T-Cell Response and Antibody Production Induced by the COVID-19 Booster Vaccine in Japanese Chronic Kidney Disease Patients Treated with Hemodialysis.

Humoral and cellular responses are critical in understanding immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Here, we evaluated these responses in hemodialysis (HD) patients after the booster vaccination. SARS-CoV-2 immunoglobulin (IgG) levels, neutralizing antibody titers, and the T-SPOT®.COVID test (T-SPOT) were measured prior to, three weeks after, and three months after the booster administration. The HD group had significantly higher SARS-CoV-2 IgG levels and neutralizing antibody titers against the original strain at three weeks and three months after the booster vaccination compared to the control group, albeit the HD group had lower SARS-CoV-2 IgG levels and neutralizing antibody titers before the booster administration. Moreover, the HD group had significantly higher T-SPOT levels at all three time points compared to the control group. The HD group also had significantly higher local and systemic adverse reaction rates than the control group. By booster vaccination, HD patients could acquire more effective SARS-CoV-2-specific humoral and cellular immunity than the control group.

Investigation for the efficacy of COVID-19 vaccine in Japanese CKD patients treated with hemodialysis.

Background: Dialysis patients are predisposed to severe disease and have a high mortality rate in coronavirus disease 2019 (COVID-19) due to their comorbidities and immunocompromised conditions. Therefore, dialysis patients should be prioritized for vaccination. This study aimed to examine how long the effects of the vaccine are maintained and what factors affect antibody titers. Methods: Hemodialysis patients (HD group) and age- and sex-matched non-dialysis individuals (Control group), receiving two doses of BNT162b2 vaccine, were recruited through the Japanese Society for Dialysis Therapy (JSDT) Web site in July 2021. Anti-SARS-CoV-2 immunoglobulin (IgG) (SARS-CoV-2 IgG titers) was measured before vaccination, 3 weeks after the first vaccination, 2 weeks after the second vaccination, and 3 months after the second vaccination, and was compared between Control group and HD group. Factors affecting SARS-CoV-2 IgG titers were also examined using multivariable regression analysis and stepwise regression analysis (least AIC). In addition, we compared adverse reactions in Control and HD groups and examined the relationship between adverse reactions and SARS-CoV-2 IgG titers. Results: Our study enrolled 123 participants in the Control group (62.6% men, median age 67.0 years) and 206 patients in the HD group (64.1% men, median age 66.4 years). HD group had significantly lower SARS-CoV-2 IgG titers at 3 weeks after the first vaccination (p < 0.0001), 2 weeks after second vaccination (p = 0.0002), and 3 months after the second vaccination (p = 0.045) than Control group. However, the reduction rate of SARS-CoV-2 IgG titers between 2 weeks and 3 months after the second vaccination was significantly smaller in HD group than in Control (p = 0.048). Stepwise regression analysis revealed that dialysis time was identified as the significant independent factors for SARS-CoV-2 IgG titers at 2 weeks after the second vaccination in HD group (p = 0.002) and longer dialysis time resulted in higher maximum antibody titers. The incidences of fever and nausea after the second vaccination were significantly higher in the HD group (p = 0.039 and p = 0.020). Antibody titers in those with fever were significantly higher than those without fever in both groups (HD: p = 0.0383, Control: p = 0.0096). Conclusion: HD patients had significantly lower antibody titers than age- and sex-matched non-dialysis individuals over 3 months after vaccination. Dialysis time was identified as a factor affecting SARS-CoV-2 IgG titers in HD group, with longer dialysis time resulting in higher maximum SARS-CoV-2 IgG titers.

Committee report: Questionnaire survey on the treatment of COVID-19 in patients receiving dialysis therapy.

