Igg Subclasses in Capd Patients

Objective

To make a comparison of serum levels of immunoglobulin G (lgG) subclasses in adult continuous ambulatory peritoneal dialysis (CAPD) patients with those in age-and sex-matched hemodialysis patients and healthy volunteers, and to analyze the contribution of removal of these proteins in peritoneal effluent to their plasma values.

Design

A cross-sectional study.

Setting

A renal unit of a university hospital.

Patients

Twenty-three CAPD patients, 21 hemodialysis patients, and 21 healthy volunteers. Peritoneal transport studies were done in 8 of the 23 CAPD patients.

Methods

IgG subclasses were measured in serum by nephelometry. For the peritoneal transport studies an ELISA method on ethylenediamine tetracetic acid plasma was used. The same method was used in seven-to ten-fold concentrated peritoneal dialysate.

Results

CAPD patients had lower IgG2 and IgG4 1evels than hemodialysis patients and healthy volunteers (p < 0.01). lgG2 values below 1.5 glL were present in 43% of the CAPD patients (p < 0.001 compared to healthy volunteers). Peritonitis incidence was not different between CAPD patients with low or normal IgG2 plasma levels. Peritoneal clearance of IgG3 was lower than that of the other subclasses. Evidence was obtained for a depressed synthesis of IgG2 and IgG4 in CAPD patients. The hypothesis that interleukin-2 may be involved in the low synthesis rate of IgG2 is discussed.

Conclusion

Low serum IgG2 and IgG4 1evels are present in stable, adult CAPD patients. These were not caused by increased peritonealloss, but by decreased synthesis.

The Serum Complement System in Children on Continuous Ambulatory Peritoneal Dialysis

Objective

During continuous ambulatory peritoneal dialysis (CAPD), the loss of complement factors via the dialysate may cause complement deficiencies. This hypothesis was tested in a group of children treated with CAPD.

Design

Classical (CH50) and alternative (AP50) complement activity and serum levels of factors C1 q, C3, C4, C3d, B, D, and P in CAPD patients were compared to normal controls and to children with preterminal renal failure.

Setting

Patients were seen in a university hospital; normal controls were seen in an outpatient clinic of a general hospital.

Patients

A group of 22 children on CAPD was compared to a normal control group of 44 children and to a group of 12 children with preterminal renal failure with a creatinine clearance below 25 mL/min/1.73 m2.

Results

CH50, AP50, C3, and B were not significantly different from the control group in both the CAPD and preterminal groups. Factors C1q (p=0.01) and C4, C3d, D, and P (p<0.001) were higher in the CAPD group in comparison to the normal control group. The factors D (p<0.001) and P (p=0.02) were also elevated in the preterminal group. For the measured factors there was no significant difference between the CAPD group and the preterminal group.

Conclusions

There is no deficiency of complement in children treated with CAPD. High levels of C3d and D can be explained by the reduction of their elimination by the kidney. The increased levels of the other factors are presumably due to increased synthesis in renal failure. This does not seem to be caused by CAPD.

Characteristics of Peripheral and Peritoneal White Blood Cells in Children with Chronic Renal Failure, Dialyzed or Not

Objective

To explore further the mechanisms leading to immune deficiency in chronic renal failure and the role of dialysis treatment in these mechanisms.

Design

Cross-sectional and longitudinal analysis.

Patients

We studied 39 children treated with peritoneal dialysis (PD), 23 children treated with hemodialysis (HD), 33 children not yet dialyzed [chronic renal failure (CRF)], and 27 healthy children. Peritoneal cells were also obtained from PD children for analysis.

Methods

White blood cells (WBCs) were isolated from blood and peritoneal dialysis effluent by centrifugation. The number of CD2+, CD4+, and CD8+T cells, B cells, and natural killer cells were measured by flow cytometry.

