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Biomedical subjects

M Milgrom

Publications and source records attributed to M Milgrom.

At least 37 records · Page 2Linked to original sources

Posttransplant hyperglycemia. Increased incidence in cyclosporine-treated renal allograft recipients.

The incidence of posttransplant diabetes mellitus (PTDM) was compared in two groups of renal allograft recipients. These were all nondiabetic patients who had been transplanted between 1979 and 1987 and received either azathioprine-methylprednisolone (group 1) or cyclosporine-methylprednisolone (group 2) therapy as maintenance immunosuppression. The incidence of PTDM in group 1 was 9.1% vs. 18.6% in group 2 (P less than .05). The mean daily dose of methylprednisolone during the initial 2 months posttransplant was not greater among the PTDM patients of groups 1 or 2. Cyclosporine levels and mean daily CsA doses during the initial 2 posttransplant months were also not different among the CsA-PTDM and euglycemic CsA patients. Posttransplant diabetes mellitus occurred rapidly (less than 2 months) and required insulin therapy in the majority of cases. Increased age (greater than 40 years) was associated with a higher risk for PTDM, however, the greater incidence accompanying increased body weight only approached significance. Patient gender and donor source were not associated with significant risk for PTDM. The development of PTDM was accompanied by a significant decrease in graft survival at 3 years in the entire PTDM population and at 4 years in the CsA-PTDM subgroup. Actuarial patient survival was not adversely affected. The current study suggests that CsA may be diabetogenic when administered with methylprednisolone to renal allograft recipients. The adverse effect on allograft survival requires further investigation. These results may also have important implications for pancreatic and islet cell transplantation.

Actuarial Analysis↗

Interaction of antibodies with human glomerular epithelial cells.

We tested the hypothesis that the pathogenesis of human idiopathic membranous glomerulonephritis is similar to that of Heymann glomerulonephritis, a model of membranous glomerulonephritis induced in rats by immunization with renal brush border preparations; the characteristic subepithelial deposits result from interaction of antibodies with a brush border antigen (gp330) expressed on the plasma membrane of glomerular visceral epithelial cells (GEC), followed by redistribution and shedding of gp330 immune complexes. The experiments were performed in cultured glomerular visceral epithelial cells, in living monkeys and rats, and in isolated perfused human, monkey, and rat kidneys. Antigens from plasma membranes of human renal brush border vesicles (HBBV) and GEC vesicles (HGECV) and their corresponding polyclonal and monoclonal antibodies reactive with human and monkey GEC were prepared. First, polyclonal antibodies to HGECV bound diffusely to cultured GEC; monoclonal antibody 8G5, recognizing a 60-kDa protein, mainly bound to the coated pits and apical invaginations; both polyclonal HGECV and 8G5 monoclonal antibodies induced antigen redistribution (capping) at 37 degrees C. Second, monkeys were actively or passively immunized, and isolated human and monkey kidneys were perfused with the antibodies. Active immunization with HBBV induced tubular immune deposits, whereas active immunization with HGECV did not provoke renal lesions. After passive immunization HBBV and HGECV antibodies bound diffusely to glomerular cells, and subepithelial deposits were observed during the autologous phase; in contrast, 8G5 induced early (day 3) granular deposits. Third, fine granular deposits developed in glomeruli of human and monkey kidneys perfused for 4 hours at 37 degrees C with 8G5; these deposits were more difficult to detect by electron microscopy than those occurring in kidneys of Lewis rats perfused with sheep antiHBBV. The results show that some antibodies redistribute antigens at the surface of human and monkey GEC in vitro, in vivo, and ex vivo and induce formation of granular deposits in human glomerular capillary walls. Failure to induce more severe lesions in human and monkey kidneys may be ascribed to lack of GEC antigens comparable to rat gp330, insufficient cross linking by monoclonal antibody, lack or insufficient concentration of epitope-specific antibodies, insufficient time of kidney perfusion, or a combination of these factors.

Animals↗

Effects of in vitro and in vivo anticanine T lymphocyte and anticanine class II-specific monoclonal antibodies in the beagle.