Background: Patients with coronavirus disease 2019 (COVID-19) who receive dialysis therapy develop more severe disease and have a poorer prognosis than patients who do not. Although various data on the treatment of patients not receiving dialysis therapy have been reported, clinical practice for patients on dialysis is challenging as data is limited. The Infection Control Committee of the Japanese Society for Dialysis Therapy decided to clarify the status of treatment in COVID-19 patients on dialysis. Methods: A questionnaire survey of 105 centers that had treated at least five COVID-19 patients on dialysis was conducted in August 2021. Results: Sixty-six centers (62.9%) responded to the questionnaire. Antivirals were administered in 27.7% of facilities treating mild disease (most patients received favipiravir) and 66.7% of facilities treating moderate disease (most patients with moderate or more severe conditions received remdesivir). Whether and how remdesivir is administered varies between centers. Steroids were initiated most frequently in moderate II disease (50.8%), while 43.1% of the facilities initiated steroids in mild or moderate I disease. The type of steroid, dose, and the duration of administration were generally consistent, with most facilities administering dexamethasone 6 mg orally or 6.6 mg intravenously for 10 days. Steroid pulse therapy was administered in 48.5% of the facilities, and tocilizumab was administered in 25.8% of the facilities, mainly to patients on ventilators or equivalent medications, or to the cases of exacerbations. Furthermore, some facilities used a polymethylmethacrylate membrane during dialysis, nafamostat as an anticoagulant, and continuous hemodiafiltration in severe cases. There was limited experience of polymyxin B-immobilized fiber column-direct hemoperfusion and extracorporeal membrane oxygenation. The discharge criteria for patients receiving dialysis therapy were longer than those set by the Ministry of Health, Labor and Welfare in 22.7% of the facilities. Conclusions: Our survey revealed a variety of treatment practices in each facility. Further evidence and innovations are required to improve the prognosis of patients with COVID-19 receiving dialysis therapy.

Multicenter study of pegylated interferon α-2a monotherapy for hepatitis C virus-infected patients on hemodialysis: REACH study.

Many studies have reported poor vital prognosis in hepatitis C virus (HCV)-infected dialysis patients. The rate of HCV-infected dialysis patients in Japan is as high as 9.8%, and antiviral therapy is believed to be important for improving vital prognosis. We conducted a multicenter study to examine the administration method for pegylated interferon α-2a (PEG-IFNα-2a) monotherapy in HCV-infected dialysis. We studied 56 patients: 14 with low viral loads (HCV RNA < 5.0 log IU/mL) were treated with 90 µg PEG-IFNα-2a weekly, 42 with high viral loads (HCV RNA ≥ 5.0 log IU/mL) were treated with 135 µg PEG-IFNα-2a weekly. We examined the sustained virological response (SVR), factors affecting the SVR, and treatment safety. The overall SVR rate was 39% (22/56); that for genotype 1, genotype 2, low viral loads, and high viral loads was 29%, 67%, 93%, and 21%, respectively. From receiver operating characteristic (ROC) analysis, the HCV RNA cutoff values likely to achieve SVR for genotypes 1 and 2 were <5.7 log IU/mL (SVR rate: 64% 9/14) and <6.5 log IU/mL (SVR rate: 88% 7/8), respectively. If there was HCV RNA negativation at 4 weeks (rapid virological response), the SVR rate was 94% (16/17), whereas it was 6% (1/16) if there was HCV RNA positivity at 24 weeks. The rate of treatment discontinuation from adverse events or aggravated complications was 25% (14/56). High SVR rates can potentially be achieved with PEG-IFN monotherapy by identifying the target patients, based on virus type and viral load before initiating treatment and by modifying therapy during treatment according to responsiveness.

Pretreatment by low-dose fibrates protects against acute free fatty acid-induced renal tubule toxicity by counteracting PPARα deterioration.

