Negative Modulation of B Cell Activation by Melanocortin 1 Receptor Signaling Protects against Membranous Nephropathy.

SIGNIFICANCE STATEMENT: Emerging evidence suggests that melanocortin neuropeptides-specifically adrenocorticotropic hormone-offer a novel, steroidogenic-independent therapeutic modality for membranous nephropathy (MN). The molecular mechanism underlying this beneficial effect, however, remains largely elusive. To investigate whether melanocortins modulate humoral immunity, the authors induced passive Heymann nephritis, a model of human MN, in wild-type and melanocortin 1 receptor (MC1R) knockout rats and treated them with melanocortin agents. Additional rats received adoptive transfer of bone marrow-derived cells beforehand from wild-type or MC1R knockout rats. The findings indicate that MC1R signaling plays a key role in negative modulation of B-cell activation and thereby suppresses humoral immune responses in passive Heymann nephritis, and suggest that MC1R signaling might offer a novel B cell-targeted therapeutic strategy for MN. BACKGROUND: Emerging evidence suggests that the pituitary neuropeptide melanocortins-specifically, adrenocorticotropic hormone-offer a novel nonsteroidogenic therapeutic modality for membranous nephropathy (MN). However, the mechanism(s) of action remains elusive. METHODS: To investigate whether melanocortins modulate humoral immunity, we induced passive Heymann nephritis (PHN), a model of MN, in wild-type (WT) and melanocortin 1 receptor (MC1R) knockout (KO) rats. We treated the animals with melanocortin agents-repository corticotropin injection, the nonsteroidogenic pan-melanocortin receptor agonist [Nle 4 , DPhe 7 ]-α-melanocyte stimulating hormone, the selective MC1R agonist MS05, vehicle gel, or phosphate-buffered saline-and evaluated kidney function, histology, and molecular changes. Additional rats received adoptive transfer of syngeneic bone marrow-derived cells beforehand from WT or MC1R KO rats. RESULTS: KO of MC1R worsened PHN and this was associated with increased deposition of autologous immunoglobulin G (IgG) and complement C5b-9 in glomeruli and higher circulating levels of autologous IgG-evidence of a sensitized humoral immune response. Melanocortin therapy ameliorated PHN in WT rats, coinciding with reduced glomerular deposition of autologous IgG and C5b -9. The beneficial efficacy of melanocortins was blunted in KO rats but restored by adoptive transfer of syngeneic bone marrow-derived cells derived from WT rats. Mechanistically, MC1R was expressed in B lymphocytes and was negatively associated with B cell activation. MC1R agonism triggered the expression of microphthalmia-associated transcription factor in activated B cells in a cAMP-dependent mode and also repressed the expression of interferon regulatory factor 4 (a lymphoid transcription factor essential for B-cell development and maturation), resulting in suppressed plasma cell differentiation and IgG production. CONCLUSIONS: MC1R signaling negatively modulates B cell activation and suppresses humoral immune responses in PHN, suggesting that MC1R signaling might offer a novel therapeutic target for MN.

Hemopexin accumulates in kidneys and worsens acute kidney injury by causing hemoglobin deposition and exacerbation of iron toxicity in proximal tubules.

Hemopexin, a heme scavenging protein, accumulates in the kidneys during acute kidney injury (AKI). However, the function of this accumulated hemopexin in the kidney is unclear. In both the cisplatin-induced and the unilateral kidney ischemia-reperfusion injury models of AKI, we found accumulation of hemoglobin and hemopexin in the kidneys localized to the proximal tubules. Next, hemopexin wild-type and knockout mice were compared in both AKI models and hemopexin wild type mice had significantly worse kidney injury. Furthermore, there was increased kidney expression of kidney injury molecule-1 (a biomarker of AKI) and heme oxygenase-1 (an indicator of oxidative stress) in hemopexin wild type compared with knockout mice in both models of AKI. Next, the interaction of hemopexin and hemoglobin in vitro was investigated using cultured proximal tubular cells. Co-incubation of hemopexin with hemoglobin resulted in hemoglobin deposition and exaggerated hemoglobin-induced injury. Deferoxamine, an iron chelator, and ferrostatin-1, a ferroptosis inhibitor, inhibited this deleterious effect of hemoglobin and hemopexin in proximal tubular cells, implicating iron toxicity in the mechanism of hemopexin mediated injury. Furthermore, the protective effect of deferoxamine in cisplatin-induced AKI was apparent in hemopexin wild type, but not in hemopexin knockout mice, further implicating hemopexin as a mediator of iron toxicity in AKI. Thus, our findings demonstrate that hemopexin accumulates in the kidneys and worsens kidney injury in AKI by increasing hemoglobin deposition on proximal tubular cells to exaggerate hemoglobin-induced cell injury.

