Dendritic cell-lymphoid cell aggregation and major histocompatibility antigen expression during rat cardiac allograft rejection.

To determine the pattern of cellular expression of donor MHC class I and class II antigens during the course of rat cardiac allograft rejection, ACI cardiac allografts transplanted to BN recipients were examined from day 2 to day 6 using immunohistologic and immunoelectron microscopic methods. We used both monomorphic and donor-specific mouse anti-rat MHC class I and class II mAbs in this study. In normal ACI hearts, MHC class I reactivity was confined to the vascular endothelium and to interstitial cells. Ongoing rejection was characterized by an increased donor MHC class I staining intensity of microvascular endothelium and induction of donor class I surface reactivity on cardiac myofibers. Donor MHC class II reactivity was exclusively confined to interstitial dendritic cells (IDC) in both normal ACI hearts and in rejecting allografts, although rejection was associated with marked fluctuations in class II IDC frequency. An early numerical depression in class II IDC present in both allografts and syngeneic heart grafts was attributed to a direct effect of the transplantation procedure. By days 3-4, allografts showed an absolute overall increase in donor class II IDC frequency, which was associated with the presence of multiple localized high-density IDC-lymphocyte aggregates. The lymphocytes present in the focal areas were predominantly of the class II-reactive Th cell subpopulation. These aggregates may thus represent the in vivo homologue of dendritic cell-lymphocyte clustering, which has been shown to be required for primary class II allosensitization in the rat and mouse in vitro. During the late phase of rejection, there was a marked numerical fall in donor class II IDC, which correlated with extensive overall graft destruction. This study has shown that acute rat cardiac allograft rejection can occur in the absence of donor MHC class II expression by allograft vascular endothelium and cardiac myofibers. The IDC, which are believed to represent the principal class II alloantigen presenting cells in the rat heart, remain the sole class II-expressing cellular constituents of the graft throughout the course of rejection.

Immunologic and genetic studies of diabetes in the BB rat.

The spontaneous development of diabetes in the Bio-Breeding (BB) rat is an excellent model of human insulin-dependent diabetes mellitus (IDDM). Disease expression is dependent on several genetically determined abnormalities, including specific major histocompatibility complex (MHC) genes. At least one MHC class II locus of the U haplotype is a necessary, but not sufficient, condition for disease expression. The immune system of BB rats is markedly abnormal. There is a striking reduction in the number and function of mature cytotoxic/suppressor T cells, a poor proliferative response to mitogens and in mixed lymphocyte culture, poor interleukin-2 production, and a reduced ability to reject skin allografts. While these immune system abnormalities are closely related to the development of diabetes, the immune recognition and effector mechanisms resulting in islet cell destruction are still poorly understood. The hypothesis that MHC class II induction on pancreatic beta cells serves to target these lymphokines, natural killer (NK) cells, macrophages, etc.) have been implicated in islet cell killing. The incidence of IDDM is reduced by immunosuppressive therapy in both rats and humans, further supporting the role of immune mechanisms in this disease.

Linkage of AD HSP and cognitive impairment to chromosome 2p: haplotype and phenotype analysis indicates variable expression and low or delayed penetrance.

We report linkage of a family affected with autosomal dominant hereditary spastic paraparesis (HSP) and/or cognitive impairment to the HSP locus on chromosome 2p. To date all families linked to this locus have been affected with 'pure' HSP. The specific pattern of cognitive impairment in this family is characterised primarily by deficits in visuo-spatial functions. We also present genetic studies that indicate variable expression and low or delayed penetrance. We have constructed a haplotype flanked by polymorphic markers D2S400 and D2S2331 that was present in 12 individuals affected with spastic paraparesis. The severity of spasticity varied markedly among these individuals. In addition four of these individuals (aged 62-70) also had a specific form of cognitive impairment. The disease haplotype was also present in an individual (age 57) who had an identical pattern of cognitive impairment as the only sign of the disease supporting the hypothesis that spastic paraparesis and cognitive impairment are the result of variable expression of a single gene (rather than a co-incidental occurrence). Haplotype reconstruction for all participating family members revealed the presence of this disease haplotype in six individuals who had normal neurological and neuropsychological examinations. All six are below the maximal age of onset in the family--60 years. This is evidence for low or late penetrance of the AD HSP gene in this family. The identification of normal individuals carrying the disease haplotype demonstrates the importance of genetic studies in combination with clinical examination when counselling at risk family members.

