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Microcrystalline cellulose (MCC) is an insoluble material commonly used as a binder and filler in oral medications. Identification of pulmonary intravascular deposition of MCCin transbronchial biopsies from lung transplant (LT) recipients following parenteral injection of oral medications has only been reported once. A search of our surgical pathology electronic database was performed from January 1, 2000 to November 1, 2017 using the text “transplant transbronchial.” The diagnosis field for all cases retrieved was then searched for the text “cellulose.” These cases were queried for patient demographics and outcomes. Between January 1, 2000 and November 1, 2017, 1558 lung transplants were performed in 1476 individual patients at our institution; 12 were identified to have MCCin their lung tissue. Patients with MCCidentified on biopsies were more likely to be transplanted for cystic fibrosis versus other indications and younger versus older. MCCidentified in 2 of our cases was favored to be donor derived. Of the 12 patients, 6 (50%) are deceased. MCCwithin the pulmonary vasculature may be an indicator of increased complications, mortality, or shortened survival in LTrecipients. Detecting intravascular MCCand distinguishing it from aspirated foreign material can be challenging. Awareness of the differential diagnosis for pulmonary foreign material is of paramount importance for the pathologist. The authors retrospectively review lung transplant biopsies and identify a cohort of lung transplant recipients engaging in parenteral use of oral medications.

Microcrystalline cellulose (MCC) is an insoluble material commonly used as a binder and filler in oral medications. Identification of pulmonary intravascular deposition of MCC in transbronchial biopsies from lung transplant (LT) recipients following parenteral injection of oral medications has only been reported once. A search of our surgical pathology electronic database was performed from January 1, 2000 to November 1, 2017 using the text “transplant transbronchial.” The diagnosis field for all cases retrieved was then searched for the text “cellulose.” These cases were queried for patient demographics and outcomes. Between January 1, 2000 and November 1, 2017, 1558 lung transplants were performed in 1476 individual patients at our institution; 12 were identified to have MCC in their lung tissue. Patients with MCC identified on biopsies were more likely to be transplanted for cystic fibrosis versus other indications and younger versus older. MCC identified in 2 of our cases was favored to be donor derived. Of the 12 patients, 6 (50%) are deceased. MCC within the pulmonary vasculature may be an indicator of increased complications, mortality, or shortened survival in LT recipients. Detecting intravascular MCC and distinguishing it from aspirated foreign material can be challenging. Awareness of the differential diagnosis for pulmonary foreign material is of paramount importance for the pathologist.

Background. A 57-year-old African American man presented to a tertiary care center with a 6-month history of fatigue and worsening abdominal pain. He had lost 9.1 kg in weight in the 3 months leading up to presentation, and described subjective fevers and night sweats for 1 month with a nonproductive cough and blurred vision for several weeks before presentation. He had chronic renal insufficiency, sleep apnea, hypertension, and peripheral vascular disease.Investigations. Physical examination, complete blood count, peripheral blood smear, leukocyte alkaline phosphatase score, bone marrow biopsy, CT of the chest, abdomen, and pelvis, MRI of the abdomen and pelvis, measurement of plasma and urine metanephrines, 24 h urine testing for cortisol and 17-ketosteroids, measurement of serum granulocyte colony-stimulating factor (G-CSF) level, histopathologic examination and immunohistochemical staining of resected tumor.Diagnosis. G-CSF-secreting adrenal carcinoma with rhabdoid-like differentiation.Management. En bloc surgical resection of kidney, suprarenal mass and spleen was performed, followed by initiation of mitotane chemotherapy 3 months later.

The immunity‐related GTPases (IRG), also known as p47 GTPases, are a family of proteins that are tightly regulated by IFNs at the transcriptional level and serve as key mediators of IFN‐regulated resistance to intracellular bacteria and protozoa. Among the IRG proteins, loss of Irgm1 has the most profound impact on IFN‐γ‐induced host resistance at the physiological level. Surprisingly, the losses of host resistance seen in the absence of Irgm1 are sometimes more striking than those seen in the absence of IFN‐γ. In the current work, we address the underlying mechanism. We find that in several contexts, another protein in the IRG family, Irgm3, functions to counter the effects of Irgm1. By creating mice that lack Irgm1 and Irgm3, we show that several phenotypes important to host resistance that are caused by Irgm1 deficiency are reversed by coincident Irgm3 deficiency; these include resistance to Salmonella typhimuriumin vivo, the ability to affect IFN‐γ‐induced Salmonellakilling in isolated macrophages, and the ability to regulate macrophage adhesion and motility in vitro. Other phenotypes that are caused by Irgm1 deficiency, including susceptibility to Toxoplasma gondiiand the regulation of GKS IRG protein expression and localization, are not reversed but exacerbated when Irgm3 is also absent. These data suggest that members of the Irgm subfamily within the larger IRG family possess activities that can be opposing or cooperative depending on the context, and it is the balance of these activities that is pivotal in mediating IFN‐γ‐regulated host resistance.

