Early critical cortical infarction by anti-angiotensin II type 1 receptor antibody: A case report and literature review

RATIONALE

Anti-angiotensin II type 1 receptor antibodies (AT1R-Abs) have been demonstrated to increase the risk of antibody-mediated rejection. We report a case of AT1R-Ab mediated rejection which caused early critical cortical infarction.

PATIENT CONCERNS

A 52-year-old man with end-stage kidney disease underwent preemptive kidney transplantation (KT) from his wife. He had no immunologic risk except ABO incompatibility. Proper desensitization treatment were applied prior to KT. On postoperative day 1, he showed stable clinical course with adequate urine output, but there was no decrease in serum creatinine level and imaging studies showed hypoperfusion in the transplanted kidney.

DIAGNOSES

Allograft biopsy revealed total cortical infarction with severe necrotizing vasculitis, but the medullary area was preserved. Serum AT1R-Ab concentration was elevated from 10.9 U/mL before KT to 19.1 U/mL on 7 days after KT.

INTERVENTIONS

He was treated with plasmapheresis, intravenous immunoglobulin, rituximab, high-dose methylprednisolone, and bortezomib.

OUTCOMES

The treatment showed a partial response, and he was discharged with 7.3 mg/dL creatinine level. At 4 months, his creatinine plateaued at 5.5 mg/dL and AT1R-Ab decreased to 3.6 U/mL.

LESSONS

This case highlights the risk of early active antibody-mediated rejection by preformed AT1R-Ab, suggesting its ability to exhibit atypical histopathologic findings, such as total cortical infarction.

Renal Morphology in Coronavirus Disease: A Literature Review

Renal biopsy is useful to better understand the histological pattern of a lesion (glomerular, tubulointerstitial, and vascular) and the pathogenesis that leads to kidney failure. The potential impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the kidneys is still undetermined, and a variety of lesions are seen in the kidney tissue of coronavirus disease patients. This review is based on the morphological findings of patients described in case reports and a series of published cases. A search was conducted on MEDLINE and PubMed of case reports and case series of lesions in the presence of non-critical infection by SARS-CoV-2 published until 15/09/2020. We highlight the potential of the virus directly influencing the damage or the innate and adaptive immune response activating cytokine and procoagulant cascades, in addition to the genetic component triggering glomerular diseases, mainly collapsing focal segmental glomerulosclerosis, tubulointerstitial, and even vascular diseases. Kidney lesions caused by SARS-CoV-2 are frequent and have an impact on morbidity and mortality; thus, studies are needed to assess the morphological kidney changes and their mechanisms and may help define their spectrum and immediate or long-term impact.

Lectin pathway proteins of the complement system in normotensive pregnancy and pre-eclampsia

PROBLEM

The lectin pathway of the complement system may be involved in the pathogenesis of pre-eclampsia. We aimed to investigate changes in serum concentrations of a broad range of lectin pathway proteins during normal pregnancy and their association with pre-eclampsia, placental infarctions and intrauterine growth restriction (IUGR).

METHOD OF STUDY

We included 51 women with normotensive pregnancies and 54 women with pregnancies complicated by pre-eclampsia. Blood samples were obtained at gestational weeks 16, 33, 37, and after delivery for the normotensive pregnant women and before and after delivery for women with pre-eclampsia. Mannose-binding lectin (MBL), H- and M-ficolin, collectin liver-1 (CL-L1), MBL-associated serine protease (MASP)-1, MASP-2 and MASP-3 and MBL-associated proteins of 19 (MAp19) and 44 (MAp44) kDa were analysed. Clinical information was obtained from medical records. The placentae were examined by two experienced perinatal pathologists.

RESULTS

Lectin pathway protein concentrations generally increased during normal pregnancy and decreased after delivery in both normotensive pregnant women and women with pre-eclampsia. Exceptions were MASP-3 which increased after delivery in both groups (P < 0.0001) and H-ficolin which increased after delivery in pre-eclampsia (P < 0.0001). H-ficolin (P < 0.0001), M-ficolin (P = 0.005) and MASP-3 (P = 0.03) concentrations were lower in women with pre-eclampsia than in normotensive pregnant women. Low MASP-3 concentrations were associated with placental infarction (P = 0.03) and IUGR (P = 0.04). Low H-ficolin concentrations were associated with IUGR (P < 0.01).

