Interferon-gamma and interleukin-10 messenger RNA are up-regulated after orthotopic liver transplantation in tolerant rats: evidence for cytokine-mediated immune dysregulation

BACKGROUND

Immune regulation requires antigen recognition, signaling, activation, secretion of cytokines, and effector function by lymphocytes. Although there is redundancy in the activation and function of the immune response, some cytokines simultaneously promote and suppress different pathways of immunity. In the experiments reported here we compare cytokine gene expression within liver allografts from tolerant rats with normal and isografted liver tissue. We also compare the secretion of interferon-gamma (IFN-gamma) in the supernatant from mixed lymphocyte cultures by using peripheral blood lymphocytes stimulated against donor antigen.

METHODS

Orthotopic liver transplantations were performed using the cuff technique without hepatic artery revascularization. Nonisotopic in situ hybridization (ISH) was used to detect and localize messenger RNA to specific cells within tissue. Antisense DNA probes were generated to interleukin-2 (IL-2), IL-4, IL-10, and IFN-gamma. One-way mixed lymphocyte cultures were set up against irradiated donor splenocytes, and the supernatant was collected to measure IFN-gamma by enzyme-linked immunosorbent assay.

RESULTS

Expression of IFN-gamma and IL-10 was up-regulated in tolerant animals versus normal or isografted liver (p = 0.0002 and 0.0001, IFN-gamma and IL-10, respectively). In situ hybridization localized the expression of messenger RNA predominantly to the cytoplasm of the hepatocytes. Levels of IFN-gamma were higher in the supernatant from proliferating peripheral lymphocytes against donor antigen from tolerant animals versus naive control animals.

CONCLUSIONS

Expression of IFN-gamma and IL-10 is up-regulated in hepatocytes from allograft tissue after orthotopic liver transplantation. We believe that the up-regulation of IL-10 cross-regulates the effector function of IFN-gamma and supports cytokine-mediated immune dysregulation, which may be a mechanism of tolerance after orthotopic liver transplantation in rats.

Association of down-regulation of cytokine activity with rat hind limb allograft survival

Cytokines are short-acting protein modulators of many physiologic processes including graft rejection. An understanding of the production, action, and interaction of cytokines may lead to better appreciation of the complex mechanism of graft rejection. The potential would then exist for more selective and less-toxic means of modulating the immune response. A rat hind limb allograft model with major immunohistoincompatibility was used to study the local mRNA expression of IL-1 alpha, IL-2, IL-6, gamma interferon (gamma INF), platelet-derived growth factor-alpha (PDGF-alpha), basic fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta) during acute allograft rejection. A 14-day postoperative course of immunosuppressive therapy with FK506 or rapamycin was administered. In situ hybridization was performed on serial full-thickness skin punch biopsies of the untreated rejecting limb allograft and compared with tissue from treated allografts, isografts, and to normal limb tissue. A sequential pattern of cytokine mRNA expression was demonstrated which progressed in a time-dependent manner and paralleled observed clinical rejection. Maximal cytokine mRNA expression correlated with peak graft rejection. Cellular expression of IL-1 alpha, IL-2, IL-6, gamma-INF, FGF, and TGF-beta mRNA was suppressed with FK506 to below isograft levels, and clinical rejection was not observed with the doses, routes, and schedules used. Rapamycin was ineffective in suppressing cytokine expression, and allograft rejection was not prevented. Isografts demonstrated no evidence of rejection. The in situ hybridization technique demonstrates a time-dependent, selective expression of cytokines within rejecting allograft tissue, and the modification of this response with immunosuppressive therapy. Down-regulation of cytokine expression is associated with clinical allograft survival.

Cardiac allograft vascular disease. Relationship to microvascular cell surface markers and inflammatory cell phenotypes on endomyocardial biopsy

BACKGROUND

Cardiac allograft vascular disease is characterized by accelerated and diffuse intimal proliferation involving both the microvasculature and epicardial vessels. Because in vivo documentation of this complication is now possible with intracoronary ultrasound imaging, we can examine the relationship of intimal proliferation to markers of immunity and endothelial activation. We hypothesize that alterations of microvascular cell surface markers likely mirror changes in the epicardial vessels that may be important in the pathophysiology of intimal proliferation.

