Renal Involvement in Transthyretin Amyloidosis: The Double Presentation of Transthyretin Amyloidosis Deposition Disease.

Transthyretin (TTR) amyloidosis (ATTR) is either an inherited condition or a non hereditary disease due to misfolding of wild-type (WT) TTR. Amyloid deposits can be mainly detected in nerves in the inherited form and in myocardium in the acquired variant. Renal involvement has been described only in the Val30Met mutation of the familial form and is thought to be extremely rare in the WT TTR. However, ATTR is multi-organ disease, and even in the WT forms, apparently limited to the heart, carpal tunnel syndrome and lumbar or cervical spine amyloid deposition have been described. A series of 4 cases of biopsy-proven renal TTR amyloid deposition is reported in the present paper. We describe 2 WT ATTR patients, 1 patient with c.424G>A (p.(Val142Ile)) mutation of the TTR gene, and 1 patient with Val30Met mutation of the TTR gene. In all patients, the biopsy showed the presence of amyloid deposits with different distribution (#1 pericapsular, #2-3 vessels, #4 vessels, interstitium of medulla and cortex, and tubular basement membrane). The use of immunohistochemistry has enabled the identification of TTR, and identify the precursor protein. The possibility of kidney involvement in TTR amyloidosis should be taken into account in patients with renal impairment and unexplained cardiomyopathy and/or neuropathy. This is even of greater interest to the elderly for the possible confounding co-existence of plasma cell dyscrasia that could lead the clinician, in the presence of renal amyloid deposits, to misdiagnose AL amyloidosis and undertake inappropriate treatments.

Caveolin-1 in Kidney Chronic Antibody-Mediated Rejection: An Integrated Immunohistochemical and Transcriptomic Analysis Based on the Banff Human Organ Transplant (B-HOT) Gene Panel.

Caveolin-1 overexpression has previously been reported as a marker of endothelial injury in kidney chronic antibody-mediated rejection (c-ABMR), but conclusive evidence supporting its use for daily diagnostic practice is missing. This study aims to evaluate if Caveolin-1 can be considered an immunohistochemical surrogate marker of c-ABMR. Caveolin-1 expression was analyzed in a selected series of 22 c-ABMR samples and 11 controls. Caveolin-1 immunohistochemistry proved positive in peritubular and glomerular capillaries of c-ABMR specimens, irrespective of C4d status whereas all controls were negative. Multiplex gene expression profiling in c-ABMR cases confirmed Caveolin-1 overexpression and identified additional genes (n = 220) and pathways, including MHC Class II antigen presentation and Type II interferon signaling. No differences in terms of gene expression (including Caveolin-1 gene) were observed according to C4d status. Conversely, immune cell signatures showed a NK-cell prevalence in C4d-negative samples compared with a B-cell predominance in C4d-positive cases, a finding confirmed by immunohistochemical assessment. Finally, differentially expressed genes were observed between c-ABMR and controls in pathways associated with Caveolin-1 functions (angiogenesis, cell metabolism and cell-ECM interaction). Based on our findings, Caveolin-1 resulted as a key player in c-ABMR, supporting its role as a marker of this condition irrespective of C4d status.

Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue.

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aß2M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part I.

The nervous system exerts a profound influence on the function of the immune system (IS), mainly through the sympathetic arm of the autonomic nervous system. In fact, the sympathetic nervous system richly innervates secondary lymphoid organs (SLOs) such as the spleen and lymph nodes. For decades, different research groups working in the field have consistently reported changes in the sympathetic innervation of the SLOs during the activation of the IS, which are characterized by a decreased noradrenergic activity and retraction of these fibers. Most of these groups interpreted these changes as a pathological phenomenon, referred to as "damage" or "injury" of the noradrenergic fibers. Some of them postulated that this "injury" was probably due to toxic effects of released endogenous mediators. Others, working on animal models of chronic stimulation of the IS, linked it to the very chronic nature of processes. Unlike these views, this first part of the present work reviews evidence which supports the hypothesis of a specific adaptive mechanism of neural plasticity from sympathetic fibers innervating SLOs, encompassing structural and functional changes of noradrenergic nerves. This plasticity mechanism would involve segmental retraction and degeneration of these fibers during the activation of the IS with subsequent regeneration once the steady state is recovered. The candidate molecules likely to mediate this phenomenon are also here introduced. The second part will extend this view as to the potential changes in sympathetic innervation likely to occur in inflamed non-lymphoid peripheral tissues and its possible immunological implications.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part II.