CONCLUSION

In general, lectin pathway protein serum concentrations increased during normal pregnancy. H-ficolin and MASP-3 may be involved in the pathophysiology of pre-eclampsia and IUGR and could be potential future pre-eclampsia biomarkers.

Distinct patterns of C4d immunoreactivity in placentas with villitis of unknown etiology, cytomegaloviral placentitis, and infarct

C4d deposition is considered to be evidence of antibody-mediated rejection. This study was conducted to compare C4d immunoreactivity between villitis of unknown etiology (VUE) and cytomegaloviral placentitis. C4d immunohistochemistry was performed in cases with VUE (n = 16) and cytomegaloviral placentitis (n = 5). Distinct, linear C4d immunoreactivity along the syncytiotrophoblast was found in all VUE cases. In cytomegaloviral placentitis, the intensity of C4d immunoreactivity along the syncytiotrophoblast was not prominent, but cytoplasmic C4d immunoreactivity of villous cytotrophoblasts was frequently observed. Further screening of the cases with placental infarcts (n = 5) demonstrated prominent C4d immunoreactivity in the chorionic villi adjacent to the infarct. We report the characteristic co-localization of VUE and C4d immunoreactivity. The overall findings in this study strongly suggest that the complement activation is a common mechanism of diverse placental injuries associated with rejection, infection, and ischemia.

Post-surgical hemorrhagic infarction of the adrenal gland as the first clinical manifestation of antiphospholipid syndrome after 43 years of antibody-positivity

We report on a male patient who tested positive for antiphospholipid antibodies for 43 years without thromboembolic manifestation of antiphospholipid syndrome (APS). He has been followed up in a prospective cohort study since 2001. Following his second hip replacement surgery, the patient developed acute adrenal failure due to bilateral hemorrhagic infarction. Prophylactic anticoagulation, surgery, or an immunological reaction to blood transfusion may have triggered this late and unusually located primary manifestation of APS in our patient.

Catastrophic multiple organ ischemia due to an anti-Pr cold agglutinin developing in a patient with mixed cryoglobulinemia after treatment with rituximab

Cold agglutinin disease occurring with cryoglobulinemia is a rare occurrence. Here, we report a patient with mixed cryoglobulinemia that was treated with rituximab and, after response, developed an anti-Pr cold agglutinin that manifested with hemolysis and microvascular occlusion causing mesenteric ischemia and cerebral infarction. Unlike previous reports of patients with cryoglobulinemia and cold agglutinin disease, our patient did not have a detectable cryoprecipitate when his cold agglutinin manifested.

Yersinia enterocolitica-associated generalized microinfarctions of bone and spleen in a child

We report a case of unusual extraintestinal yersiniosis in a 16-year-old girl with generalized microinfarctions of the bone and spleen. For the past 2 years she had been repeatedly admitted to our hospital with reactive arthritis, erythema nodosum and iridocyclitis of unknown aetiology. Ultrasound showed multiple round hypoechoic lesions in the spleen that were shown to have low T2 signal on MRI. MRI also showed disseminated nodular lesions of the skeleton that were low T1 and high T2 signal and demonstrated inhomogeneous contrast enhancement. The patient is currently in good health on low-dose nonsteroidal immunosuppressive therapy. This is a unique case of microinfarctions of the skeleton and spleen caused by a severe postinfectious autoimmune reaction following extraintestinal Yersinia enterocolitica infection.

The role of resection for patients with renal carcinoma

Metastatic renal cancer is responsive in some cases to immunotherapeutic agents. Indications for nephrectomy in the face of metastatic disease have traditionally included palliation of symptoms caused by the primary tumor, and nephrectomy combined with metastatectomy in patients with resectable metastases. Recent findings from a Southwest Oncology Group trial strongly suggest that cytoreductive nephrectomy, combined with immunotherapy, may also result in improved survival in patients with unresectable metastases.