Results

The total peripheral blood lymphocyte count was lower in PD children (2.6 x 109/L), HD children (2.1 x 109/L), and CRF children (2.0 x 109/L) compared with healthy children (3.1 x 109/L, p < 0.05). The B lymphocyte count was also lower in PD children (0.34x109/L), HD children (0.22 x 109/L), and CRF children (0.33 x 109/L) compared with healthy children (0.52 x 109/L, p < 0.01). Numbers of CD4+T cells were not different, but numbers of CD8+T cells were lower in PD children (0.56 x 109/L), HD children (0.63 x 109/L), and CRF children (0.53 x 109/L) compared with healthy children (0.77 x 109/L, p < 0.05). The count of natural killer cells was lower in PD children (0.21 x 109/L), HD children (0.17 x 109/L), and CRF children (0.18 x 109/L) compared with healthy children (0.50 x 109/L, p < 0.0001). The CD4/CD8 ratio of lymphocytes in peritoneal effluent was 0.8 versus 1.9 in peripheral blood ( p < 0.001). The CD2/CD19 ratio was not different. The cell subsets remained stable during the first year of PD treatment. The CD2/CD19 ratio in peritoneal effluent was higher in children with a peritonitis incidence ≥ 1 per year.

Conclusions

The reduced numbers of B lymphocytes, CD8+T cells, and natural killer cells found in CRF children, dialyzed or not, may favor the frequent occurrence of infections.

Children with chronic renal failure have reduced numbers of memory B cells

Reduced serum IgG and subclass levels have been demonstrated in children with chronic renal failure. To study possible causes of this reduction, we analysed B cell subset composition, T helper cell frequencies and immunoglobulin (Ig) production capacity in vitro in children with chronic renal failure, with or without dialysis treatment. B cell subsets were characterized by determining CD27, IgM, IgD and CD5 expression within the CD19(+) population. Intracellular expression of interferon (IFN)-gamma, interleukin (IL)-2 and IL-4 in PMA/ionomycin-stimulated peripheral blood mononuclear cells (PBMC) was used to evaluate T helper frequencies. The capacity of B cells to secrete Ig in vitro was determined by measuring IgG(1), IgG(2) and IgM in culture supernatants of anti-CD2/CD28 monoclonal antibody (MoAb)- or SAC/IL-2-stimulated PBMC. Memory B cell numbers (identified as percentage or absolute number of CD19(+) IgM-IgD- or CD19(+)CD27(+) lymphocytes) were lower in children treated with haemodialysis (HD), peritoneal dialysis (PD) and children with chronic renal failure before starting dialysis treatment (CRF) compared to healthy controls (HC) (P < 0.05). Compared with HC, CD5(+) (naive) B cells were reduced in HD-treated patients but not for PD or for children with chronic renal failure before starting dialysis treatment (CRF). No significant differences in CD4(+) T helper cell subsets were found between the groups. However, CRF children had a higher percentage of IFN-gamma producing CD8(+) T lymphocytes compared to HC (P = 0.02). Finally, IgG(1), IgG(2) and IgM production in vitro was similar in the four groups. In conclusion, significantly lower numbers of memory type B cells were found in children with chronic renal failure compared to healthy controls. This reduction may contribute to the low Ig levels found in these children.

Management of peritonitis in children receiving chronic peritoneal dialysis

Bacterial peritonitis is a major threat to long-term peritoneal membrane function in pediatric patients receiving chronic peritoneal dialysis (CPD). This review summarizes the demographics, risk factors, and current recommendations regarding diagnostic procedures, management, and prevention of peritonitis in children. Albeit decreasing in incidence, bacterial peritonitis remains a major cause of technique failure in children with endstage renal disease receiving CPD. The use of standardized diagnostic procedures, efficacious antibacterial treatment, and objective response criteria are crucial in improving the outcome of this complication. Current guidelines recommend combining a first- and third-generation cephalosporin for empiric therapy in uncomplicated cases. The initial use of a glycopeptide/third-generation cephalosporin combination should be restricted to patients with risk factors for severe disease, as defined by clinical presentation, young age (<2 years), and recent infection with a methicillin resistant micro-organism. Several risk factors for primary or relapsing peritonitis have been identified, some of which are amenable to preventive measures. These relate to catheter design and implantation technique, connection methodology, early catheter removal in refractory or relapsing peritonitis, and eradication of Staphylococcus aureus from the catheter exit site and/or nasal reservoirs in patients and their caregivers.

