Cytomegalovirus infection of the liver transplant: virological, histological, immunological, and clinical observations.

The most common organ-specific manifestation of cytomegalovirus (CMV) infection after liver transplantation is hepatitis. Here we retrospectively describe the detailed virological, histological, immunological, and clinical findings associated with CMV infection in 229 consecutive adult liver transplantation patients. CMV infection was diagnosed by pp65 antigenemia. From 439 liver biopsies, CMV antigens were demonstrated by immunohistochemistry and CMV DNA by hybridization. The Banff criteria were used for histology. The expression of various adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], endothelial leukocyte adhesion molecule-1 [ELAM-1]), their ligands (leukocyte function antigen-1 [LFA-1], very late antigen-4 [VLA-4], Sialyl-LewisX-molecule [SLeX]), and lymphoid activation markers (major histocompatibility complex [MHC] Class II, interleukin-2-receptor [IL-2R]) was demonstrated by immunohistochemistry. CMV infection of the transplant occurred in 26 patients (11% of all 229 patients and 17% of the 151 patients with liver biopsy). The incidence was higher among seronegative (26%) than in seropositive recipients (9%), but most cases 18/26 (70%) were reactivations. The CMV pp65 antigenemia levels were usually high in primary infections (893+/-1069, range 50-3000 pp65+cells), but varied widely in reactivations (388+/-740, range 3-3000). The histological Banff score was slightly increased (2.3+/-0.9). Microabscesses, lymphocytic infiltration, Kupffer cell reaction, and parenchymal alterations were common but viral inclusions rare. CMV significantly (P<0.05) increased ICAM-1 and VCAM-1 expression and the number of LFA-1, VLA-4, and Class II-positive lymphocytes in the graft. All CMV infections were successfully treated with antivirals. Intragraft CMV infection had no influence on the long-term outcome, but biliary complications were common. In conclusion, CMV infection of the liver transplant occurred both in primary infection and in reactivation, and also in the cases with low pp65 antigenemia levels. Microabscesses and other histological alterations were common but viral inclusions rare. Increased adhesion molecule expression was associated with lymphocyte infiltration. Successfully treated CMV hepatitis had no influence on the long-term clinical outcome.

Protocol core needle biopsy and histological chronic allograft damage index as surrogate endpoint for Long-Term graft survival.

Following encouraging results from several single-center studies showing that early histological manifestations of chronic rejection are seen in the graft before a decline in transplant function, we tested this concept in a multicenter study and investigated whether protocol needle biopsy may be used as a surrogate to late graft survival in multicenter renal transplantation trials. During two mycophenolate mofetil trials, 621 representative protocol biopsies were obtained at baseline, 1 year, and 3 years. The samples were coded and evaluated blindly by two pathologists and a Chronic Allograft Damage Index (CADI) score was constructed. At 1 year only 20% of patients had elevated (>1.5 mg/100 mL) serum creatinine, whereas 60% of the biopsies demonstrated an elevated (>2.0) CADI score. The mean CADI score at baseline, 1.3 +/- 1.1, increased to 3.3 +/- 1.8 at 1 year and to 4.1 +/- 2.2 at 3 years. The patients at 1 year were divided into 3 groups, those with CADI <2, between 2 and 3.9, and >4.0, the first two groups having normal (1.4 +/- 0.3 and 1.5 +/- 0.6 mg/dL) and the third group pathological (1.9 +/- 0.8 mg/dL) levels of serum creatinine. At 3 years there were no lost grafts in the "low" CADI group, six lost grafts (4.6%) in the "elevated" CADI group, and 17 lost grafts (16.7%) in the "high" CADI group (P <.001). One-year histological CADI score predicts graft survival even when the graft function is still normal. This observation makes it possible to use CADI as a surrogate endpoint in prevention trials and to identify the patients at risk for intervention trials.

Collagens I and III in a porcine bronchial model of obliterative bronchiolitis.

The main extracellular matrix components of the lung, type I and III collagens, were studied in chronic allograft rejection developing in a porcine heterotopic bronchial transplantation model. Specific porcine complementary DNA probes were constructed for detection of the expression of type I and III procollagen messenger RNAs in the bronchial wall structures and in the obliterative plug by in situ hybridization. In autografts, and in allografts immunosuppressed with 40-O-(2-hydroxyethyl)-rapamycin, cyclosporine A, and methylprednisolone, no histological changes of obliterative bronchiolitis (OB) developed, and the number of fibroblast-like cells expressing type I and III procollagen mRNA remained low. In nontreated allografts obliterating within 21 d, a preponderance of fibroblast-like cells showing positivity for type III procollagen mRNA existed in the obliterative plug and bronchial wall. This study shows for the first time the temporal and spatial activation of type I and III procollagen genes during the course of obliterative bronchiolitis. The number of cells expressing procollagen III mRNA increased parallel to developing obliteration and fibrosis in nontreated allografts, whereas autografts and immunosuppressed allografts exhibited no such trend. This finding suggests a positive association between type III collagen mRNA expression in fibroblast-like cells and development of obliterative bronchiolitis.