Development of a preventive strategy against tubular damage associated with proteinuria is of great importance. Recently, free fatty acid (FFA) toxicities accompanying proteinuria were found to be a main cause of tubular damage, which was aggravated by insufficiency of peroxisome proliferator-activated receptor alpha (PPARα), suggesting the benefit of PPARα activation. However, an earlier study using a murine acute tubular injury model, FFA-overload nephropathy, demonstrated that high-dose treatment of PPARα agonist (0.5% clofibrate diet) aggravated the tubular damage as a consequence of excess serum accumulation of clofibrate metabolites due to decreased kidney elimination. To induce the renoprotective effects of PPARα agonists without drug accumulation, we tried a pretreatment study using low-dose clofibrate (0.1% clofibrate diet) using the same murine model. Low-dose clofibrate pretreatment prevented acute tubular injuries without accumulation of its metabolites. The tubular protective effects appeared to be associated with the counteraction of PPARα deterioration, resulting in the decrease of FFAs influx to the kidney, maintenance of fatty acid oxidation, diminution of intracellular accumulation of undigested FFAs, and attenuation of disease developmental factors including oxidative stress, apoptosis, and NFκB activation. These effects are common to other fibrates and dependent on PPARα function. Interestingly, however, clofibrate pretreatment also exerted PPARα-independent tubular toxicities in PPARα-null mice with FFA-overload nephropathy. The favorable properties of fibrates are evident when PPARα-dependent tubular protective effects outweigh their PPARα-independent tubular toxicities. This delicate balance seems to be easily affected by the drug dose. It will be important to establish the appropriate dosage of fibrates for treatment against kidney disease and to develop a novel PPARα activator that has a steady serum concentration regardless of kidney dysfunction.

Direct hemoperfusion with a beta2-microglobulin-selective adsorbent column eliminates inflammatory cytokines and improves pulmonary oxygenation.

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are characterized by a high mortality rate; therefore, ARDS/ALI in humans is a leading cause of morbidity and mortality in critically ill patients. As previously reported, cytokines play a critical role as signaling molecules that initiate, amplify, and perpetuate inflammatory responses on a local and systemic basis, and the polymyxin-B immobilized direct hemoperfusion system (PMX-DHP) is effective for the treatment of ARDS/ALI. Furthermore, another direct hemoperfusion system using the beta2-microglobulin-selective adsorbent column, Lixelle, the direct hemoperfusion treatment (Lixelle-DHP), has been applied in some cases to patients who are affected with systemic inflammatory response syndrome. The aim of this study is to evaluate the therapeutic efficacy of Lixelle-DHP in the treatment of ARDS/ALI. Four patients, aged 67-79 years old (mean 72 +/- 6.2 years), diagnosed with ARDS/ALI were treated with Lixelle-DHP. The P(a)O(2)/fraction of inspired oxygen (F(i)O(2)) ratio (PF ratio) was 90.0 +/- 22.9 before the treatment, and it increased to 129.9 +/- 5.6 at 72 h afterward the start of treatment. Inflammatory cytokines such as interleukin (IL)-1 beta, IL-6, soluble intercellular adhesion molecule 1 (sICAM-1) decreased significantly after the treatment. All patients were still alive after one month. However, while IL-2 had decreased significantly after the treatment, it had returned by the next treatment. It is possible that Lixelle-DHP might be able to improve the PF ratio and mortality rate as a result of decreased cytokines, and it has been suggested that Lixelle-DHP has a beneficial influence in the treatment of ARDS/ALI.

PPAR{alpha} attenuates the proinflammatory response in activated mesangial cells.

