Post-transplantation polyomavirus infections.

Increasing attention has been recently accorded to BK and JC viruses (BKV and JCV). Both these human polyomavirus (HPV) are members of the papovavirus family which includes the simian virus SV 40. BKV and JCV infect more than 60% of the population worldwide. After primary infection, they remain harboured in the kidneys and may become reactivated in situations of immune impairment. HPV were first described in 1971. BKV was isolated in a renal transplant patient with ureteral stricture and JCV in a patient with progressive multifocal leukoencephalopathy (PML). BKV was known to be involved in post-bone marrow transplantation (BMT) hemorrhagic cystitis. In renal transplantation, BKV and JCV were initially found in the post-transplant ureteric stricture and PML. They are now recognised as a possible cause of transplant interstitial nephritis, mimicking rejection (satisfying the Banff criteria for acute rejection) or drug toxicity. In HPV nephritis there is a mixed interstitial inflammatory infiltrate with focal tubular injury; the tubular epithelium shows marked anisonucleosis, nuclear atypia and basophilic or amphophilic intranuclear inclusions. Tubulitis is frequent. DNA hybridisation or gene amplification by polymerase chain reaction usually demonstrate HPV. Although histology with viral nucleic acid detection may be helpful in differentiating viral infection and rejection, confusion between these complications may lead to either anti-rejection therapy, with the risk of over-immunosuppression, or reduction of immunosuppression, with the risk of graft loss. Confusion may also arise with inclusions of other viruses, such as cytomegalovirus, herpes virus and adenovirus. Reactivation of BKV and JCV infection was demonstrated in respectively 22.2% and 10.9% of renal transplant recipients and 55% and 6.7% of BMT patients. Unfortunately, no routine screening is available for these viruses, so this complication is probably underestimated. No specific therapy of HPV infection is currently available.

Human parvovirus B19 infection in organ transplant recipients.

We report a 61-yr-old kidney transplant recipient with human Parvovirus B19 (HPV B19) infection presenting as a severe pancytopenia 1 month after transplantation. Bone marrow aspiration revealed severe erythroid hypoplasia with giant and dystrophic proerythroblasts. Bone marrow cells were positive for HPV B19 DNA detected by polymerase chain reaction (PCR). Pancytopenia resolved shortly after administration of intravenous immunoglobulins. Nineteen cases of HPV B19 infection in organ transplant recipients have been so far reported in the literature. Immunocompromised patients should be considered at risk from developing symptomatic HPV B19 infections. In such patients, specific anti-HPV B19 IgM and IgG antibodies may be absent or transient and therefore their negativity cannot rule out the diagnosis of HPV B19 infestation. Bone marrow smear morphological findings may suggest the diagnosis but testing for viral DNA by PCR is mandatory. Patients may spontaneously recover. However, since specific anti-viral therapy is not currently available, intravenous immunoglobulin administration appears to be the more efficacious treatment.

Incidence and consequences of post-transplantation lymphoproliferative disorders.

Post-transplant lymphoproliferative disorder (PTLD) is a recognized severe complication arising in allograft recipients treated with immunosuppressive drugs. Although not common, PTLD is one of the most frequent tumours among graft recipients, comprising 15-25% of neoplasms, compared with 5% in the general population. The introduction of cyclosporin A (CyA) in the early 1980's and the very potent new immunosuppressants such as anti-CD3 monoclonal OKT3 and FK506 have been associated with a significant rise in the incidence of PTLD and with their earlier presentation. The incidence of this malignancy varies with the organ transplanted (1-2% of renal transplant recipients) and with the nature and severity of the accompanying immunosuppressive regimen. While the precise etiology of PTLD is still unclear, significant advances have been made recently in the understanding of its pathogenesis. Most PTLD tumour cells present an activated B-cell phenotype and an unrestricted pattern of latent EBV gene products. It is generally accepted that Epstein-Barr virus (EBV) infection or reactivation and intensive anti-T lymphocyte regimens play a major role in the genesis of PTLD. They include a spectrum of EBV-related disorders ranging from lymphoid hyperplasia to frank malignant non-Hodgkin's lymphoma. Although different therapeutic attempts have been proposed, optimal treatment remains elusive. The mortality rate for monoclonal lymphomas was reported to be as high as 80%. Infusion of anti-B monoclonal antibodies seems to be a promising modality. Different preventive approaches have been proposed, including EBV sero-negative donor/recipient matching and careful monitoring of EBV infection. Cautious use of anti-rejection treatment in combination with prophylactic antiviral therapy is recommended.

