A novel mutation of LAMB2 in a multigenerational mennonite family reveals a new phenotypic variant of Pierson syndrome

PURPOSE

To describe a novel laminin β-2 (LAMB2) mutation associated with nephrotic syndrome and severe retinal disease without microcoria in a large, multigenerational family with Pierson syndrome.

DESIGN

Retrospective chart review and prospective family examination.

PARTICIPANTS

An extended consanguineous family of 52 members.

METHODS

The eyes, urine, and serum DNA were evaluated in all family members after discovering 2 patients, both younger than 10 years, with bilateral retinal detachments and concurrent renal dysfunction. Linkage analysis was performed in the 9 living affected individuals, 7 using the Illumina Human Hap370 Duo Bead Array (Illumina, San Diego, CA) and 2 using GeneChip 10K (Affymetrix, Santa Clara, CA) mapping arrays.

MAIN OUTCOME MEASURES

The prevalence and severity of ocular and kidney involvement and genetic findings.

RESULTS

Eleven affected family members were identified (9 living), all manifesting chronic kidney disease and bilateral chorioretinal pigmentary changes, with or without retinal detachments, but without microcoria or neurodevelopmental deficits, segregating in an autosomal recessive pattern. The causative gene was localized to a 9-Mb region on chromosome 3. Comprehensive gene sequencing revealed a novel LAMB2 variant (c.440A → G; His147R) that was homozygous in the 9 living, affected family members, observed at a frequency of 2.1% in the Old Order Mennonite population, and absent in 91 non-Mennonite controls. The mutation is located in a highly conserved site in the N-terminal domain VI of LAMB2.

CONCLUSIONS

This study describes a novel mutation of LAMB2 and further expands the spectrum of eye and renal manifestations associated with defects in the laminin β-2 chain.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Banff '09 meeting report: antibody mediated graft deterioration and implementation of Banff working groups

The 10th Banff Conference on Allograft Pathology was held in Banff, Canada from August 9 to 14, 2009. A total of 263 transplant clinicians, pathologists, surgeons, immunologists and researchers discussed several aspects of solid organ transplants with a special focus on antibody mediated graft injury. The willingness of the Banff process to adapt continuously in response to new research and improve potential weaknesses, led to the implementation of six working groups on the following areas: isolated v-lesion, fibrosis scoring, glomerular lesions, molecular pathology, polyomavirus nephropathy and quality assurance. Banff working groups will conduct multicenter trials to evaluate the clinical relevance, practical feasibility and reproducibility of potential changes to the Banff classification. There were also sessions on quality improvement in biopsy reading and utilization of virtual microscopy for maintaining competence in transplant biopsy interpretation. In addition, compelling molecular research data led to the discussion of incorporation of omics-technologies and discovery of new tissue markers with the goal of combining histopathology and molecular parameters within the Banff working classification in the near future.

Mechanisms of alloantibody production in sensitized renal allograft recipients

While clinical protocols have been developed to allow for successful kidney transplantation in patients with high levels of donor-specific alloantibody (DSA), significant limitations still exist including high rates of early humoral rejection and decreased long-term graft survival compared to conventional transplants. A better understanding of the mechanisms of alloantibody production at baseline and at various phases posttransplant would be an important step toward the development of improved therapeutic approaches. The goal of this review is to outline recent studies regarding antibody production in general and specific studies that illustrate what is known about alloantibody production in sensitized patients.

The spectrum of antibody-mediated renal allograft injury: implications for treatment

Improvements in anti-HLA antibody detection and diagnostic criteria have increased recognition of antibody-mediated rejection (AMR) following renal transplantation. Therapy of acute AMR is directed toward rapidly lowering circulating donor-specific antibody (DSA) activity. Despite reversal of acute renal dysfunction, however, antibody-secreting plasma cells in spleen and bone marrow are not depleted by treatment and circulating DSA commonly remains detectable in peripheral blood. Sequential ultrastructural studies of renal allografts during acute AMR show progression of microvascular endothelial abnormalities from necrosis and apoptosis to glomerular and peritubular capillary basement membrane duplication, termed transplant glomerulopathy (TG), a manifestation of chronic AMR. Additionally, long-term exposure to anti-HLA antibodies (particularly against class II antigens) is associated with shortened allograft survival and TG even in the absence of documented acute AMR. The association of TG with prior acute AMR and with circulating DSA provides evidence that antibody-mediated allograft injury exists as a spectrum of renal injury. Although effective therapy is available for acute AMR, allografts remain at risk for chronic AMR and shortened survival. The optimum approach to treatment for chronic AMR remains to be determined.