Immune cells and immunosuppression in a porcine bronchial model of obliterative bronchiolitis.

BACKGROUND: To study obliterative bronchiolitis (OB), we have developed a porcine heterotopic bronchial model. Allografts obliterate within 3 weeks, the immunosuppression cyclosporine (CsA)-azathioprine (AZA)-methylprednisolone (MP) delays OB, but OB is prevented when AZA is switched to 40-0-(2-hydroxyethyl)-rapamycin (RAD). To characterize our model, we studied immune cells under various immunosuppressive conditions. METHODS: The groups studied were autografts (U), allografts (A), and allografts given either CsA-RAD-MP (R), or CsA-AZA-MP (C). The implants were harvested at 3, 7, 10, 14, 21, 30, 60, and 90 days after transplantation. Epithelial damage and obliteration were graded histologically, and the number of CD4, CD8, MHC class II expressing cells, macrophages, and B lymphocytes were counted (mean+SEM)/high-power visual field. RESULTS: In group U, normal epithelium was regained with no obliteration and only few immune cells. In group A, consistent with initially acute ejection, an influx of CD4 (105+23), CD8 (166+23), and class II (92+20) cells was seen up to day 21, when total obliteration preceded by epithelial destruction had already developed. Some macrophages were seen and B cells were scarce. In group R, epithelial damage and obliteration were insignificant, but moderate numbers of CD4, CD8, and class II cells were seen. In group C, epithelial damage and obliteration were only delayed, but the immune cell response was clearly blunted. CONCLUSIONS: In our model, rejection with significant immune cell influx was still active when obliteration was total in nontreated allografts. In immunosuppressed allografts, decrease in the number of immune cells alone did prevent OB. These results support OB being T-cell mediated. RAD may have additional important effects on growth factors and proliferation in prevention of OB.

Histological alterations in implant and one-year protocol biopsy specimens of renal allografts.

BACKGROUND: The natural course of histological changes and their correlations with clinical parameters have not been studied in large numbers in renal allograft specimens. The aim of this study was to determine whether any histological alterations developed during the first posttransplantation year. Immunological and nonimmunological factors possibly associated with subsequent histopathological changes and development of chronic rejection were also assessed. METHODS: We studied 102 cadaveric kidney allografts for which both implant and 1-year protocol biopsy specimens were available. The chronic allograft damage index (CADI) was used to quantify the extent of histological changes that developed during the first year. RESULTS: Overall, an increase in histological alterations were seen during the first posttransplantation year, and the CADI increased significantly. The mean CADI was 0.7 in relation to implant biopsy samples and 2.9 in relation to 1-year biopsy samples (P<0.05). Although the degree of changes increased during the first posttransplantation year, they were seldom severe. Significant increases in incidences of interstitial inflammation and fibrosis, tubular atrophy, and basement-membrane thickening were seen. Vascular intimal proliferation and glomerular mesangial matrix increase and glomerular sclerosis were also noted. In contrast, anisometric vacuolization in the tubular epithelium decreased significantly in incidence during the first year. CADI values 1 year after transplantation were significantly affected by donor age, occurrence of acute rejection episodes, and prevalence of HLA-DR mismatches. CADIs were also significantly higher in grafts with decreased function. CONCLUSIONS: Histopathological alterations increased in almost every graft, even well-functioning grafts, during the first year. The CADIs relating to alterations seen in cases of chronic rejection increased significantly and were strongly affected by both immunological and nonimmunological factors.

MC1288, a vitamin D analog, prevents acute graft-versus-host disease in rat bone marrow transplantation.

