Comprehensive Analysis of Transcript Changes Associated With Allograft Rejection: Combining Universal and Selective Features.

We annotated the top transcripts associated with kidney transplant rejection by p-value, either universal for all rejection or selective for T cell-mediated rejection (TCMR) or antibody-mediated rejection (ABMR; ClinicalTrials.gov NCT01299168). We used eight class-comparison algorithms to interrogate microarray results from 703 biopsies, 205 with rejection. The positive comparators were all rejection, TCMR, or ABMR; the negative comparators varied from normal biopsies to all nonrejecting biopsies, including other diseases. The universal algorithm, rejection versus all nonrejection, identified transcripts mainly inducible by interferon γ. Selectivity for ABMR or TCMR required the other rejection class as well as nonrejection biopsies in the comparator to avoid selecting universal transcripts. Direct comparison of ABMR versus TCMR yielded only transcripts related to TCMR, the stronger signal. Transcripts highly associated with rejection were never completely specific for rejection: Many were increased in biopsies without rejection, reflecting sharing between rejection and injury-induced innate immunity. Union of the top 200 transcripts from universal and selective algorithms yielded 454 transcripts that permitted unsupervised analysis of biopsies in principal component analysis: PC1 was rejection, and PC2 was separation of TCMR from ABMR. Appreciating rejection-associated molecular changes requires a diverse case mix, accurate histologic classification (including C4d-negative ABMR), and both selective and universal algorithms.

The molecular landscape of antibody-mediated kidney transplant rejection: evidence for NK involvement through CD16a Fc receptors.

The recent recognition that antibody-mediated rejection (ABMR) is the major cause of kidney transplant loss creates strong interest in its pathogenesis. We used microarray analysis of kidney transplant biopsies to identify the changes in pure ABMR. We found that the ABMR transcript changes in the initial Discovery Set were strongly conserved in a subsequent Validation Set. In the Combined Set of 703 biopsies, 2603 transcripts were significantly changed (FDR < 0.05) in ABMR versus all other biopsies. In cultured cells, the transcripts strongly associated with ABMR were expressed in endothelial cells, e.g. cadherins CDH5 and CDH13; IFNG-treated endothelial cells, e.g. phospholipase PLA1A and chemokine CXCL11; or NK cells, e.g. cytotoxicity molecules granulysin (GNLY) and FGFBP2. Other ABMR transcripts were expressed in normal kidney but not cell lines, either increased e.g. Duffy chemokine receptor (DARC) or decreased e.g. sclerostin (SOST). Pathway analysis of ABMR transcripts identified angiogenesis, with roles for angiopoietin and vascular endothelial growth factors; leukocyte-endothelial interactions; and NK signaling, including evidence for CD16a Fc receptor signaling elements shared with T cells. These data support a model of ABMR involving injury-repair in the microcirculation induced by cognate recognition involving antibody and CD16a, triggering IFNG release and antibody-dependent NK cell-mediated cytotoxicity.

Molecular landscape of T cell-mediated rejection in human kidney transplants: prominence of CTLA4 and PD ligands.

We used expression microarrays to characterize the changes most specific for pure T cell-mediated rejection (TCMR) compared to other diseases including antibody-mediated rejection in 703 human kidney transplant biopsies, using a Discovery Set-Validation Set approach. The expression of thousands of transcripts--fold change and association strength--changed in a pattern that was highly conserved between the Discovery and Validation sets, reflecting a hierarchy of T cell signaling, costimulation, antigen-presenting cell (APC) activation and interferon-gamma (IFNG) expression and effects, with weaker associations for inflammasome activation, innate immunity, cytotoxic molecules and parenchymal injury. In cell lines, the transcripts most specific for TCMR were expressed most strongly in effector T cells (e.g. CTLA4, CD28, IFNG), macrophages (e.g. PDL1, CD86, SLAMF8, ADAMDEC1), B cells (e.g. CD72, BTLA) and IFNG-treated macrophages (e.g. ANKRD22, AIM2). In pathway analysis, the top pathways included T cell receptor signaling and CTLA4 costimulation. These results suggest a model in which TCMR creates an inflammatory compartment with a rigorous hierarchy dominated by the proximal aspects of cognate engagement of effector T cell receptor and costimulator triggering by APCs. The prominence of inhibitors like CTLA4 and PDL1 raises the possibility of active negative controls within the rejecting tissue.

Alternative macrophage activation-associated transcripts in T-cell-mediated rejection of mouse kidney allografts.

Macrophages display two activation states that are considered mutually exclusive: classical macrophage activation (CMA), inducible by IFNG, and alternative macrophage activation (AMA), inducible by IL4 and IL13. CMA is prominent in allograft rejection and AMA is associated with tissue remodeling after injury. We studied expression of AMA markers in mouse kidney allografts and in kidneys with acute tubular necrosis (ATN). In rejecting allografts, unlike interferon gamma (IFNG) effects and T-cell infiltration that developed rapidly and plateaued by day 7, AMA transcripts (Arg1, Mrc1, Mmp12 and Ear1) rose progressively as tubulitis and parenchymal deterioration developed at days 21 and 42, despite persistent IFNG effects. AMA in allografts was associated with transcripts for AMA inducers IL4, IL13 and inhibin A, but also occurred when hosts lacked IL4/IL13 receptors, suggesting a role for inhibin A. Kidneys with ATN injured by ischemia/reperfusion also had increased expression of AMA markers and inhibin A. Thus kidneys undergoing T-cell-mediated rejection progressively acquire macrophages with alternative activation phenotype despite strong local IFNG effects, independent of IL4 and IL13. Although the mechanisms and causal relationships remain to be determined, high AMA transcript levels in rejecting allografts are strongly associated with and may be a consequence of parenchymal deterioration similar to ATN.

Attitudes of Jamaicans in Kingston and St.Andrew towards homosexuality [abstract]

OBJECTIVE: Jamaica has long been considered to be a homophobic society. The aim of this survey was to examine the attitudes of the Jamaican populance towards homosexuality, thus shedding light on the important issue of homosexuality, disclosure of one's sexual preference and the relationship to the HIV/AIDS epidemic. METHODS: There have been several subjective reports on the issue of homosexuality in Jamaica. Many of these reports have suggested that Jamaica is not truly a homophobic society. No objective study on attitudes towards homosexuality in Jamaica has been done to date; this is an attempt in that regard. A survey was conducted in the Kingston and St.Andrew region. A questionnaire consisting of 17 knowledge and attitude items with six items to determine demographic data was prepared. This was administered to every third person in 6 designated areas, ensuring that equal numbers of males and females aged 16 years and over were polled. RESULTS: The analysis indicates that the majority of those surveyed thought that the homosexuality lifestyle was unaccepatable. Of significance, views varied depending on the level of educational attainment: 100 percent of persons with primary level education found homosexuality unacceptable in contrast with 76 percent of those with teritiary level education with a similar opinion (p=0.028). There was a generally negative attitude towards befriending an acknowledged homosexual or having such persons in positions of authority. Many participants agreed that homosexual partners should have access to social services, including insurance plans, with 37 percent in outright agreement and 21 percent remaining neutral. There was a dramatic decrease in the number of persons who believed that HIV was solely a homosexual disease (13 percent) in contrast with the results of a 1989 survey conducted by the Ministry of Health (81 percent). CONCLUSION: Despite changing global opinions of the homosexual lifestyles, several biases still remain within the Jamaican society. These conditions force homosexuals to remain ensconced within the cloak of the more acceptable heterosexual lifestyle, which may have significant social and health implications. (AU)