Nephrotoxicity From Molecularly Targeted Chemotherapeutic Agents

The introduction of novel molecularly targeted therapies in the last 2 decades has significantly improved the patient survival compared to standard conventional chemotherapies. However, this improvement has been accompanied by a whole new spectrum of kidney adverse events. Although known as "targeted," many of these agents lack specificity and selectivity, and they have a tendency to inhibit multiple targets including those in the kidneys. Early detection and correct management of kidney toxicities is crucial to preserve kidney functions. The knowledge of these toxicities helps guide optimal and continued utilization of these potent therapies. The incidence, severity, and pattern of nephrotoxicity may vary depending on the respective target of the drug. Here, we review the mechanism of action, clinical findings of kidney adverse events, and their proposed management strategies.

Bortezomib Treatment for Refractory PLA2R-Positive Membranous Nephropathy

Introduction

B-cell depletion has been shown to be an effective strategy for the majority of patients with membranous nephropathy (MN), and in PLA2R-positive MN, immunologic remission (improvement or elimination of measurable serum anti-PLA2R antibodies) precedes renal remission. Yet, cases exist of patients who do not achieve immunologic remission despite achieving peripheral B-cell depletion. This has led to the hypothesis that some patients have plasma cells that are responsible for producing anti-PLA2R antibodies.

Case Presentation

A 66-year-old man with a past medical history of hypertension, hyperlipidemia, and cerebrovascular disease presented with nephrotic syndrome and was diagnosed with PLA2R-positive MN on kidney biopsy. He was refractory to multiple therapies including tacrolimus, and was resistant to rituximab despite having achieved B-cell depletion. He also did not enter into remission with plasmapharesis and cyclophosphamide. He then achieved immediate immunologic remission after treatment with the proteasome inhibitor bortezomib, which is used as first-line therapy for multiple myeloma.

Discussion/Conclusion

This case suggests that considering the source of PLA2R antibody production could lead to individualized and targeted therapies for MN.

Hypertension in Cancer Patients and Survivors: Epidemiology, Diagnosis, and Management

Cancer patients and survivors of cancer have a greater burden of cardiovascular disease compared to the general population. Much of the elevated cardiovascular risk in these individuals is likely attributable to hypertension, as individuals with cancer have a particularly high incidence of hypertension following cancer diagnosis. Treatment with chemotherapy is an independent risk factor for hypertension due to direct effects of many agents on endothelial function, sympathetic activity, and renin-angiotensin system activity as well as nephrotoxicity. Diagnosis and management of hypertension in cancer patients requires accurate blood pressure measurement and consideration of potential confounding factors, such as adjuvant treatments and acute pain, that can temporarily elevate blood pressure readings. Home blood pressure monitoring can be a useful tool to facilitate longitudinal blood pressure monitoring for titration of antihypertensive medications. Selection of antihypertensive agents in cancer patients should account for treatment-specific morbidities and target organ injury.

Incidence and prevalence of hepatitis B and hepatitis C viruses in hemodialysis patients in Lebanon

AIM: To determine the incidence and the prevalence of hepatitis B and C viral infections in patients on hemodialysis (HD) across Lebanon.

METHODS: We reviewed the data registry at the Lebanese Ministry of Public Health where records of monthly hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) serology are reported from 60 affiliated HD centers across Lebanon. All patients who were on HD or who started HD between October 2010 and July 2012 were included in the study. Patients from seven HD centers were excluded due to inadequate and incomplete results reporting. During the selected period, HBsAg and HCV serology were available for 3769 patients from 53 HD centers distributed at all Lebanese governorates. The prevalence was calculated by dividing the number of patients with positive HBsAg or HCV serology to the total number of patients. The Incidence was calculated by dividing the number of newly acquired infection to number of patients-years (p-y). Incidence rates at different governorates were compared to each other using two tailed Z test and a P value of < 0.05 was considered significant.

RESULTS: Sixty out of 3769 HD patients were found to have positive HBS Ag and 177 out of 3769 were positive for HCV Antibodies. The prevalence of hepatitis B virus (HBV) and HCV in HD patients across Lebanon was 1.6%, and 4.7%, respectively. The comparison of prevalence according to geographic distribution could not be done accurately due to the frequent shift of patients between dialysis centers at different governorates. The incidence rate was 0.27 per 100 p-y for HBV and 0.37 per 100 p-y for HCV. There was no significant difference concerning the incidence of HBV between HD centers at different governorates (all P values > 0.1), but this difference was highly significant concerning the incidence rates of HCV which occurred predominantly in the southern centers (1.47 per 100 p-y) with a P value of 0.00068 and 0.00374 when compared to Mount Lebanon (0.21 per 100 p-y) and the Northern centers (0.19 per 100 p-y), respectively.

CONCLUSION: The incidence rate of HBV and HCV is very low in the Lebanese HD centers and their prevalence is decreasing over the last two decades.

The renin-angiotensin system: an old, newly discovered player in immunoregulation

Clinical and experimental studies that discuss the different immune functions of the renin-angiotensin system (RAS) in kidney diseases were reviewed, with emphasis on studies of kidney transplantation. The RAS has been shown to affect both the innate and adaptive immune responses and has a well-established role in fibrinogenesis. Of special clinical interest is the ability of the RAS to activate the transforming growth factor beta(1) and the Smad pathways leading to fibrinogenesis. In addition to the RAS enhancing effect on the activity of T cells, several components of the RAS have also been shown to be chemotactic to macrophages, T cells, and natural killer cells. Experimental studies have found that RAS blockade decreases the histologic lesions of chronic allograft nephropathy but can enhance acute graft vasculopathy. Although the blockade of RAS has been commonly practiced to reduce posttransplantation hypertension, proteinuria, and erythrocytosis, however, its role in prolonging graft survival is not well established.

Lupus cerebritis after visiting a tanning salon

A 53-year-old female was admitted to the intensive care unit for lupus cerebritis; she had a 15-year history of stable lupus. Over the prior 1 to 2 months, the patient visited a tanning salon and this triggered the exacerbation of lupus. Her initial symptoms were cutaneous in the form of an erythematous rash. Within 2 weeks she started to have headaches and was admitted for seizure and psychosis. Ultraviolet A exposure in the tanning salon is known to exacerbate lupus by modulation of the immune system at the level of the skin. It has also been found that ultraviolet light can lead to the formation of antinuclear antibodies. This case illustrates the need to emphasize the danger of the tanning salon to patients with systemic lupus erythematous; the risk is not only cutaneous, it can also be systemic.