Charge-dependent binding of polymeric IgA1 to human mesangial cells in IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is characterized by raised serum IgA1 and predominant mesangial IgA1 deposits of polymeric nature. The mechanism of polymeric IgA1 (pIgA1) deposition in the kidney mesangium is poorly understood in IgAN. It has been suggested that increased sialic acid content and anionic charge of the pIgA1 molecules may be operational in the IgA1 deposition in human mesangial cells (HMCs). The present study examined the binding of pIgA1 with different surface charges to HMCs. The binding characteristics of IgA1 to HMCs in the presence of polycation (poly-L-lysine) or polyanion (heparin) were also investigated.

METHODS

IgA1 was purified in sera from patients with IgAN and from healthy controls by jacalin affinity chromatography. IgA1 was further separated into pIgA1 and monomeric IgA1 (mIgA1) by fast protein liquid chromatography (FPLC). pIgA1 or mIgA1 with different net charges on their surface were resolved by ion exchange chromatography (IEC) with a Mono Q column. The binding characteristics of pIgA1 and mIgA1 to HMCs in the presence or absence of polycation or polyanion were examined by flow cytometry.

RESULTS

In patients with IgAN, the absolute amount of mIgA1 and pIgA1 is significantly higher than that of healthy controls (P < 0. 001). There was significant increase in binding of pIgA1 from patients with IgAN to HMC and cell lysate. pIgA1 that interacted strongly with the ion exchanger also bound more to HMCs when compared with IgA1 interacted weakly with the ion exchanger (P < 0. 001). The anionic charged pIgA1 from patients was significantly higher than that of healthy controls (P < 0.001). Preincubation with poly-L-lysine increased the binding of pIgA1 to HMCs. The binding of pIgA1 to HMCs was decreased by preincubation with heparin.

CONCLUSIONS

The binding of IgA to HMCs is charge dependent. Polymeric IgA with the highest net negative charge binds more to HMCs. Preincubation with polyanion decreased the binding of polymeric IgA to HMCs. These results suggest an important role for anionic charge in IgA1 deposition onto the kidney mesangial cells.

Identification of polyamides that enhance adenovirus-mediated gene expression in the urothelium

Adenovirus-mediated gene therapy of bladder diseases has been limited by the inability to transduce the urothelium successfully using adenoviral vectors. We have sought to identify agents that would increase adenovirus-mediated transgene expression in the bladder. We have utilized a rat model to screen compounds for their ability to enhance viral transgene expression in the rat bladder. Rats received intravesical administration of replication-deficient adenovirus (rAd) formulated in various agents, and transgene expression was evaluated after 48 h by determining the amount of lacZ expression in the luminal epithelium of the bladder. We report the identification of two different polyamides, each capable of dramatically increasing viral transgene expression in the bladder without causing detectable alteration of the umbrella cell layer of the urothelium. We have utilized a carcinogen-induced rat bladder tumor model to demonstrate that these polyamides are also capable of enhancing viral transgene expression in tumor tissue. The identification of these polyamides potentiates the use of adenovirus-mediated gene therapy for the treatment of superficial bladder cancer or other bladder diseases.

Alloimmune hemolysis after renal transplantation

A 35-year-old patient with blood group AB developed hemolysis 1 week after receiving a blood group B cadaveric kidney transplant. The patient's serum was shown to contain anti-A antibody, which was likely to have been derived from passenger lymphocytes transplanted concurrently with the graft. The alloimmune hemolysis subsided spontaneously without treatment. The present case underscores the potential complication of ABO blood group-compatible but nonidentical organ transplantation. Clinical vigilance is important to differentiate from other more sinister causes of posttransplant hemolysis.

Efficacy of mycophenolate mofetil in patients with diffuse proliferative lupus nephritis. Hong Kong-Guangzhou Nephrology Study Group

BACKGROUND

The combination of cyclophosphamide and prednisolone is effective for the treatment of severe lupus nephritis but has serious adverse effects. Whether mycophenolate mofetil can be substituted for cyclophosphamide is not known.