Activation of the renin-angiotensin system contributes to the progression of chronic kidney disease. Based on the known cellular effects of ANG II to promote inflammation, we posited that stimulation of lymphocyte responses by ANG II might contribute to the pathogenesis of hypertensive kidney injury. We therefore examined the effects of the immunosuppressive agent mycophenolate mofetil (MMF) on the course of hypertension and kidney disease induced by chronic infusion of ANG II in 129/SvEv mice. Although it had no effect on the severity of hypertension or cardiac hypertrophy, treatment with MMF significantly reduced albuminuria and ameliorated kidney injury, decreasing glomerulosclerosis and reducing lymphocyte infiltration into the renal interstitium. Attenuation of renal pathology with MMF was associated with reduced expression of mRNAs for the proinflammatory cytokines interferon-γ and tumor necrosis factor-α and the profibrotic cytokine transforming growth factor-β. As infiltration of the kidney by T lymphocytes was a prominent feature of ANG II-dependent renal injury, we carried out experiments examining the effects of ANG II on lymphocytes in vitro. We find that exposure of splenic lymphocytes to ANG II causes prominent rearrangements of the actin cytoskeleton. These actions require the activity of Rho kinase. Thus, ANG II exaggerates hypertensive kidney injury by stimulating lymphocyte responses. These proinflammatory actions of ANG II seem to have a proclivity for inducing kidney injury while having negligible actions in the pathogenesis of cardiac hypertrophy.

Postinfectious glomerulonephritis (PIGN) is a rare etiology of de novo glomerulonephritis following kidney transplantation. To date, there have only been eight cases reported in the literature. We report an additional three patients transplanted at our institution between January 2000 and October 2004 who had clinical and pathologic findings consistent with posttransplant PIGN. All three patients were type 1 diabetics. One had received a cadaveric kidney transplant, one a simultaneous kidney-pancreas transplant, and the third a living related kidney transplant followed by a pancreas transplant. All patients were on triple immunosuppressive therapy with tacrolimus, mycophenolate mofetil, and prednisone. In each case, an acute decline in allograft function developed in association with a known or suspected infectious process, and renal biopsies revealed an immune complex glomerulonephritis with features of PIGN. All regained renal function with treatment of their known or suspected infections and without specific therapies for their glomerulonephritis, including corticosteroids.

Glomerular lesions that complicate patients with human immunodeficiency virus (HIV) infection include HIV-associated nephropathy, membranous glomerulopathy, and immune-complex glomerulonephritides. This case series presents 3 patients with clinically significant renal disease and positive test results for anti–glomerular basement membrane (anti-GBM) antigen. Characteristic histological findings that would suggest anti-GBM antibodies have a significant role in the pathological state of each patient’s kidney disease were absent. In addition, each patient recovered without specific treatment for anti-GBM disease. This case series suggests that anti-GBM antibodies likely are related to the B-cell expansion previously described in patients with HIV infection. We propose that clinicians interpret results of anti-GBM antibody tests carefully for patients with HIV infection, considering biopsy before empiric therapy, particularly in a clinical presentation that is atypical for Goodpasture disease.

To understand the physiological role of angiotensin type 1 (AT1) receptors in the proximal tubule of the kidney, we generated a transgenic mouse line in which the major murine AT1receptor isoform, AT1A, was expressed under the control of the P1 portion of the γ-glutamyl transpeptidase (γGT) promoter. In transgenic mice, this promoter has been shown to confer cell-specific expression in epithelial cells of the renal proximal tubule. To avoid random integration of multiple copies of the transgene, we used gene targeting to produce mice with a single-copy transgene insertion at the hypoxanthine phosphoribosyl transferase (Hprt) locus on the X chromosome. The physiological effects of the γGT-AT1Atransgene were examined on a wild-type background and in mice with targeted disruption of one or both of the murine AT1receptor genes (Agtr1aand Agtr1b). On all three backgrounds, γGT-AT1Atransgenic mice were healthy and viable. On the wild-type background, the presence of the transgene did not affect development, blood pressure, or kidney structure. Despite relatively low levels of expression in the proximal tubule, the transgene blunted the increase in renin expression typically seen in AT1-deficient mice and partially rescued the kidney phenotype associated with Agtr1a−/−Agtr1b−/−mice, significantly reducing cortical cyst formation by more than threefold. However, these low levels of cell-specific expression of AT1receptors in the renal proximal tubule did not increase the low blood pressures or abolish sodium sensitivity, which are characteristic of AT1receptor-deficient mice. Although our studies do not clearly identify a role for AT1receptors in the proximal tubules of the kidney in blood pressure homeostasis, they support a major role for these receptors in modulating renin expression and in maintaining structural integrity of the renal cortex.