A Francisella tularensis L,D-carboxypeptidase plays important roles in cell morphology, envelope integrity, and virulence.

Francisella tularensis is a Gram-negative, intracellular bacterium that causes the zoonotic disease tularemia. Intracellular pathogens, including F. tularensis, have evolved mechanisms to survive in the harsh environment of macrophages and neutrophils, where they are exposed to cell envelope-damaging molecules. The bacterial cell wall, primarily composed of peptidoglycan (PG), maintains cell morphology, structure, and membrane integrity. Intracellular Gram-negative bacteria protect themselves from macrophage and neutrophil killing by recycling and repairing damaged PG--a process that involves over 50 different PG synthesis and recycling enzymes. Here, we identified a PG recycling enzyme, L,D-carboxypeptidase A (LdcA), of F. tularensis that is responsible for converting PG tetrapeptide stems to tripeptide stems. Unlike E. coli LdcA and most other orthologs, F. tularensis LdcA does not localize to the cytoplasm and also exhibits L,D-endopeptidase activity, converting PG pentapeptide stems to tripeptide stems. Loss of F. tularensis LdcA led to altered cell morphology and membrane integrity, as well as attenuation in a mouse pulmonary infection model and in primary and immortalized macrophages. Finally, an F. tularensis ldcA mutant protected mice against virulent Type A F. tularensis SchuS4 pulmonary challenge.

Higher exhaled nitric oxide at 6 weeks of age is associated with less bronchiolitis and wheeze in the first 12 months of age.

BACKGROUND: Nitric oxide in exhaled air (eNO) is used as a marker of type 2 immune response-induced airway inflammation. We aimed to investigate the association between eNO and bronchiolitis incidence and respiratory symptoms in infancy, and its correlation with eosinophil protein X (EPX). METHODS: We followed up infants at 6 weeks of age born to mothers with asthma in pregnancy and measured eNO during natural sleep using a rapid response chemiluminescense analyser (CLD88; EcoMedics), collecting at least 100 breaths, interpolated for an expiratory flow of 50 mL/s. EPX normalised to creatinine was measured in urine samples (uEPX/c). A standardised questionnaire was used to measure symptoms in first year of life. Associations were investigated using multiple linear regression and robust Poisson regression models. RESULTS: eNO levels were obtained in 184 infants, of whom 125/184 (68%) had 12 months questionnaire data available and 51/184 (28%) had uEPX/c measured. Higher eNO was associated with less respiratory symptoms during the first 6 weeks of life (n=184, ß-coefficient: -0.49, 95% CI -0.95 to -0.04, p=0.035). eNO was negatively associated with uEPX/c (ß-coefficient: -0.004, 95% CI -0.008 to -0.001, p=0.021). Risk incidence of bronchiolitis, wheeze, cold or influenza illness and short-acting beta-agonist use significantly decreased by 18%-24% for every unit increase in eNO ppb. CONCLUSION: Higher eNO levels at 6 weeks of age may be a surrogate for an altered immune response that is associated with less respiratory symptoms in the first year of life.

ZRSR2 mutation in a child with refractory macrocytic anemia and Down Syndrome.

Here we report a case of refractory macrocytic anemia with a spliceosomal point mutation involving the ZRSR2 gene in a child with Down syndrome (DS). Such mutations have been shown to cause refractory macrocytic anemia and myelodysplastic syndrome (MDS) in elderly individuals. We report the hematological indices of a child with DS and a ZRSR2 spliceosomal mutation. DS is known to produce macrocytic anemia but does not lead to transfusion dependence. In this case, the ZRSR2 mutation was the likely implicating factor for severe transfusion-dependent anemia in a child with DS. The clinical implication of a ZRSR2 mutation in a child with DS has not been previously described and warrants close surveillance to detect potential insidious transformation to MDS.

MYH9-macrothrombocytopenia caused by a novel variant (E1421K) initially presenting as apparent neonatal alloimmune thrombocytopenia.

