Pathophysiology of peritoneal fluid eosinophilia in peritoneal dialysis patients

Peritoneal dialysis related eosinophilic peritonitis: a case report and review of the literature

BACKGROUND

Overt eosinophilic peritonitis (EP) is a relatively uncommon complication of peritoneal dialysis (PD), although not rare. Here we reported a case of EP relieved after changing dialysate.  CASE PRESENTATION: A 28-year old male patient developed cloudy PD effluents within the first month after PD started. Cytological study of PD effluents showed elevated white blood cells and polynuclear cells. Bacteria culture of PD effluents repeated for several times were all negative, and no pathogen was found by metagenomics next generation sequencing (mNGS). Antibiotic therapy for 28-day was ineffective. Based on these and increased eosinophils in peritoneal fluid, he was finally diagnosed as EP. PD dialysate was changed (consists of the same buffer agent and electrolytes, but is packed in bags that do not contain PVC), and the patient's PD effluent became clear. Of note, EP did not relapse 5 months later when the patient started to use the former PD solution again.

CONCLUSION

Although PD effluent turbidity almost always represents infectious peritonitis, there are other differential diagnoses including EP. For patients with cloudy fluid accompanied by mild symptoms who do not response to antibiotic therapy, it is reasonable to consider the possibility of this disease. EP tends to heal spontaneously, however, antihistamines or glucocorticoids are required sometimes to avoid catheter obstruction. For patients with no obvious incentives, replacement of dialysate may be useful.

Eosinophilic peritonitis in children undergoing maintenance peritoneal dialysis: A case report and literature review

Eosinophilic peritonitis (EP) constitutes a significant number of culture-negative peritonitis cases that can affect 16-60% of the patients who are treated with maintenance peritoneal dialysis (PD). Although it is mainly considered to be the hypersensitivity response of the peritoneum to foreign substances, it can also develop following culture-positive peritonitis attacks. Besides the presence of more than 100 white blood cells (WBC)/ml, the diagnosis is made with the high number of eosinophils in the dialysate fluid (>10%), usually accompanied by peripheral eosinophilia. In this study, a 12-year-old male patient, who was diagnosed as EP as early as in the first week of PD catheter placement and treated with systemic antihistamines was reported. Additionally, clinical aspects and treatment modalities of EP are presented with a detailed literature review. Although EP is usually a self-limiting clinical manifestation with a benign outcome, it can be overlooked due to the lack of a routine reporting of the count and percentage of peritoneal eosinophils in most centers. For this reason, a detailed examination in culture-negative peritonitis cases for EP in order to avoid unnecessary antibiotic use for these patients should be the strategy.

Eosinophilic Reaction at the Time of Catheter Insertion Predicts Survival in Patients Initiating Peritoneal Dialysis

INTRODUCTION

Despite excellent biocompatibility, insertion of silicone peritoneal dialysis (PD) catheters can induce minor foreign body reaction, affecting long-term patient outcomes. We evaluated the effect of eosinophilic reaction associated with PD catheter insertion on outcomes of patients initiating PD.

METHODS

Eosinophilic reaction to PD catheter insertion was defined as the ratio of peripheral blood eosinophil count at 1 week after insertion (E1W) to pre-insertion eosinophil count (E0), and the association of E1W/E0 with technique survival, peritonitis-free survival, and heart failure (HF)-related hospitalization-free survival was analyzed.

RESULTS

This retrospective cohort study included 116 patients (89 male patients) who underwent PD catheter insertion between January 2008 and June 2018 (61.3 ± 12.9 years). The follow-up duration was 46.2 (23.8-75.3) months. E1W was significantly higher than E0 (median, 333 vs. 234/μL, p < 0.001), with a median E1W/E0 of 1.54. The log-rank test showed that technique survival, peritonitis-free survival, and HF-related hospitalization-free survival were significantly better in patients with E1W/E0 < 1.54 than in those with E1W/E0 ≥ 1.54 (p = 0.002, <0.001, and <0.001, respectively). By the Cox regression analysis adjusted for age, sex, the Charlson comorbidity index, the estimated glomerular filtration rate, and the geriatric nutritional risk index, E1W/E0 remained a significant risk factor for technique failure, peritonitis, and hospitalization for HF (hazard ratio (HR) 1.68, p = 0.01; HR 2.19, p < 0.001; HR 2.15, p < 0.001, respectively).