Posttransplant lymphoproliferative disorder (PTLD) is a relatively infrequent but devastating complication that occurs after solid-organ transplantation. Although the optimal treatment for this condition is unknown, rituximab, a murine/human chimeric monoclonal antibody, has shown promise in the treatment of PTLD. In this report, we define the incidence, clinical features at presentation, and response to treatment of all cases of PTLD observed at our institution over a 10-year period, including four patients who received treatment with rituximab.

With a continuing demand for donor kidneys for organ transplantation, it is important to understand the significance of pathologic findings in the donor organ before transplantation. Microvascular thrombosis is sometimes encountered in association with disseminated intravascular coagulation in the donor, and it is unclear whether this finding may affect immediate allograft function and long-term graft survival. To further elucidate this question, we examined our experience with microvascular thrombosis in donor biopsies in the kidney transplant program at our institution.

Acute humoral rejection (AHR) has been associated with enhanced graft loss. Our study compared the renal allograft survival of patients with AHR treated with plasmapheresis (PP) and intravenous immunoglobulin (IVIG) with allograft survival in patients with acute cellular rejection (ACR).

Polyomavirus infections are a significant problem for immunocompromised patients. In particular, interstitial nephritis caused by BK polyomavirus, a pathogen with tropism for the human urinary tract, has been encountered with increasing frequency in renal transplant recipients and has emerged as an important cause of graft loss. Though no specific therapies are currently available for polyomavirus infections, the progression of polyomavirus nephritis in renal transplant patients can often be halted by a decrease or change in maintenance immunosuppression. As such, rapid and accurate diagnosis and monitoring of infection is crucial. This is best accomplished by concerted use of a range of diagnostic techniques, including careful clinical profiling, various anatomic pathology methods (routine histology, cytopathology, immunohistochemistry, electron microscopy), and clinical laboratory tests (particularly molecular diagnostic approaches). Properly applied, these diagnostic tools provide complementary information that often allows successful management of polyomavirus nephritis.

Chronic allograft rejection manifested as bronchiolitis obliterans syndrome (BOS) is the leading cause of late death after lung transplantation. Although increasing evidence suggests an association between anti-human leukocyte antigens (HLA) antibodies and chronic rejection of kidney or heart allografts, the clinical significance of anti-HLA antibodies in lung recipients is less clear, especially in previously unsensitized recipients. The use of flow cytometry based panel reactive antibody (flow-PRA) provides a highly sensitive means to identify the development of de novo anti-HLA antibodies in lung recipients.

Influenza infection is increasingly recognized to cause significant morbidity and mortality in the community, especially in pediatric patients and elderly persons. Influenza infection, however, has not been well described among thoracic organ transplant recipients. We provide the first detailed clinical, radiographic, and histologic description of influenza pneumonia among three lung transplant recipients. The presentation varied considerably among the three patients and, in some cases, was atypical for influenza. Despite treatment, a persistent decline in pulmonary function occurred in all three patients after the acute illness. Interestingly, on follow-up biopsy specimens, each patient had histologic evidence of acute rejection and/or obliterative bronchiolitis. Additional research, therefore, is needed to clarify the relationship between influenza infection, acute rejection, and obliterative bronchiolitis.

Gastroesophagealreflux (GER) is increasingly recognized as contributing to a number of pulmonary disorders. The relationship of GER to pulmonary allograftdysfunction after lung transplantation is unknown. In this report, wedescribe a lung transplant recipient who developed an acute decline inpulmonary function several months after a retransplantation for chronicrejection. A pulmonary workup at that time, including bronchoscopy withbiopsy, revealed bronchial inflammation with no allograft rejection orinfection. Because of increasing GI symptoms after retransplantation, the patient also underwent additional testing, which revealed severeacid reflux. The treatment of this patient's acid reflux with Nissenfundoplication surgery resulted in a prompt and sustained improvementin his pulmonary function. We suggest that GER should be consideredamong the potential causes of allograft dysfunction after lungtransplantation.