Improved diagnosis and prognosis of mucormycosis. A clinicopathologic study of 33 cases.

Mucormycosis is an uncommon, frequently fatal, fungal infection which rarely arises in otherwise healthy people (15, 18, 92). An underlying disease, frequently diabetes mellitus, is almost always present. It appears stereotypically in different anatomic sites: paranasal, rhinoorbital, rhinocerebral, cerebral, pulmonary, and gastrointestinal areas; and in the soft tissue of the extremities. It can also appear as disseminated disease. Tissue invasion by the hyphae of mucormycosis must be seen microscopically to establish the diagnosis, but culture is required to identify the fungal species involved. A study of 33 cases seen in one hospital over five decades suggests that the incidence of this infection is increasing. There has been a dramatic improvement in outcome, which has been paralleled by a major shift from postmortem to premortem diagnosis. Premortem diagnosis gives the opportunity for metabolic stabilization, surgical excision, and amphotericin-B therapy appropriate to this disease.

Age-related cognitive decline in hereditary spastic paraparesis linked to chromosome 2p.

OBJECTIVES: To investigate whether cognitive decline is part of the phenotype of SPG4-linked hereditary spastic paraparesis (HSP) and to determine whether cognitive changes are present in haplotype carriers before the onset of paraparesis. BACKGROUND: The major locus for "pure" autosomal dominant HSP is the SPG4 locus on chromosome 2p. Cognitive impairment linked to this locus has been described in two families. METHODS: The authors identified 19 families with "pure" autosomal dominant HSP. Five had linkage to the SPG4 locus (maximum lod score for D2S2374: 5.99 at zero recombination in four smaller families and 3.86 at zero recombination in the largest family). Haplotype construction identified a disease haplotype for all families; 41 individuals carried this haplotype (30 affected by HSP, 11 unaffected). All haplotype carriers and 41 matched controls underwent Cambridge Cognitive (CAMCOG) examination. Nonparametric significance tests were used comparing total and subset scores. RESULTS: Haplotype carriers affected by HSP had lower total CAMCOG scores than control subjects (85.86/107 versus 96.2/107; p < 0.0005). The subsets of orientation, memory, language expression, and comprehension were also significantly lower. Ten individuals had scores < or =80/107, indicating mild dementia. Unaffected haplotype carriers had mean total CAMCOG scores lower than control subjects (91.82/107 versus 98. 09/107; p = 0.016). In both groups cognitive decline was age-dependent and scores diverged from control subjects from age 40. All SPG4-linked families showed the effect. CONCLUSION: Mild, age-related cognitive impairment is a feature common to these families. It illustrates variable phenotypic expression at this locus and may be the first manifestation of the disease gene in individuals as yet unaffected by paraparesis.

Phenotype of AD-HSP due to mutations in the SPAST gene: comparison with AD-HSP without mutations.

BACKGROUND: "Pure" autosomal dominant hereditary spastic paraparesis (AD-HSP) is clinically and genetically heterogeneous. There are at least seven genetic loci with varying ages at onset and disability. The SPAST gene at the SPG4 locus on chromosome 2p is the major disease gene for AD-HSP. OBJECTIVES: To investigate whether there are distinct clinical features among families with AD-HSP due to SPAST mutations compared with families excluded from SPG4. METHODS: Nineteen families with "pure" AD-HSP were identified, and the clinical features of family members were compared using a standard protocol. With use of genetic studies, the families were divided into two groups for comparison: those with mutations in SPAST, the "mutation-positive" group, and those excluded from SPG4 on the basis of linkage studies, the "SPG4-excluded" group. RESULTS: Twenty-nine individuals from four families had mutations in SPAST, whereas 22 individuals from three families comprised the SPG4-excluded group; in 11 families, the pattern of linkage was unknown. In the one remaining family, no mutations were found despite strong linkage to SPG4. Different mutations were identified in the four SPAST pedigrees, but the clinical picture was similar in each. Comparison of the mutation-positive group with the SPG4-excluded group revealed an older age at onset (p = 0.03), more disability (p = 0.001), more rapidly progressive paraparesis (p = 0.044), and more cognitive impairment (p = 0.024) among affected individuals with SPAST mutations, not confounded by disease duration. CONCLUSION: Despite different mutations, SPAST families have a similar phenotype that can be distinguished from other genetic groups.

