify the mechanism underlying this association.

A 61-year-old man was transferred to our hospital with the complaints of dizziness, severe nausea and abdominal discomfort after consuming approximately 50 g of the flowers of Rhododendron japonicum. On admission, hypotension and sinus bradycardia were evident. Symptoms including hypotension and bradycardia completely recovered within 12 hours following normal saline infusion and intravenous atropine. The ingestion of certain types of Rhododendron species can cause intoxication, referred to as "mad honey poisoning", due to the action of grayanotoxins. This is the first local case of acute intoxication caused by Rhododendron japonicum.

There have been many previously reported cases of adult-onset Still's disease (AOSD) which were successfully treated with tocilizumab (TCZ). However, the efficacy and safety of TCZ therapy for AOSD-associated macrophage activation syndrome (MAS), and the optimal duration of TCZ therapy, remain unclear. We herein report two cases of refractory AOSD, one of which was associated with MAS. These two patients were treated with TCZ, and the withdrawal of TCZ was planned according to the serum interleukin-6 level, which resulted in TCZ-free remission.

An 88-year-old woman presented with fever and acute posterior neck pain. A CT scan revealed calcification of the transverse ligament and crown-like calcification around the odontoid process. According to the clinical and radiological findings, she was diagnosed with crowned dens syndrome (CDS). Her symptoms drastically improved following treatment with oral nonsteroidal anti-inflammatory medication. An X-ray of her wrist, elbow, shoulder and knee joints showed asymptomatic calcium deposits, suggesting underlying crystalline deposition disease. CDS may occur as the initial presentation of crystalline deposition disease. The measurement of procalcitonin and an X-ray survey of the major joints may be helpful for the diagnosis of CDS.

Although biological agents are of considerable benefit to patients with rheumatoid arthritis (RA), the potential for opportunistic infections is a critical issue. It is therefore important to achieve a balance between treatment efficacy and controlling opportunistic infection. We herein report the successfully managed case of a 53-year-old patient with RA who developed pulmonary Mycobacterium abscessus infection during treatment with tocilizumab and methotrexate.

A 53-year-old man with an asymptomatic anterior mediastinal tumor undergoing hemodialysis was referred to our institution. He was diagnosed with thymic basaloid carcinoma based on the findings of a chest tomography-guided biopsy and successfully treated with carboplatin (300 mg/m(2)/day) and paclitaxel (200 mg/m(2)/day) on day 1 for six three-week cycles. To our knowledge, this is the first report regarding the efficiency of a carboplatin dose-definition method based on the body surface area with paclitaxel in a hemodialysis patient. This report may therefore be useful for treating hemodialysis patients who are candidates for carboplatin and paclitaxel therapy.

Objective Direct hemoperfusion with polymyxin B-immobilized fiber columns (PMX-DHP) has been used for the treatment of septic shock. It was recently suggested that PMX-DHP may also be effective in acute exacerbations of idiopathic pulmonary fibrosis (IPF). However, all previous reports are case series without controls. The aim of the study was to determine the effects of PMX-DHP on the prognosis of the patients with rapidly progressive interstitial lung diseases (ILDs) in a case-control setting. Methods We herein retrospectively examined the clinical records of consecutive patients with acute exacerbation of IPF or rapidly progressive ILDs treated in our institute. We excluded those who had been treated with steroid pulse therapy for lung diseases, including those who had been taking more than 15 mg of oral prednisolone daily, or had undergone an operation within one month before the onset of acute respiratory failure. We compared the results of the laboratory tests and survivals between patients treated with and without PMX-DHP. Results Twenty-six patients were enrolled in the study. Among them, 13 patients were treated with PMX-DHP in addition to immunosuppressive therapy, including steroid pulse therapy. The mean survival time of patients treated with PMX-DHP tended to be longer than patients not treated with PXM-DHP (p=0.067). Six patients who underwent PMX-DHP on the first day of steroid pulse therapy had significantly longer survival times than those who were treated with standard medication alone (p Conclusion These results suggest that PMX-DHP performed on the first day of steroid pulse therapy may improve the prognosis of patients with rapidly progressive ILDs.

Short bowel syndrome (SBS) is characterized by a malabsorptive state. It is conceivable that the coexistence of SBS and end-stage renal disease can lead to severe metabolic acidosis; however, such a condition has rarely been documented. We herein describe the case of a 64-year-old man with SBS who required maintenance hemodialysis. Persistent metabolic acidosis and mineral and bone disorders should be of particular concern in hemodialyzed patients with SBS.