Background. Panel-reactive antibody (PRA) is used to estimate the degree of humoral sensitization in the recipient before transplantation. Although pretransplant sensitization is associated with increased complications in other solid organ transplant recipients, less is known about the outcome of sensitized lung transplant recipients. Therefore, we sought to determine the impact of elevated pretransplant PRA on clinical outcomes after lung transplantation.

Focal segmental glomerulosclerosis (FSGS) is a pathological entity characterized by proteinuria, nephrotic syndrome, and the progressive loss of renal function. It is a common cause of end-stage renal disease (ESRD). Recently, familial forms of FSGS have been identified. Two families with autosomal dominant FSGS were evaluated for linkage using 351 genomic microsatellite markers. Linkage, multipoint analysis, and tests for heterogeneity were performed on the subsequent results. In addition, three small families were used for haplotype analysis. Evidence for linkage was found on chromosome 11q21–q22 for the largest family, with a maximum lod score of 9.89. The gene is currently localized to an 18-cM area between flanking markers D11S2002 and D11S1986. The disease in a second family was not linked to this locus or to a previously described locus on chromosome 19q13. There were no shared haplotypes among affected individuals in the three smaller families. Our findings demonstrate that genetic heterogeneity is prevalent in FSGS in that at least three genes cause the FSGS phenotype. Identification of the genes that cause familial FSGS will provide valuable insights into the molecular basis and pathophysiology of FSGS.

Focal segmental glomerulosclerosis (FSGS) has increasingly been recognized to occur in a familial pattern. We have observed the development of biopsy-confirmed FSGS and subsequent end-stage renal disease (ESRD) in one live related kidney donor and ESRD without biopsy in another. Both donors had family members with ESRD secondary to FSGS. Both donors were apparently healthy by routine physical examination, urinalysis, and serum creatinine at the time of evaluation as live related donors. We believe these cases emphasize the need for great caution when evaluating siblings as potential live related donors.

This is a case report of an immunocompromised individual who presented with progressive alopecia, friable follicular spinous processes, and erythematous, indurated papules. Examination of skin biopsies using light microscopy and immunohistochemistry revealed pathologic changes of the follicular inner root sheath epithelium with dystrophic trichohyaline granules. Electron microscopy of thin sections of tissue revealed intracellular viral particles with a size and appearance consistent with those in the Papovaviridae family. Electron microscopy of negatively stained extract from a homogenized lesion also demonstrated icosahedral viruses with papovavirus morphology. We believe this is a previously unreported folliculocentric viral infection in an immuno-suppressed human host and have termed this entity “trichodysplasia spinulosa”.Journal of Investigative Dermatology Symposium Proceedings (2004) 4, 268–271; doi:10.1038/sj.jidsp.5640227

Interstitial nephritis caused by BK polyomavirus is a recognized complication of renal transplantation. A study of renal transplant recipients at Duke University Medical Center was undertaken to evaluate diagnostic modalities and assess clinical outcomes in transplant polyomavirus infections.

Donor-specific blood transfusion (DSBT) given 1–2 weeks prior to transplantation prolongs the survival of fully allogeneic ACI (RT1n) renal allografts in PVG (RT1c) recipients from 6–8 days to >100 days. We have previously demonstrated that ACI kidneys transplanted to autologous blood transfusion (ABT)- or DSBT-pretreated PVG recipients stimulated an increase in CD8(OX8) cells in the peripheral blood by 6 days after transplantation. To determine whether this increase represents a general expansion of the entire CD8population or only a subpopulation of CD8cells, subset analysis was performed on peripheral blood lymphocytes depleted of cells reactive with monoclonal antibodies against rat αβ T cell receptor (TCR), CD8, or NK cells (R7.3, OX8, or 3.2.3, respectively). Phenotypic studies of PBL depleted of CD8cells demonstrated that all 3.2.3 NK cells coexpressed CD8; depletion of 3.2.3PBL revealed a second subpopulation of CD83.2.3-cells comprised predominantly of αβTCRT cells. In naive PVG rats the prevelence of these two CD8sub-populations was approximately equal. Both ABT- and DSBT-pretreated renal allograft recipients demonstrated a significant and equivalent expansion of the CD8cell subpopulation that coexpresses the 3.2.3 NK marker. In contrast, the second subpopulation of CD83.2.3-cells did not change significantly after allografting. There were also no differences between DSBT and ABT pretreated rats in activity of PBL against the NK targets YAC-1 and Doxie at 6 days after renal transplantation, though the level of activity was modestly increased compared with naive controls. These findings indicate that renal transplantation in the rat is associated with a significant increase in PBL with the NK phenotype (CD83.2.3) and a modest increase of NK activity, but that DSBT enhancement does not affect this NK cell response.