SPG15, a new locus for autosomal recessive complicated HSP on chromosome 14q.

The authors studied two families with autosomal recessive hereditary spastic paraplegia (HSP) complicated by the presence of additional symptoms of pigmented maculopathy, distal amyotrophy, dysarthria, mental retardation, and further intellectual deterioration. Evidence was obtained for linkage to a locus on chromosome 14q that is distinct from the SPG3 locus for autosomal dominant HSP (D14S77: lod score of 4.20 at zero recombination). Haplotype construction of nearby markers confirms the existence of this novel HSP locus (SPG15) and narrows it to a 19-cM interval flanked by D14S1038 and D14S61.

Hepatic fibrosis in the mucopolysaccharidoses.

The mucopolysaccharidoses are a group of clinically progressive, heritable, lysosomal storage disorders. Many organ systems are affected due to widespread accumulation of incompletely degraded mucopolysaccharide. The novel finding of hepatic fibrosis in each of six cases of mucopolysaccharidosis examined at autopsy (including examples of Hurler syndrome, Hunter syndrome, and Sanfilippo syndrome) is described. In each instance, the liver was diffusely involved by fibrosis that outlined the lobules, and there was extensive hepatocyte and Kupffer cell vacuolization. The pattern of hepatic fibrosis is not explained by either cardiac failure or drug toxicity. It is hypothesized that the hepatic fibrosis is due to the abnormal accumulation of a hepatotoxic metabolite. The frequency and severity of liver disease in the mucopolysaccharidoses deserve further study. In particular, with the advent of bone marrow transplantation as therapy for some of the mucopolysaccharidoses, the question of whether cirrhosis develops in these patients and, if so, what its rate of progression is, should be addressed.

Increased major histocompatibility complex antigen expression in unilateral ischemic acute tubular necrosis in the mouse.

In many studies of renal transplant recipients, acute tubular necrosis has been shown to predispose to a higher rate of graft loss, apparently due to rejection, but the mechanism of this effect is unknown. One possibility is an increased immunogenicity of the graft. To study this possibility, we examined the expression of major histocompatibility complex antigens in kidneys damaged by ischemia, using a mouse model of ischemic ATN. ATN was produced in the left kidney of male CBA mice by temporary clamping of the vascular pedicle for up to 60 min. Class I and II MHC expression was quantified by the extent of binding of monoclonals in radioimmunoassay, after 1 to 35 days in both kidneys. MHC induction was localized by indirect immunoperoxidase staining. Specific steady state mRNA for beta 2 microglobulin and class II were quantified by northern blotting using 32P-labeled probes. Changes in MHC expression were assessed by comparing the ischemically injured left kidney to the control right kidney. By day 1, ATN was evident by histology but there was no change in MHC expression. By day 3, class I was increased in the left kidney by 3-6-fold over the right. In tissue sections, the class I increase was localized to tubular epithelial cells. Starting on day 7 and persisting to day 35, class II was increased by 1.5 to 3 times for the ischemic kidney over the control, primarily in interstitial cells but also in tubular cells. This increase in class II was associated with the appearance of Thy 1.2-positive cells in the interstitial areas. Increased antigen expression was preceded by increased steady state mRNA. Thus unilateral ischemic ATN causes increased MHC expression in tubular cells and the accumulation of an inflammatory infiltrate, both of which may contribute to the increased rate of rejection and graft loss in ischemically injured kidneys.

Evidence that nonlymphoid tissue injury in acute graft-versus-host disease is limited to epithelial cells aberrantly expressing MHC antigens.