Clinical implications and value of immunohistochemical staining in the evaluation of lymph node infarction after fine-needle aspiration

We report on a series of 3 patients who underwent fine-needle aspiration (FNA) for clinically apparent lymphadenopathy. In all 3 cases, a diagnosis of malignancy was rendered based on cytologic findings (two metastatic squamous-cell carcinomas and one melanoma). However, initial follow-up surgical pathology reported only "extensive coagulative necrosis, no viable tumor seen." Subsequent immunohistochemical stains (cytokeratins (AE1/AE3), HMB45, S100, and Melan A) demonstrated the presence of metastatic tumor in the area of infarction in each case, thus establishing the presence of metastatic tumor and correct interpretation of the initial FNA. We conclude, based on our own experience and a few previously reported cases, that total infarction of the lymph nodes following FNA can occur, and immunohistochemistry can be helpful in clinical management.

Origin of antiphospholipid antibodies: induction of aPL by viral peptides

The clinical associations of antiphospholipid antibodies (aPL) are well recognized but the mechanism(s) causing the production of these antibodies are not yet known. We demonstrated the induction of pathogenic aPL antibodies that caused intrauterine fetal death and transverse myelopathy due to spinal cord infarction in mice by immunization with foreign beta2GPI. We also induced aPL and anti-beta2-GPI in mice by immunization with PL-binding viral peptides and hypothesized that in APS patients, aPL may be induced by beta2GPI-like-PL-binding products of common human bacteria and viruses.

Dermatological presentation of disease associated with antineutrophil cytoplasmic antibodies: a report of two contrasting cases and a review of the literature

Antineutrophil cytoplasmic antibody (ANCA)-associated disease (AAD) constitutes a pathological disease spectrum of a necrotizing vasculitis of small- and medium-sized vessels, extravascular granuloma formation, and necrotizing and crescentic glomerulonephritis, and also a clinical disease continuum which ranges from renal-limited disease to a widespread systemic vasculitis, including Wegener's granulomatosis and microscopic polyangiitis. In the latter, circulating ANCA are an aid to diagnosis and also may play a pathogenic part. Two contrasting patients with AAD are described, both of whom presented primary with dermatological features. These included a cutaneous purpuric vasculitis, orogenital ulceration, infarction of the fingertip, and pyoderma gangrenosum-like ulceration. These cases will familiarize dermatologists with both the concept and dermatological features of AAD.

Activation of the terminal complement cascade in renal infarction

Ischemic injury is an important cause of functional derangement in the kidney. The complement (C) system has previously been shown to be an important mediator of ischemic tissue injury in myocardial infarction. In the present study we therefore investigated the possible role of C in renal ischemic lesions. The deposition and distribution of various C components (C1q, C3c, C3d, C4, C5, C6, C9) and regulators [vitronectin, clusterin and protectin (CD59)] in human renal infarction lesions were studied by indirect immunofluorescence microscopy. Deposition of components of the terminal C complex (TCC), as well as vitronectin and clusterin, were observed throughout the infarcted areas. The strongest deposits were seen on the membranes of tubular epithelial cells and in the tubular lumina of the infarction areas, especially in the border zone between normal and infarcted tissue. Using markers for different segments of tubuli (Tamm-Horsfall glycoprotein and brush border antigens) it was possible to localize deposits of TCC predominantly to the proximal tubuli. In the glomeruli of the infarcted areas deposits of TCC were seen as a crescent-like pattern at and immediately beneath the Bowman's capsule. The expression of cell membrane-associated protectin was diminished in tubular epithelial cells of the infarction lesions. A clue for the possible mechanism of C activation in renal infarction was obtained from in vitro experiments, in which the contact of normal human serum with urine was observed to lead to the generation of TCC.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic infarction and nodular regenerative hyperplasia of the liver with associated anticardiolipin antibodies in a young woman

An 18-year-old woman developed acute congestive hepatic infarction in the presence of a circulating anticardiolipin antibody. She subsequently developed nodular regenerative hyperplasia of the liver (NRHL) with associated portal hypertension. Unlike previously reported cases of NRHL, this case offers a prospective follow-up of the development of NRHL. Its occurrence following an episode of hepatic venous impairment in an otherwise normal liver supports the hypothesis that NRHL may develop as a consequence of diminished hepatic venous drainage.