METHODS AND RESULTS

Forty-three heart transplant patients were examined by intracoronary ultrasound more than 1 year after transplantation, and these images were analyzed to obtain mean intimal thickness and intimal thickness class (I through IV), calculated from the mean thickness and circumferential involvement. Right ventricular endomyocardial biopsies obtained at the time of intracoronary ultrasound were examined by immunohistochemistry to detect microvascular expression of histocompatibility leukocyte antigen (HLA) classes I and II (HLA ABC, DR, DP, and DQ); endothelial-specific antigen detected by the monoclonal antibody E 1.5; intercellular adhesion molecules (ICAM-1); CD4+ and CD8+ lymphocytes and macrophages (CD 14+). Microvascular antigen expression was graded 1 through 5 on the basis of the diffuseness of positive staining. The number of each inflammatory cell phenotype present per high-power field was counted. By ANOVA, scores for HLA DR, HLA DQ, and E1.5 expression were lower in intimal thickness classes II, III, and IV compared with class I. This inverse relationship was significant by linear regression analysis of mean intimal thickness. Inflammatory cells were not significantly correlated with intimal thickening. Rejection incidence was higher, and time since transplantation longer, in intimal thickness classes II, III, and IV compared with class I.

CONCLUSION

Transplant coronary artery intimal proliferation is associated with alteration of microvascular endothelial cell surface markers. These changes in cell surface antigen expression could provide the substrate for coronary artery intimal proliferation and narrowing.

Intravenous methylprednisolone and oral alkylating agent therapy of prednisone-resistant pediatric focal segmental glomerulosclerosis: a long-term follow-up

Prednisone-resistant nephrotic syndrome (NS) due to focal segmental glomerulosclerosis (FSGS), the most common acquired disease requiring chronic dialysis and transplantation in children, has a low likelihood of response to alkylating agent therapy. This report summarizes the results of a 0.75-12.5 (average 6.33) year follow-up of 32 pediatric cases of prednisone-resistant FSGS treated with a regimen of high-dose intravenous methylprednisolone (M-P) and alternate-day prednisone, plus an alkylating agent in 25/32. On last followup: 21/32 were in remission [urine protein-to-creatinine ratios (Pru/Cru) < or = 0.2]; 3/32 had mild proteinuria (Pru/Cru > 0.2-0.5); 2/32 had moderate proteinuria (Pru/Cru > 0.5-1.9); and 6/32 remained nephrotic (Pru/Cru > or = 2.0). Of the incomplete or nonresponders; 3/11 progressed to end-stage renal failure; 5/11 had decreased creatinine clearances (CrCl): and 3/11 had persistent proteinuria with normal CrCl. All of the persistently nephrotic children, but none of the complete responders, developed decreased CrCl. All of the complete responders were able to stop treatment; four relapsed but responded well to retreatment.

CONCLUSIONS

This regimen of methylprednisolone and alternate-day prednisone, with or without an alkylating agent, is effective in achieving sustained remissions and preserving normal renal function in the great majority of children with FSGS and prednisone-resistant NS.

Mechanisms of filtration failure during postischemic injury of the human kidney. A study of the reperfused renal allograft

Postischemic filtration failure in experimental animals results primarily from depression of the transcapillary hydraulic pressure difference (delta P), a quantity that cannot be determined in humans. To circumvent this limitation we determined the GFR and each of its remaining determinants in transplanted kidneys. Findings in 12 allografts that exhibited subsequent normofiltration (group 1) were compared with those in 11 allografts that exhibited persistent hypofiltration (group 2). Determinations were made intraoperatively in the exposed graft after 1-3 h of reperfusion. GFR (6 +/- 2 vs 29 +/- 5 ml/min) and renal plasma flow by Doppler flow meter (140 +/- 30 vs 315 +/- 49 ml/min) were significantly lower in group 2 than group 1. Morphometric analysis of glomeruli obtained by biopsy and a structural hydrodynamic model of viscous flow revealed the glomerular ultrafiltration coefficient to be similar, averaging 3.5 +/- 0.6 and 3.1 +/- 0.2 ml/(min.mmHg) in group 2 vs 1, respectively. Corresponding values for plasma oncotic pressure were also similar, averaging 19 +/- 1 vs 21 +/- 1 mmHg. We next used a mathematical model of glomerular ultrafiltration and a sensitivity analysis to calculate the prevailing range for delta P from the foregoing measured quantities. This revealed delta P to vary from only 20-21 mmHg in group 2 vs 34-45 mmHg in group 1 (P < 0.001). Further morphometric analysis revealed the diameters of Bowman's space and tubular lumens, as well as the percentage of tubular cells that were necrotic or devoid of brush border, to be similar in the two groups. We thus conclude (a) that delta P depression is the predominant cause of hypofiltration in this form of postischemic injury; and (b) that afferent vasoconstriction rather than tubular obstruction is the proximate cause of the delta P depression.