To explore the relationship between aberrant MHC antigen expression and tissue injury in acute graft-versus-host disease, we performed a sequential histological and immunohistochemical analysis of multiple tissues in acute GVHD generated across complete MHC and multiple minor H incompatibilities in the rat. Two patterns of MHC antigenic modulation were recognized. Aberrant MHC class I and class II antigen expression occurred simultaneously on the epithelial cells of nonlymphoid target tissues early in acute GVHD. This coincided with a lymphoproliferative phase that preceded nonlymphoid tissue injury. The extent of epithelial class II antigen induction predicted the extent of subsequent histological injury. Changes in MHC class II antigen expression were also seen on nonepithelial cells. Interstitial dendritic cells (IDCs) expressing recipient MHC class II antigens increased in both target and nontarget tissues during early GVHD. Recipient class II antigens were also induced on large numbers of microglialike cells in the brain and Kupffer cells in the liver. However, tissue injury did not follow MHC class II antigen induction on nonepithelial cells. These findings are consistent with a role for aberrant epithelial MHC antigen expression in nonlymphoid tissue injury in acute GVHD.

The decreased incidence of aseptic necrosis in renal transplant recipients--a case control study.

Before 1971 the incidence of aseptic necrosis in renal transplant recipients was 29%, and after 1971 it was 5%. To investigate the reasons for this decreased incidence and to elucidate the causes of aseptic necrosis we studied all 26 transplant patients with aseptic necrosis and 42 controls matched for year of transplantation, age, and sex. Development of aseptic necrosis was not related to duration of dialysis before transplant, severity of uremia at the time the patient started dialysis, adequacy of dialysis before transplantation, transplant dysfunction at the time aseptic necrosis was diagnosed, hyperparathyroidism before or after transplantation, lack of Vitamin D supplementation after transplantation, or fatty infiltration of liver. Total steroid dose 1 month after transplantation was actually lower in aseptic necrosis compared with the control group (2.47 +/- 0.3 g vs. 3.6 +/- 0.3 g SEM g) and was similar after 4 months (6.72 +/- 0.55 g vs. 7.14 +/- 0.6 g), as were total numbers of i.v. doses of methylprednisolone or hydrocortisone. However, blood urea nitrogen (BUN) during the dialysis period was significantly higher in the aseptic necrosis group. Of the aseptic necrosis group, 27% had a previous transplant compared with 5% of controls. Half the aseptic necrosis group (5/10) had parenchymal iron on liver biopsy one year after transplant compared with 15% (2/13) of those without aseptic necrosis. Patients transplanted before 1971 (with and without aseptic necrosis) received significantly more i.v. hydrocortisone and less i.v. methylprednisolone, had higher BUN levels at the time of starting dialysis, and had lower serum calcium and higher serum phosphate at transplantation compared with patients transplanted in or after 1971. The incidence of aseptic necrosis following transplantation has decreased during the past 13 years for reasons that are unclear. Risk factors for aseptic necrosis may include previous transplantation, severe iron overload that may lead to marrow fibrosis and osteopenia, and increased protein catabolism/turnover during dialysis.

Post-transplant lymphoproliferative disorder in renal allograft recipients. Clinical experience and risk factor analysis in a single center.

Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized complication of solid organ transplantation. The University of Alberta Renal Transplant Program had not experienced a case of PTLD occurring in the early post-transplant period until March 1989. Since then, 4 patients have developed this complication. To identify the major risk factors for the recent appearance of PTLD, a retrospective analysis was carried out on 162 cadaveric renal transplants performed between July 1987 and December 1990. Four cases of polymorphic PTLD were seen. Two patients presented with fatal disseminated disease. Two others developed PTLD confined to the renal allograft; both are disease free at > 24 months of follow-up. Seventy-two (44.4%) of the cadaveric transplant recipients had received Minnesota antilymphocyte globulin (MALG) induction therapy during the study period. Twenty-four of these also received OKT3 for steroid-resistant rejection. Of the 4 patients with PTLD, 3 had received both MALG induction and OKT3; the remaining patient had received MALG induction only. The incidence of PTLD in the MALG/OKT3 group was 12.5%, which is significantly higher than that of patients receiving other immunosuppressive regimes (0.7%, P = 0.015). The incidence of PTLD was also significantly greater in the 13 patients at risk for primary EBV infection compared to the EBV seropositive patients (23.1 vs. 0.7%, P = 0.002). Only 2 seronegative patients received sequential MALG/OKT3; both developed PTLD. Thus, the population most at risk is that receiving potent antilymphocyte preparations in the setting of primary EBV infection. Allograft involvement with PTLD must be considered in the differential diagnosis of allograft dysfunction, as early diagnosis may permit the successful management of this complication.