Hepatic infarction in a pregnant patient with the 'primary' antiphospholipid syndrome

We describe a patient with previous venous thrombosis while using oral contraceptives and recurrent pregnancy loss, who presented with massive hepatic infarction in the last trimester of the fourth gestation. Thrombocytopenia, the lupus anticoagulant (LA) and the anticardiolipin antibody (aCL) were detected and a diagnosis of a 'primary' antiphospholipid syndrome (APS) was made. The clinical and histological manifestations and the differential diagnosis, especially with DIC and pre-eclampsia, are discussed.

Fatal adult Henoch-Schönlein purpura due to small intestinal infarction

A 57-year-old woman presented with classical symptoms of Henoch-Schönlein purpura including arthralgia, abdominal pain, palpable purpuric rash and abnormalities of the urinary sediments. The clinical course was subsequently complicated by severe paralytic ileus leading to respiratory embarrassment. Laparotomy confirmed patchy areas of small bowel infarction due to necrotizing vasculitis. Skin biopsy revealed extensive leukocytoclastic vasculitis with granular deposits of IgA in the blood vessels. Anti-neutrophil cytoplasmic autoantibodies (ANCA) were not detectable. The patient continued to deteriorate despite bowel resection, intensive immunosuppressive therapy and plasma exchange, and eventually died. Gastrointestinal involvement in adult Henoch-Schönlein purpura has previously been reported to have a favourable clinical course. However, our case illustrates the rate but lethal complication of intestinal infarction in patients who fail to respond to conservative treatment.

Association of fetal heart block and massive placental infarction due to maternal autoantibodies

Two different effects of maternal autoantibodies presented in a third-trimester pregnancy. The first was complete fetal heart block, demonstrated ultrasonographically, which correlated with the presence of anti-Ro and anti-La antibodies in the maternal serum. The second effect was decidual vasculopathy and thrombosis, a morphologic finding in the placenta that caused massive placental infarction and intrauterine death. The placental pathology correlated with the presence of anticardiolipin antibodies in the maternal serum at the time of stillbirth.

Clonal immunoglobulin gene rearrangement in the infarcted lymph node syndrome

The authors report a case of complete lymph node infarction in which a specific etiology could not be determined by morphologic or immunophenotypic studies; however, clonal rearrangement of the immunoglobulin gene was demonstrated by Southern blot hybridization of DNA extracted from the necrotic tissue. A subsequent lymph node biopsy later was diagnosed as malignant lymphoma, using morphologic, immunophenotypic and genotypic criteria. Identical clonally rearranged bands were present in DNA from both the infarcted nodal and the subsequent tissue biopsies. In the setting of lymph node necrosis, gene rearrangement studies may provide diagnostic information concerning clonality, even if morphologic and immunophenotypic studies are indeterminate for a lymphoproliferative process.

Heparin therapy for pregnant women with lupus anticoagulant or anticardiolipin antibodies

Maternal lupus anticoagulants and anticardiolipin antibodies are associated with a syndrome of recurrent pregnancy loss or preterm birth in live-borns, fetal growth retardation, and placental infarction. Fourteen women with one or more abnormal pregnancy outcomes (total 28 losses, one severely growth-retarded premature live-born) and no normal outcomes were treated with full-dose, subcutaneous, twice-daily heparin therapy in subsequent pregnancies. Treatment was started at an estimated gestational age of 10.3 +/- 4.0 (mean +/- SD) weeks (range 6-18), in a mean total daily dosage of 24,700 +/- 7400 units (range 10,000-36,000). Fourteen of 15 pregnancies resulted in live births at 36.1 +/- 1.7 weeks (range 33-39). The mean birth weight percentile was 57 +/- 21 (range 10-90), and Apgar scores were good to excellent. The number of placental infarcts was fewer in treated cases than in previous deliveries. Five fetuses had third-trimester or perinatal problems with no sequelae, four discovered by close maternal-fetal monitoring. There was an increased rate of preterm and cesarean deliveries. Maternal complications of treatment were few and minor, with no hypertension, preeclampsia, or serious drug-related complications. Heparin appears suitable for further investigation in the treatment of this obstetric syndrome.