Virus-associated hemophagocytic syndrome characterized by clonal Epstein-Barr virus genome

Virus-associated hemophagocytic syndromes are a heterogeneous group of disorders in which viral infection is associated with a proliferation of hemophagocytic histiocytes throughout the reticuloendothelial system. The authors report the case of a 24-year-old Vietnamese male who developed a hemophagocytic syndrome associated with Epstein-Barr virus (EBV) and who died following a rapidly progressive course. A proliferation of reactive-appearing lymphoid cells was associated with an extensive proliferation of erythrophagocytic histiocytes. Immunophenotypically, the lymphoid infiltrate consisted of CD56+ natural killer cells, predominantly CD8+ T-cells and rare B-cells (CD20+). Double-label immunohistochemical studies showed CD3+ T-cells and CD56+ natural killer cells to be distinct cell populations. Combined immunohistochemical-in situ hybridization studies localized EBV to CD43+, CD3-, CD68-, lymphoid-appearing cells, indicating the presence of EBV within natural killer cells. Southern hybridization analysis of EBV genomic termini revealed clonal EBV genome. However, there was no detectable immunoglobulin or T-cell receptor gene rearrangements. The findings indicate that this case of hemophagocytic syndrome represents a clonal proliferation of natural killer cells containing EBV and highlights the importance of the analysis of EBV genomic termini for determination of clonality in EBV-associated proliferations. It is possible that other cases of fulminant EBV-associated hemophagocytic syndromes represent clonal natural killer cell proliferations.

Light microscopic and immunohistochemical features in serial biopsies of epidermal versus dermal allografts

The local immune response to allograft dermis and epidermis was studied in a rat skin-graft model. Biopsies taken at varying times after transplantation were analyzed using routine light microscopy and a panel of monoclonal antibodies. The dermis appeared to be spared by the rejection process, whereas the epithelium and adnexal elements of the dermis were destroyed. The persistence of dermis transplanted across major histoincompatibilities may allow it to be useful in reconstructing large skin losses.

Congenital unilateral hydronephrosis in a rat model: continuous renal pelvic and bladder pressures

We investigated a rat model with inbred unilateral congenital hydronephrosis. Simultaneous bladder and renal pelvic pressures were measured during different urinary flows, and during bladder filling and voiding in these congenitally hydronephrotic rats (approximately 45 days old) and normal nonhydronephrotic rats from the same colony. Differential pressures between pelvis and proximal ureter were determined. Upon termination of the experiment the urinary tract was removed and processed for histological examination. Hydronephrotic rats had significantly higher renal pelvic pressures throughout bladder filling at all urinary flow rates than normal rats. These elevated renal pelvic pressures exceeded bladder pressures at high flows (for example bladder pressure at 50% capacity was 8.9 +/- 3.1 cm. water and corresponding pelvic pressure was 20.8 +/- 2.1 [hydronephrosis] versus pelvic pressure 7.4 +/- 1.1 [control]). While pressures in the proximal ureter were higher than in the pelvis in normal rats the hydronephrotic rats showed significantly higher pressures in the pelvis, suggesting that the site of obstruction is the ureteropelvic junction. Histological evaluation of the excised kidneys revealed only minimal tubular changes. This study represents a unique animal model with unilateral hydronephrosis from a partially obstructing ureteropelvic junction. Moreover, the data indicate that partial urinary obstruction and the associated renal pelvic pressures should be defined with reference to bladder fullness and urinary flow rates.

