Gary S. Hill

Induction of specific tolerance to class I-disparate renal allografts in miniature swine with cyclosporine

Previous studies in miniature swine have suggested that the mechanism underlying the spontaneous development of tolerance in one third of one-haplotype class I disparate renal allografts (i.e., ag→ad) involves a relative T cell help deficit at the time of first exposure to antigen. If this hypothesis were correct, then one might expect the administration of an immunosuppressive agent capable of inhibiting lymphokine production during this period to lead to the induction of tolerance to class I MHC antigens in two-haplotype class I mismatched renal allografts (i.e., gg→dd), which are otherwise uniformly and acutely rejected. This hypothesis was tested in eight two-haplotype class I disparate, class II matched donor-recipient pairs, in which recipients were treated with cyclosporine 10 mg/kg, i.v. q.d. for 12 days. This protocol led to the induction of long-term (>100 days) specific tolerance in 100% of recipients, as compared with control animals that rejected grafts in 13.7 ± 0.9 days (P<0.0001). The specificity of tolerance was assessed both in vivo

Electron microscopic study of so-called "pulmonary sclerosing hemangioma". Report of a case suggesting epithelial origin.

A lesion typical clinically and histologically of so‐called “pulmonary sclerosing hemangioma” was removed from the right middle lobe of a 19‐year‐old girl. Electron microscopic study reveals that, rather than being composed primarily of vascular and histiocytic components, it is made up predominantly of epithelial elements and appears to arise from primitive respiratory epithelium.

Histopathologic characterization of hereditary benign prostatic hyperplasia

OBJECTIVES Recent studies suggest the presence of a hereditary form of benign prostatic hyperplasia (H-BPH). This study was undertaken to characterize the histopathologic features of BPH in these men. METHODS Because study subjects with H-BPH were young (mean age 59 years) and had a large prostate (mean prostate weight 61 g), we compared the histopathologic findings in these men with those in two different control groups: (1) age-matched control subjects (mean age 59 years; mean prostate weight 31 g), and (2) prostate weight-matched control subjects (mean age 70 years; mean prostate weight 61 g). Using a color video image analysis system, we morphometrically determined stromal/epithelial ratios in histologic sections taken from 12 men with H-BPH, 36 age-matched control subjects, and 36 prostate weight-matched control subjects. RESULTS The stromal/epithelial ratio was 2.6 +/- 1.4 in the men with H-BPH, 2.7 +/- 1.7 in the age-matched control subjects, and 1.7 +/- 0.9 in the prostate weight-matched control subjects. Regression analysis, which controlled for the differences in prostate weight or patient age between men with H-BPH and age-matched and prostate weight-matched control subjects, respectively, revealed a significant difference between men with H-BPH and prostate weight-matched control subjects (P = 0.015) but no difference from age-matched control subjects (P = 0.36). CONCLUSIONS The larger prostates in young men with H-BPH are characterized by a higher stromal/epithelial ratio than are similar-sized prostates in older men with sporadic BPH. This finding gives rise to speculation that H-BPH is associated with an increase in stromal elements.

The Failure Of Skin Grafting To Break Tolerance To Class I-disparate Renal Allografts In Miniature Swine Despite Inducing Marked Antidonor Cellular Immunity

Long-term specific tolerance to one haplotype class I plus minor antigen disparate renal allografts develops without exogenous immunosuppression in approximately 35% of miniature swine (n=128). Previous studies have suggested that this phenomenon is related to limited class I-specific helper T cell activity as evidenced by the failure of antibody class switching in vivo and the ability of exogenous interleukin 2 to elicit antidonor responses in vitro. To determine whether tolerance could be broken by inducing antidonor reactivity with donor antigen and a source of T cell help, multiple skin grafts bearing donor class I plus third-party class II antigens were placed on tolerant animals. Skin grafts were placed at least 3 months after the kidney transplant, at which time all recipients had normal renal function as measured by blood urea nitrogen and serum creatinine. First-set rejection of skin grafts by SLAad and SLAdd hosts occurred in 11.8±1.1 days (mean ± SEM, n=6) and in 9.3±0.9 days (n=4), respectively. Coincident with skin rejection, most animals developed a transient rise in BUN to 62±11 mg/dl (n=10) and a similar rise in Cr to 4.9±1.2 mg/dl (n=10), with normal levels returning in all animals within two weeks. Subsequent skin grafts with the same disparity did not undergo second-set rejection and did not induce BUN or Cr elevations. Prior to skin grafting, animals showed no antidonor activity in mixed lymphocyte reaction or cellmediated lymphocytotoxicity assays. After two skin grafts, all animals developed donor-specific CML and secondary MLR responses, and additional skin grafts amplified this cellular immunity. Development of marked antidonor immunity without a break in tolerance suggested that either graft adaptation or local suppression might be involved in maintaining tolerance to class I MHC antigens. In preliminary studies, an immunized SLAad animal and an immunized SLAdd animal were retransplanted with kidneys MHC matched to their first allografts. In both cases, the second graft was accepted permanently without immunosuppression, suggesting that graft adaptation is not necessary for the maintenance of tolerance to renal allografts in miniature swine.