The activated mesangial cell is an important therapeutic target for the control of glomerulonephritis. The peroxisome proliferator-activated receptor alpha (PPARalpha) has attracted considerable attention for its anti-inflammatory effects; however, its roles in the mesangial cells remain unknown. To determine the anti-inflammatory function of PPARalpha in mesangial cells, wild-type and Ppara-null cultured mesangial cells were exposed to lipopolysaccharide (LPS). LPS treatment caused enhanced proinflammatory responses in the Ppara-null cells compared with wild-type cells, as revealed by the induction of interleukin-6, enhanced cell proliferation, and the activation of the nuclear factor (NF)-kappaB signaling pathway. In wild-type cells resistant to inflammation, constitutive expression of PPARalpha was undetectable. However, LPS treatment induced the significant appearance and substantial activation of PPARalpha, which would attenuate the proinflammatory responses through its antagonizing effects on the NF-kappaB signaling pathway. The induction of PPARalpha was coincident with the appearance of alpha-smooth muscle actin, which might be associated with the phenotypic changes of mesangial cells. Moreover, another examination using LPS-injected wild-type mice demonstrated the appearance of PPARalpha-positive cells in glomeruli, suggesting in vivo correlation with PPARalpha induction. These results suggest that PPARalpha plays crucial roles in the attenuation of inflammatory response in activated mesangial cells. PPARalpha might be a novel therapeutic target against glomerular diseases.

Relationship between effluent levels of beta(2)-microglobulin and peritoneal injury markers in 7.5% icodextrin-based peritoneal dialysis solution.

The removal of low molecular weight proteins such as beta(2)-microglobulin (beta(2)MG) is accelerated by using a 7.5% icodextrin-based peritoneal dialysis solution (ICO) dwell. To examine the possibility of peritoneal injury in ICO, we investigated the relationship between beta(2)MG and the injury markers in effluent. Sixteen ICO-treated patients (11 male and five female, mean age 50.1 +/- 10.9 years) with continuous ambulatory peritoneal dialysis (CAPD; mean duration 54.6 +/- 30.8 months) were studied. The patients were treated with ICO 2 L and 2.27% glucose-based solution 2 L for an 8-h dwell and the effluent was collected. We investigated the correlations between beta(2)MG and the injury markers (e.g. hyaluronic acid [HA], interleukin-6 [IL-6], matrix metalloproteinase-2 [MMP-2]) in each effluent sample. The beta(2)MG level in the ICO effluent was 8978 +/- 2431 microg/L, significantly higher than in the 2.27% glucose-based solution effluent (6454 +/- 2956 microg/L; P = 0.0032). The levels of HA and MMP-2 in ICO effluent were significantly higher than those in the 2.27% glucose-based solution effluent (P = 0.00214, P = 0.0113, respectively). There was a trend toward higher IL-6-values in ICO effluent, although no significant differences were seen. There were positive correlations between levels of various injury markers and beta(2)MG. We propose that the subclinical injury of the peritoneum by ICO treatment may accelerate peritoneal permeability to increase beta(2)MG in effluent. ICO's biocompatibility might not be superior to that of glucose-based solution.

Effects of PMX-DHP treatment for patients with directly induced acute respiratory distress syndrome.

Endotoxin-removal direct hemoperfusion column containing polymyxin B immobilized fibers (PMX-DHP) is an effective procedure for the treatment of sepsis-induced acute respiratory distress syndrome (ARDS). We investigated retrospectively the effects and appropriate timing of PMX-DHP induction for directly induced ARDS in 38 patients. PMX-DHP was carried out twice for two hours. Blood pressure, heart rate (HR) and PaO(2)/FIO(2) (PF) ratio, leukocytes, platelets, endotoxin, inflammatory cytokines and clusters of differentiated peripheral neutrophils and monocytes were measured before and after PMX-DHP. Acute Physiology and Chronic Health Evaluation (APACHE) II scores, Sequential Organ Failure Assessment (SOFA) scores and lung injury scores (LIS) were determined at the time of starting PMX-DHP. The underlying causes of ARDS were pneumonia in 29 patients and aspiration pneumonia in 9 patients. The patients were divided into Survivors (n = 21) and Nonsurvivors (n = 17). Mortality was 45% at 30 days after PMX-DHP. The APACHE II and SOFA scores and the LIS were not significantly different between the two groups. The time from the onset of ARDS to the start of PMX-DHP was significantly delayed between the two groups. PMX-DHP significantly improved the PF ratio, HR and systolic blood pressure in the Survivors compared to the Nonsurvivors. The function of active monocytes in the peripheral blood was significantly suppressed after PMX-DHP. This early induction of PMX-DHP is indicated for directly induced ARDS. In the Nonsurvivors, this delay could have led to undesirable responses to oxygenation and circulation after PMX-DHP.