MYH9-related disease is a rare cause of thrombocytopenia. We report an infant girl who presented with severe thrombocytopenia at birth and was initially diagnosed with and treated for neonatal alloimmune thrombocytopenia. However, persistent thrombocytopenia led to the suspicion of congenital thrombocytopenia and subsequent identification of a novel variant in MYH9 (E1421K). In silico analysis strongly predicts that this is a disruptive substitution. Immunofluorescent analysis of neutrophils demonstrates abnormal aggregates of MYH9 protein. This case also suggests that a very high immature platelet fraction (≥40%) may be useful for rapidly differentiating MYH9-related disease from other causes of neonatal thrombocytopenia.

A Case Report of in Utero Williams Syndrome Arterial Malformation.

INTRODUCTION: Williams syndrome (WS), an autosomal dominant condition linked to gene deletions on chromosome 7, can cause supravalvular aortic narrowing and death. WS-associated mutations are believed to disrupt arterial elastin fibers, causing smooth muscle malformation, endomysial fibrosis and severe hypertension. Previous studies demonstrated arterial ultrastructural anomalies in adult WS patients. It is not presently known if the arterial phenotype of WS is also present in utero. CASE REPORT: A 34-week stillborn was delivered to a 28-year-old with genetically confirmed WS. Aortic tissue from the patient was compared with non-WS fetal aorta of similar gestational age using EM and light microscopy. Both sections were taken from the proximal aortic root. This demonstrated internal elastic lamina disruption, malformed elastic fibers, smooth muscle proliferation and abnormal collagen fibers, consistent with adult WS phenotype. CONCLUSION: Our analysis indicated the cardiovascular changes of WS in a fetus as young as 34 weeks.

Gastro-Enteropancreatic Neuroendocrine Tumor Cell Dynamics in Liver Microvasculature.

For many cancers, liver metastasis is common and usually indicates poor prognosis. Gastro-enteropancreatic neuroendocrine tumors (GEPNETs) of the midgut are a heterogeneous group of cancers that typically remain asymptomatic until they metastasize to the liver. However, the mechanisms by which these usually indolent cancers establish distal metastasis remain unclear. To begin to elucidate this process, we performed standard in vitro assays to assess cell motility, transendothelial migration, and invasion using BON cells, a widely used model GEPNET cell line. In addition, transmission electron microscopy was used in combination with a novel ex vivo organ slice xenograft model to reveal ultrastructural details of the initial events of BON cell extravasation and re-distribution within the liver. The ultrastructural resolution of the extravasation process revealed the route, sequence, and time course by which tumor cells migrated from the sinusoidal lumen into the hepatic parenchyma in this organ slice model. Both standard in vitro assays and our organ slice model indicated that tumor cells migrated through the discontinuous sinusoidal endothelium to invade the liver parenchyma.

THSD7A-associated membranous nephropathy involves both complement-mediated and autonomous podocyte injury.

Membranous nephropathy (MN) continues to be a leading cause of nephrotic syndrome in non-diabetic adults. As a unique subtype in the serology-based classification of MN, thrombospondin type 1 domain containing 7A (THSD7A)-associated MN has attracted increasing interest, because, unlike other autoantigens, THSD7A is also expressed in preclinical species, facilitating the study of its role in MN. A heterologous mouse model of THSD7A-associated MN was previously established using a proprietary in-house antibody that was unfortunately not available to the research community. Here, we developed a mouse model of THSD7A-associated MN by administering a commercially available antibody targeting the most N-terminal part of THSD7A. Our model was characterized by heavy proteinuria and pathological features of human MN without sex differences. Complement depletion with cobra venom factor only partially attenuated proteinuria and glomerular injury in this model, entailing that complement-independent pathomechanisms also contribute. Consistently, in vitro in primary podocytes, exposure to the anti-THSD7A antibody caused evident podocytopathic changes, including disruption of actin cytoskeleton integrity, podocyte hypermobility, oxidative stress, and apoptotic cell death. These signs of podocytopathy were preserved, albeit to a lesser extent, after complement inactivation, indicating autonomous podocyte injury. Furthermore, as the first FDA-approved treatment for primary MN, adrenocorticotropic hormone therapy with repository corticotropin injection (Purified Cortrophin Gel®) appeared to be beneficial and significantly attenuated proteinuria and glomerular injury, suggesting that this model may be useful for developing novel treatments or understanding the pathogenesis of MN. Collectively, our model, based on the use of a commercially available anti-THSD7A antibody, will be an important tool for MN research.

The Medich giant platelet syndrome: two new cases.