Complications, resource utilization, and cost of ABO-incompatible living donor kidney transplantation

BACKGROUND

The transplantation of living donor renal allografts across blood group barriers requires protocols to reduce and maintain anti-blood group antibody at safe levels. These protocols lead to an increase in resource utilization and cost of transplantation and may result in increased complications.

METHODS

In this retrospective study, we compared 40 ABO-incompatible to 77 matching ABO-compatible living donor renal allografts with respect to complications, resource utilization, and cost from day -14 to 90 days after transplantation.

RESULTS

Overall, surgery-related complications and resource utilization were increased in the ABO-incompatible group, primarily due to the desensitization protocol and antibody-mediated rejection. In the absence of rejection, the mean number of complications was similar for both groups. ABO-incompatible kidney transplantation was approximately 38,000 US dollars more expensive than ABO-compatible transplants, but was cost effective when compared to maintaining the patient on dialysis while waiting for a blood group compatible deceased donor kidney. Actuarial graft and patient survival was similar in the two groups.

CONCLUSIONS

We conclude that ABO-incompatible living donor kidney transplantation is a viable option for patients whose only donor is blood group incompatible despite the additional resource utilization and cost of therapy.

A comparison of plasmapheresis versus high-dose IVIG desensitization in renal allograft recipients with high levels of donor specific alloantibody

Several protocols allow for the successful transplantation of sensitized renal allograft recipients, yet no one best method has emerged. The aim of the current study was to compare the efficacy of high-dose IVIG with two different plasmapheresis (PP)-based regimens in kidney transplant recipients with high levels of donor specific alloantibody (DSA) defined as a positive T-cell cytotoxicity crossmatch. With the primary goal of achieving a negative crossmatch, we employed three protocols sequentially between April 2000 and May 2005: (i) PP, low-dose IVIG, anti-CD20 antibody (n = 32); (ii) high-dose IVIG (n = 13); and (iii) PP, low-dose IVIG, anti-CD20 antibody and pre-transplant Thymoglobulin combined with post-transplant DSA monitoring (n = 16). IVIG decreased DSA activity in all treated patient, yet only 38% (5/13) achieved a negative crossmatch. In contrast, a negative crossmatch was achieved in 84% in PP group and 88% in the PP/monitoring group (p < 0.01 vs. IVIG). Even with a negative crossmatch, the rejection rates were 80% (IVIG), 37% (PP) and 29% (PP/monitoring), respectively, (p < 0.05 IVIG vs. PP). We conclude that multiple PP treatments leads to more reproducible desensitization and lower humoral rejection rates than a single high-dose of IVIG, but that no regimen was completely effective in preventing humoral rejection.

Kidney transplantation in the hyperimmunized patient

Individuals who have developed anti-HLA class I and II antibodies are said to be immunized or sensitized. High levels of donor specific anti-HLA antibodies present at the time of transplantation frequently result in early allograft loss due to humoral rejection. Lower levels of donor specific anti-HLA antibodies (DSA) are also associated with poor outcome. Technological advances in tissue typing permit the detection of low levels of DSA not seen with standard cytotoxicity cross-match tests. These tests which previously were used to screen patients to avoid transplantation of donor-immunized patients are now being used to stratify patients based on their degree of donor alloreactivity. New protocols have been developed which permit successful transplantation despite the presence of DSA. These protocols utilize intravenous immunoglobulin infusions prior to transplantation, either alone or in combination with plasmapheresis to block or remove DSA. Using these protocols many persons previously considered essentially nontransplantable are now able to successfully receive transplants. Improved recognition of the clinicopathological characteristics of humoral rejection have allowed earlier diagnosis and treatment of antibody-mediated allograft injury and improved the outcome. Although these advances have improved the outlook for highly immunized kidney transplant candidates, more study is needed to delineate the optimal approach to transplantation in this population.

Blood Pressure and Renal Function after Kidney Donation from Hypertensive Living Donors

BACKGROUND

Rising numbers of patients reaching end-stage kidney disease intensify the demand for expansion of the living-kidney-donor pool. On the basis of low risk in white donors with essential hypertension, our transplant center undertook a structured program of accepting hypertensive donors if kidney function and urine protein were normal. This study reports outcomes of hypertensive donors 1 year after kidney donation.

METHODS

We studied detailed measurements of blood pressure (oscillometric, hypertensive therapy nurse [RN], and ambulatory blood pressure monitoring [ABPM]), clinical, and renal characteristics (iothalamate glomerular filtration rate [GFR], urine protein, and microalbumin) in 148 living kidney donors before and 6 to 12 months after nephrectomy. Twenty-four were hypertensive (awake ABPM>135/85 mm Hg and clinic/RN BP>140/90 mm Hg) before donation.