Peroxisome proliferator-activated receptor alpha protects against glomerulonephritis induced by long-term exposure to the plasticizer di-(2-ethylhexyl)phthalate.

Safety concerns about di-(2-ethylhexyl)phthalate (DEHP), a plasticizer and a probable endocrine disruptor, have attracted considerable public attention, but there are few studies about long-term exposure to DEHP. DEHP toxicity is thought to involve peroxisome proliferator-activated receptor alpha (PPARalpha), but this contention remains controversial. For investigation of the long-term toxicity of DEHP and determination of whether PPARalpha mediates toxicity, wild-type and PPARalpha-null mice were fed a diet that contained 0.05 or 0.01% DEHP for 22 mo. PPARalpha-null mice that were exposed to DEHP exhibited prominent immune complex glomerulonephritis, most likely related to elevated glomerular oxidative stress. Elevated NADPH oxidase, low antioxidant enzymes, and absence of the PPARalpha-dependent anti-inflammatory effects that normally antagonize the NFkappaB signaling pathway accompanied the glomerulonephritis in PPARalpha-null mice. The results reported here indicate that PPARalpha protects against the nephrotoxic effects of long-term exposure to DEHP.

Chronic inhibition of nitric oxide production aggravates diabetic nephropathy in Otsuka Long-Evans Tokushima Fatty rats.

BACKGROUND: Nitric oxide (NO) is known to play a role in diabetic nephropathy, but the molecular basis for this effect remains unclear. METHOD: Otsuka Long-Evans Tokushima Fatty spontaneous diabetic rat models were used along with Long-Evans Tokushima Otuska rat models as age-matched controls. Either L-arginine (a NO precursor) or L-NAME (a nitric oxide synthase inhibitor) was administered from the age of 22 weeks. Clinical parameters and serum and urinary NO2+NO3 levels were measured, in addition to renal histological findings and ED-1-positive cell counts in glomeruli. RESULTS: There were no significant differences in creatinine clearance between any of the groups at any point. The levels of urinary NO2+NO3 in the diabetic group were significantly lower than those in the control groups after 40 weeks; that in the L-NAME diabetic group was significantly lower than in the other diabetic groups at 52 weeks. Compared with the other diabetic groups, the L-NAME diabetic group had significantly higher urinary protein excretion levels, histological scores, and numbers of ED-1-positive cells in glomeruli. Diabetic rats administered L-arginine excreted more urinary protein than the diabetic controls. CONCLUSION: Diabetic nephropathy was exacerbated drastically by a nitric oxide synthase inhibitor and mildly by a NO precursor. These data suggested that NO may modify type 2 diabetic nephropathy in Otuska Long-Evans Tokushima Fatty rats through factors other than hemodynamics.

Severe alcoholic hepatitis with extremely high neutrophil count successfully treated by granulocytapheresis.

We report a severe alcoholic hepatitis (SAH) patient with an extremely high WBC count, high serum bilirubin and low prothrombin time (PT) successfully treated with granulocytapheresis. After neutrophil-elastase inhibitor failed to reduce WBC count, methylprednisolone pulse therapy was performed. However, WBC count continued to be elevated to 97,190/microl (neutrophils 97.0%) despite improvement of total bilirubin and PT. After 5 sessions of granulocytapheresis and ulinastatin administration, increased serum IL-6, IL-8, neutrophil-elastase and WBC count gradually decreased. We could conclude that granulocytapheresis and ulinastatin can be very effective in reducing cytokines and neutrophil-elastase, and in improving the general status of SAH patients.

[Estimation of glomerular filtration rate by inulin clearance: comparison with creatinine clearance].