Ehlers-Danlos syndrome IV due to a novel defect in type III procollagen.

Ehlers-Danlos syndrome type IV (EDS IV) is characterized by variable changes in the skin, arterial fragility, bowel perforation, minimal joint involvement, and either autosomal recessive or autosomal dominant inheritance. The unifying biochemical abnormality is a deficiency of type III collagen; all patients studied thus far have shown a defect in either synthesis or in secretion of type III procollagen. We report on an adolescent boy who inherited EDS IV from his father and who developed a spontaneous subclavian artery aneurysm. In vitro studies of collagen production in dermal fibroblasts showed normal amounts of pro alpha 1 (III) messenger RNA and synthesis and secretion of nearly equal amounts of normal and of structurally abnormal pro alpha 1 (III) monomers. This patient is biochemically distinct from previous cases of EDS IV and is likely heterozygous for a mutation that results in an aberrant type III procollagen that is particularly susceptible to protease degradation.

Cyclosporine-induced autoimmunity and immune hyperreactivity.

Cyclosporine (CS) is a potent immunosuppressive agent which under some circumstances paradoxically augments DTH responses, aggravates some autoimmune diseases, and induces specific forms of autoimmunity. The enhancement of DTH and other immune responses is closely related to the timing of CS administration relative to immunization. CS inhibits IL-2 production (and several other lymphokines) at a pretranscriptional level, but does not usually prevent the antigen-specific priming of T cells, such that T cells may be poised to respond as soon as CS is withdrawn. Thus, accelerated GVHD and allograft rejection may occur after withdrawal of CS. CS has been shown to aggravate and/or induce relapse in several autoimmune diseases including collagen-induced arthritis, EAE, autoimmune thyroiditis, uveitis in SDA chickens, and an autoimmune form of myocarditis in mice. CS may enhance immune responses by inactivating suppressor cells, by altering Th1/Th2 antagonism (e.g., CS promotes a protective Th1-type response in BALB/c mice infected with Leishmania major), or by promoting T cell activation through a CS-resistant IL-2-independent T cell activation/differentiation pathway. At least three forms of CS-induced autoimmunity have been described: Syngeneic or autologous GVHD which occurs in CS-treated syngeneic or autologous bone marrow transplant recipients after CS is withdrawn in rats, mice, and humans; a systemic autoimmune disease with polyarthritis and glomerulonephritis which occurs in irradiated CBA/N mice treated with CS; and organ-specific autoimmune diseases which occur in mice treated with CS during the neonatal period. The precise mechanisms by which CS induces these autoimmune diseases are not clear, however, CS affects immune tolerance at three levels. CS induces thymic medullary involution with loss of medullary Ia+ cells, and appears to at least partially block the transition from double positive (CD4+CD8+) to single positive (mature type) thymocytes. In syngeneic bone marrow chimeras, CS appears to inhibit the intrathymic deletion of clones with relatively low affinity, but not those with high affinity, to self antigens. CS appears to inhibit the action of suppressor T cells which normally maintain an innate form of resistance to autoimmunity. Finally, CS has been shown to prevent the development of T cell clonal anergy. There is redundancy in immune tolerance mechanisms, i.e., clonal deletion, clonal anergy, and suppressor cells can each maintain tolerance to similar antigens, such that it is likely that CS must cripple more than one tolerance mechanism for autoimmunity to occur.

Elastosis in benign and malignant breast disease.