RESULTS

After 282 days, normotensive donors had no change in awake ABPM pressure (pre 121 +/- 1/75 +/- 2 vs. post 120 +/- 1/ 5 +/- 1 mm Hg), whereas BP in hypertensive donors fell with both nonpharmacologic and drug therapy (pre 142 +/- 3/85 +/- 2 to post 132 +/- 2/80 +/- 1 mm Hg, P<.01). Hypertensive donors were older (53.4 vs. 41.4 years, P<.001) and had lower GFR after kidney donation (61 +/- 2 vs. 68 +/- 1 mL/min/1.73m, P<.01). After correction for age, no independent BP effect was evident for predicting GFR either before or after nephrectomy. Urine protein and microalbumin did not change in either group after donor nephrectomy.

CONCLUSIONS

Our results indicate that white subjects with moderate, essential hypertension and normal kidney function have no adverse effects regarding blood pressure, GFR, or urinary protein excretion during the first year after living kidney donation. Although further studies are essential to confirm long-term safety, these data suggest that selected hypertensive patients may be accepted for living kidney donation.

Living-donor kidney transplantation at Mayo Clinic--Rochester

With the established benefits of living-donor kidney transplantation, our primary emphasis at Mayo Clinic, Rochester has been to develop protocols that allow living donation to occur even in the presence of relatively unusual or generally contraindicated situations. This approach has significantly increased the number of patients receiving kidney transplants in the past few years. Our protocols for extended criteria donors and recipients along with the exclusive use of laparoscopic donor nephrectomy have been major contributors to the increase in volume. ABO-incompatible and positive-crossmatch living-donor kidney transplant protocols also have increased the availability of transplants for our patients. Protocol biopsies have aided in the diagnosis of subclinical rejection, polyoma virus and chronic allograft nephropathy. Innovative immunosuppressive protocols such as calcineurin inhibitor-free immunosuppression have decreased rejection and improved both short and long-term renal allograft survival.

Blood pressure evaluation among older living kidney donors

With more patients reaching end-stage renal disease, the demand for living kidney donation is increasing rapidly. Many potential donors are now in older age groups. The effects of increasing BP with age and the measurement criteria for hypertension in this group are not well defined. A total of 238 potential donors between 18 and 72 yr of age were prospectively studied, with a comparison of "clinic" BP values measured in the outpatient clinic with an oscillometric recorder (Dinamap; Critikon), ambulatory BP monitoring (ABPM) findings, and standardized BP values determined by nurses using American Heart Association criteria. Renal function was evaluated on the basis of iothalamate clearance (GFR) and urinary protein and microalbumin excretion. Ninety-six percent of subjects were Caucasian. All subjects exhibited normal GFR and urinary protein excretion. Three age groups were defined (group I, </=35 yr, n = 64; group II, 36 to 49 yr, n = 109; group III, >/= 50 yr, n = 65). BP increased with age, as determined with all methods. Subjects >/= 50 yr of age exhibited the highest clinic readings (145 +/- 2/83 +/- 1 mmHg, compared with 129 +/- 2/76 +/- 1 mmHg for group I, P < 0.01). Awake ABPM and nurse-determined BP measurements were lower than clinic readings, including those for group III (131 +/- 2/80 +/- 1 mmHg, compared with 145 +/- 2/83 +/- 1 mmHg in the clinic, P < 0.001). With the use of systolic BP values of >140 mmHg and/or diastolic BP values of >90 mmHg, 36.7% of subjects were initially considered hypertensive; this proportion decreased to 11% overall with awake ABPM findings (>135/85 mmHg). Measurement variability (SD in ABPM) and the effects of misclassification were greatest for donors >/= 50 yr of age. Multivariate regression indicated that GFR of both donors and recipients decreased with age, but regression identified no independent effect of BP. Recipient outcomes for up to 2 yr were equally good for donor kidneys considered normotensive or hypertensive on the basis of clinic BP measurements. These data indicate that higher arterial BP with age can lead to misclassification of many older living kidney donors. Sixty-two subjects with excellent kidney function were misclassified as hypertensive with clinic oscillometric measurements alone. Detailed evaluations of ABPM findings, GFR, and urinary protein levels are warranted for Caucasian subjects with high clinic BP readings who are otherwise suitable potential donors.

Kidney transplantation without calcineurin inhibitors using sirolimus

INTRODUCTION

With the introduction of new immunosuppressive medicines, it has become possible to determine the extent to which nephrotoxic medicines contribute to CAN. The aim of this study is to compare the safety and efficacy of calcineurin inhibitor (CI) free immunosuppression in a prospective, randomized trial comparing sirolimus-mycophenolate mofetil (MMF)-prednisone to tacrolimus- MMF-prednisone.