Two murine anticanine lymphocyte monoclonal antibodies, designated T83 and B1F6, were assessed for (1) in vitro antiepitope activity to circulating lymphocyte subsets, their functional effects on lymphoproliferative assays and binding specificities to diverse cell suspensions and tissue sections; (2) in vivo effects after administration on cells expressing the target epitopes, lymphoproliferation, and allograft survival; and (3) the host immune response to the injected murine immunoglobulins. The monoclonal antibody T83 (IgG3) appeared to be specific for a T cell subset with an up-regulating function on lymphoproliferation. It caused a profound depletion of cells with the appropriate epitope after intravenous administration but it bound to lymphocyte membrane epitopes on some cells in peripheral blood that did not become depleted and putatively caused other modulating effects on lymphocyte function. The monoclonal antibody B1F6 (IgG2a, previously described) was immunologically specific in vitro for cells expressing class II major histocompatibility complex antigens. In the dog, this also consisted of 50% of T lymphocytes. After intravenous administration, there were functional effects similar to those of T83. A modest prolongation of survival of renal allografts was observed when both mAbs were used as the sole immunosuppressive agent. These studies also demonstrated the occurrence of natural canine antimurine IgG antibodies. Administration of either monoclonal antibody was followed by a rapid increase in the concentration of the antimouse antibody(s). We postulate that the presence of canine natural antimouse IgG markedly influenced the biologic effects of in vivo administered monoclonals.

Animals↗

In vivo and in vitro induction of class II molecules on canine renal cells and their effect on the mixed lymphocyte kidney cell culture.

Canine renal cortical cells were obtained by collagenase extraction from allogeneic haploidentical, donor-recipient beagle littermate pairs and from unrelated mongrels. Peripheral blood lymphocytes (PBL) of the mongrels, as well as of one member of the beagle pair that exhibited high mixed lymphocyte culture (MLC) reactivity against the other were also stimulated by renal cortical cells derived from both normal and rejected transplanted kidneys in mixed lymphocyte kidney cell culture (MLKC). A moderate autologous MLKC reactivity occurred in response to normal renal cortical cells. However, rejected kidney cortical cells were markedly more stimulatory than normal renal cortical cells in both allogeneic and autologous MLKC reactions. Lymphocytes from donor animals responded more strongly to autologous cortical cells isolated during rejection of the transplant than to cortical cells from normal allogeneic kidneys. Recipient infiltrating lymphocytes and propagated T cell lines extracted from the rejected kidney also responded more strongly than PBL to cortical cells from this kidney. Gradient purification of the stimulating cortical cells resulted in one virtually pure preparation of distal tubular epithelial cells, as demonstrated by immunohistochemical stains and electron microscopy, which caused enhanced stimulation in MLKC. Class II marker analysis of the canine renal cells from rejected kidneys revealed the presence of these molecules on tubular cells that were absent on normal kidney cells. A 16-hr coculture of normal renal cortical cells not exhibiting class II surface markers in the presence of allogeneic or autologous lymphocytes induced the expression of these molecules, associated with an increased stimulatory capacity. This also occurred to a lesser extent with MLC (and MLKC) cell culture media supernatants. However, the low level of class II expression by all the various gradient-purified fractions in the absence of rejection or coculture, and the increased but equivalent expression on all fractions after coculture did not correlate with the preferential stimulatory capacity of the purified distal tubular cell layer. We conclude that two signals are necessary for the MLKC reaction, one involving tissue (kidney)-associated epitopes (the nominal antigen demonstrated in this study to be present in normal distal tubular cells), the other involving class II molecules as costimulatory (amplification) moieties.

Animals↗

Renal transplantation in systemic lupus erythematosus: one center's experience.

A retrospective analysis of 15 renal transplant patients with end-stage renal disease (ESRD) secondary to systemic lupus erythematosus (SLE) was performed. Overall actuarial patient and graft survival at 6 years was 93 and 84%, respectively. Recipients of HLA-identical kidneys did not appear to be at increased risk of allograft failure due to rejection or recurrent disease. Two biopsy-proven cases of recurrent lupus involving the allograft were observed and are discussed. Those patients currently experiencing excellent graft function (creatinine less than 2 mg/dl) had a significantly longer pretransplantation dialytic interval than the group whose most recent serum creatinine exceeds 2 mg/dl (or returned to dialysis). Posttransplantation monitoring of antinuclear antibody, antidouble-stranded DNA, C3, C4, and circulating immune complexes was not predictive of renal or extrarenal disease activity. Renal transplantation should be considered an excellent therapeutic modality for the lupus patient with ESRD, although an interim period on dialysis of at least 1 year seems warranted.

Follow-Up Studies↗

T cell lines and clones preferentially recognizing kidney-associated antigens in end-stage renal disease.