CONCLUSION

Eosinophilic reaction at the time of PD catheter insertion is a novel marker that may predict outcomes in patients initiating PD.

Higher Eosinophils Predict Death-Censored Technique Failure in Peritoneal Dialysis Patients

INTRODUCTION

Eosinophilia (eosinophil fraction of leukocytes >5%), an indicative parameter for bioincompatibility in various circumstances, is well established in hemodialysis. However, change in eosinophil count (EOC) and its association with death-censored technique failure among peritoneal dialysis (PD) patients remain unclear.

METHODS

We compared eosinophils before and after PD initiation among 1,432 eligible continuous ambulatory PD patients regularly followed up in our PD center during 2007-2018. Risk factors of early-stage eosinophilia were examined by the logistic regression test. The relationship of early-stage eosinophilia and EOC with death-censored technique failure was examined using the Cox proportional hazards model for overall patients and for men and women separately.

RESULTS

After PD initiation, the EOC and percentage of patients with eosinophilia were significantly increased compared with baseline. Being male (odds ratio [OR]: 2.26; 95% confidence interval [CI]: 1.55-3.31; p < 0.001) and higher EOC at baseline (100 cells/μL increase, OR: 1.62; 95% CI: 1.45-1.82; p < 0.001) were risk factors of early-stage eosinophilia after PD initiation. During follow-up, 204 death-censored technique failures were recorded. In fully adjusted models, each with 100 cells/μL increase in EOC, the adjusted hazard ratios (HRs) of technique failure were 1.11 (95% CI: 1.03-1.20; p = 0.009) in the whole cohort, 1.29 (95% CI: 1.10-1.51; p = 0.002) in women, and 1.07 (95% CI: 0.97-1.17; p = 0.196) in men. Eosinophilia was significantly associated with the risk of technique failure for women (HR: 2.24; 95% CI: 1.07-4.70; p = 0.033), which was especially significant for women aged <55 years (HR: 7.61; 95% CI: 1.88-30.90; p = 0.005).

CONCLUSION

EOC was increased significantly after PD initiation, and increased numbers of eosinophils were associated with higher death-censored technique failure in PD patients, especially women.

Incidence and Significance of Peritoneal Eosinophilia during Peritoneal Dialysis-Related Peritonitis

Objective

To determine the incidence and significance of peritoneal eosinophilia (PEo) during peritoneal dialysis (PD)-related peritonitis.

Design

Retrospective observational study.

Setting

Tertiary-care public hospital.

Patients and Method

We performed a cytological study of dialysate at the start of 465 cases of peritonitis diagnosed between January 1987 and May 2002. Cases associated with PEo (> 10% eosinophils) were classified according to their infectious or seemingly noninfectious origin. We compared the two groups, trying to disclose differentiating patterns of presentation.

Results

We found PEo in 42 cases. Infectious peritonitis was the final diagnosis in 22 of the 42 cases; a diagnosis of idiopathic eosinophilic peritonitis was finally established in 20 cases. The etiologic spectrum of infectious peritonitis with PEo did not differ markedly from the global spectrum of peritonitis in our unit. Infectious peritonitis with PEo tended to appear later in the course of PD therapy, presented with more severe clinical symptoms, displayed higher total peritoneal leukocyte and neutrophil counts, and showed lower degrees of PEo than idiopathic eosinophilic peritonitis, but overlap between the groups was significant.

Conclusions

Peritoneal eosinophilia is infrequent but not rare during infectious PD-related peritonitis. Our findings agree with established concepts on idiopathic eosinophilic peritonitis, but overlap in presentation with infectious eosinophilic peritonitis is significant, which should be taken into consideration at the time of planning therapy for this condition.

