K. Malinowska

Plasmapheresis with intravenous immunoglobulin G is effective in patients with elevated panel reactive antibody prior to cardiac transplantation

BACKGROUNDnPatients with a PRA >10% are considered to be at greater risk for the development of not only acute cellular and humoral rejection but also increased mortality when compared to nonsensitized patients following transplantation. All patients with a PRA >10% at our institution are treated with plasmapheresis and intravenous immunoglobulin G immediately prior to cardiac transplantation.nnnMETHODSnSixteen (Group 1) of 118 patients awaiting cardiac transplantation were found to be sensitized. These patients underwent plasmapheresis followed by 20 gm of intravenous immunoglobulin G (IVIG) immediately prior to cardiac transplantation. Group 1 was compared to the remaining 102 patients with a PRA <10% (Group 2).nnnRESULTSnDespite more patients in Group 1 having a positive crossmatch, pulmonary hypertension, and requiring mechanical circulatory support, there was no statistically significant difference in length of stay or mortality at a mean follow-up of 21.6+/-15.0 months. There was no difference in the occurrence of mild, moderate or severe cellular rejection or humoral rejection in these sensitized patients when compared to Group 2.nnnCONCLUSIONSnPretransplant plasmapheresis followed by intravenous immunoglobulin G may be an effective therapy that obviates the need for a prospective crossmatch and allows sensitized patients to undergo cardiac transplantation. There is no increase in the post transplant length of stay, occurrence of rejection or short term mortality. Long term follow up is necessary to evaluate whether there is a difference in the development of late rejection, transplant vasculopathy and survival.

Induction of TNFα and TNFβ gene expression in rat cardiac transplants during allograft rejection

The expression of the cytotoxic cytokines tumor necrosis factor a and TNF→ bT or lymphotoxin (LT) was assessed in rat cardiac transplants during rejection. Newborn rat cardiac grafts placed in adult rat ear pinnae were retrieved on days 1 through 10 posttransplantation; the average time to rejection, assessed by the absence of detectable electrocardiographic activity, was determined to be 7 days. Total cellular RNA and tissue homogenates were prepared from cardiac transplants in order that relative levels of TNFα and LT mRNA and TNF protein could be determined. A biphasic pattern of TNFα gene expression was consistently seen in cardiac allografts. TNFα mRNA transcripts were detected as early as day 2 post-tx, with peak levels appearing on day 3 post-tx. Although transcript levels decreased by day 4, a significant increase appeared again on day 6 post-tx, coincident with the onset of rejection. Similar to TNFα gene expression, LT transcripts demonstrated a biphasic pattern of induction. LT mRNA transcripts also reached peak levels on day 3 post-tx, with a second increase in transcript levels coincident with rejection. TNF protein levels in allografts displayed a biphasic pattern, similar to that shown by the cytokine mRNAs. Peak levels of TNF protein were detected on day 3 post-tx, with a second increase again coinciding with rejection. In contrast to TNF expression found in allografts, TNFα and LT mRNA transcripts were not detected in isografts on days 1 through 10 post-tx. TNF protein levels in cardiac isografts were consistently at or below the standard limits of detection, and on days 3 through

Five-year follow-up of hepatitis C-naïve heart transplant recipients who received hepatitis C-positive donor hearts

BACKGROUNDnDue to the risk of transmission of hepatitis C virus, the use of hepatitis C seropositive donors in heart transplantation is controversial. The transmission rate of hepatitis C in this patient population is estimated to range from 67% to 80%. Long-term clinical outcomes of heart transplant recipients of hepatitis C-positive donor hearts are not well described. We report the 5-year long-term outcome of seven hepatitis C-naïve heart transplant recipients who received hepatitis C-positive donor hearts.nnnMETHODSnRetrospective analysis of clinical course, liver biochemistry, serology, and hepatitis C virology data.nnnRESULTSnSeven hearts transplant recipients, six men and one woman were included in our study. After a mean follow-up of 63.3 +/- 20.4 months (range 28.2 to 85.9), four of seven (57.1%) patients are hepatitis C-negative, have normal liver function tests, and no clinical evidence of hepatitis. Three of seven (43%) have been diagnosed with hepatitis C by liver biopsy or the HCV-RNA reverse transcriptase polymerase chain reaction at a mean follow-up of 35.1 months (18.8 months posttransplantation). One had an accelerated course of hepatitis that was ultimately fatal, one was successfully treated with interferon, and the third died from other causes than liver injury. Overall, the 5-year survival was 71.4%.nnnCONCLUSIONSnThe 5-year survival of hepatitis C-naïve recipients of hearts from hepatitis C-positive donors is similar to heart transplant recipients with hepatitis-negative donor hearts. Nevertheless, the transmission rate is high and hepatitis C infection in this population can lead to considerable morbidity and accelerated, fatal hepatitis.