Severe immune thrombocytopenia and the development of skin infarctions in a patient with an overlap syndrome

A 49-year-old woman with clinical features of systemic lupus erythematosus, systemic sclerosis, Sjögren's and the antiphospholipid syndromes developed severe immune thrombocytopenia and skin infarctions. Both complications responded to immunosuppressive agents.

Hepatic infarction in a patient with the lupus anticoagulant

We describe a 31-year-old patient with missed abortion, thrombocytopenia, and clinical, laboratory, and radiologic evidence of hepatic infarction. On evaluation, she was found to have the lupus anticoagulant. The association between enhanced thrombosis and the lupus anticoagulant is discussed, and previously reported thrombotic complications are described. The etiology, clinical course, and radiologic features of liver infarction are summarized, and the importance of recognizing and treating this form of hypercoagulability is stressed. To our knowledge, this is the first description of liver infarction associated with the lupus anticoagulant.

Antigen preservation in infarcted lymphoid tissue. A novel approach to the infarcted lymph node using monoclonal antibodies effective in routinely processed tissues

We studied 11 cases of malignant lymphoma diagnosed concurrently with or following lymph node infarction. Cases included seven B-cell lymphomas, three T-cell lymphomas, and one case of Hodgkin's disease. Sections of viable and infarcted tissue were immunostained in parallel using a panel of antibodies effective in routinely processed, wax-embedded tissue. The panel included anti-leucocyte-common antigen (CD45), T-cell-associated antigens (UCHL1, MT1), B-cell-associated antigens (MB1, 4KB5 (CD45R), MT2, LN1), a B-cell-specific antigen (L26), C3D-1 (CD15), and BER-H2 (CD30). Antibodies to intermediate filament cytoskeletal proteins, epithelial membrane antigen, and Factor VIII-related antigen were also used. In eight cases, staining of the infarcted material gave evidence of a lymphoid proliferation of either T- or B-cell type; an in the case of Hodgkin's disease, the results supported this diagnosis. The immunophenotype derived in the infarcted tissue mirrored the findings in the viable material in these eight cases of non-Hodgkin's lymphoma. A case of testicular infarction with concurrent intraosseous lymphoma was also examined. Staining in this case provided evidence of infarcted lymphoma. Thus, immunostaining of infarcted lymphoid tissue with these novel antibodies provides valuable information that conventional light microscopy cannot offer.

Splenic and renal infarction in systemic lupus erythematosus: association with anti-cardiolipin antibodies

A 37-year-old female, known to have systemic lupus erythematosus (SLE) and markedly raised anti-cardiolipin antibody levels in association with the lupus anticoagulant, presented with a symptomatic segmental splenic infarction. There was a past history of cerebral infarction. Abdominal computed tomography (CT) demonstrated the area of splenic infarction, and an asymptomatic right renal infarct. This patient illustrates the unusual occurrence of multiple visceral infarcts, in association with anti-cardiolipin antibodies, complicating SLE.

Mechanisms of partial renal infarct hypertension

Contributions of both the renin-angiotensin and immune systems to the aetiology of renal infarct hypertension were examined in Sprague-Dawley rats. Partial renal infarction was produced by ligating and sectioning two out of three branches of the left renal artery. The right kidney remained intact. Renal infarction resulted in rapid development of stable hypertension. One week following infarction, the plasma renin activity (PRA) increased more than threefold. However, PRA returned to control levels 4 weeks after infarction. Chronic immunosuppressive therapy with cyclophosphamide at most only attenuated the development of renal infarct hypertension associated with this transient renin elevation. However, cyclophosphamide prevented the later maintenance phase of the hypertension, and could also completely reverse established infarct hypertension. Activation of the renin-angiotensin system plays a role in the onset of partial renal infarct hypertension, but an intact immune system is required for maintenance of the hypertension. It is hypothesized that immunological reactions against renal tissue maintain renal infarct hypertension.