Immunoglobulins in chronic renal failure of childhood: effects of dialysis modalities

BACKGROUND

It is not clear whether low serum levels of IgG (subclasses), previously demonstrated in children on peritoneal dialysis (PD), are related to the PD procedure or to factors associated with chronic renal failure (CRF). The aim of our study was to analyze the effect of PD on serum and PD effluent (PDE) IgG and subclass levels in children with end-stage renal failure.

METHODS

We measured albumin, IgG, IgA, IgM, and IgG subclasses in serum and PDE from children on PD (N = 40) and compared the serum values with those of children treated with hemodialysis (HD, N = 23) or presenting with CRF but not yet dialyzed (CRF; N = 63), and with a group of healthy controls (HCs; N = 67). Sixteen PD children could be followed sequentially from before starting PD and eight during a peritonitis episode.

RESULTS

Forty percent of the PD children showed reduced serum IgG2 levels (P = 0.0003) compared with 35% in HD (P = 0.006), 33% in CRF (P = 0.001), and 9% in HC children. IgG1 deficiencies were observed in 25% of PD patients (P < 0.0001), 4% of HD (P = NS), 16% of CRF (P = 0.0005), and 0% of HC children. IgG3 and IgG4 deficiencies were observed less frequently. Peritoneal clearances were similar for total IgG, IgG1, IgG2, and IgG4, but were lower for IgG3 (P < 0.05). No relationships were found between clearances and age or duration of PD treatment. Total IgG (P = 0. 003) and IgG1 (P = 0.002) levels declined just after starting PD. Peritonitis was associated with temporarily increased peritoneal loss of Ig, while the serum concentrations were unaffected. No significant relationship was found between the peritonitis incidence and reduced IgG or subclasses. However, all children with two or more peritonitis episodes per year had a reduced Ig level.

CONCLUSIONS

Although the mean serum concentrations of immunoglobulins were normal in all studied groups, a deficiency of one or more IgG subclasses was present in all groups with renal failure, suggesting inhibition of their synthesis by the uremic state. Ig deficiencies were more frequently found in PD, likely caused by protein loss in PDE. A high peritonitis incidence was associated with reduced serum Ig levels.

Immunizations for pediatric dialysis patients

Children maintained on chronic dialysis are at high risk for infection, and although the burden of vaccine-preventable disease in this population has not been fully documented, primary care of these patients should include careful compliance with the routine childhood immunization schedule. There have been considerable changes in this schedule in recent years, and an update is provided. In addition the supplemental vaccines for pneumococcal and influenza vaccines are discussed. Where available, data regarding vaccine response in children on dialysis are presented.

Haemophilus influenzae type b immunization in infants on peritoneal dialysis. Pediatric Peritoneal Dialysis Study Consortium

As part of a multi-center collaborative study, we measured antibody levels to Haemophilus influenzae type b (Hib) in ten chronic peritoneal dialysis (CPD) patients, aged 39 months or less, who were immunized while on CPD. Nine of the ten developed protective antibody levels to Hib. Four patients had serial measurements of antibody and all maintained protective levels, although the levels did decrease in two patients. Thus most, but not all, infants immunized with Hib vaccine while on CPD develop protective antibody levels. The factors responsible for vaccine failure are not clear. Whether patients maintain protective antibody over time needs to be determined.