The major obstacle to successful bone marrow transplantation (BMT) is graft-versus-host disease (GVHD). Vitamin D analogs have shown their efficacy in solid organ transplantation. The purpose of this study was to investigate the suitability of a novel vitamin D analog, MC1288, in the prevention of acute GVHD in a rat BMT model. Allogeneic BMT were performed from Lewis to BN rats (n = 18). The animals were divided into four groups: an untreated control group, MC1288, cyclosporin A (CsA), and MC1288 + CsA-treated groups. Rats were harvested for histology and immunohistochemistry on day 20 after BMT. Histological changes for GVHD in liver, skin, and spleen were scored. Positivity in immunostaining was quantified as the number of positive cells/high power field. Treatment with MC1288 decreased clinical signs of GVHD compared with untreated or CsA-treated rats. Histological manifestations of GVHD, expressed as mean total increment, were significantly lower (1.4 +/- 0.5) in MC1288 than in untreated (5.0 +/- 1.6) or CsA (3.5 +/- 1.0) groups. Combining MC1288 and CsA further improved histology (1.1 +/- 0.6). The expression of CD4, CD8, MHC class II, interleukin-2 receptor, nitric oxide 2, and NKR-P1A (NK cells) positivity was significantly decreased in the liver and skin of BMT rats by MC1288. MC1288 was effective in preventing clinical and histological signs and symptoms of GVHD. This novel vitamin D analog could be used as an immunomodulating agent in BMT.

Comparison of endobronchial and transbronchial biopsies with high-resolution CT (HRCIT) in the diagnosis of sarcoidosis.

High-resolution computed tomography (HRCT) has been shown to accurately visualise parenchymal infiltrates of sarcoidosis. The aim of this study was to compare the diagnostic yield (DY) of HRCT with that of endobronchial (EBB) and transbronchial (TBB) biopsies in establishing the diagnosis of sarcoidosis. Forty-five patients referred to Helsinki University Central Hospital with a presumptive diagnosis of sarcoidosis underwent fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL), EBB, TBB and HRCT. Thirty-seven of the patients were diagnosed as having sarcoidosis, 34 of whom showed a parenchymal infiltrate in HRCT. One of the three patients with no parenchymal findings, had positive findings in TBB, and all had lymphocytosis in BAL. The DY for sarcoidosis by EBB and TBB was 24.3% and 50.0%, respectively. The addition of EBB to TBB improved the DY by 8.3%, whereas adding TBB to EBB improved the DY by 30.6%. There were no major complications after the FOB, which was always performed under fluoroscopic control. In conclusion, HRCT is a valuable tool in diagnosing sarcoidosis. However, the HRCT findings cannot be seen in all patients with positive findings in lung biopsy, nor is the parenchymal infiltrate specific for sarcoidosis. Attempting biopsy-proven diagnosis of sarcoidosis is still recommended. Fiberoptic bronchoscopy with EBB and TBB under fluoroscopic control is a safe and well-tolerated procedure.

Fine-needle aspiration biopsy allows early detection of acute rejection in children after renal transplantation.

UNLABELLED: analysis detected rejections often before clinical signs. Half of the patients had increased serum creatinine concentration and 38% had fever at the time of rejection diagnosis. Both signs were present in only 19% of the episodes. A decrease in urine output (>20%) was seen in a third of the episodes. The rejections responded well to oral methylprednisolone (3 mg/kg/day), and lymphoglobulins were needed in only 12% of the episodes. More than 90% of the rejections were completely reversible and no transplant was lost because of acute rejection. CONCLUSION: The results indicate that FNAB is a safe and sensitive method for the diagnosis and follow-up of acute cellular rejection in pediatric recipients of different ages.

Structure of carotid artery in baboon and rat and differences in their response to endothelial denudation angioplasty.

BACKGROUND: Most studies dealing with vascular response to injury have been conducted using rodent and rabbit models, although it is expected that the response to injury in these species is dissimilar from man. AIMS: Here we compare the structure of native carotid artery in rat and baboon and the response of these vessels to endothelial denudation angioplasty. METHODS: In both species, the carotid is a musculoelastic artery. Only baboon carotid has a distinct intima, correlating in size with the weight of male baboons. Complete endothelial denudation of left carotid was performed on eight male baboons and 24 male rats by applying an equivalent pull force with a Fogarthy catheter. The animals were sacrificed prior to and 15 min and 2, 3, 4, 7, 14 and 28 days postinjury, one baboon and three rats per time point. RESULTS: Re-endothelialization in the baboon was complete already on day 4, whereas in the rat it was still incomplete on day 28. The proliferative response to injury was far smaller in the baboon than in the rat, the intimal area increased only by 5-fold in baboon compared with 25-fold in rat, and the number of intimal nuclei by 4-fold in baboon compared with 12-fold in rat. Complete compensatory remodelling of the lumen size occurred in the baboon, whereas in the rat remodelling remained incomplete. The cell types participating in the response were, however, similar: deposition of thrombocytes on denuded luminal surface, expression of alpha-actin by intimal cells, and lack of any significant white cell infiltration in the denuded intima. CONCLUSIONS: Baboon carotids are very different from rat carotids both in their native structure and in their response to injury. With the limited amount of information available from human vessels, baboon carotids closely resemble human carotids in both respects.