Morphologic features of chronic rejection in kidney and less commonly transplanted organs

Chronic rejection is characterized by morphological evidence of destruction of the transplanted organ. The injury to the organ is associated with collagenization of variable degree. The destruction and fibrosis of the organ is probably the result of 1) direct alloimmune cytotoxic injury (i.e., acute and/or ongoing rejection) of the organ tissue, and 2) end-organ ischemic injury secondary to fibroproliferative endarteritis (i.e., chronic vascular rejection). The cardinal morphological feature of chronic rejection in all allografts is fibroproliferative endarteritis, which is characterized by widening of the subendothelial space due to a cellular fibrosis which may have an onion-skin appearance with a PAS or silver stain. Macrophages with foamy cytoplasm and lymphocytes may be present in this fibrotic tissue. The smooth muscle wall may show foci of fibrosis as well, if involved by previous necrotizing rejection. These features are commonly found in needle core biopsies of kidney allografts and may involve the interlobular, arcuate, and interlobar arteries. They are less commonly found in pancreatic needle biopsies, and only rarely in hepatic and pulmonary allograft biopsies, rendering the diagnosis of chronic rejection often difficult to establish. Though the vascular lesions may not be apparent in biopsies, they are typically found in explanted organs where larger vessels can be examined. Thus, the diagnosis of chronic rejection may rest upon other and in some instances less specific abnormalities, usually ischemic in origin due to vascular lesions and consequent decreased perfusion of the graft.(ABSTRACT TRUNCATED AT 250 WORDS)

RANTES chemokine expression in cell-mediated transplant rejection of the kidney

RANTES (regulated upon activation, normal T cell expressed and secreted) is a chemotactic cytokine (a chemokine) for memory T lymphocytes, monocytes, and eosinophils. RANTES expression was studied in renal allograft biopsy specimens. Although RANTES was not expressed in samples taken one hour after transplantation, or in native renal biopsy specimens from patients with cyclosporin nephrotoxicity, it was expressed during cell-mediated transplant rejection. RANTES mRNA was detected in infiltrating mononuclear cells and renal tubular epithelium, and RANTES protein was localised to mononuclear cells, tubular epithelium, and vascular endothelium. This suggests RANTES has a role in allograft rejection.

Cyclosporin A nephropathy: standardization of the evaluation of kidney biopsies

An advisory board of nephropathologists with personal experience in the evaluation of biopsies from patients treated with cyclosporin A (CyA) was set up to address the following problems: 1. Definition of CyA nephropathy as seen in patients with autoimmune diseases; 2. Evaluation of the reliability and reproducibility of the diagnostic criteria for the different morphological lesions seen in CyA nephropathy; 3. Classification of the morphological lesions according to their clinical relevance; 4. Estimation of the possible progression of CyA nephropathy with continuous CyA therapy. The most frequent lesions attributable to CyA therapy in patients with autoimmune diseases are tubular atrophy, interstitial fibrosis, and arteriolar hyalinosis. All other lesions are rare. The reproducibility and diagnostic reliability is high for tubular atrophy and interstitial fibrosis, but low for arteriolar lesions even among experienced nephropathologists. The biopsies may be classified according to the severity of tubular atrophy, interstitial fibrosis and arteriolar hyalinosis with regard to their clinical relevance: In group I (within normal limits), CyA therapy can be continued; in group III (moderate-to-severe CyA-related lesions), CyA should be stopped if possible. Among group II biopsies (slight CyA-related abnormalities), no recommendation can be made in the absence of a second biopsy after a further year of CyA therapy. No clear-cut answer can be given concerning the progression of CyA-induced lesions. However, no significant progression has been found in the cases studied to date.

Monocyte haptotaxis induced by the RANTES chemokine

BACKGROUND

Soluble mediators and inducible cell-surface molecules coordinate the ordered cascade of events giving rise to inflammation. The specific mechanisms underlying the attraction of antigen-specific cells into a site of inflammation remain sketchy, however. In particular, it is unclear how chemoattractants cause rapidly moving immune cells to adhere to the blood vessel wall and to enter inflamed tissues.

RESULTS

Here we show that RANTES, a potent chemo-attractant for monocytes and T lymphocytes, is inducibly expressed within an inflamed organ, binds to endothelial cells, and promotes haptotaxis, the migration of cells induced by surface-bound gradients.

CONCLUSION

These findings lead us to propose a model for the role of RANTES in the migration of antigen-specific immune cells into an inflammatory site.