Evidence for Less Irritation to the Peritoneal Membrane in Rats Dialyzed with Solutions Low in Glucose Degradation Products

Background

Acidic pH and the presence of glucose degradation products (GDP) are believed to compromise the biocompatibility of peritoneal dialysis fluids (PDF). The present study examines the effects of long-term exposure to GDP and low pH by comparing conventional PDF and a new, neutral pH, low GDP solution.

Methods

All experiments were performed using a chronic infusion model of dialysis in nonuremic rats. The animals were treated for 6 weeks with 2 daily injections of 4.25% glucose-containing PDF. The following PDF were tested: CAPD3 (single-chamber bag, low pH, high GDP), CAPD3 pH 7.4 (single-chamber bag, neutral pH, high GDP), CAPD3-Balance (double-chamber bag, neutral pH, low GDP). All test solutions were obtained from Fresenius Medical Care, Bad Homburg, Germany.

Results

After 6 weeks of exposure, peritoneal permeability to water, urea, creatinine, glucose, and sodium, assessed by peritoneal equilibration test, was similar in all groups. However, compared to other PDF, dialysis with CAPD3-Balance was associated with reduced concentrations of protein and hyaluronan in the dialysate, decreased peritoneal eosinophilia, and reduced dialysate levels of chemokines CCL2/MCP-1 and CCL5/RANTES. Morphologic changes in the peritoneal membrane of CAPD3-Balance-treated animals were much less pronounced and included reduced vascular density, preservation of the mesothelial monolayer and intercellular junction, and no reduplication of the submesothelial basement membrane.

Conclusions

A new generation of PDF with physiologic pH and low GDP level produce less irritation to the peritoneal membrane and better preserve its structural integrity. This effect seems to be related predominantly to minimized GDP concentrations.

Cytomorphological changes induced by intraperitoneal chemotherapy present important diagnostic pitfalls in peritoneal fluid cytology

OBJECTIVE

Intraperitoneal chemotherapy (IP ChT) is an emerging modality in the treatment of advanced gastric adenocarcinoma with peritoneal disease. Cytological evaluation of peritoneal fluid specimens from patients undergoing IP ChT is important in clinical management. However, direct intraperitoneal exposure to chemotherapeutic agents induces cytomorphological changes in benign constituents of peritoneal fluid, presenting particular challenges to accurate cytological interpretation. These morphological changes have not been well characterised in the literature. We systematically reviewed the cytomorphological features in immunocytochemically-confirmed positive and negative IP ChT peritoneal fluid samples to elucidate the degree of morphological overlap between malignant and reactive cells.

METHODS

We reviewed 39 peritoneal fluid samples of patients treated with IP ChT, and scored specific cytomorphological parameters of both benign and malignant cells with the aid of relevant immunocytochemical interrogation.

RESULTS

The present findings show a significant degree of morphological overlap between reactive and malignant cells. Abnormal, "exploding" mitotic figures, nuclear membrane irregularities, multi-nucleation and cytoplasmic vacuolation were commonly observed in negative fluid specimens. The most helpful feature that favoured malignant cells was the increased nuclear-to-cytoplasmic ratio. A background inflammatory milieu of eosinophils and/or neutrophils was seen in 45-58% of post IP ChT peritoneal fluid specimens. The presence of pseudoparakeratotic cells, a novel observation in post IP ChT fluid specimens is also described.

CONCLUSIONS

The extent of reactive cytomorphological anomalies arising from treatment with IP ChT poses unique diagnostic challenges and may prompt a malignant or 'atypical' diagnosis in benign reactive samples.