Expression of CD43 (leukosialin, sialophorin) by rat blood monocytes was analyzed by flow cytometric, microscopic, and biochemical techniques. Monocytes were identified cytometrically using a combination of light-scatter parameters and binding of the anti-monocyte/macrophage monoclonal antibody (mAb) OX-41. Two-color flow cytometry studies with W3/13 and HIS 17, two anti-CD43 mAb that react with different antigenic epitopes, revealed two subpopulations of monocytes expressing disparate levels of CD43 (referred to hereafter as hi-CD43 MO and lo-CD43 MO). In three-color flow cytometry studies, hi-CD43 MO were found to express higher levels of CD4 than lo-CD43 MO; in contrast, lo-CD43 MO bound higher levels of RP-3, a mAb raised against rat neutrophils. Hi- and lo-CD43 MO expressed comparable amounts of CD14, CD45, and intercellular adhesion molecule-1 (CD54); hi-CD43 MO expressed somewhat more lymphocyte function-associated antigen-1 α chain (CD11a) and CD18 than their lo-CD43 MO counterparts. A minority of cells in both subpopulations expressed class II histocompatibility antigens. Hi- and lo-CD43 MO isolated by fluorescence-activated cell sorting had features typical of monocytes as assessed by light and electron microscopy. In Western blotting experiments, lo-CD43 MO and elicited peritoneal macrophages were found to express a less heavily sialylated form of CD43 than hi-CD43 MO.

The pathogenesis of posterior polymorphous dystrophy was analyzed by immunohistologic methods. Sections of corneal buttons from two patients undergoing transplantation owing to posterior polymorphous dystrophy were stained with 2B4.14.1, a monoclonal antibody that reacts with human corneal endothelium, and with a cocktail of antihuman cytokeratin monoclonal antibodies that do not react with normal corneal endothelium. Single-stained sections revealed a variegated, intermittent staining pattern of antibody reactive and nonreactive cells. Double-stained sections revealed some cells that stained with only one of the antibodies and many cells that stained with both antibodies. The presence of cells staining positively for both 2B4.14.1 antigen and cytokeratins supports the hypothesis that the cytokeratin-expressing epithelial-like cells found in corneas with posterior polymorphous dystrophy arise via a metaplastic process in which the phenotype of endothelial cells becomes progressively abnormal.

The effects of preoperative donor-specific blood transfusion (DSBT) on the physiologic, morphologic, and immunologic aspects of aspects of allograft responsiveness were evaluated in a rat renal transplant model, using the ACI (RT1a) into PVG (RT1c) high-responder strain combination. Indefinite graft survival (mean >63 days) could be induced by DSBT administration alone. In comparison, animals receiving autolgous blood transfusion (ABT) all died within 7 days posttransplantation. As assessed by clearance of inulin and paraaminohippurate, renal allograft function in DSBT-pretreated recipients at 6 days was equivalent to that of isograft recipients, and in contrast to the significant reduction seen in ABT treated rats. Likewise, thromboxane B2(TXB2) production by ex-vivo-perfused allografts from DSBT-treated recipients was comparable to that of isografts, and significantly lower than that of allografts from ABT-treated rats. A significant inverse correlation was found between renal TXB2production and inulin clearance. Despite these substantial differences in renal function and eicosanoid metabolism, morphologic evaluation of renal allografts from DSBT-enhanced and ABT-rejecting recipients at comparable time points showed equivalent histologic manifestations of rejection. In addition, immunohistologic labeling of renal allograft sections and fluorescence-activated cell sorter analysis of cells eluted from allografts showed the same phenotype and pattern of infiltrating T cell subsets in both groups. Specific antidonor cytotoxic T lymphocyte precursor (pCTL) frequencies of cells eluted from kidney grafts were equivalent in DSBT and ABT-pretreated animals, and both groups expressed significantly higher (but equivalent) pCTL frequencies in the kidneys than spleens. Comparisons of the lysis of PVG.R1 (RT1.Aaon a PVG background) and ACI targets indicated that cytotoxic responses from effector cells freshly eluted from DSBT and ABT kidneys were primarily directed against allogeneic class I major histocompatibility complex (MHC) specificities, whereas several long term T cell lines generated from 6-day kidney transplants of both groups expressed a predominant W3/25+(T helper) phenotype and cytotoxic activity against donor specificites other than RT1.Aaclass I MHC. Specific antidonor proliferative T lymphocyte (pPTL) precursor frequencies of cells eluted from renal allografts were also equivalent for both DSBT- and ABT-treated recipients, and the range of pPTL frequencies for allograft cell eluates was similar to that in spleens, regardless of the source of the transfusion. Thus, in the rat, the prolonged renal allograft survival seen with DSBT pretreatment is associatated with reduced thromboxane production, and does not appear to involve early depletion of alloreactive cytotoxic or proliferative T cell clones or activity. Moreover, these findings suggest that the presence of significant alloreactive cytotoxic and helper T cell populations within the spleen and allograft itself does not necessarily result in renal transplant dysfunction or rejection.