The diagnosis of obliterative bronchiolitis after heart-lung and lung transplantation: low yield of transbronchial lung biopsy

Obliterative bronchiolitis is the most significant long-term complication of lung and heart-lung transplantation characterized by the rapid development of obstructive airway disease. It is thought to be a manifestation of chronic rejection and has been treated, with limited success, with augmentation of immunosuppression. Early detection of obliterative bronchiolitis and prompt initiation of therapy may result in an improved outcome. The role of transbronchial biopsy has been reported in the diagnosis of acute rejection and infection but not for obliterative bronchiolitis. To study this problem we retrospectively reviewed the transbronchial biopsy results of patients with advanced clinical obliterative bronchiolitis, as defined physiologically. Between January 1, 1988, and December 31, 1991, 46 "sets" of adequate transbronchial biopsy specimens were obtained from 16 patients (15 heart-lung recipients and one double lung recipient). Seven sets of transbronchial biopsy specimens (15.2%) showed obliterative bronchiolitis by pathologic study. In four patients with severe clinical obliterative bronchiolitis, only one transbronchial biopsy specimen of seven (14.3%) showed obliterative bronchiolitis. The pathologic diagnosis of obliterative bronchiolitis was confirmed in three of these patients at the time of autopsy or retransplantation. Twelve patients were still alive at the end of the study period, and all experienced further deterioration of lung function typical for obliterative bronchiolitis. We conclude that the sensitivity of transbronchial biopsy for obliterative bronchiolitis is poor. Possible explanations for these results are explored.

Adenine phosphoribosyltransferase deficiency with renal deposition of 2,8-dihydroxyadenine leading to nephrolithiasis and chronic renal failure

Homozygous adenine phosphoribosyltransferase deficiency is a genetic defect that is associated with 2,8-dihydroxyadenine urolithiasis. Since the prevalence of the heterozygous state is found in 0.4% to 1.2% of the population, it is surprising that more cases of 2,8-dihydroxyadenine urolithiasis have not been reported. Herein we describe a patient with complete adenine phosphoribosyltransferase deficiency with 2,8-dihydroxyadenine urolithiasis leading to chronic renal failure. Gene sequencing revealed that the patient is a compound heterozygote. One of the mutations (a T insertion between bases 346 and 347) has been encountered before, but the second (a G-to-A substitution at base 1356) has not been previously reported. Possible explanations for the unexpected rarity of 2,8-dihydroxyadenine urolithiasis are discussed.

The role of transbronchial biopsies in the management of lung transplant recipients

We examined the utility of the transbronchial biopsy in the management of 53 lung transplant patients. One hundred thirty-three protocol biopsies were performed to ascertain the frequency and nature of abnormalities in clinically stable or asymptomatic patients; 128 diagnostic biopsies were performed in clinically ill patients to assess the morphologic abnormalities before the institution of therapy, and 105 biopsies were performed to assess the response to therapy. Histologic evidence of acute rejection was found in 24% of the protocol biopsies, and infection was found in 17%. Twenty-five patients with grade 1 or grade 2 perivascular infiltrates in protocol biopsies did not receive antirejection therapy. Follow-up biopsy in these patients showed spontaneous resolution of the infiltrates in 19% and increased infiltrates in 6. Only two of these patients became clinically ill, representing "progression" to clinical rejection in only 8% of the nontreated patients. Forty percent of the biopsies performed to rule out acute rejection or infection had histologic features of acute rejection, and another 23% had features of infection. Treatment of patients with clinical and histologic evidence of rejection was associated with rapid resolution of clinical symptoms in nearly 90% of the patients, but follow-up biopsies showed residual infiltrates compatible with ongoing or resolving rejection in 52%. Despite repeat antirejection therapy in some patients, these infiltrates persisted for an average of 30 days after the diagnostic biopsy. Follow-up biopsies also showed asymptomatic infection, usually cytomegalovirus pneumonitis, which often persisted for weeks despite the lack of symptoms. Perivascular infiltrates compatible with acute rejection were also found in 38% of biopsy specimens with evidence of infection. These perivascular infiltrates resolved with antibiotic treatment alone in nearly 50% of the patients with these features. Although perivascular mononuclear cell infiltrates are the cardinal histologic feature of acute rejection, similar infiltrates occur in patients who apparently have infection alone and other patients who have both infection and rejection; infiltrates compatible with minimal, mild, and moderate acute rejection also occur in clinically asymptomatic patients. These histologic findings are a challenge to both the pathologists' and the clinicians' skills in the management of the lung transplant patient.