Hypogranular platelet disorders in human subjects are relatively rare. They include the gray platelet syndrome, αδ storage pool deficiency, the Hermansky-Pudlak syndrome, and the white platelet syndrome. Perhaps the rarest of them all is the Medich giant platelet disorder. No additional cases of this condition have been reported since description of the first case in 2004. This study describes two children with thrombocytopenia and giant, hypogranular platelets found shortly after birth. Electron microscopic study of their platelets revealed sheets of membrane wrapped into tubes resembling scrolls. The scroll-like structures were open at both ends and often filled with glycogen particles. The abnormal structures are identical to those found in the initial case. As a result, the disorder can now be referred to as the Medich giant platelet syndrome.

Concomitant Polyoma BK Virus and West Nile Virus in Renal Allografts.

Surveillance of the renal allograft recipient is essential when monitoring renal function to detect the early onset of rejection and alter therapeutic treatments to treat acute rejection or other causes and improve long-term graft function. If renal function begins to deteriorate, a renal biopsy is often indicated to assess the Banff grade of potential rejection or other causes, especially in the setting of polyoma BK viral load elevation. Although BK infection in the allograft is asymptomatic, reactivation of the virus is known to be associated with the acceleration of pathologic change and a poor outcome in the allograft. BK reactivation in a transplant kidney is not uncommon, and determining inflammation related to the virus versus acute rejection is paramount for appropriate immunosuppressive therapy management. We identified a concomitant polyoma BK virus and West Nile Virus (WNV) infection in two renal transplant patients which, to our knowledge, has not previously been reported. However, other concomitant infections have been reported in renal allografts including BK virus and cytomegalovirus (CMV), CMV and hepatitis C (HCV), and HCV and human immunodeficiency virus (HIV). As WNV has become endemic in many regions of the United States, and since the transmission of the virus via transplanted organs is associated with significant morbidity and mortality, it may be prudent to consider serologic screening for WNV in living donors prior to organ procurement. Regardless, the observation we made and report here should underscore the potential for concomitant viral infections that may be masked when a renal allograft has a significant inflammatory response to BK virus.

Regulation of Ca²âº/calmodulin-dependent protein kinase II signaling within hippocampal glutamatergic postsynapses during flurazepam withdrawal.

Cessation of one-week oral administration of the benzodiazepine flurazepam (FZP) to rats results in withdrawal anxiety after 1 day of withdrawal. FZP withdrawal is correlated with synaptic incorporation of homomeric GluA1-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) in the proximal stratum radiatum of CA1 neurons. After 2 days of withdrawal, Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) phosphorylates GluA1 subunits at Ser(831), increasing channel conductance. Secondary to AMPAR potentiation, GluN2B-containing N-methyl-D-aspartate receptors (NMDARs), known binding partners of CaMKII, are selectively removed from the postsynaptic density (PSD). While activation of synaptic CaMKII is known to involve translocation to the PSD, CaMKII bound to NMDARs may be removed from the PSD. To distinguish these possibilities, the current studies used postembedding immunogold electron microscopy to investigate alterations in CaMKII signaling at CA1 stratum radiatum synapses after 2 days of FZP withdrawal. These studies revealed decreased total, but not autophosphorylated (Thr(286)) CaMKIIα expression in CA1 PSDs. The removal of CaMKII-GluN2B complexes from the PSD during drug withdrawal may serve as a homeostatic mechanism to limit AMPAR-mediated CA1 neuron hyperexcitability and benzodiazepine withdrawal anxiety.

Virtual patients for assessment of medical student ability to integrate clinical and laboratory data to develop differential diagnoses: comparison of results of exams with/without time constraints.

INTRODUCTION: We have evaluated medical student ability in a problem-based learning course using a virtual patient (VP)-based exam with variable parameters for assessment purposes. METHODS: A class of 155 second year medical students was assessed using a VP exam with unlimited access during a 1-week period; 2 years later, the identical exam was administered to 175 students with a 3-h time limit. RESULTS: Students taking the exam without time constraints utilized approximately twice as much time than students with the time limit. Without the pressure of a time-limit, students utilized half as many inquiries of the patient history, physical, and lab/imaging tests than were used by students having a time constraint, indicating that the time limited students used a "shotgun approach" to try to collect as many "required" inquiries as possible. Most students (91%) taking the untimed exam were able to correctly diagnose the exam case but only 31% of the time limited students correctly diagnosed the VP exam case, despite their higher number of inquiries. CONCLUSIONS: Our results demonstrate that an identical VP exam, administered with variables to compare untimed versus time-limited conditions, resulted in an unraveling of student's ability to integrate the data discovered during the process of progressive disclosure.