Use of low-dose cyclosporine A/methotrexate to prolong rat cardiac allograft survival.

Cyclosporine A (CSA) is the standard immunosuppressive agent used in human cardiac transplantation to prevent rejection; however, adverse side effects have been reported at therapeutic doses. Therefore, a need remains for the implementation of specific therapies designed to achieve transplant success with a minimum of undesirable side effects. The aims of the present study were: (1) to evaluate the efficacy of a low-dose CSA (1.0 mg/kg/day) / methotrexate (MTX) (450 micrograms/kg/week) combination therapy in prolonging rat cardiac allograft survival, and (2) to determine the effects of low-dose CSA/MTX on interleukin-2 (IL-2) gene expression in rat cardiac allografts. The average time to rejection of newborn donor Brown Norway (BN) rat hearts transplanted into the ear pinnae of CSA/MTX-treated adult Lewis recipients, measured by the absence of electrocardiographic (ECG) activity, more than doubled from day 8 post-transplantation (post-tx) to day 18 post-tx when compared to allografts in untreated control recipients (p < or = 0.01). Northern blot analysis demonstrated that IL-2 mRNA transcripts in cardiac allografts treated with low-dose CSA/MTX were detected as early as day 1 post-tx, and at increasing levels as rejection progressed post-tx. When IL-2 gene expression in allografts from CSA/MTX-treated recipients was compared to levels in allografts from untreated recipients, no significant difference in the pattern of IL-2 induction was observed. In contrast, IL-2 mRNA transcripts were not detected post-tx in allografts from recipients treated with high-dose (15 mg/kg/day) CSA or in cardiac isografts. The presence of IL-2 gene transcripts, therefore, appears to be allograft-specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Diminished cytotoxic gene expression in rat cardiac transplants with low-dose cyclosporine/ methotrexate combination therapy

We have previously shown that administration of a combination low-dose cyclosporine (CsA) (1.0 mg/kg/day)/methotrexate (MTX) (450 μUg/kg/wk) treatment significantly increases the survival of rat cardiac al-lografts, and may therefore potentially serve as an alternative immunosuppressive therapy designed to promote transplant survival while minimizing high-dose CsA side effects. In contrast to high-dose CsA, low-dose CsA/MTX treatment does not appear to alter IL-2 gene expression, since similar patterns of IL-2 gene transcripts were found in both low-dose CsA/ MTX-treated and untreated control allografts on days 1 through 8 posttransplantation (post-tx). The mechanism(s) by which low dose CsA/MTX therapy increases the time of allograft survival remains to be elucidated. The aim of the present study was to determine the effects of low-dose CsA/MTX on the expression of the cytotoxic cytokines, TNFα, TNFβ, or lymphotoxin (LT), and the serine proteases HF and C11 (granzymes A and B, respectively) in rat cardiac allografts during rejection. RNA blot analysis showed significant suppression of TNFα, LT, HF, and Cll gene expression on days 1 through 8 post-tx in cardiac allografts from low-dose CsA/MTX-treated recipients compared with untreated allograft controls. TNF protein levels in cardiac allografts from low-dose CsA/MTX-treated recipients were also found to be significantly reduced on days 1 through 8 post-tx when compared with time-matched untreated allograft controls (P<0.001). We conclude that low-dose CsA/MTX treatment, while effective in prolonging cardiac transplant survival, appears to act at the mRNA level to downregulate cytotoxic cytokine gene expression. Such trials aimed at evaluating lowdose combination therapy may afford new insight into mechanisms underlying improvement in immunosuppressive treatment.