Infarct-kidney hypertension in the rat mutant nude

Infarct-kidney hypertension was induced in congenital athymic nude rats, and in their immunologically normal haired littermates. In both groups a significant initial increase in blood pressure was seen in the course of the first 30 days. In the remainder of the observation period of 120 days the mean blood pressure in the nude rats decreased to a significantly lower level where-as in the haired rats the mean blood pressure remained unchanged at the high level. Although a high mortality weakened the results, it is hypothesized that the failing ability to maintain the elevated blood pressure into the late phase in the nude rats could be due to impaired thymus function. Nine of 14 haired rats had increased numbers of lymphocytes around intrarenal arteries, in contrast to only 1 of 10 nude rats. A periarteritis nodosa like picture was observed around mesenterial arteries of 3 nude and 2 haired rats. The level of plasma renin was similar preoperatively in nude and haired rats. Infarction of the kidney was followed by a significant decrease in the plasma renin level in both nude and haired rats, which at 10 days was significantly lower in haired than in nude rats, despite a higher blood pressure in the latter.

Fibrin gel investment associated with line 1 and line 10 solid tumor growth, angiogenesis, and fibroplasia in guinea pigs. Role of cellular immunity, myofibroblasts, microvascular damage, and infarction in line 1 tumor regression

Line 1 and line 10 tumors became invested in a fibrin-gel cocoon within hours after transplantation to the subcutaneous spaces of unsensitized syngeneic inbred Sewall Wright strain 2 guinea pigs. The fibrin gel comprised more than 80% of the line 1 tumor mass and, after day 3, became organized and was subsequently replaced by fibrous connective tissue, which gave the tumor the appearance of a scirrhous carcinoma. A cellular infiltrate of lymphocytes and basophils developed at the periphery of line 1 tumors after day 8, and tumors regressed by day 13. The fibrin gel investing the highly malignant line 10 tumors accounted for less than 10% of the tumor mass and persisted without fibrous organization as a tumor grew progressively and invaded adjacent tissues. These data provide new and potentially important insights into the biology of solid tumor growth and the mechanisms of immunologic tumor rejection. Envelopment of tumors in a fibrin gel created an anatomic barrier separating the tumors from the host. Neovascularization mimicking that about line 1 and line 10 tumors was induced by sc fibrin implants; these data suggest that activation of the clotting and/or fibrinolytic systems by tumor cells may itself provide sufficient stimulus for induction of tumor angiogenesis without requiring a separate tumor angiogenesis factor. The scirrhous pattern of growth characteristic of line 1 tumors apparently was achieved by organization of an abundant fibrin gel. Line 1 tumor regression did not for the most part involve direct contacts between tumor cells and any type of inflammatory cell, including macrophages; rather, tumor destruction was effected by ischemic necrosis secondary to widespread microvascular injury. The mechanisms of such injury are uncertain, but tumor rejection was correlated with evidence of developing cellular immunity and anatomic associations between lymphocytes and myofibroblasts. Further experiments will be necessary before these findings can be generalized to other tumor systems.

Adenohypophysial necrosis in rats following destruction of the pituitary stalk. A histologic, immunocytologic and fine structural study

Adenohypophyses of adult male rats have been investigated by light microscopy, immunocytology and electron microscopy 30 minutes, 1, 2, 4, 6 and 24 hours following electrolyte destruction of the pituitary stalk. Light microscopy revealed massive ischemic infarction of the adenohypophysis. Immunoreactive growth hormone, prolactin, TSH, FSH and LH were demonstrated up to 24 hours after surgery in necrotic adenohypophysial cells by the immunoperoxidase technique. Fine structural abnormalities were already noticeable 30 minutes following stalk lesion. The changes rapidly progressed and within 2 hours unmistakable signs of cellular necrosis became evident. Mitochondria, especially those of growth hormone cells, seemed to be affected at an early stage, whereas alterations in rough-surfaced endoplasmic reticulum membranes developed later. Nuclear changes, formation of cytoplasmic vacuoles and disruption of cell membranes were conspicuous findings. No evidence, indicating the participation of lysosomes in the development of cellular damage, was obtained. Secretory granules were prominent and well preserved even in cells which showed advanced necrosis. The failure of discharge and degradation of secretory granules in the necrotic cells suggest that factors accounting for their intracellular migration and extrusion are very sensitive to ischemia and are paralyzed at an early phase.