Medich Giant Platelet Syndrome: An Evolving Qualitative and Quantitative Platelet Disorder.

Qualitative platelet disorders remain rare and varied. We describe here 2 additional patients with giant platelets, thrombocytopenia, deficiency in alpha granules and the presence of membranous inclusions within the cytoplasm. Collectively known as Medich syndrome, we further elucidated structural and clinical features of this rare syndrome. Platelets obtained from 2 patients with macro-thrombocytopenia were evaluated by electron microscopy. Structural findings were correlated with clinical characteristics. The defining morphologic feature found in the platelets of these patients is the presence of long, tubular inclusions consisting of several layers of membrane wrapped around a core of cytoplasm. These inclusions may deform the discoid shape of the platelet. In addition, abnormal giant alpha granules are present. Clinically all patients in the current report and review of the literature had mucosal bleeding and were often misdiagnosed as having immune related thrombocytopenia. To date five cases of Medich giant platelet syndrome have been reported. The cases are unified by the ultrastructural findings of abnormal alpha granules and unusual cytoplasmic scrolls. All patients experienced mucosal bleeding, however many clinical, biologic and genetic characteristics of this rare disorder remain to be determined.

Platelet Storage Pool Deficiency and Elevated Inflammatory Biomarkers Are Prevalent in Postural Orthostatic Tachycardia Syndrome.

A significant number of postural orthostatic tachycardia syndrome (POTS) patients have platelet delta granule storage pool deficiency (δ-SPD). The etiology of POTS is unknown but a number of laboratories, including ours, have reported elevations of G-protein-coupled adrenergic receptor and muscarinic acetylcholine receptor autoantibodies in POTS patients, detected by a variety of techniques, suggesting that the disorder is an autoimmune condition. Thus, it could also be considered an inflammatory disease. In a pilot study, we investigated a limited number of platelet-related cytokines and chemokines and discovered many that were elevated. This case−control study validates our pilot study results that POTS patients have an activated innate immune system. Plasma of 35 POTS patients and 35 patients with unexplained bleeding symptoms and categorized as "non-POTS" subjects was analyzed by multiplex flow cytometry to quantify 16 different innate immune system cytokines and chemokines. Electron microscopy was used to quantify platelet dense granules. Ten of 16 biomarkers of inflammation were elevated in plasma from POTS patients compared to non-POTS subjects, with most of the differences extremely significant, with p values < 0.0001. Of particular interest were elevations of IL-1ß and IL-18 and decreased or normal levels of type 1 interferons in POTS patients, suggesting that the etiology of POTS might be autoinflammatory. All POTS patients had δ-SPD. With a growing body of evidence that POTS is an autoimmune disease and having elevations of the innate immune system, our results suggest a potential T-cell-mediated autoimmunity in POTS characteristic of a mixed-pattern inflammatory disease similar to rheumatoid arthritis.

Age-related GSK3ß overexpression drives podocyte senescence and glomerular aging.

As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3ß (GSK3ß) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3ß substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16INK4A and p53, contain high numbers of GSK3ß consensus motifs, physically interact with GSK3ß, and act as its putative substrates. In addition, therapeutic targeting of GSK3ß by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3ß activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3ß appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.

A novel aza-anthrapyrazole blocks the progression of experimental autoimmune encephalomyelitis after the priming of autoimmunity.

Mitoxantrone is one of the few FDA-approved drugs available to treat rapidly progressing forms of multiple sclerosis; however, its utilization is compromised by a cardiotoxic potential and the risk of mitoxantrone-induced leukemia. BBR3378, a novel aza-anthrapyrazole, is structurally similar to mitoxantrone, but lacks the ring hydroxyls that may contribute to cardiotoxicity. Here, we investigated the therapeutic activity of BBR3378 in a C57BL/6 mouse model of multiple sclerosis. Mice given BBR3378, before or after the priming and expansion of MOG-specific responses, were protected from ascending paralysis. Strikingly, two doses of BBR3378 given a week after EAE induction were sufficient to provide significant protection from clinical symptoms and reduce MOG-specific proinflammatory T cell cytokine production, and serum IgG responses. Furthermore, while mitoxantrone is associated with persistent lymphopenia and cardiotoxicity, no such outcomes were detected in BBR3378-treated mice. Our findings show that BBR3378 can ameliorate encephalitogenic mechanisms in EAE and antagonize underlying autoimmune mechanisms.

Platelet Aggregation Assays Do Not Reliably Diagnose Platelet Delta Granule Storage Pool Deficiency.