METHODS

In 42 patients with diffuse proliferative lupus nephritis we compared the efficacy and side effects of a regimen of prednisolone and mycophenolate mofetil given for 12 months with those of a regimen of prednisolone and cyclophosphamide given for 6 months, followed by prednisolone and azathioprine for 6 months. Complete remission was defined as a value for urinary protein excretion that was less than 0.3 g per 24 hours, with normal urinary sediment, a normal serum albumin concentration, and values for serum creatinine and creatinine clearance that were no more than 15 percent above the base-line values. Partial remission was defined as a value for urinary protein excretion that was between 0.3 and 2.9 g per 24 hours, with a serum albumin concentration of at least 30 g per liter.

RESULTS

Eighty-one percent of the 21 patients treated with mycophenolate mofetil and prednisolone (group 1) had a complete remission, and 14 percent had a partial remission, as compared with 76 percent and 14 percent, respectively, of the 21 patients treated with cyclophosphamide and prednisolone followed by azathioprine and prednisolone (group 2). The improvements in the degree of proteinuria and the serum albumin and creatinine concentrations were similar in the two groups. One patient in each group discontinued treatment because of side effects. Infections were noted in 19 percent of the patients in group 1 and in 33 percent of those in group 2 (P = 0.29). Other adverse effects occurred only in group 2; they included amenorrhea (in 23 percent of the patients), hair loss (19 percent), leukopenia (10 percent), and death (10 percent). The rates of relapse were 15 percent and 11 percent, respectively.

CONCLUSIONS

For the treatment of diffuse proliferative lupus nephritis, the combination of mycophenolate mofetil and prednisolone is as effective as a regimen of cyclophosphamide and prednisolone followed by azathioprine and prednisolone but is less toxic.

Castleman's disease and mesangial proliferative glomerulonephritis: the role of interleukin-6

Renal complications of Castleman's disease (angiofollicular lymph node hyperplasia) are uncommon. The reported cases are very heterogeneous and their renal pathology ranged from minimal change disease, mesangial proliferative glomerulonephritis, to amyloidosis. We have previously reported two cases of Castleman's disease with renal complications. We now present two more such cases. In contrast to other reports, all our cases are of the plasma cell type and their renal pathology showed remarkable similarities, namely mesangial proliferation, interstitial plasma cell infiltration and negative immunofluorescence. The level of serum interleukin-6 (IL-6) in both patients was elevated at presentation and came down with immunosuppressive therapy.

Oral health status, oral microflora, and non-surgical periodontal treatment of renal transplant patients receiving cyclosporin A and FK506

OBJECTIVES

To determine the oral health status, oral microflora and the effect of non-surgical periodontal treatment on gingival overgrowth of renal allograft recipients receiving either cyclosporin A (CsA) or FK506 (Tacrolimus) as an immunosuppressant.

MATERIALS AND METHODS

A total of 47 patients receiving CsA (mean age 43.1 years) and 10 receiving FK506 (mean age 40.1 years) were included in the study. Stone casts were taken for measurement of gingival overgrowth. An oral rinse technique was used to investigate the prevalence of yeasts, and aerobic and facultatively anaerobic Gram-negative rods (AGNR).

RESULTS

The CsA and FK506 patients exhibited a Gingival Overgrowth Index (GOI) of 45.2%, and 25.1%, respectively (p < 0.05). The CsA patients had a GOI of 15.2% after one year of non-surgical periodontal treatment. The difference between pre- and postoperative gingival overgrowth indices was significant (p < 0.0001). Candida albicans and Klebsiella pneumoniae were the most notable yeast and AGRN found.

CONCLUSIONS

Renal transplant patients, being immunocompromised, constitute a high-risk group for gingival overgrowth. However, the FK506 regime appeared to ameliorate this effect, compared with CsA. Non-surgical periodontal treatment was effective in reducing established gingival overgrowth in both CsA and FK506 patients (p < 0.05). Adequate pre- and post-transplant oral health care is recommended, for these patients, irrespective of the drug regime.