We herein report the case of a 62-year-old Japanese man who presented with jaundice, dry eyes and abdominal discomfort. Imaging studies revealed swelling of the periorbital tissue, parotid and submandibular glands, pulmonary hilar lymph nodes, pancreas, bile ducts, gall bladder walls, bilateral kidneys, arterial walls and prostate. A significant increase in the serum level IgG4 was seen, and the patient was diagnosed with IgG4-related disease after undergoing a biopsy of the pancreas and prostate. We herein report a case of IgG4-related disease with multiple ten organ involvement at the onset of the disease that was successfully treated with prednisolone (PSL) therapy.

Hypogammaglobulinemia is a reduction or absence of immunoglobulin, which may be congenital or associated with immunosuppressive therapy. In addition to infectious diseases, autoimmune diseases have also been reported in patients with hypogammaglobulinemia. A 26-year-old man with hypogammaglobulinemia had multiple joint pain and swelling with erosive changes in the proximal interphalangeal joint of the right middle finger on X-ray film, mimicking rheumatoid arthritis (RA). As polyarthritis remained after immunoglobulin replacement therapy and there was no finding indicating any infection at that time, a diagnosis of RA was made. Prednisolone and etanercept were started. However, his polyarthritis did not improve and he developed meningitis and massive brain ischemia. Finally, a diagnosis of disseminated Mycoplasma hominis infection was made. The differential diagnosis of polyarthritis in patients with hypogammaglobulinemia should strictly exclude Mycoplasma infection by culture with special media or longer anaerobic culture, and molecular methods for mycoplasma.

BACKGROUND Despite the use of inhaled corticosteroid (ICS) becoming increasingly widespread, many problems related to asthma management still need to be addressed. One of them, obesity, has been reported to exert a harmful influence on asthma control. However, there have been few reports focusing not only on both obesity and its influence on Japanese asthma patients but also on the Japanese definition of obesity, as defined by the Japan Society for the Study of Obesity (JASSO). AIMS & METHODS The aim of this study was to confirm the influence of obesity, as defined by the JASSO, on asthma management in Japanese asthmatic patients. Using data from the Niigata Asthma Treatment Study Group 2008 questionnaire survey, differences between the "normal" group (18.5 kg/m(2) ≤ BMI

We report an elderly man with chronic tubulointerstitial nephritis (TIN) showing a high serum immunoglobulin G4 (IgG4) concentration. His serum creatinine (Scr) level had gradually increased from 0.9 mg/dL to 5.6 mg/dL over 18 months. Renal biopsy showed marked IgG4-positive plasma cell infiltration in the interstitium without glomerular abnormalities and IgG4-related TIN was diagnosed. Oral prednisolone reduced his Scr and IgG4 levels immediately. The present case indicates that IgG4-related TIN can not only progress rapidly but also chronically over a long period without significant urinary abnormalities, and we should consider hidden IgG4-related TIN in cases of chronic renal insufficiency.

We treated a case of adult-onset severe-form anaphylactoid purpura. This case had been diagnosed as anaphylactoid purpura pathologically by skin biopsy. However, his clinical manifestations were atypical in view of complicated massive gastrointestinal hemorrhage. Intensive therapy including corticosteroid and cyclophosphamide transiently improved his condition. Nevertheless, the beta-D-glucan value in peripheral blood was gradually elevated. Prophylactic use of fluconazole failed to prevent contraction of invasive mycosis. Finally, he suddenly suffered from diffuse cerebral hemorrhage. Postmortem examination revealed systemic invasive aspergillosis as the cause of death.

Objective In order to explore the possibility that genetic predisposition to dysfunction of mucosal immunity and the IgA processing pathway plays a role in the pathogenesis of mesangial IgAl deposition in IgAN, we examined the possible association of the gene polymorphism of pIgR in the patients with and without IgAN. Subjects and Methods Genomic DNA of peripheral blood cells was isolated from 372 individuals including 172 histologically confirmed IgAN patients. Segments of the PIgR gene were PCR amplified and restriction fragment length polymorphism was determined as Al and A2 with and without Pvu II site, respectively. Results The PIgR genotype distribution was significantly different between the patients with IgAN and those without IgAN. Allele frequency of A2 was higher in IgAN than in other renal diseases (Al and A2; 0.516 and 0.484 in IgAN, 0.641 and 0.359 in others, X2=9.84, P=0.0017, Odds ratio=1.71). Moreover, the subjects with A2A2 genotype were associated with a relatively low level of serum IgA only in the patients with IgAN but not in other renal diseases. The difference of allele frequencies was more remarkable in the patients with a serum IgA level of less than 300 mg/dl (Al and A2; 0.439 and 0.561 in IgAN, 0.702 and 0.298 in others, X2=12.44, P=0.0004, Odds ratio=3.01). Conclusion This is the first demonstration of the PIgR gene polymorphisms in IgAN which are associated with its clinical phenotype. Gene polymorphisms of PIgR may be candidate genetic markers of susceptibility to IgAN.(Internal Medicine 40: 867-872, 2001)