ADVERSE EFFECTS OF MEGLUMINE DIATRIZOATE ON RENAL FUNCTION IN THE EARLY POST-TRANSPLANT PERIOD

Thirty-four renal transplant recipients received drip infusion urograms from 2–24 days post-transplantation. Twenty-two patients exhibited changes in renal function within 1–4 days of the urogram that were indistinguishable from allograft rejection: a tender, swollen kidney, elevation of serum creatinine, oliguria, decreased urine sodium concentration, weight gain, and hypertension. Two patients developed acute tubular necrosis and required hemodialysis, but renal function in the remaining 20 patients improved after therapy for “graft rejection” with i.v. methyprednisolone sodium succinnate. Kidneys from older-age donors that were functioning suboptimally and kidneys which exhibited subsequent clinical allograft rejection were more at risk for contrast media toxicity. This suggests that occult vascular lesions may have been present in the allograft which were exacerbated when exposed to the irritant vascular effects of contrast media, producing a mild, reversible toxic nephritis. However, several kidneys with normal function and several kidneys which never exhibited rejection activity were also adversely affected by exposure to contrast media. It appears these agents should be used cautiously, if at all, in the early post-transplant period.

Immune injury from organ preservation. A potential cause of hyperacute rejection in human cadaver kidney transplantation.

Two pairs of plasma-perfused human cadaver kidneys were rejected in a hyperacute manner by recipients who had not previously received a transplant. Crossmatches between recipient sera and donor lymphocytes were negative in all cases. A fifth kidney was plasma-perfused but not transplanted because the perfusate was shown to be cytotoxic to donor lymphocytes. IgM and complement, but not IgG, were demonstrated in these kidneys by immunofluorescent microscopy and confirmed by further immunological studies. The IgM was broadly reactive against multiple HL-A specificities and was present in 11% of sera from normal, healthy male donors. It appears from our studies that cytotoxic IgM may be present in homologous plasma and cause immune injury to the kidney during ex vivo pulsatile preservation. This may be responsible for some cases of otherwise unexplained accelerated allograft rejection.

Retransplantation in miniature swine. Lack of a requirement for graft adaptation for maintenance of specific renal allograft tolerance.

In miniature swine, one-haplotype class I disparate renal allografts are accepted without exogenous immunosuppression by approximately 35% of recipients. Alternatively, transplants bearing a two-haplotype class I mismatch are always rejected acutely. However, long-term acceptance in the latter animals can be achieved uniformly with a 12-day course of cyclosporine. In vitro studies of recipient cell-mediated lymphocytotoxicity responses have shown donor-specific cytotoxic T lymphocyte clones in tolerant animals, suggesting that tolerance may be a local phenomenon or a central phenomenon activated in the milieu of the graft. Six animals were retransplanted with kidneys MHC-matched to their original allograft to determine whether (1) tolerance is a central phenomenon; (2) host tolerance can be broken with a fresh challenge of donor antigen and antigen-presenting cells; and (3) graft adaptation is required for maintenance of tolerance. Four of the retransplanted animals had been spontaneous acceptors of one-haplotype class I-disparate grafts and two had been rendered tolerant to two-haplotype class I-mismatched kidneys with CsA induction. All six explanted allografts showed no histological evidence of rejection and all six retrans-plants were accepted without exogenous immunosuppression. These findings suggest that in miniature swine tolerance of class I-disparate kidneys is a stable, centrally mediated phenomenon that cannot be broken with a challenge of fresh donor antigen and donor-type APCs. Furthermore, successful retrans-plantation without immunosuppression in animals receiving CsA induction therapy for their first transplant suggests that graft adaptation is not necessary for the maintenance of tolerance.