Inulin clearance (Cin) is widely believed to be the gold standard of the glomerular filtration rate (GFR). However, in Japan, Cin has not been officially recognized by the Ministry of Health, Labour and Welfare of Japan for clinical use. Creatinine clearance (Ccr) has been used to estimate the renal function of patients, but there have been many studies in which Ccr estimates were GFR falsely high because the metabolism and tubular excretion of creatinine widely varied according to the pathophysiological state of the patient. In the present study, we determined Cin and Ccr simultaneously in 116 adult patients with renal diseases and diabetic mellitus. The clearance study was performed by the modified Wesson's method. The inulin preparation was FFI-1010 (Fuji Yakuhin Co. Ltd.). Inulin in serum and urine was determined by the newly devised enzymatic assay (Toyobo Co. Ltd.), which is specific for inulin. The mean Cin was 35.0 +/- 14.4 ml/min/1.73 m2. The mean Ccr(the enzyme assay) was 63.6 +/- 24.1 ml/min/1.73 m2 and that of the kinetic Jaffe assay was 55.3 +/- 19.3 ml/min/1.73 m2. Mean Ccr/Cin was 1.93 +/- 0.73, 1.69 +/- 0.62, respectively. This ratio was significantly different(p < 0.05) in the degree of reduction of Cin, with values of 2.07 +/- 0.82 (Cin < 40 ml/min/1.73 m2) and 1.64 +/- 0.32(40 < Cin < 80 ml/min/1.73 m2), respectively. Only 8 patients were classified into the same degree of reduced renal function (the Guideline of Japanese Society of Nephrology). The findings of this study suggest that the GFR determined by Ccr could misjudge the renal function of patient and delay the administration of proper treatment of the patient. Introduction of Cin into the clinical field is necessary to avoid this delay.

A case of drug-induced hypersensitivity syndrome with multiple organ involvement treated with plasma exchange.

A 53-year-old male patient began treatment for systemic exanthema with diaphenylsulfone (DHS) on 21 November 2002. On 18 December 2002, the patient developed a fever and additional systemic erythematous exanthema. Systemic lymphadenopathy, hepatosplenomegaly, leukocytosis (in particular, an increase in the number of atypical lymphocytes) and liver dysfunction followed. After cessation of the DHS treatment on 25 December 2002, acute renal failure occurred and the patient was transferred to Shinshu University Hospital on 4 January 2003. The patient was diagnosed with drug-induced hypersensitivity syndrome (DIHS). Steroid pulse therapy (methylprednisolone 1000 mg/day for 3 days) was given, followed by 60 mg/day of prednisolone. The patient's renal functions recovered and he was taken off hemodialysis therapy. However, the patient relapsed twice despite two sessions of steroid pulse therapy and an increase in the dose of prednisolone to 100 mg/day. Plasma exchange (PE) was carried out to reduce the activity of the disease. With a total of four plasma exchanges, we were able to reduce the dose of prednisolone from 100 mg/day to 60 mg/day without relapse. There were no adverse effects from the plasma exchanges. Plasma exchange should be considered in the treatment with corticosteroid-resistant DIHS with multiple organ lesions.

Immunohistochemical detection of immunoglobulins and complements in formaldehyde-fixed and paraffin-embedded renal biopsy tissues; an adjunct for diagnosis of glomerulonephritis.