Topographical dissociation of BCL-2 messenger RNA and protein expression in human lymphoid tissues

Immunohistochemistry and in situ hybridization with a synthetic oligonucleotide probe were used to compare the topographical distribution of BCL-2 proto-oncogenic protein with that of its messenger RNA (mRNA) in normal lymphoid tissues, follicular lymphomas, and lymphoma-derived cell lines. In normal lymph nodes, BCL-2 protein was most abundant in the small lymphocytes of primary lymphoid follicles and the mantle zones of secondary follicles, virtually absent within germinal centers, and of variable abundance in many interfollicular cells. In contrast, the distribution of BCL-2 mRNA was roughly reciprocal to that of the protein with intense hybridization signal in germinal centers and almost none in mantle zones. Discordant BCL-2 RNA and protein levels were also observed in tonsillar epithelial cells and cortical thymocytes. Concordant and abundant expression of BCL-2 mRNA and protein was detected in biopsy tissues and cell lines from t(14;18)-carrying lymphomas. The contrasting distributions of BCL-2 protein and RNA in normal lymphoid tissues suggest that translational and posttranslational control mechanisms play a significant role in regulating BCL-2 protein levels in germinal center cells, epithelial cells, and cortical thymocytes. Concordant BCL-2 mRNA and protein levels in follicular lymphomas suggest that translational control mechanisms may be disrupted as part of the sequence of genetic changes that transforms normal lymphoid cells into neoplastic follicular lymphoma cells.

Extent and course of glomerular injury in human membranous glomerulopathy

Glomerular permselectivity and dynamics were evaluated serially in 14 nephrotic patients with membranous glomerulopathy (MG). Analysis of transglomerular dextran sieving, before and again after proteinuria remitted, revealed persistent depression by 60-80% of glomerular pore density and the two-kidney ultrafiltration coefficient, Kf. The glomerular filtration rate was lowered by half on each occasion. Morphometric examination of glomeruli in a second group of 16 nephrotic patients with MG revealed a low prevalence of glomerulosclerosis (5 +/- 3%) and a twofold increase in filtration surface due to marked glomerular hypertrophy. Presumably, widening by threefold of the basement membrane and/or epithelial podocytes accounted for the computed reduction in ultrafiltration capacity. There was no correlation between glomerular structure and the subsequent course of MG over the ensuing 24-96 mo. Rather, a twofold expansion of the interstitial compartment predicted those who went on to exhibit progressive renal insufficiency. We conclude that increasing resistance to water flow by walls of patent and perfused glomerular capillaries is the proximate cause of progressive renal insufficiency in MG.

Renal insufficiency secondary to 2,8-dihydroxyadenine urolithiasis

A 48-year-old man with a history of recurrent urolithiasis and chronic renal failure underwent a nephrectomy for a renal mass. At surgery the mass proved to be a calculus impacted in a dilated calyx. Gross examination of the kidney revealed chalky white deposits in the deep medulla and papillary tips. Histologic examination revealed chronic interstitial nephritis with brown spicules within some tubular epithelial cells and larger deposits of brown crystals within tubular lumina, the interstitium of the medulla, and papillary tips. Polarization microscopy revealed individual crystals scattered throughout the renal parenchyma. Although the arrangement of the crystals was reminiscent of uric acid, and, in fact, a clinical diagnosis of gouty nephropathy was made, x-ray diffraction analysis demonstrated crystals of 2,8-dihydroxyadenine. Enzymatic studies confirmed the complete absence of adenine phosphoribosyltransferase activity in erythrocyte lysates.

Renal transplant function after ten years of cyclosporine

Although the nephrotoxic side effects of cyclosporine are well known, the impact of long-term CsA on renal transplant function is uncertain. We studied 5-10-year renal function in 347 CsA-treated patients, and in 64 randomly selected non-CsA-treated patients who had a minimum of 55 months of graft function. Non-CsA patients had a lower creatinine (Cr) level at one year than CsA patients (P = .001), with no change in renal function over time (P = .6). In CsA-treated patients there was also no suggestion of progressive renal damage, as evidenced by no change in Cr or 1/Cr. Simple linear regression models of 1/Cr vs. time for the first 10 years posttransplant were fit to the data for each patient. Analysis of the Y-intercept estimates from these regressions showed that age (P = .001), sex (P = .001), cyclosporine toxicity (P = .024), and initial cyclosporine dosage (P = .016) significantly affected the one-year serum Cr. Variables not affecting one-year Cr included donor source, early rejection episodes, late rejection episodes, ATN, diabetes, transplant number, HLA ABDR mismatch (for cadaver transplants), maximum PRA, and PRA at transplant. Analysis of the slope estimates from the regressions revealed that only age (P = .001) and late rejection episodes (P = .001) significantly affected the rate of change in 1/Cr over time. We conclude that, in long-term renal transplant patients, there is no evidence of progressive deterioration in renal function due to CsA nephrotoxicity.