Cytological monitoring of peripheral blood, bronchoalveolar lavage fluid, and transbronchial biopsy specimens during acute rejection and cytomegalovirus infection in lung and heart--lung allograft recipients.

STUDY OBJECTIVES: Acute rejection and cytomegalovirus (CMV) infection are important complications after lung and heart--lung transplantation. We sought to investigate whether acute rejection and CMV infection demonstrated as CMV antigenemia had an effect on the cell profiles of peripheral blood (PB), bronchoalveolar lavage fluid (BAL-F), or TBB histology. PATIENTS AND DESIGN: In this prospective study, composition of cells in PB, BAL-F, and TBB samples from 20 lung or heart-lung transplantation patients were analyzed during episodes of acute rejection or CMV antigenemia. Rejection was graded according to the International Society for Heart and Lung Transplantation criteria. As controls, samples with no evidence of rejection or infection were used. To evaluate the effect of time on cellular findings, samples were divided into three groups according to time after transplantation: 1--30, 31--180, and more than 180 d after transplantation. RESULTS: Acute rejection was associated with mild blood basophilia (p<0.05; specificity 94%, sensitivity 42%). In BAL-F during rejection, the number of basophils (p<0.05), eosinophils (p<0.05), and lymphocytes (p<0.05; specificity 77%, sensitivity 64%) was increased compared to controls during the post-operative month 1. Later-occurring rejections were associated with increased amounts of neutrophils in BAL-F (p<0.05; specificity 82%, sensitivity 74%). In TBB histology, acute rejections were associated with perivascular and/or peribronchial infiltration of lymphocytes (p<0.001) and plasma cells (p<0.05) compared to controls. In our patients receiving gancyclovir prophylaxis, CMV antigenemia did not significantly alter the cell profiles in PB and BAL-F nor the inflammatory cell picture in TBB histology. CONCLUSION: TBB histology remains the 'gold standard' for diagnosing rejection in lung and heart-lung transplantation patients, as the inflammatory cell findings in TBB specimens are highly specific for rejection. The cellular changes associated with rejection, mild PB basophilia and increased proportions of lymphocytes in early- and neutrophils in later-occurring rejection, observed in BAL-F cannot be considered specific for rejection, but may warrant clinical suspicion of rejection.

Factors affecting the cytology outcome of Pap smears--a brief approach to internal quality control in private cytopathology laboratory practice.

We evaluated the effect of intrauterine device (IUD), patient age and hormone replacement therapy (HRT) on cytology outcome in Pap smears together with the important IQC procedures: 1) manual double-screening by cytotechnologists, and 2) retrospective senior pathologist review during 1996-1999. The results from primary double-screening (119 of 87,409 Pap smears) showed an excellent inter-observer correlation. The estimation of hormonal effects showed higher incidence of disagreements (p=0.013) in patients <47 yr. Some individual trends were found in the assessments of both cellular atypia (p=0.012) and Papanicolaou classification (p=0.018). The IUD had no influence on the accuracy when the degree of inflammatory reaction was evaluated (p>0.050), but showed an adverse effect on the estimation of cellular atypia (p=0.001). HRT distinctly equalized the entire sample material, since fewer disagreements were found in the age groups <47 yr and >47 yr when estimating the hormonal effects (p=0.013), inflammatory reaction (p=0.044) or cellular atypia (p=0.006) compared to those without HRT. The continuous cytopathologist supervision had a positive impact on the accuracy of hormonal effect estimation during the 4 years. The senior cytopathologists' reviews (354 of 87,409 Pap smears) showed mutually good interobserver correlation, and diagnostic conclusions of the same specimens differed only slightly between the cytopathologists. We found these state-of-the-art cytopathological IQC procedures to be effective and fit-for-purpose when evaluating hormonal effects, inflammatory reaction and cellular atypia.

Healing of bronchial allografts in pigs.