METHODS

Patients are randomized at the time of transplant to receive either tacrolimus (target level 12 to 15 ng/mL in the first month) or sirolimus (target level 12 to 18 ng/mL in the first month). All patients also receive MMF (750 mg bid) and prednisone tapered to 10 mg/d by 3 months and thymoglobulin induction (1.5 mg/kg/d on days 0, 1, 2, 4 and 6).

RESULTS

At this point we have 4-month follow-up in 85 patients. The acute rejection rate is 7.5% (3/40) in the tacrolimus group and 6.7% (3/45) in the sirolimus group. We have discontinued sirolimus in eight patients so far, with wound complications being the most common indication. Renal function appears to be better in the sirolimus group at 1 month after transplantation, but the difference is not statistically significant.

CONCLUSIONS

While longer follow-up is needed, these results demonstrate that total avoidance of CI can be achieved with extremely low acute cellular rejection rates using sirolimus-based immunosuppression in combination with thymoglobulin, MMF, and prednisone.

Selection of treatment of cefaclor-associated urticarial, serum sickness-like reactions and erythema multiforme by emergency pediatricians: lack of a uniform standard of care

BACKGROUND

Serum sickness-like reactions (SSLR) and erythema multiforme are common adverse effects of cefaclor therapy and can be associated with significant morbidity. No standardized evidence-based protocol for the optimal treatment of drug-induced SSLR exists.

OBJECTIVES

To define the standard of care used by physicians treating adverse reactions associated with cefaclor.

METHODS

A retrospective review of the medical records of children discharged from a pediatric emergency room with a diagnosis of adverse events to cefaclor was conducted. Charts of patients were reviewed to determine which therapy was prescribed.

RESULTS

During the study period, 74 cases of adverse events attributed to cefaclor presented to the emergency department. SSLR were the most common pattern of adverse events seen (31 cases, 42%), followed by urticarial reactions (26 cases, 35%) and erythema multiforme (17 cases, 23%). An antihistamine was the treatment most often prescribed (88%) for erythema multiforme. Significantly more children with SSLR than with erythema multiforme or urticaria were treated with prednisone, either alone or in combination (P<0.05).

CONCLUSIONS

The treatment most often prescribed for serious cefaclor-associated erythema multiforme was an antihistamine. In the case of SSLR, an antihistamine and prednisone were most commonly used. Prospective randomized, controlled trials are needed to define the role of various therapeutic agents and to determine the optimal therapy for SSLR and other serious adverse drug reactions.

Comparison of the acid-base status of blood obtained from intraosseous and central venous sites during steady- and low-flow states

OBJECTIVE

To compare the acid-base status of blood obtained from the tibial intraosseous site with that status obtained from a central venous site during stead- and low-flow states in a piglet model.

DESIGN

A prospective, observational study.

SETTING

Animal laboratory at a university medical center.

SUBJECTS

Nine 2-day-old piglets.

INTERVENTIONS

Animals were anesthetized, intubated, and mechanically ventilated. A thermodilution pulmonary artery catheter was inserted via the right internal jugular vein and directed into the pulmonary artery. An arterial catheter was inserted into the right carotid artery and an intraosseous needle was inserted into the proximal tibial marrow cavity. Cardiorespiratory arrest was induced by discontinuation of ventilation. The animals were subsequently resuscitated by precordial compressions and ventilation. Blood samples were obtained from central venous and intraosseous sites during steady state and during resuscitation (low-flow state).

RESULTS

No significant differences (p < .05) were found for pH, PCO2, and bicarbonate concentration when values that were obtained from the central venous and intraosseous sites were compared during steady- and low-flow states.

CONCLUSIONS

The acid-base status of intraosseous blood is similar to that status of central venous blood. Intraosseous blood gas values may be an acceptable alternative to central venous blood gas values in judging central acid-base status during cardiopulmonary resuscitation.

Acute testicular pain: Henoch-Schönlein purpura versus testicular torsion

A skilled examiner may not be able to exclude testicular torsion by physical examination maneuvers in a patient who presents with acute scrotal pain. Diagnostic adjunctive studies may be of assistance. However, if a diagnosis cannot be established with certainty, surgical exploration is warranted. Patients with Henoch-Schönlein purpura who present with a vascular eruption on the scrotum, lack a rash elsewhere, and have no arthritis or hematuria are likely to be explored.

Dinferentiation in biology

In this paper the authors give a survey of biological phenomena (both at the cellular level and in organisms), for which the term 'differentiation', used in the widest sense, has a meaningful application. The last chapter deals with some general aspects of differentiation and connected phenomena, such as polarity, symmetry, loss of potencies, dedifferentiation, redifferentiation, adifferentiation, regulation and integration. To prevent this article becoming too voluminous, the authors had to refrain from extending the treatment of differentiation to non-living matter and to human society.