IgG subclass levels in pediatric patients on chronic peritoneal dialysis

Patients maintained on chronic peritoneal dialysis (CPD) have been reported to have a variety of abnormalities of humoral immunity, including hypogammaglobulinemia, altered response to vaccination, and selective absence of IgG2. We measured serum immunoglobulin and IgG subclass levels in 22 pediatric CPD patients followed at our institution; 8 patients had low total IgG; 4 of these had low levels of IgG2 and 3 also had low IgG1, but IgG2 levels were detected in all patients. Thus, many pediatric CPD patients may have low IgG, and some may have low IgG1 and IgG2 as a reflection of low total IgG. However, we did not demonstrate a selective absence of IgG2 in these patients.

Infectious and catheter-related complications in pediatric patients treated with peritoneal dialysis at a single institution

Continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) are the predominant dialytic modalities for the majority of children while awaiting transplantation. Wide acceptability of peritoneal dialysis is hindered by infectious complications. A retrospective review of 367 pediatric patients treated with CAPD/CCPD for at least 3 months from September 1980 through December 1994 revealed that the peritonitis incidence ranged from 1.7 to 0.78 episodes per patient-year. No differences in peritonitis rates were observed between patients treated with CAPD or CCPD. Gram-positive organisms were responsible for the majority of peritonitis episodes. Age, sex, race, primary renal disease, presence of nephrotic syndrome, and serum albumin level were not associated risk factors. Longer time on treatment and diminished serum IgG level were associated with increased peritonitis incidence. Treatment was successfully completed at home in most cases. Almost half of the catheter losses were caused by Staphylococcus, Pseudomonas, and fungal peritonitis and tunnel/exit-site infections. Infectious complications are still the major causes of morbidity and treatment failure in patients treated with CAPD/CCPD. Thus, controlled studies are needed to assess methods for prevention or improvement of peritonitis rates in this patient population.

Defective antibody response to Hemophilus influenzae type b immunization in children receiving peritoneal dialysis

Pediatric end-stage renal disease patients, maintained on chronic peritoneal dialysis (CPD), may have a variety of immunological abnormalities, including hypogammaglobulinemia and poor responses to vaccines. We measured antibody levels to Hemophilus influenzae type b (Hib) in 24 CPD patients. Eight children received primary Hib immunization while undergoing CPD. Of these, 1 of 8 (12%) lacked protective levels of antibody. In another child, who had an initial protective response, antibody levels were undetectable 12 months after immunization. Sixteen of the patients had not been immunized with Hib vaccine because they were more than 5 years old when the vaccine was licensed. In this group, 5 of 16 (31%) lacked protective levels of anti-Hib antibody. Of those available for follow-up, 3 responded normally to Hib vaccine. It is not sufficient to provide childhood immunizations to CPD patients with the assumption that those immunizations will lead to long-lived immunity. Antibody levels should be measured within a month of immunization and at regular intervals thereafter to document immunity.

Hypogammaglobulinemia and fatal sepsis in an infant maintained on peritoneal dialysis

Chronic peritoneal dialysis (CPD) is a common form of renal replacement therapy in children. Recent studies suggest that immunological abnormalities, in particular hypogammaglobulinemia, may develop in children and infants on peritoneal dialysis. We report an infant maintained on CPD who died of gram-negative sepsis. At post-mortem examination, he was noted to have severe panhypogammaglobulinemia.

Group B streptococcus: an unusual cause of severe peritonitis in young children treated with continuous ambulatory peritoneal dialysis

Peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients is only rarely caused by beta-hemolytical streptococci species. We describe two young children, aged 15 months and 5 years, respectively, who presented an unusually severe course of peritonitis due to group B beta-hemolytical streptococci. This course of the disease showed a strong similarity with neonatal streptococcal septicemia. In neonates, IgG2 deficiency is thought to be partly responsible for the severity of this condition. This may also be true for young children treated with CAPD, since IgG2 deficiency has been established for children.