Our purpose was to investigate the healing of bronchial grafts in a porcine experimental model. Via left thoracotomy, a 2.5 cm long bronchial stump was anastomosed back to the same animal (autograft) or to another pig (allograft). Autotransplanted bronchi (six pigs) healed very well without infection. Allotransplantation without immunosuppression (eight pigs) was followed in all cases by rejection with formation of major bronchopleural fistula. After allotransplantation with triple-drug immunosuppressive medication (seven pigs), three pigs showed infection-free healing, but the anastomoses were slightly stenosed at the time of sacrifice (mean 30 d), while four had bronchopleural fistula. The study thus showed the healing ability of totally avascular bronchial graft in pigs to be very good when it is autotransplanted, but poor when allotransplanted without immunosuppressive treatment.

Obliterative lesions in a heterotopic bronchial xenograft model--a preliminary study.

BACKGROUND: We further developed our heterotopic pig model of obliterative bronchiolitis to study airway obliteration in xenografts. METHODS: Four domestic piglets each received 40 bronchial xenografts s.c. from a donor lamb. Piglet X was not immunosuppressed. The other animals received daily oral cyclosporine, 15 mg/kg (XC), or SDZ RAD, 1.5 mg/kg (XR), or both (XCR). Five implants at a time were serially removed from each animal during 17 days for histological assessment. RESULTS: In contrast to the grafts of the others, the xenografts of XCR recovered after initial ischemic damage. No epithelial damage (P<0.01) or mural necrosis occurred on day 7. Airway obliteration developed in all, but was significantly delayed in XCR. CONCLUSIONS: Invariably developing airway obliteration in nontreated xenografts was delayed by immunosuppression, making the model useful, especially in testing the efficacy of immunosuppressive drugs in a xenogeneic system.

Obliterative airway disease in a porcine heterotopic bronchial allograft model.

Representative animal models are needed for the study of posttransplant obliterative bronchiolitis (OB). Because human OB originates in terminal bronchi, the validity of tracheal models can be questioned. Using our hetrotopic model, we implanted pieces of a lobar bronchus subcutaneously into domestic pigs. Five groups were included: autograft implants, allograft implants, allograft implants with 2 regimens of cyclosporine (CsA)azathioprine (AZA)-methylprednisolone (MP), and allograft implants with CsA-SDZ RAD-MP. Samples were harvested at 2 weeks and at 1, 2, and 3 months. The histological findings were graded from 0 to 3. Following initial ischemic epithelial damage, autograft implants recovered, but untreated allografts and those treated with CsA-AZA-MP were totally and permanently damaged within one month. In the group treated with CsA-SDZ RAD-MP, a maximal grade 1.5 +/- 0.5 epithelial injury was seen at one month. Epithelial damage preceded and correlated with luminal obliteration. The obliterative lesions histologically resembled human OB. Differences from our previous findings with terminal bronchioles were minor. This study supports the use of larger-size airways in the study of OB.

Prevention of small airway obliteration in a swine heterotopic lung allograft model.

BACKGROUND: In our swine model of obliterative bronchiolitis preventing obliteration by the standard immunosuppression with cyclosporine, methylprednisolone, and azathioprine was not successful. The purpose of this study was to test the ability of a new immunosuppressive regimen to prevent alloimmune reaction and obliteration of the allografts. This regimen includes the novel macrolide SDZ RAD, i.e., 40-O-(2hydroxyethyl)-rapamycin. METHODS: Donor lung allografts of 1 cm3 were implanted sub-cutaneously into 11 random-bred non-related domestic pigs receiving daily oral cyclosporine (10 mg/kg) and methylprednisolone (20 mg). In addition, the animals received either oral azathioprine (2 mg/kg) (Group 1) or oral SDZ RAD (1.5 mg/kg) (Group 2). Histologic alterations were graded from 0 to 3 based on repeatedly removed implants during a follow-up period of 3 months. RESULTS: Total epithelial destruction and permanent luminal obliteration occurred within 37 days in Group 1. After an initial grade of 2.3+/-0.3 destruction, epithelial recovery was evident in Group 2 (P < 0.01), and the bronchi stayed patent. Cartilaginous destruction was milder in Group 2 (P < 0.05) than in Group 1, but chondrocytic proliferation was more intense (P < 0.05). Alveolar tissue and native structures of the bronchial wall were destroyed in Group 1, but preserved in Group 2 with total recovery after a mild-grade initial necrosis. CONCLUSIONS: Unlike the standard triple therapy, SDZ RAD combined with cyclosporine and methylprednisolone preserves the pulmonary allografts and prevents epithelial destruction and subsequent luminal obliteration. This suggests that this regimen might efficiently suppress obliterative bronchiolitis and improve long-term results in lung transplant recipients.