IGG and complement receptor expression on peripheral white blood cells in uraemic children

Cutaneous warts in children before and after renal transplantation

Cutaneous warts occur in 3.9-4.9% of children in the UK. The incidence is increased in organ transplant recipients and may be increased in patients with chronic kidney disease (CKD), since uraemia reduces the immune system's function. We surveyed the records from our CKD and renal transplant clinic to ensure patients with warts were identified and appropriately treated. Data were collected by questionnaire. The presence of warts, location, treatment, levels of pain and emotional upset were recorded. Nine of 49 (18.4%) pre-transplantation patients (33 male, median age 12.1 years) were currently suffering from warts compared with 17 of 60 (28.3%) post-transplantation patients (34 male, median age 13.9 years). A further 14 pre-transplantation and 16 post-transplantation patients had previously suffered from warts which had resolved. Forty-one patients had sought treatment for warts, mainly from primary care. Five patients, all having received transplants, were seen by a dermatologist. Self-rated levels of pain and emotional upset were generally low, apart from those of four adolescent patients who expressed significant emotional upset. We concluded that cutaneous warts are more common among CKD patients. Appropriate information and treatment are required before and after transplantation. The majority of warts can be treated in primary care, but selected patients with extensive warts that cause distress need early referral for dermatology opinion.

The uraemic retention solute para-hydroxy-hippuric acid attenuates apoptosis of polymorphonuclear leukocytes from healthy subjects but not from haemodialysis patients

BACKGROUND

Disturbed polymorphonuclear leukocyte (PMNL) apoptosis contributes to the dysregulation of the non-specific immune system in uraemia. Intracellular Ca(2+) modulates PMNL apoptotic cell death. We investigated the effect of para-hydroxy-hippuric acid (PHA), an erythrocyte plasma membrane Ca(2+)-ATPase inhibitor accumulating in uraemic sera, and of cyclopiazonic acid (CPA), an inhibitor of the sarko/endoplasmatic Ca(2+)-ATPase, on PMNL apoptosis.

METHODS

Apoptosis of PMNLs from healthy subjects and from haemodialysis (HD) patients was assessed after incubation for 20 h by evaluating morphological features under the fluorescence microscope and by measuring the DNA content and caspase activities by flow cytometry. The intracellular calcium concentration ([Ca(2+)](i)) was determined by measurement of fura-2 fluorescence using the 340/ 380 nm dual wavelength excitation.

RESULTS

Spontaneous apoptosis of PMNLs from healthy subjects and from HD patients did not differ. PHA significantly attenuated, while CPA increased, the apoptotic cell death of PMNLs from healthy subjects. The PHA effect was not observed with PMNLs from HD patients, irrespective of whether the blood was drawn before or after HD treatment. Baseline [Ca(2+)](i) was increased in PMNLs obtained from HD patients before dialysis but reversed after dialysis. The PHA effects were not mediated via [Ca(2+)](i). The chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) induced a [Ca(2+)](i) increase and reduced PMNL survival. Extracellular Ca(2+) did not affect CPA- and fMLP-induced apoptosis.

CONCLUSIONS

PHA, without affecting [Ca(2+)](i), attenuates apoptosis of healthy but not of uraemic PMNLs. CPA and fMLP enhance PMNL apoptosis independently of Ca(2+) influx.

Intracellular cytokines in peripheral blood leucocytes in children with chronic renal failure

We have previously shown that children with mild renal impairment show significant changes in leucocyte subsets and circulating cytokines, indicating that these patients show an increased inflammatory state. We hypothesised that measurement of intracellular cytokine production by lymphocytes and monocytes would more precisely define the immunological mechanism associated with the inflammatory state in children with pre-dialytic chronic renal failure. Blood was collected from children with chronic renal failure (CRF) who were not yet on dialysis and an age-matched control group. Leucocyte subsets and intracellular cytokine production were determined using flow cytometry. Children with CRF showed increased production of interleukin (IL)-12 by monocytes accompanied by decreased production of interferon (IFN)-gamma and increased production of IL-4 by T cells. There were no significant changes in the production of IL-8, IL-10, IL-6, IL-1alpha or tumour necrosis factor (TNF)-alpha by monocytes or in IL-2 or TNF-alpha production by T cells. There were no significant differences in total white cell count or lymphocyte count. There was a significant decrease in both B and NK cells. This study examines intracellular cytokine production in children with CRF in detail. It is the first to show that children with relatively mild renal failure display significant immunological changes of lymphocyte subsets and leucocyte cytokine production. These data provide a more accurate understanding of the immunological changes that may contribute to the clinical manifestations and progression of the disease.

Changes in leukocyte subsets: clinical implications for children with chronic renal failure

Increased systemic inflammation and an impaired immune response are features of adult chronic renal failure (CRF). These patients have increased rates of infection, cardiovascular disease, anemia, and malnutrition. We measured inflammatory and immunological markers in a group of children with pre-dialytic CRF. No prior studies have explored these markers even though children with non-dialysed CRF exhibit similar complications to those seen in adults with CRF. Blood was collected from children with mild, moderate, or severe CRF and an age-matched control group. Functional leukocyte subsets were determined using flow cytometry. Circulating levels of interleukin (IL)-1beta, IL-6, IL-8, IL-12, IL-10, and tumor necrosis factor-alpha were measured using a flow cytometric bead assay. Children with severe CRF showed significantly reduced total white cell count and absolute neutrophil and lymphocyte counts. Absolute numbers of CD3+/CD45RO+ memory T cells and CD3+/CD45RO+/CD62L+ memory Th2 cells were significantly reduced in all CRF groups versus controls. Children with severe CRF showed increased CD11b expression on neutrophils and monocytes. Some patients showed increases in pro-inflammatory cytokines that were not related to their level of residual renal function. As CD11b expression mediates leukocyte adhesion to vascular endothelium, upregulation may contribute to the increased endothelial dysfunction observed in children with CRF. L-selectin mediates extravasation of leukocytes into tissue and homing of peripheral blood lymphocytes to lymph nodes. The reduction in L-selectin may inhibit these actions and predispose patients to increased infection later in life. This is the first study to comprehensively investigate leukocyte functional molecules and inflammatory cytokine profiles in children with pre-dialytic CRF and provides new immunological evidence for the clinical manifestations associated with the disease.