Mycophenolate mofetil-induced neutropenia in liver transplantation.

BACKGROUND: Mycophenolate mofetil (MMF) is a potent, safe immunosuppressive agent for rescue therapy of acute and chronic rejection in orthotopic liver transplant recipients. It helps to reduce the serious toxic side effects of calcineurin inhibitors (CNIs). The side effects of MMF, such as bone marrow toxicity, have been reported. Herein we report four patients who underwent liver transplantation and developed neutropenia while receiving MMF. METHODS: Between April 2002 and October 2003, we performed 24 liver transplants in 25 patients. Eighteen patients were given MMF for the following reasons: renal failure in nine (50%); treatment of acute rejection in three (16.6%); primary prophylaxis of rejection in five (27.7%); and CNI withdrawal in one (5.5%). RESULTS: Of the 18 patients treated with MMF, there were 11 men (61.1%) and seven women (38.8%), with an overall mean age of 55.5 years. This therapy was ceased in four patients due to neutropenia (22%). Discontinuation of MMF was followed by a rapid and spontaneous rise in neutrophils in two patients. Granulocyte colony stimulating factor (GCSF) was administered to one patient and in another a bone marrow biopsy was performed due to persistent anemia, leukopenia, and thrombocytopenia. The mean time from starting MMF to the development of neutropenia was 4 months. Only the third patient showed elevated levels of MMF. CONCLUSIONS: MMF is a potent immunosuppressive agent in liver transplantation. However, because serious hematologic toxicity has been reported, we recommend caution in administration and careful monitoring of blood levels.

Developmental and auxin-induced expression of the Arabidopsis prha homeobox gene.

A single-copy Arabidopsis homeobox gene, prha, which encodes a homeodomain protein with a molecular weight of 90,500 has been characterized. The position of the gene was mapped to the distal part of chromosome 4. Expression of the gene differs in various vegetative and floral plant tissues and is positively influenced by the phytohormone auxin. In Arabidopsis plants, a complex pattern of prha promoter-driven GUS expression is observed, often associated with regions of developing vascular tissue. Exogenously applied auxin strongly increased endogenous prha transcript levels. In addition, the prha promoter is highly responsive to the synthetic auxin, naphthalene acetic acid, in transient assays using tobacco protoplasts. The PRHA protein has the capacity to bind to TAATTG core sequence elements but requires additional adjacent bases for high-affinity binding. These findings are discussed in relation to studies of other plant homeobox genes as well as possible in vivo target genes for PRHA.

Interaction of elicitor-induced DNA-binding proteins with elicitor response elements in the promoters of parsley PR1 genes.

PR1 is a pathogenesis-related protein encoded in the parsley genome by a family of three genes (PR1-1, PR1-2 and PR1-3). Loss- and gain-of-function experiments in a transient expression system demonstrated the presence of two fungal elicitor responsive elements in each of the PR1-1 and PR1-2 promoters. These elements, W1, W2 and W3, contain the sequence (T)TGAC(C) and mutations that disrupt this sequence abolish function. Gel shift experiments demonstrated that W1, W2 and W3 are bound specifically by similar nuclear proteins. Three cDNA clones encoding sequence-specific DNA-binding proteins were isolated by South-Western screening and these proteins, designated WRKY1, 2 and 3, also bind specifically to W1, W2 and W3. WRKY1, 2 and 3 are members of the family of sequence-specific DNA-binding proteins, which we call the WRKY family. Treatment of parsley cells with the specific oligopeptide elicitor Pep25 induced a transient and extremely rapid increase in mRNA levels of WRKY1 and 3. WRKY2 mRNA levels in contrast showed a concomitant transient decrease. These rapid changes in WRKY mRNA levels in response to a defined signal molecule suggest that WRKY1, 2 and 3 play a key role in a signal transduction pathway that leads from elicitor perception to PR1 gene activation.