CD43 is a hematopoietic cell antigen whose distribution includes T lymphocytes, plasma cells, neutrophils, and platelets. Although it has been detected on peripheral blood monocytes, its expression by other mononuclear phagocytes has not been well documented. Possible changes in monocyte/macrophage CD43 expression in response to inflammation are also poorly defined. To examine these questions, the expression of CD43 by rat peripheral blood monocytes and both resident and elicited peritoneal macrophages was examined. By flow cytometry with two anti‐CD43 monoclonal antibodies, blood monocytes were found to express large amounts of surface CD43, whereas surface CD43 expression by resident peritoneal macrophages was negligible. Peritoneal macrophage populations elicited by intraperitoneal injection of thioglycollate were uniformly positive for surface CD43, although the level of expression was lower than that found on monocytes. By labeling resident macrophages with a fluorescent tracer dye, this phenotypic shift was found to reflect an influx of CD43‐positive elicited macrophages coupled with a disappearance of CD43‐negative resident cells. Evidence from both flow cytometry and Western blotting studies suggests that the CD43 expressed by elicited peritoneal macrophages is less heavily sialylated than that expressed by blood monocytes. These findings, coupled with recent evidence that CD43 influences cellular adhesion, indicate that differential expression of CD43 may play a role in monocyte/macrophage trafficking. J. Leukoc. Biol. 55: 536–544; 1994.

To define the epidemiology, clinical manifestations, and long-term complications of respiratory viral infections in adult lung transplant recipients.

The mode of expression of novel HLA-DR antigens on hybrids of human T and B lymphoblastoid cell lines (LCL) was examined by several approaches. In each case, the results indicated that the novel antigens are T-LCL-encoded. First, hybrids of sublines of the T-LCL CEM with three different B-LCL express indistinguishable sets of novel HLA-DR antigens. Second, the novel HLA-DR and MT specificities of WI-L2 × HSB (a hybrid of a subline of the T-LCL HSB and the B-LCL WI-L2) match those of SB, a B-LCL derived from the same individual as HSB. Finally, an immunoselected variant of SB × CEM.1 (a hybrid of a subline of CEM and SB) lacking one copy of chromosome 6 and one of the hybrid's novel HLA-DR specificities also lacks a class I antigen known to be encoded by CEM.

Hyperacute rejection is a major obstacle to successful transplantation of vascularized xenogeneic organs and is believed to be mediated at least in part by preformed xenoreactive “natural antibodies” (NAb). In this study, human NAb that could be involved in hyperacute rejection of pig heart xenografts were identified and characterized using an ex vivo model in which pig hearts were perfused with whole blood from individual human or pig donors. This ex vivo perfusion model allows for the continuous monitoring of physiologic parameters of cardiac function as well as sequential sampling of tissue and blood. Pig hearts perfused with allogeneic pig blood maintained normal function for at least 4 hr, whereas those perfused with xenogeneic AB+human blood never achieved normal function and rejected completely after 30 min. In three separate experiments involving different human blood donors and pig hearts, sequential samples of perfused blood revealed a progressive depletion of antiporcine NAb. Samples of all three rejected cardiac xenografts were homogenized, and the specifically bound human anti-porcine antibodies were eluted with citric acid. The eluted antibodies were enriched approximately 50–120-fold for anti-porcine reactivity compared with serum from the corresponding donor. Eluates contained NAb of predominately IgM and IgG2 isotypes. Immunofluorescence histology confirmed the deposition of IgM and IgG2 but not other IgG subclasses in the rejected pig hearts. Since IgG2 utilized predominantly in response to bacterial polysaccharide antigens, our findings are consistent with the possibility that some NAb arise via crossreactivity with microbial antigens and are predominantly directed against carbohydrate rather than protein antigens.