BACKGROUND: The present study was undertaken to demonstrate the deposition of immunoglobulins or complements in formaldehyde-fixed and paraffin-embedded renal biopsy tissues through the unmasking of antigens with microwave treatment plus protease digestion or trypsin digestion. METHODS: Biopsy samples from patients with IgA nephritis (n = 7), lupus nephritis (7), membranous nephropathy (7) and mesangiocapillary glomerulonephritis (3) were used. Antigen unmasking was performed with (i) microwave treatment plus protease digestion for 10, 30 or 60 min, or (ii) digestion with 0.25% trypsin for 60 or 120 min. RESULTS: Microwave treatment plus protease digestion for 30 or 60 min and trypsin digestion for 120 min provided good results for the unmasking of immunoglobulins in glomeruli with structural preservation. The IgA deposits in IgA nephritis and IgG deposits in lupus nephritis and membranous nephropathy were clearly revealed in more than 80% of cases by both pretreatments. Microwave treatment plus protease digestion for 30 min revealed the deposition of C3 in all cases of mesangiocapillary glomerulonephritis and lupus nephritis and was superior to trypsin digestion. Characteristic patterns of C3 deposition were observed for these forms of glomerulonephritis, although C3 deposits in membranous nephropathy were detected in only 50% of cases. It was not possible to unmask all of the antigens in the glomeruli, especially those with weak immunofluorescence. CONCLUSION: Microwave treatment plus protease digestion is effective for the unmasking of antigens in paraffin sections and as useful for the diagnosis of immune-mediated glomerulonephritis as trypsin digestion.

Epstein-Barr virus-related primary central nervous system lymphoma after cadaveric renal transplantation improved by treatment with high-dose methotrexate followed by irradiation.

A 57-year-old man was admitted to hospital because of motor aphasia on 16 September 2000. He had an approximate 2-year history of haemodialysis treatment, since April 1997, and had received a cadaveric renal transplantation in July 1999. Computed tomography and magnetic resonance imaging (MRI) revealed a mass with ringed enhancement in the left temporal-parietal lobe. Primary central nervous system (CNS) lymphoma (diffuse large B cell type) was diagnosed based on an open brain tumour biopsy. Epstein-Barr virus early RNA (EBER) in situ hybridization showed positive signals in the nuclei of the CNS lymphoma cells. A dose reduction of immunosuppressant and three series of high-dose methotrexate (MTX) therapy with leucovorine rescue followed by irradiation (whole brain irradiation, 30 Gy; partial brain tumour irradiation, 20 Gy) were carried out for his primary CNS lymphoma. The patient is currently in good condition (September 2004) with no enlargement of the lymphoma, as examined by MRI every 3 months, and preserved renal function.

Renal cholesterol embolism: analysis of two spontaneous autopsy cases.

Two cases of spontaneous cholesterol embolism, which followed different clinical courses, acute and chronic renal failure, are presented and histopathological lesions are compared. Both cases were diagnosed as cholesterol embolism post-mortem. Case 1 (a 66-year-old man) had acute onset of illness with fever, leucocytosis and renal failure, diagnosed as vasculitis, and died of rupture of an abdominal aortic aneurysm. Case 2 (an 84-year-old man) had eosinophilia of unknown aetiology for 7 years with intermittent worsening of renal function and died of sepsis. Case 1 had diffuse cholesterol crystal emboli in the interlobular arteries and arterioles of the kidney, but case 2 had patchy cholesterol emboli in the interlobular arteries of the kidney. The aorta of case 1 was diffusely ulcerated, which is in contrast to that of case 2, who had limited ulceration in thoracic aorta, which might have contributed to the long duration of illness. Immunohistochemically, the number of macrophages and T cells that infiltrated around cholesterol emboli in the arteries was more in case 1 (macrophages 27.7, T cells 36.1/mm(2)) than in case 2 (2.7, 1.38/mm(2)). Focal interstitial inflammation occurred in both cases. In case 1, marked tubulitis was observed. Case 2 had rather severe atrophy of the tubules and fibrotic interstitium where mast cells were rich (31.9/mm(2)). The number of B cells and eosinophils was few in case 2 (11.35, 0.7/mm(2)) compared with case 1 (101.9, 16.15/mm(2)). These results suggest that in acute lesions of renal cholesterol embolism, macrophages and T cells accumulate around cholesterol crystals and cause tubulointerstitial inflammatory lesions with other inflammatory cells. In chronic lesions, macrophages, T cells and mast cells are the major inflammatory cells present in the interstitium.