Benefit of B7-1 staining and abatacept for treatment-resistant post-transplant focal segmental glomerulosclerosis in a predominantly pediatric cohort: time for a reappraisal.

BACKGROUND: Primary FSGS manifests with nephrotic syndrome and may recur following KT. Failure to respond to conventional therapy after recurrence results in poor outcomes. Evaluation of podocyte B7-1 expression and treatment with abatacept (a B7-1 antagonist) has shown promise but remains controversial. METHODS: From 2012 to 2020, twelve patients developed post-KT FSGS with nephrotic range proteinuria, failed conventional therapy, and were treated with abatacept. Nine/twelve (< 21 years old) experienced recurrent FSGS; three adults developed de novo FSGS, occurring from immediately, up to 8 years after KT. KT biopsies were stained for B7-1. RESULTS: Nine KTRs (75%) responded to abatacept. Seven of nine KTRs were B7-1 positive and responded with improvement/resolution of proteinuria. Two patients with rFSGS without biopsies resolved proteinuria after abatacept. Pre-treatment UPCR was 27.0 ± 20.4 (median 13, range 8-56); follow-up UPCR was 0.8 ± 1.3 (median 0.2, range 0.07-3.9, p < 0.004). Two patients who were B7-1 negative on multiple KT biopsies did not respond to abatacept and lost graft function. One patient developed proteinuria while receiving belatacept, stained B7-1 positive, but did not respond to abatacept. CONCLUSIONS: Podocyte B7-1 staining in biopsies of KTRs with post-transplant FSGS identifies a subset of patients who may benefit from abatacept. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical outcomes in HIV+/HCV+ coinfected kidney transplant recipients in the pre- and post-direct-acting antiviral therapy eras: 10-Year single center experience.

BACKGROUND: Previous studies have demonstrated inferior patient and graft survival following kidney transplant (KT) in HIV+/HCV+ coinfected patients compared to HIV+/HCV- recipients. However, these studies were conducted prior to the availability of direct-acting antiviral (DAA) agents and data in the modern era are lacking. METHODS: Single center retrospective study of HIV+/HCV+ coinfected KT recipients (2007-2017). Outcomes were assessed for the pre-DAA and post-DAA (ie, after December 2013) eras including 1-year patient survival, death-censored graft survival, and acute rejection; and serious infections (defined as infections requiring admission to the intensive care unit during initial transplant hospitalization or re-admission to the hospital after discharge) within the first 6 months post-transplant. RESULTS: A total of 13 consecutive HIV+/HCV+ recipients were identified. Median time of post-transplant follow-up was 722 days. Seven patients were transplanted in the DAA era; five of them had anti-HCV Ab+ donors, with two donors being HCV NAT positive; all received DAA therapy, six of them post-transplant (median time from KT to DAA: 83 days; IQR, 54-300). All the patients in the pre-DAA era were on a protease inhibitor-containing ART regimen. One-year patient and death-censored graft survivals were 83% and 67%, respectively, for the patients transplanted in the pre-DAA era, and 100% for both outcomes in the subgroup of patients transplanted in the post-DAA era (P > 0.05). Compared to patients in the post-DAA era, those in the pre-DAA era had higher incidence of serious infections (0 vs 67%; P = 0.02). Acute rejection exclusively occurred in the pre-DAA group (n = 1; 17%). CONCLUSIONS: Outcomes of HIV+/HCV+ KT recipients, including HIV-/HCV+ to HIV+/HCV+ transplants, in the DAA era were excellent in this small cohort. Larger studies are needed.

A cluster of donor-derived Cryptococcus neoformans infection affecting lung, liver, and kidney transplant recipients: Case report and review of literature.

Donor-derived infections (DDIs) are a very rare but potentially devastating complication of solid organ transplantation. Here we present a cluster of proven donor-derived cryptococcal infection in the kidney, liver, and lung recipients from a single donor. Remarkably, the onset of illness in the kidney and liver recipients occurred more than 8-12 weeks after transplantation, which is beyond the incubation period previously reported for donor-derived cryptococcosis. DDI should always be considered in the differential diagnosis of transplant recipients admitted with febrile illness, even when presenting beyond the first month post-transplant. Communication between reference laboratories, transplant centers, and organ procurement organizations is critical to improve outcomes.

Hypercalcaemia in Mycobacterium kansasii pulmonary infection.

A gentleman in his 60s with end-stage kidney disease status post kidney transplantation on prednisone and tacrolimus presented with generalised weakness for 7 days, associated with altered mental status. Investigations revealed pancytopenia, acute kidney injury, hypercalcaemia, decreased parathyroid hormone (PTH) and normal calcitriol levels. CT of the chest showed multifocal lung opacities suspicious for malignancy. Bronchoscopy with biopsy yielded no malignant cells, and bronchoalveolar lavage specimens grew Mycobacterium kansasii The patient was treated with bisphosphonates, calcitonin and antibiotics for non-tuberculous mycobacteria pulmonary infection, with improvement in serum calcium levels, and was discharged after 5 weeks of hospitalisation.The work-up for hypercalcaemia begins with PTH measurement, and low PTH levels are consistent with malignancy, immobilisation and granulomatous diseases. Hypercalcaemia in the lattermost is classically caused by overproduction of calcitriol by activated macrophages. However, there are case reports of mycobacterial infections with hypercalcaemia despite normal calcitriol levels, supporting the existence of an additional mechanism of hypercalcaemia in granulomatous infections.

Viral-Associated GN: Hepatitis C and HIV.