Late recurrence of Wegener's granulomatosis presenting as tracheal stenosis in a renal transplant patient.

An unusual case of a 46-year-old man who had end-stage renal disease due to crescentic glomerulonephritis that was treated by a cadaveric renal allograft is presented. About 18 months post-Tx, the patient developed severe tracheal stenosis which, on biopsy, revealed granulation tissue and chronic inflammation. After another 18 months he developed necrotizing glomerulonephritis involving the renal allograft and an inflammatory retro-orbital pseudotumor. The latter, on biopsy, revealed granulomatous vasculitis characteristic of Wegener's granulomatosis. This diagnosis was further confirmed by strongly positive anti-neutrophil antibodies with diffuse granular cytoplasmic immunofluorescence (C-ANCA). The patient was treated successfully with cyclophosphamide therapy.

Wegener's granulomatosis limited to the kidney as a masslike lesion.

We report on a 45-year-old female who presented with end-stage renal disease due to Wegener's granulomatosis limited to the kidneys. Ultrasonography and computed tomography revealed a masslike expansion involving the upper pole of an otherwise small right kidney. Histopathology of a nephrectomy specimen revealed cystic dilatation of renal tubules and active lesions of Wegener's granulomatosis in the upper pole. The lower part of the kidney showed atrophic changes. Wegener's granulomatosis presenting as a renal mass is extremely rare. Only 3 cases have been previously reported in the literature. Wegener's granulomatosis only limited to the kidney is also rare. A brief review of 23 previously reported cases who initially presented with renal disease is presented. All but 2 patients subsequently manifested extrarenal lesions. Our patient continues to be free of any extrarenal involvement 18 months following presentation, although subsequent development of extrarenal lesions cannot be ruled out.

Post renal transplantation non-Hodgkin's lymphoma: Local experience and review of the literature.

Among a population of 600 renal transplant patients, only three cases (0.5%) have developed a non-Hodgkin's lymphoma, while in the same population, 28 cases (4.6%) have developed a Kaposi's sarcoma. The significant low incidence of lymphoma in the Saudi grafted population must be underlined, particularly because of the very high incidence of this malignancy among either the post-transplant Western population, up to 20% of the cancers, or the Saudi general population where the incidence can reach 15% of malignancies.

[The "National Kidney Foundation": a new experience in Saudi Arabia]. / La "National Kidney Foundation": une nouvelle expérience en Arabie Saoudite.

The nephrology is a new field in Saudi Arabia, the National Kidney Foundation was established in 1986 to look after the renal patients, and supply the renal centers with the medical staff, equipment and consumable materials. The National Kidney Foundation established criteria for acceptance of cadaver donors, criteria for priority patients for transplantation, and brain death policy and protocol. One of the main functions that National Kidney Foundation will carry on is the task of matching kidney donors and recipients. In order to do this, a major computer terminal have been established connected with 21 terminals in the major hospitals. All patients on dialysis have been entered and registered in the Computer program. This gives a chance to proper statistical reports graphs and better coordination in renal transplantation.

[Intravenous digital angiography in the kidney transplant patient: results of a systematic prospective study in 164 patients]. / Angiographie numérisée par voie intraveineuse chez le transplanté rénal: résultats d'une étude prospective systématique chez 164 patients.

A prospective study on digital intravenous angiography (DIVA) in 164 renal transplant recipients performed from 1 to 2 months post-transplant was conducted to assess its usefulness in the screening of post-transplant renal artery stenosis (RAS). DIVA was uninterpretable in 32 patients (19%) on technical grounds (blood vessel or metallic clip superimposed). The global prevalence of RAS was 10.7% in 132 patients whose DIVA was informative. No correlation was found between the prevalence of RAS and renal function. The prevalence of RAS was significantly higher (p less than 0.01) in the hypertensive (26%) than in the normotensive group (6.6%), but RAS may occur in normotensive or even asymptomatic patients. Our data confirm the usefulness of routine post-transplant renal artery screening but arterial way will be preferred.