Comparison of the CMV brite turbo assay and the digene hybrid capture CMV DNA (Version 2.0) assay for quantitation of cytomegalovirus in renal transplant recipients

We compared the CMV Brite Turbo Kit (BT) and the Digene Hybrid Capture CMV DNA (version 2.0) assay (HC2) in the quantitation of pp65 antigenemia and cytomegalovirus (CMV) DNA levels in immunosuppressed renal transplant recipients. Of 123 blood specimens collected from 24 renal transplant recipients, BT and HC2 assays detected 35 and 39 positive samples, respectively. The overall concordance rate between the two assays was 90%. Discordant results were observed at low levels of viremia, so that 8 samples were HC2 positive but BT negative and another 4 were BT positive but HC2 negative. There was good correlation (R(2) = 0.766; P<0.01) between the levels of CMV DNA and pp65 antigenemia in the 31 concordant positive samples. Correlation between results obtained with the two assays was confirmed by longitudinal studies for a patient who developed clinical CMV disease. HC2 may be more sensitive at low viremia levels and allow earlier detection of impending CMV disease. The BT assay offered the advantage of a rapid (2-h) turnaround time. We conclude that BT and HC2 assays have similar sensitivity and efficacy in the diagnosis and monitoring of CMV infection and disease in renal transplant recipients. While the HC2 assay would be appropriate for centers that handle a large number of samples, the BT test may be more suitable for small sample numbers or when results are needed urgently.

Post-transplantation lymphoproliferative disease of natural killer cell lineage: a clinicopathological and molecular analysis

Post-transplantation lymphoproliferative disorders (PTLD) occur after solid organ and bone marrow transplantation. They are predominantly of B-cell and occasionally of T-cell lineage. We report a case of PTLD of natural killer (NK) cell lineage. A renal allograft recipient developed progressive pancytopenia 1 year after transplantation. Serial bone marrow biopsies showed an increasing infiltration by large granular lymphoid cells. A subsequent leukaemic phase also developed with systemic infiltration of other organs. Immunophenotyping showed that these cells were CD2+, CD3-, CD3epsilon+, CD56+, CD94+, CD158a- and CD158b-. In situ hybridization showed Epstein-Barr virus (EBV) infection of the neoplastic cells. Genotypical analysis showed the T-cell receptor gene in germline configuration and clonal EBV episomal integration. The overall features were consistent with NK cell lymphoma/leukaemia. The patient did not respond to cessation of immunosuppression or anti-EBV treatment. Combination chemotherapy was given, but the patient died ultimately of disseminated fungal infection. In conclusion, we have demonstrated that NK cell lymphoma is another rare type of PTLD that appears to be highly aggressive and therefore may require early chemotherapy to improve treatment outcome.

Changes of cytokine profiles during peritonitis in patients on continuous ambulatory peritoneal dialysis

Continuous ambulatory peritoneal dialysis (CAPD) has emerged as an important dialysis treatment modality worldwide. One of the major complications is bacterial peritonitis, which may result in subsequent technique failure because of loss of peritoneal clearance or peritoneal fibrosis. Bacterial peritonitis leads to the release of proinflammatory cytokines from resident and infiltrating cells in the peritoneal cavity. We studied 35 patients undergoing CAPD with acute bacterial peritonitis. All patients treated with antibiotics for 2 weeks after the clinical diagnosis of peritonitis had a good recovery. Peritoneal dialysate effluent (PDE) was collected on days 1, 3, 5, 10, 21, and 42 after the start of treatment. Cell populations were monitored by flow cytometry. PDE levels of interleukin-1beta (IL-1), IL-6, transforming growth factor-beta (TGF-beta), and basic fibroblast growth factor (FGF) were measured by enzyme-linked immunosorbent assay. Gene transcription of TGF-beta in macrophages from PDE was measured by quantitative polymerase chain reaction. Bacterial peritonitis was associated with a sharp increase in total cell and neutrophil counts (400-fold) in PDE up to 3 weeks after peritonitis despite clinical remission (P < 0.0001). There was an increased absolute number of macrophages during the first 3 weeks despite the reduced percentage of macrophages among total cells in PDE compared with noninfective PDE. There was a progressive increase in the percentage of mesothelial cells or dead cells in the total cell population in PDE over the entire 6-week period. PDE levels of IL-1, IL-6, TGF-beta, and FGF increased markedly on day 1 before their levels decreased gradually. PDE levels of these cytokines or growth factors were significantly greater than those in noninfective PDE (n = 76) throughout the study period (P < 0.01). Similarly, TGF-beta complementary DNA (cDNA) molecules per macrophage were significantly greater than those of macrophages in noninfective PDE throughout this period (P < 0.01). There was no significant correlation between PDE levels of TGF-beta and TGF-beta cDNA molecules per macrophage, suggesting that peritoneal macrophages are not the only source of TGF-beta in PDE. We conclude there is an active release of proinflammatory cytokines and sclerogenic growth factors through at least 6 weeks despite apparent clinical remission of peritonitis. The peritoneal cytokine networks after peritonitis may potentially affect the physiological properties of the peritoneal membrane.