In the preceding work, a hypothesis on the existence of a specific neural plasticity program from sympathetic fibers innervating secondary lymphoid organs was introduced. This proposed adaptive mechanism would involve segmental retraction and degeneration of noradrenergic terminals during the immune system (IS) activation followed by regeneration once the IS returns to the steady-state. Starting from such view, this second part presents clinical and experimental evidence allowing to envision that this sympathetic neural plasticity mechanism is also operative on inflamed non-lymphoid peripheral tissues. Importantly, the sympathetic nervous system regulates most of the physiological bodily functions, ranging from cardiovascular, respiratory and gastro-intestinal functions to endocrine and metabolic ones, among others. Thus, it seems sensible to think that compensatory programs should be put into place during inflammation in non-lymphoid tissues as well, to avoid the possible detrimental consequences of a sympathetic blockade. Nevertheless, in many pathological scenarios like severe sepsis, chronic inflammatory diseases, or maladaptive immune responses, such compensatory programs against noradrenergic transmission impairment would fail to develop. This would lead to a manifest sympathetic dysfunction in the above-mentioned settings, partly accounting for their underlying pathophysiological basis; which is also discussed. The physiological/teleological significance for the whole neural plasticity process is postulated, as well.

Induction of anergic or regulatory tumor-specific CD4+ T cells in the tumor-draining lymph node.

CD4+ T cell antitumor responses have mostly been studied in transplanted tumors expressing secreted model antigens (Ags), while most mutated proteins in human cancers are not secreted. The fate of Ag-specific CD4+ T cells recognizing a cytoplasmic Ag in mice bearing autochthonous tumors is still unclear. Here we show, using a genetically engineered lung adenocarcinoma mouse model, that naive tumor-specific CD4+ T cells are activated and proliferate in the tumor-draining lymph node (TdLN) but do not differentiate into effectors or accumulate in tumors. Instead, these CD4+ T cells are driven toward anergy or peripherally-induced Treg (pTreg) differentiation, from the early stage of tumor development. This bias toward immune suppression is restricted to the TdLN, and is maintained by Tregs enriched in the tumor Ag-specific cell population. Thus, tumors may enforce a dominant inhibition of the anti-tumor CD4 response in the TdLN by recapitulating peripheral self-tolerance mechanisms.

Efficacy of novel benznidazole solutions during the experimental infection with Trypanosoma cruzi.

Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi. About 8 million people throughout Latin America are infected causing approximately 10,000 deaths annually. Benznidazole, available as unique 100 mg tablets in many of the endemic countries, is currently the drug of choice for the specific treatment of this condition. Despite of the large number of pediatric patients infected, there are no commercial liquid dosage forms available to treat this trypanosomiasis. This work showed that novel benznidazole-water-polyethylene glycol 400 solutions are active against T. cruzi in a murine model of Chagas' disease. Present results constitute the first demonstration on the usefulness of benznidazole solutions in infected mice.

Beneficial effects of benznidazole during an infectious-based situation of systemic inflammatory response: cecal ligation and puncture.

We have shown that benznidazole (BZL), a drug used to treat Chagas disease, markedly reduced the production of pro-inflammatory cytokines and NO-derived metabolites in experimentally Trypanosoma cruzi-infected rats. Treatment with BZL exerted beneficial effects in a model of inflammation-based pathology like murine experimental endotoxemia. Based on these findings, we wished to ascertain the effect of BZL in a closer situation to sepsis: the cecal ligation and puncture (CLP) model in C57BL/6 mice. We analyzed clinical course, survival, circulating levels of inflammation-related compounds (NO, tumor necrosis factor [TNF]-alpha), and bacteriemia. Recipients of BZL, 25 mg/kg, had an increased survival rate at 24 hours after CLP, showing a better clinical situation and a significant reduction of TNF-alpha levels and bacteriemia, with respect to the other groups. BZL failed to inhibit in vitro bacterial growth, suggesting that these effects may be partly caused by the immunomodulatory effects of BZL.