The specificity in the mixed lymphocyte kidney culture (MLKC) of T cell lines and clones derived from human end-stage renal disease (ESRD) kidneys was studied using collagenase dispersed kidney cells compared with lymphocytes as stimulating cells. These experiments were performed because of previous studies in which infiltrating lymphocytes freshly isolated from ESRD kidney tissue at nephrectomy (as well as autologous splenic T cells) were seen to directly generate this lymphoproliferative MLKC response when stimulated with autologous renal cortical cells. In the current studies, histopathologic staining of tissues and suspensions of infiltrating kidney lymphocytes showed predominance of OKT4 labeled phenotypes, and the stimulation indices in MLKC in general showed a direct relationship with the percentage of helper cells seen in the infiltrates. When T cell lines and clones derived from lymphocytes infiltrating the ESRD kidneys were tested in MLKC, there was evidence of kidney-associated, as opposed to lymphocyte-associated (MLC) reactivity using (3H) thymidine uptake as a reflection of a lymphoproliferative response. Several cell lines and clones derived from these T lymphocytes exhibited a dual reactivity. They served as responding cells in the MLKC reaction and completely suppressed a non-specific allogeneic MLC when added as third-party cells. Quantitatively, some clones suppressed when third-party x-irradiated cells were only 5% of the responding cell number in coculture. In addition to the dual reactivity, phenotypic analysis of these same cell lines and clones employing monoclonal antibodies revealed that individual cells expressed both OKT4 and OKT8 determinants. However, approximately 90% of the cells in the MLC enhancing line were labeled with OKT4. These results indicate that there is a complexity in the autologous MLKC response in that cells with both helper/inducer and suppressor/cytotoxic function take part in the reaction. Although delayed-type hypersensitivity to kidney-associated antigens is inferred as a result of these in vitro assays, nonspecific suppression of other Ia-dependent reactions can simultaneously occur.

Antibodies, Monoclonal↗

Transplacental transmission of antibodies to tubular basement membrane in guinea-pigs with autoimmune tubulointerstitial nephritis.

The offspring of female guinea-pigs with tubulo-interstitial nephritis were studied for possible passive transfer of disease. Whereas no immune deposits were seen on or before day 30 of gestation, IgG was detected in the tubular basement membrane (TBM) of fetuses at and after day 44. Serum of offspring contained antibodies to TBM, albeit in much lower titres than found in circulation of the mother guinea-pigs. No histopathological changes were seen in fetal kidneys. Thus, autoantibodies induced by heteroimmunization of pregnant guinea-pigs may be transmitted to offspring in the last third of the gestation period and can bind to fetal TBM. However, this transfer of antibodies does not cause disease.

Animals↗

Response of thiazide-induced hypokalemia to amiloride.

The effects of amiloride hydrochloride on thiazide-induced hypokalemia were evaluated. In metabolic balance studies, amiloride reversed thiazide-induced urinary potassium loss, restored plasma bicarbonate concentration and pH to pretreatment levels, and produced further increases in aldosterone secretion. Effects of long-term administration of hydrochlorothiazide and an amiloride-hydrochlorothiazide combination were compared in outpatients who had experienced thiazide-induced hypokalemia while receiving oral potassium supplements. After eight weeks, those given hydrochlorothiazide alone had an average serum potassium level of 3.01 +/- 0.08 mEq/L). Those given the amiloride-hydrochlorothiazide combination had an average serum potassium level of 3.75 +/- 0.008 mEq/L, not significantly different from the control value (3.82 +/- 0.08 mEq/L). Both groups had increased plasma aldosterone concentrations and plasma renin activity. The potassium-conserving effect of amiloride persisted with extended therapy.

Aldosterone↗

Chronic serum sickness in the rat: influence of antigen dose, route of antigen administration and strain of rat on the development of disease.

Chronic serum sickness (CSS) with systemic immune complex deposition has been produced in female Fischer (F344) rats by the daily intravenous (i.v.) administration of 2.0 mg bovine serum albumin (BSA) (Arisz et al., 1979). In the experiments described below, daily i.v. doses ranging from 0.5 to 10.0 mg BSA were found to be effective in producing CSS in F344 strain rats. The severity of renal disease and the extent of extrarenal immune complex deposition were increased with higher daily doses of BSA. Daily administration of different doses of BSA by an intraperitoneal (i.p.) route resulted only in slight mesangial glomerular abnormalities and did not cause abnormal elevation of urinary protein excretion. At the same time, extrarenal accumulation of immune deposits similar to that observed in rats given BSA by the i.v. route was seen. Wistar and Lewis (LEW) strain rats were similar to F344 strain rats in susceptibility to the induction of CSS, but daily i.v. injection of 2.0 mg BSA failed to produce the disease in Brown Norway (BN) rats. The latter observation suggests that genetic differences may influence the expression of immune complex disease in this model.

Animals↗