Ciprofloxacin-induced oral facial dyskinesia in a patient with normal liver and renal function

A 49-year-old Chinese woman with good past health presented to a general practitioner with fever, chills, dysuria, and loin pain. Urinary tract infection was diagnosed and she was treated with oral ciprofloxacin. She was hospitalized because of persistent chills and fever. Physical examination showed hyperpyrexia of 38.6°C, together with suprapubic and bilateral loin tenderness. White cell count was 11.2×109/litre. Ultrasonogram of kidneys showed no structural abnormality. She was treated as having acute pyelonephritis with ciprofloxacin 200 mg intravenously twice daily. Her symptoms improved. Urine and blood culture yielded negative results.

She developed involuntary facial grimacing 2 days after starting ciprofloxacin treatment. Neurological examination did not reveal other abnormal findings. Her only other medication was paracetamol 500 mg orally four times a day. She had no prior history of similar involuntary movements. The oral facial dyskinesia occurred intermittently every 4–6 hours, with each attack lasting about an hour. She maintained a clear sensorium during the involuntary movements. Computed tomography and magnetic resonance imaging of the brain, as well as lumbar puncture, yielded normal results. Electroencephalogram showed normal wave form. The levels of liver transaminases were raised transiently after starting ciprofloxacin treatment, with aspartate aminotransferase 82 U/litre (normal 12–28 U/litre) and alanine aminotransferase 176 U/litre (normal 5–31 U/litre). Serum albumin, bilirubin, prothrombin time and creatinine levels were normal. The involuntary movements improved slightly with clonazepam therapy, but did not subside completely. In view of the possibility of ciprofloxacin-induced neurotoxicity, ciprofloxacin was stopped and substituted with netromycin. Her oral facial dyskinesia stopped and did not recur. The patient had an uneventful recovery.

Acute renal failure after immersion in seawater polluted by diesel oil

Acute renal failure after exposure to toxic doses of hydrocarbon has been uniformly associated with multiorgan failure. We report a case of isolated acute renal failure in a patient after immersion in seawater polluted by diesel oil. The sites of absorption were likely to be skin, gastrointestinal tract, and lung. Investigations showed renal impairment as the only consequence from the exposure. The patient recovered uneventfully and did not require dialysis. This case highlighted the unusual consequence of isolated renal involvement resulting from hydrocarbon toxicity.

Osteopenia in young hypogonadal women with systemic lupus erythematosus receiving chronic steroid therapy: a randomized controlled trial comparing calcitriol and hormonal replacement therapy

OBJECTIVE

To evaluate the efficacy of calcitriol and hormonal replacement therapy (HRT) in the treatment of steroid-induced osteoporosis in hypogonadal women.