Donor-specific blood transfusion prolongs survival of fully allogeneic ACI (RT1a) renal grafts in PVG (RT1c) recipients from 6–8 days to >100 days. To determine how DSBT alters effector cytotoxic cell responses, we tested freshly isolated peripheral blood lymphocytes, spleen cells, and graft infiltrating cells (GIC) from pairs of PVG recipients of ACI kidneys pretreated with DSBT or autologous blood transfusion (ABT) for cell-mediated lympholysis, antibody-dependent cellular cytotoxicity (ADCC), and natural killer activity at the day of transplantation (day 0) and days 3 and 6 posttransplantation. PBL and GIC from the same pairs of animals were examined for their phenotypic profile (CD4, CD8, 3.2.3 NK cell marker, IL-2 receptor). CML, ADCC, and NK activity were higher in PBL than splenocytes or GIC of both ABT and DSBT groups at all time points examined. CML activity of PBL at day 3 was significantly higher in DSBT vs. ABT recipients (P<0.01), while at day 6 both groups were equally elevated. Splenocytes demonstrated significantly lower CML activity in DSBT vs. ABT recipients at day 6 (P<0.05). CML activity of GIC eluted from ABT and DSBT kidneys was not detected at day 3, but was significantly elevated and equivalent in both groups at day 6. ADCC and NK activities of PBL did not differ between ABT and DSBT groups, and were negligible in splenocytes. GIC demonstrated higher NK activity in DSBT vs. ABT recipients at day 3 (P<0.05), while ADCC activity was not detectable at any time in either group. Phenotypic analysis of PBL and GIC at day 3 showed no significant differences between ABT and DSBT groups in the percentage of CD4 or CD8 cells. However, in both ABT and DSBT groups the ratio of CD4:CD8 cells was markedly lower in GIC than PBL. By day 6, PBL from both ABT and DSBT groups showed equivalent and significant decreases in CD4+cells and increases in CD8+and 3.2.3+(NK) cells. The percentage of IL-2R+cells remained low (5) in both groups at day 3. In contrast, at day 6 there was a significant increase in IL-2R+(and to a lesser extent CD4+) GIC in ABT- but not DSBT-treated recipients, while CD8+cells were significantly increased in both groups. These findings indicate that DSBT enhancement of rat renal allo-grafts does not result in the functional deletion or depletion of CML, ADCC, or NK cytotoxic effector cells in PBL, spleen, or allograft at early times after transplantation (day 3), and only a modest reduction in CML activity of splenocytes at day 6. Furthermore, CD8+and 3.2.3+cells in PBL and the graft do not appear to be affected by DSBT enhancement, whereas the significant increase in IL-2R+(and CD4+) infiltrating cells seen in rejecting ABT controls is not observed in DSBT animals. These results suggest that DSBT enhancement in the rat is more likely to be the result of diminished alloimmune responsiveness involving noncytolytic lymphocyte functions, such as alloantibody production and delayed-type hypersensitivity.

Donor-specific blood transfusion (DSBT) in animals and humans can either promote subsequent renal graft survival or lead to sensitization and graft rejection. Using a rat renal allograft model, we have examined whether the effects of DSBT on renal allograft outcome and IgG alloantibody responses are linked to the host MHC. In F1rats produced by mating PVG (RT1c), a low IgG alloantibody responder to transfused ACI (RT1a) blood, with 3 different high-IgG responders [W/F (RT1u), LOU (RT1u), and LEW (RT11)], high IgG alloantibody production was found to be inherited as a dominant trait and associated with acute rejection of ACI renal allografts. DSBT given to offspring of (PVG±W/F)F1rats backcrossed to W/F with either RT1u//e(u/c) or RT1u/u) (u/u) phenotype induced high-IgG-alloantibody responses that were associated with acute renal allograft rejection. Likewise, offspring of (PVG±W/F)F1rats backcrossed to PVG expressing the u/c phenotype had high IgG responses to ACI DSBT associated with acute renal allograft rejection. In contrast, DSBT given to backcrossed recipients expressing the RT1c/c(c/c) phenotype elicited a transient IgM response that switched to a very low IgG response and was associated with renal allograft acceptance. Analysis of IgG isotypes demonstrated that DSBT prevented production of IgGl and IgG2a, and to a lesser extent IgG2b and IgG2c alloantibodies in c/c but not u/c renal allograft recipients. The differences in the level and isotype of IgG alloantibody responses found in sera of DSBT-pretreated backcross rats of u/c and c/c phenotypes were also present in allograft eluates and splenocyte cultures. Likewise, DSBT-pretreated renal allograft recipients of the c/c phenotype produced lower levels of alloantibodies directed to class I RT1.Aaantigens compared with their u/c counterparts; in contrast, no difference was found in alloantibody responses to class II RT1.Baantigens. These findings demonstrate that the variable ability of DSBT to enhance renal allograft survival correlates with the inhibition of antidonor class I alloantibody responses of all IgG subclasses by a mechanism that is linked to host MHC.