Elastosis, the presence of clumps of elastic fibers, is known to occur frequently in association with breast carcinoma. To test the hypothesis that the degree of elastosis increases progressively in fibrocystic disease with the severity of epitheliosis (epithelial hyperplasia, papillomatosis; widely believed to be the only premalignant component of fibrocystic disease) and increases further with intraductal and infiltrating duct carcinoma, breast tissue stained for elastic fibers from 84 women in the fifth decade of life was studied. Fourteen cases were evaluated in each of six disease categories: fibrocystic disease without epitheliosis; fibrocystic disease with epitheliosis, graded subjectively as mild, moderate, or severe (based on the degree of epithelial hyperplasia); intraductal carcinoma; and infiltrating duct carcinoma of the breast. Periductal elastosis and stromal elastosis were graded on a scale of 0 to 4 (absent to massive). The grades of both periductal elastosis and stromal elastosis were compared with those for the six disease categories ranked by increasingly advanced disease. The results indicate that the grades of periductal elastosis (Spearman rank correlation coefficient [R] = 0.54; P less than 0.001) and stromal elastosis (R = 0.75; P less than 0.001) increase progressively with the severity of breast disease.

Is pain crisis a cause of death in sickle cell disease?

It has been a matter of controversy as to whether patients with sickle cell disease die of crisis or merely in crisis. The authors reviewed the 74 patients with sickle cell disease autopsied at The Johns Hopkins Hospital. From clinical review, there were 20 (27%) who died with pain crisis, 51 (69%) who died without pain crisis, and 3 (4%) for whom documentation was insufficient. On pathology review, death was attributable to infection in 19 (26%), uremia in 9 (12%), sequestration crisis in 9 (12%), necrotic bone marrow emboli in 7 (9%), and miscellaneous causes in 14 (19%); in 16 (22%) patients no cause of death could be identified. Death was explained in 47/51 (92%) patients without pain crisis; but only in 11/20 (55%, P less than 0.01) patients dying in pain crisis. The disproportionately large number of patients dying in pain crisis with an unexplained cause of death suggests that pain crisis may account for the death of some patients with sickle cell disease.

Homozygosity mapping and linkage analysis demonstrate that autosomal recessive congenital hereditary endothelial dystrophy (CHED) and autosomal dominant CHED are genetically distinct.

BACKGROUND: Congenital hereditary endothelial dystrophy (CHED) is a corneal dystrophy characterised by diffuse bilateral corneal clouding resulting in impaired vision. It is inherited in either an autosomal dominant (AD) or autosomal recessive (AR) manner. The AD form of CHED has been mapped to the pericentromeric region of chromosome 20. Another endothelial dystrophy, posterior polymorphous dystrophy (PPM), has been linked to a larger but overlapping region on chromosome 20. A large, Irish, consanguineous family with AR CHED was investigated to determine if there was linkage to this region. METHODS: The technique of linkage analysis with polymorphic microsatellite markers amplified by polymerase chain reaction (PCR) was used. In addition, a DNA pooling approach to homozygosity mapping was employed to demonstrate the efficiency of this method. RESULTS: Conventional genetic analysis in addition to a pooled DNA strategy excludes linkage of AR CHED to the AD CHED and larger PPMD loci. CONCLUSION: This demonstrates that AR CHED is genetically distinct from AD CHED and PPMD.

Unusual renal pseudotumor (cloison) in a young woman with chronic rejection of a transplanted kidney.

Localized nontumorous conditions may simulate renal neoplasms. A case is described in which a cloison was observed in conjunction with chronic rejection of a renal transplant.

Patterns of MHC antigenic modulation in cyclosporine-induced autoimmunity. Implications for pathogenesis.

To explore the role of aberrant MHC expression in the pathogenesis of cyclosporine-induced autoimmunity (CSIA), we examined the patterns of major histocompatibility complex (MHC) class I and II antigenic modulation during disease induction and the relationship between MHC modulation and tissue injury. Disease was induced consistently in rats but never in mice. Unlike rats, mice were resistant to downmodulation by cyclosporine of class II antigen expression in the thymic medulla. In rats with CSIA, MHC class I and II antigen expression was induced on all target epithelia, frequently before mononuclear infiltration or tissue injury, consistent with a role for MHC antigens in selecting cells for injury. Much increased numbers of strongly class II-positive interstitial dendritic cells were present throughout the body, even in tissues not involved by CSIA. Thus, class II expression alone is insufficient to lead to cell injury in CSIA.