METHODS

We studied 28 young patients (aged 37 +/- 6 yr) with systemic lupus erythematosus (SLE) on chronic steroid therapy for 130 +/- 22 months and requiring more than 10 mg/day prednisone. They were amenorrhoeic for more than 2 yr with proven ovarian failure. All had osteopenia with a T score at L2-4 of less than -1. They were randomized to receive HRT (conjugated oestrogen 0.625 mg daily from day 1 to day 21 plus medroxyprogesterone acetate 5 mg daily days 10-21) or calcitriol 0.5 microg daily. All received calcium carbonate 1 g/day.

RESULTS

There were no differences in the baseline demographic, bone mineral density (BMD) and biochemical data between the two groups. Lumbar spine BMD increased by 2.0 +/- 0.4% after 2 yr with HRT (P<0.05), but reduced by 1.74 +/- 0.4% (P<0.05) with calcitriol treatment. No change was seen at the distal one-third radius with HRT treatment but significant bone loss (2.3 +/- 1.4%, P<0.02) was observed with calcitriol therapy. BMD at the hip did not change in both groups. Comparing both treatment groups, significant differences in the BMD at the spine (P<0.03) and radius (P<0.05) were seen at the end of 2 yr. The changes in urinary n-telopeptide excretion but not serum osteocalcin at 6 months and 12 months were inversely correlated with the changes in lumbar spine BMD at 24 months. HRT did not cause an adverse effect on SLE disease activity.

CONCLUSION

HRT but not calcitriol could prevent bone loss in young hypogonadal women on chronic steroid therapy.

Early detection of hepatocellular carcinoma in hepatitis-B-positive renal transplant recipients

Hepatocellular carcinoma (HCC) is a leading cause of malignancy after renal transplantation in Asia, where hepatitis B virus infection is endemic. Early detection and resection are the key to successful treatment because the mortality rate for HCC is high. The value of alpha-fetoprotein monitoring in the early detection of HCC in renal transplant recipients has not been reported before. We describe 2 patients who had successful resection of HCC following early diagnosis by alpha-fetoprotein monitoring. The epidemiology of post-transplant HCC in various parts of the world and its pathogenesis are discussed.

Treatment of membranous lupus nephritis with nephrotic syndrome by sequential immunosuppression

The optimal therapy for pure membranous lupus nephritis (MLN) with nephrotic syndrome remains controversial. While the risk of progressive renal deterioration may be small, persistent heavy proteinuria leads to the complications of oedema, hypoalbuminaemia, hyperlipidaemia, hypercoagulability, and venous thrombosis. We examined prospectively the efficacy and tolerability of a sequential immunosuppressive regimen in a cohort of 20 patients with nephrotic syndrome due to pure MLN (WHO Class Va and Vb). Initial therapy comprised prednisolone (0.8 mg/kg/d p.o.) and cyclophosphamide (2-2. 5 mg/kg/d p.o.). Prednisolone dosage was gradually tapered to 10 mg/d at 6 months, when cyclophosphamide was replaced by azathioprine (2 mg/kg/d p.o.) as maintenance therapy. Within 12 months of therapy 11(55%) patients had complete remission (CR), 7(35%) patients achieved partial remission (PR) (proteinuria reduced from 6.2+/-4.0 to 2.0+/-1.7 g/24 h, P<0.01), and 2 patients failed to respond. Improvements in proteinuria and serum albumin level were observed after 3-6 months of treatment. Non-responders had lower baseline serum albumin compared to complete responders. Renal function remained stable during follow-up for 73.5+/-48.9 months. 8 patients had disease relapse at 47+/-15 months. Early complications (</=12 months) included herpes zoster (40%), minor respiratory or urinary tract infections (25%), mild leukopenia (15%), and transient amenorrhea (14.3%). 4 of the 20 patients developed pulmonary tuberculosis during follow-up, at 35+/-24 months after the diagnosis of MLN. 8 patients had hyperlipidaemia. Haemorrhagic cystitis, permanent amenorrhea, vascular complications, and mortality were not observed. We conclude that this sequential immunosuppressive regimen is effective in 90% of patients with MLN and heavy proteinuria. Prudent consideration of the benefits and potential side-effects is required to determine the optimal management for individual patients.