Pathogenesis of the glomerulopathy associated with renal infarction in rats

The present studies were designed to characterize the extent and pathogenesis of the glomerular lesions which occur in the viable portion of the kidney following partial renal infarction in rats. Control rats with two normal kidneys had a mean blood pressure of 112 mm Hg, minimal proteinuria and no glomerular pathology on light (LM), electron (EM) or immunofluorescence microscopy (IFM). Rats with two-thirds infarction of one kidney (stage II) became hypertensive, although less than 4% of the glomeruli from either kidney were abnormal. Rats with two-thirds infarction of one kidney and contralateral nephrectomy (stage III) developed proteinuria and hypertension whether fed a normal, low or high Na+ diet. By light microscopy 37% of glomeruli were abnormal 28 days after partial infarction and contralateral nephrectomy and thereafter the percent of abnormal glomeruli increased. Detectable amounts of immunoglobulin and complement (C3) were present in kidneys of stage II or III rats but were always accompanied by more extensive albumin and fibrin deposits. Basement membrane deposits characteristic of immune complexes were not seen on EM. Administration of antihypertensive medication to stage III rats significantly lowered blood pressure and reduced the number of abnormal glomeruli on LM; however, IFM abnormalities remained prominent. Platelet thrombi seen by EM and abundant glomerular fibrin deposits seen on IFM suggested that coagulation mechanisms may be prominent in the pathogenesis of the renal lesion. Heparin-treated stage III rats had significantly lower blood urea nitrogen concentrations, blood pressures and proportion of abnormal glomeruli although glomerular deposition of serum proteins was still present on IFM. These observations suggest that this glomerulopathy is initiated by an unknown agent(s) which increased capillary permeability. This lesion progresses via thrombotic mechanisms which are prevented by heparin administration.

Multiple sclerosis and cell-mediated hypersensitivity to myelin A1 protein

Cellular hypersensitivity to myelin basic (A1) protein was evaluated using the MIF assay in 246 subjects. Of 100 with multiple sclerosis positive results are seen in relationship to acute exacerbations of illness. Normal control subjects gave a mean value of 100 +/- 9% whereas patients studied within 4 weeks of onset of illness gave a result of 59 +/- 12.5%. A convalescent group studied between 5 and 12 weeks after an attack gave results of 86 +/- 22.2%. A chronic group gave a mean of 91 +/- 8.2%. Positive values were also seen in a number of other patients with central or peripheral nervous system disease especially those with "autoimmune disease". However, results of this study clearly establish a temporal relationship between in vitro evidence of hypersensitivity to A1 protein and clinical expression of disease.

Leukocyte migration in agarose, a study on multiple sclerosis

The effect of low concentrations of bovine encephalitogenic protein on the migration of human peripheral leukocytes in agarose was studied. A concentration of 0.3 mug/ml of the protein stimulated the migration of cells from many donors, including some healthy subjects. An indirect technique suggested that the migration enhancement is due to the production of soluble factor, possibly corresponding to the leukocyte migration enhancement factor described by others. The frequency of subjects whose cells could be stimulated and the recorded degree of stimulation tended to be higher in a group of patients with multiple sclerosis than in a group of healthy subjects. When the effect of some of the main peptide fragments of the protein was studied on cells that were stimulated by the intact protein, one or more of these peptides sometimes induced the opposite effect: a migration inhibition. There is, apparently, a complex balance between enhancing and inhibiting factors acting on leukocyte migration in vitro; and the character of the antigen seems to be one important factor.

An in vitro study of renal allograft recipients for cellular delayed type hypersensitivity to glomerular basement membrane and disrupted spleen cells

An in vitro study of delayed hypersensitivity by leucocyte migration inhibition using disrupted spleen cells as a source of transplantation antigens, and soluble glomerular basement membrane (GBM) antigen, was made on the peripheral blood leucocytes of six normal subjects and eleven renal allograft recipients.

There was no inhibition of migration in the control group. The cells of one allograft recipient were inhibited by disrupted spleen cells and the cells of four other recipients were inhibited by soluble GBM antigen. Three of the latter had underlying glomerulonephritis and the fourth recipient only showed inhibition after infarction of the graft and its removal. These observations suggest that the immunosuppressed transplant recipients develop hypersensitivity to GBM antigen although there is no evidence of deteriorating renal function.