Successful Treatment of Idiopathic Eosinophilic Peritonitis by Oral Corticosteroid Therapy in a Continuous Ambulatory Peritoneal Dialysis Patient

Eosinophilic peritonitis is a well-described complication of peritoneal dialysis and is often associated with either a reaction to the dialysis system constituent (tubing, sterilant or solution) or an underlying bacterial or fungal reaction. We report a case of eosinophilic peritonitis, which is treated by oral prednisone acetate therapy. A 43-year-old female patient developed end-stage renal disease and underwent continuous ambulatory peritoneal dialysis for 2.5 years. The patient received 2,000 ml of 1.5% dialysis solution (PD2) with three exchanges daily and 2,000 ml of 2.5% PDF overnight (PD2). She went to the consultation because of a constant turbid peritoneal dialysis effluent for 3 months without abdominal pain. Repeated peritoneal effluent samples showed an elevated white blood cell count of 500 cells/mm³, with 87% eosinophils. The peripheral blood test revealed a white blood cell count of 3.8 × 10⁹/l, with 32.2% eosinophils. Etiology like bacterial and fungal infection was excluded by peritoneal fluid culture. Turbidness persisted in spite of diagnostic antibiotic treatment. Given the fact that we found a significant elevation of eosinophils in the peripheral blood and an absolute increase in the eosinophil count of >30/mm³ in dialysis fluid (up to 400/mm³ in our patient), obvious dialysate effluent turbidness, negative results of repeated peritoneal fluid cultures, inefficacy of antibiotic therapy, and negativity of serum tumor and immunological markers, we drew the conclusion that the patient had idiopathic eosinophilic peritonitis. Oral corticosteroid was administered at once (20 mg prednisone acetate daily), which was gradually weaned off and stopped over an 8-week period. Afterwards, the dialysis effluent became clear, and the cytological analysis showed that the white blood cell count decreased to 1 × 10⁶/l, with no eosinophils. This case reminds us that the diagnosis of eosinophilic peritonitis should be considered when repeated cultures are always negative and the turbidness of peritoneal dialysis effluent persists in spite of an antibiotic therapy.

Intestinal Strongyloides causing peritoneal eosinophilia in peritoneal dialysis

A 59-year-old Laotian male with a past medical history of multiple myeloma on peritoneal dialysis (PD) presented with abdominal pain and peritoneal eosinophilia. He was treated empirically for bacterial peritonitis and discharged although his PD fluid did not isolate any pathogens. He soon developed a partial small bowel obstruction and his serum Strongyloides IgG was positive. After treatment with ivermectin, stool microscopic examination showed Strongyloides stercoralis larvae. This case illustrates that the differential diagnosis of peritoneal eosinophilia should include typical and atypical infections in addition to an allergic or hypersensitivity type reaction.

Regulation of the interleukin-5 receptor alpha-subunit on peripheral blood eosinophils from healthy subjects

The aim was to study in vitro regulation of the IL-5 receptor alpha (IL-5R alpha) on purified peripheral blood eosinophils from healthy subjects. The IL-5R alpha was down-regulated, in a dose-dependent manner, by recombinant IL-5 and GM-CSF, with IL-5 being most potent. This down-regulation was not induced by autocrine release of GM-CSF or IL-5, respectively. Incubation of eosinophils with cell-free peritoneal dialysis fluid (PF) collected from a patient with peritoneal fluid eosinophilia (PFE), induced up-regulation of the proportion of CD69 positive eosinophils, in parallel with down-regulation of the proportion of IL-5R alpha positive eosinophils. Experiments with neutralizing antibodies against IL-5 and GM-CSF, revealed that IL-5 was the principal cytokine responsible for the down-regulation of the IL-5R alpha. When eosinophils were incubated with PF collected from the same patient in remission or with PF collected from a newly started patient or a patient with bacterial peritonitis, less down-regulation of the IL-5R alpha was observed. In conclusion our data indicate that IL-5, as opposed to its proposed action on eosinophil progenitors, down-regulates the IL-5R alpha chain on mature eosinophils. We therefore suggest that an IL-5 driven inflammation generates an eosinophil tissue phenotype that is characterized by a low IL-5R alpha expression. These aspects of IL-5 action on IL-5R alpha expression could gain new insights into the mechanisms of specific immuno-modulatory therapies, such as anti-IL-5.