Viruses are capable of inducing a wide spectrum of glomerular disorders that can be categorized on the basis of the duration of active viremia: acute, subacute, or chronic. The variable responses of the adaptive immune system to each time period of viral infection results mechanistically in different histologic forms of glomerular injury. The unique presence of a chronic viremic carrier state with either hepatitis C (HCV) or HIV has led to the opportunity to study in detail various pathogenic mechanisms of viral-induced glomerular injury, including direct viral infection of renal tissue and the development of circulating immune complexes composed of viral antigens that deposit along the glomerular basement membrane. Epidemiologic data show that approximately 25%-30% of all HIV patients are coinfected with HCV and 5%-10% of all HCV patients are coinfected with HIV. This situation can often lead to a challenging differential diagnosis when glomerular disease occurs in this dual-infected population and requires the clinician to be familiar with the clinical presentation, laboratory workup, and pathophysiology behind the development of renal disease for both HCV and HIV. Both of these viruses can be categorized under the new classification of infection-associated GN as opposed to being listed as causes of postinfectious GN as has previously been applied to them. Neither of these viruses lead to renal injury after a latent period of controlled and inactive viremia. The geneses of HCV- and HIV-associated glomerular diseases share a total dependence on the presence of active viral replication to sustain renal injury so the renal disease cannot be listed under "postinfectious" GN. With the new availability of direct-acting antivirals for HCV and more effective combined antiretroviral therapy for HIV, successful remission and even regression of glomerular lesions can be achieved if initiated at an early stage.

Viral-Associated GN: Hepatitis B and Other Viral Infections.

By definition, viral-associated GN indicates the direct pathogenic relationship between active viral replication and the development of acute GN. This definition is in sharp contrast to the semantic label and pathophysiologic foundation behind postinfectious GN that uniquely develops only during a period of resolved and absent active infection. The primary example of postinfectious GN are the glomerular lesions described after a pharyngeal or cutaneous streptococcal infection and do not represent the clinical or immunologic pattern seen with viral-associated GN. Hepatitis B (HBV) is the most common chronic viral infection in the world affecting >400 million people which is more than double the prevalence of chronic HIV and hepatitis C carriers combined. In addition, 10%-20% of HBV patients may be coinfected with hepatitis C and 5%-10% will have coinfection with HIV. Being able to distinguish the different types of GN seen with each viral infection is essential for the practicing clinician as each virus requires its own specific antiviral therapy. HBV-induced immune complex disease with renal injury lies on one end of the spectrum of disorders that occurs after a prolonged chronic carrier state. On the opposite end of the spectrum are renal diseases that develop from acute or subacute viral infections. One important glomerular lesion in this category is the association of collapsing FSGS with acute active cytomegalovirus, Epstein-Barr virus, and parvovirus B19 infection. The data supporting or disproving this relationship for each of these viruses will be discussed. A second renal manifestation of acute viral infections often occurs with many different sporadic or epidemic infections such as dengue and hantavirus and can lead to a transient proliferative GN that resolves upon viral clearance. The complex interplay of HBV and all viruses with the immune system provides conceptual lessons on the pathophysiology of immune complex GN that can be applied to all infection-related renal disease and plays an integral role in developing an approach to therapeutic intervention.

Impact of antiretroviral therapy on clinical outcomes in HIV + kidney transplant recipients: Review of 58 cases.

Background: Antiretroviral therapy (ART) poses challenging drug-drug interactions with immunosuppressant agents in transplant recipients.  We aimed to determine the impact of specific antiretroviral regimens in clinical outcomes of HIV + kidney transplant recipients.  Methods: A single-center, retrospective cohort study was conducted at a large academic center. Subjects included 58 HIV - to HIV + adult, first-time kidney transplant patients. The main intervention was ART regimen used after transplantation.  The main outcomes assessed at one- and three-years were: patient survival, death-censored graft survival, and biopsy-proven acute rejection; we also assessed serious infections within the first six months post-transplant.  Results: Patient and graft survival at three years were both 90% for the entire cohort. Patients receiving protease inhibitor (PI)-containing regimens had lower patient survival at one and three years than patients receiving PI-sparing regimens: 85% vs. 100% ( p=0.06) and 82% vs. 100% ( p=0.03), respectively. Patients who received PI-containing regimens had twelve times higher odds of death at 3 years compared to patients who were not exposed to PIs (odds ratio, 12.05; 95% confidence interval, 1.31-1602; p=0.02).  Three-year death-censored graft survival was lower in patients receiving PI vs. patients on PI-sparing regimens (82 vs 100%, p=0.03). Patients receiving integrase strand transfer inhibitors-containing regimens had higher 3-year graft survival. There were no differences in the incidence of acute rejection by ART regimen. Individuals receiving PIs had a higher incidence of serious infections compared to those on PI-sparing regimens (39 vs. 8%, p=0.01).  Conclusions: PI-containing ART regimens are associated with adverse outcomes in HIV + kidney transplant recipients.

Pre-existing undiagnosed central diabetes insipidus unmasked after renal transplantation.

Central diabetes insipidus (CDI) is characterized clinically by the presence of polyuria with the subsequent development of volume depletion and hypernatremia. In patients with dialysis-dependent end-stage renal disease (ESRD), neither of these findings can be expressed due to the absence of renal function. A 59-year-old woman with anuric ESRD of unknown etiology had been on peritoneal dialysis for 8 years prior to receiving a cadaveric allograft. Postoperatively, she developed persistent polyuria and hypernatremia. A desmopressin test confirmed the diagnosis of CDI. A magnetic resonance imaging (MRI) of the brain revealed an empty sella turcica. Maintenance therapy with intranasal desmopressin resulted in complete resolution of the polyuria. At 6-month follow-up on daily desmopressin, the patient maintains normal serum sodium levels and stable allograft function. This is a unique case of CDI from empty sella syndrome (ESS) that was unmasked only after the restoration of normal renal function following successful renal transplantation.