Microvillous inclusion disease. The importance of electron microscopy for diagnosis

We report two cases of microvillous inclusion disease (MID) occurring in a set of siblings. Although it is a rare disorder, MID appears to be a common cause of familial intractable secretory diarrhea. Diagnosis rests on the ultrastructural finding of intracytoplasmic inclusions that are lined by intact microvilli. These inclusions are present in the absorptive surface epithelial cells of the small and large intestine and are associated with poorly developed surface brush border microvilli. The prognosis of MID is poor and curative therapy is not currently available. Because MID appears to be a hereditary disorder, genetic counseling of affected families is essential.

Helicobacter pylori infection and the risk of gastric carcinoma

BACKGROUND

Infection with Helicobacter pylori has been linked with chronic atrophic gastritis, an inflammatory precursor of gastric adenocarcinoma. In a nested case-control study, we explored whether H. pylori infection increases the risk of gastric carcinoma.

METHODS

From a cohort of 128,992 persons followed since the mid-1960s at a health maintenance organization, 186 patients with gastric carcinoma were selected as case patients and were matched according to age, sex, and race with 186 control subjects without gastric carcinoma. Stored serum samples collected during the 1960s were tested for IgG antibodies to H. pylori by enzyme-linked immunosorbent assay. Data on cigarette use, blood group, ulcer disease, and gastric surgery were obtained from questionnaires administered at enrollment. Tissue sections and pathology reports were reviewed to confirm the histologic results.

RESULTS

The mean time between serum collection and the diagnosis of gastric carcinoma was 14.2 years. Of the 109 patients with confirmed gastric adenocarcinoma (excluding tumors of the gastroesophageal junction), 84 percent had been infected previously with H. pylori, as compared with 61 percent of the matched control subjects (odds ratio, 3.6; 95 percent confidence interval, 1.8 to 7.3). Tumors of the gastroesophageal junction were not linked to H. pylori infection, nor were tumors in the gastric cardia. H. pylori was a particularly strong risk factor for stomach cancer in women (odds ratio, 18) and blacks (odds ratio, 9). A history of gastric surgery was independently associated with the development of cancer (odds ratio, 17; P = 0.03), but a history of peptic ulcer disease was negatively associated with subsequent gastric carcinoma (odds ratio, 0.2; P = 0.02). Neither blood group nor smoking history affected risk.

CONCLUSIONS

Infection with H. pylori is associated with an increased risk of gastric adenocarcinoma and may be a cofactor in the pathogenesis of this malignant condition.

T lymphocyte-synovial fibroblast interactions induced by mycobacterial proteins in rheumatoid arthritis

An in vitro system was established in which single-cell suspensions of lymphocytes and synovial cells from the joints of patients with rheumatoid arthritis were cultured and produced an outgrowth of an organized inflammatory tissue with an extracellular matrix and capsule. The tissue outgrowth, which had histologic features of pannus, required the addition of mycobacterial antigen and interleukin-2 to the tissue culture medium and was dependent upon the presence of T lymphocytes and their interaction with synovial fibroblasts.

Glomerular dysfunction in nephrotic humans with minimal changes or focal glomerulosclerosis

Fractional clearances (theta) of uncharged dextrans (radii 28-60 A) were used to characterize glomerular dysfunction in 34 nephrotic humans with either minimal-change nephropathy (MCN) or focal, segmental glomerulosclerosis (FSGS). A theoretical analysis of theta of dextran with a heteroporous membrane model revealed a similar alteration, more marked in FSGS than MCN. The number of restrictive pores perforating the major membrane component was reduced in parallel with the prevailing glomerular filtration rate (GFR). Parallel shuntlike pores in the remaining membrane component were more prominent, pointing to impaired size selectivity. However, the theta of large (60 A) dextrans attributable to these shunts exceeded control in FSGS only, suggesting that coexistent impairment of charge selectivity contributed importantly to the proteinuria in MCN. Membrane properties returned toward normal when MCN remitted. Glomerular morphometry revealed the frequency of epithelial filtration slits to vary with the extent of membrane dysfunction. Despite offsetting hypertrophy of remnant glomeruli in FSGS, a loss of filtration surface due to sclerosis likely contributed to the more marked reductions in pore number and GFR observed in this disorder than in MCN.