Background: Patients with platelet dysfunction disorders present with a variety of mucocutaneous bleeding symptoms including easy bruising, frequent epistaxis, bleeding gums upon tooth brushing and for women, heavy menstrual bleeding. Available laboratory assays to evaluate platelet function include the platelet function analyzer (PFA) and in larger centers with coagulation laboratories, light transmission platelet aggregometry (LTA) analyses. Both assays are known to have a number of limitations, especially in the diagnosis of platelet delta granule storage pool deficiency (δ-SPD). δ-SPD is an underdiagnosed condition caused by decreased numbers of platelet dense granules (DGs) and is best diagnosed by electron microscopy (EM). Patients with platelet δ-SPD have a decreased response to low levels of the agonist adenosine diphosphate (ADP) in the second wave of light transmittance with LTA or decreased ADP secretion by fluorescence lumiaggregometry. There are few reports that have evaluated patients with δ-SPD and their respective LTA results. One report published in 1987 described normal LTA assays in 23% of patients with δ-SPD; a more recent report described LTA as having the sensitivity to detect only about 52% of patients with δ-SPD. The purpose of our study was intended to review the LTA and EM results of patients suspected of having a platelet function disorder at our institution for comparison with previously published studies. Methods: Our study included 344 patients who had been evaluated by both LTA and whole mount EM. Aggregometry utilized five agonists: ADP, epinephrine, collagen, arachidonic acid, and ristocetin. DGs were enumerated in 100 whole-mounted platelets to determine a mean number of dense granules per platelet (DGs/PL). Results: Seventy-seven percent of our patients were found to have δ-SPD (264/344); 68% (179/264) of these subjects had an abnormal platelet LTA. Thirty-two percent (85/264) of our patients had normal LTA results but were found to have δ-SPD with a mean of 2.54 ± 0.15 DG/PL (normal = 4 - 6 DG/PL). Conclusion: These data confirm previous reports suggesting the utilization of LTA alone in patients with histories of unexplained bleeding may miss the diagnosis of platelet δ-SPD. It is, therefore, prudent to assess platelet DG number by EM, especially if platelet LTA assessment is normal.

Negative Fat Pad Biopsy in Systemic AL: A Case Report Analyzing the Preferred Amyloidosis Screening Test.

Light chain amyloidosis (AL) causes irreversible multi-organ damage if not diagnosed early in the disease process. Fat pad biopsy is thought to be a highly sensitive screening test in systemic AL cases, especially if greater than three organs are involved. We present a case of a 64-year-old female who was admitted to the hospital with worsening heart and kidney failure, anasarca, increased free serum lambda light chains, and a negative fat pad biopsy for amyloidosis. Later, she developed asystole, bradycardia, severe hypotension, and respiratory distress. Because X-rays of her calvarium showed multiple osteolytic lesions, a bone marrow biopsy was planned to assess for multiple myeloma. Due to her non-reassuring vitals, the biopsy was not attempted, and she passed away several weeks later. Autopsy findings identified the cause of death as multiple system organ failure due to systemic AL. Through microscopic examination, pathologists found amyloid deposits in her heart, kidneys, rectum, thyroid, adrenals, bone marrow, liver, and spleen. Postmortem fat pad biopsy was negative; however, bone marrow biopsy demonstrated clusters of CD138-positive cells, confirming plasma cell dyscrasia. In cases with a negative fat pad biopsy, an additional superficial or involved organ biopsy should be pursued to establish a diagnosis of amyloidosis if strong clinical suspicion exists.

An Investigation of ABO Blood Type and the Platelet Delta Granule Storage Pool.

Individuals with bleeding tendencies are more likely to have blood type O than blood types A, B, or AB. Platelet storage pool deficiencies are a lesser-known group of bleeding disorders which often go undiagnosed and may account for a significant number of patients with unexplained bleeding defects. We hypothesized that patients with platelet δ-storage pool deficiency might also have a predominance of type O blood. A retrospective review of medical records of 2,020 patients with unexplained bleeding and evaluated for δ-storage pool deficiency was performed. Correlations between dense granule numbers, blood type, and von Willebrand factor were analyzed for statistical differences. 51.5% of blood samples were blood type O compared to an incidence of 44.0% in the U.S. population. There was a significant association of vWF and blood type O but not with the delta storage pool. There is a preponderance of blood type O in the study population compared to the U.S. population. There is no statistically significant link between blood type O and lower dense granule numbers in this study.