Lung transplantation has become an acceptable therapeutic option for end-stage pulmonary diseases. The most common causes of long-term mortality after transplantation are infections and obliterative bronchiolitis (OB). While acute rejection has been shown to be associated with an increased risk of development of OB, cytomegalovirus (CMV) pneumonitis is more controversial as a risk factor for OB. Surveillance bronchoscopies are therefore advocated as a method of detecting silent episodes of CMV pneumonitis or acute rejection. We performed 226 bronchoscopies in 43 lung transplant recipients over 34 months. One hundred fifty-seven of the 226 bronchoscopies were performed according to a surveillance protocol. Acute rejection was diagnosed if lung histologic study revealed grade 2 to 4 rejection orif prompt reversal of clinical deterioration occurred after initiation of pulse steroid therapy. CMV pneumonitis was diagnosed when transbronchial biopsy histologic specimens revealed evidence of CMV inclusion bodies, or when CMV was recovered on BAL fluid in the presence of allograft deterioration. The proportion of patients who were free from any episode of acute rejection or CMV pneumonitis after transplantation was determined by Kaplan-Meier analysis. Twenty-one percent of our transplant recipients were free from acute rejection or CMV pneumonitis after a mean follow-up of 13 months. All patients who had acute rejection or CMV pneumonitis had the initial episode in the first 4 months after transplantation. Patients free of acute rejection or CMV pneumonitis 4 months after transplantation continued to be event free for the duration of follow-up. Our data suggest that surveillance bronchoscopy can be aborted in patients who are free from acute rejection or CMV pneumonitis by 4 months after transplantation. The role of surveillance bronchoscopy in decreasing the incidence of OB or improving survival can be determined only by future randomized prospective trials.

Regulation of HLA class I and class II antigen expression was studied in hybrids of human T and B lymphoblastoid cell lines (LCL). The T-LCL CEMR.3 expresses no HLA class II antigens. It expresses little total HLA class I antigen and no HLA-B antigens. The B-LCL 721.174 is a radiation-induced variant immunoselected for loss of class II antigen expression. In addition to showing a deletion of all HLA-DR and DQ structural genes, 721.174 expresses no HLA-B antigens and a decreased level of HLA-A antigen compared with the parental cell line. A hybrid of 721.174 and CEMR.3 expresses class II antigens encoded by CEMR.3. Increased expression of HLA class I antigens encoded by both 721.174 and CEMR.3 was also observed. Specifically, the previously undetectable HLA-B5 and HLA-Bw6 antigens encoded by 721.174 and CEMR.3, respectively, were present on the hybrid. Increased expression of the HLA-A2 antigen encoded by 721.174 was also observed. An immunoselected variant of the hybrid lacking both CEMR.3-derived copies of chromosome 6 lost expression of the HLA-B5 antigen encoded by 721.174 and expressed a decreased amount of HLA-A2. From these data, we infer that two complementary trans-acting factors mediate enhanced expression of HLA class I antigens in the hybrid. One of these factors is provided by a gene located on chromosome 6, derived from CEMR.3. The second factor, introduced by 721.174, is the gene previously postulated to induce expression of CEMR.3-encoded class I antigens in hybrids of CEMR.3 with B-LCL.

Expression of class I histocompatibility antigens (HLA-A and B) on hybrids of human T and B lymphoblastoid cell lines (LCL) was examined. The T-LCL CEM expressed low levels of HLA-A and B antigens. CEMR and CEMR.3, two 8-azaguanine- and ouabainresistant sublines of CEM used for fusion, expressed no detectable HLA-B antigens and expressed HLA-A antigens at a level below that of CEM. The three B-LCL studied expressed class I histocompatibility antigens at levels 50-to 80-fold in excess of that found on CEM as assessed by indirect immunofluorescence and flow cytometry. Total levels of class I histocompatibility antigens on hybrids of CEMR and CEMR.3 with B-LCL were similar to those found on the B-LCL. CEM-encoded HLA-A and B antigens were expressed on the hybrids at levels much greater than those seen on CEM itself; expression by the hybrids of CEM-encoded and B-LCL-encoded class I antigens was comparable. By RNA-DNA filter hybridization, CEMR.3 was found to have extremely low levels of class I heavy-chain mRNA compared with two B-LCL and with HSB, a T-LCL that expresses high levels of class I histocompatibility antigens. Thus, the paucity of HLA-A and B expression by CEMR.3 (and by inference, CEMR and CEM), as well as the enhancement of CEM-encoded HLA-A and B antigen expression on B-LCL × T-LCL hybrids, must be due, at least in part, to modulation of the level of transcripts encoding HLA class I heavy chains.