Infections in solid organ transplantation in special situations: HIV-infection and immigration

Soluble fibrinogen like protein 2 (sFGL2), the novel effector molecule for immunoregulation

Soluble fibrinogen-like protein 2 (sFGL2) is the soluble form of fibrinogen-like protein 2 belonging to the fibrinogen-related protein superfamily. It is now well characterized that sFGL2 is mainly secreted by regulatory T cell (Treg) populations, and exerts potently immunosuppressive activities. By repressing not only the differentiation and proliferation of T cells but also the maturation of dendritic cells (DCs), sFGL2 acts largely as an immunosuppressant. Moreover, sFGL2 also induces apoptosis of B cells, tubular epithelial cells (TECs), sinusoidal endothelial cells (SECs), and hepatocytes. This mini-review focuses primarily on the recent literature with respect to the signaling mechanism of sFGL2 in immunomodulation, and discusses the clinical implications of sFGL2 in transplantation, hepatitis, autoimmunity, and tumors.

Tuberculosis and Transplantation

Mycobacterium tuberculosis is a major opportunistic pathogen in transplant recipients. Compared to that in the general population, the frequency of tuberculosis (TB) is 10 to 40 times higher in hematopoietic stem cell transplant (HSCT) recipients and 20 to 74 times higher in solid-organ transplant (SOT) recipients. Transplant recipients with TB are also more likely to develop disseminated disease, have longer time to definitive diagnosis, require more invasive diagnostic procedures, and experience greater anti-TB treatment-related toxicity than the general population. Specific risk factors for TB in SOT recipients include previous exposure to M. tuberculosis (positive tuberculin skin tests and/or residual TB lesions in pretransplant chest X ray) and the intensity of immunosuppression (use of antilymphocyte antibodies, type of basal immunosuppression, and intensification of immunosuppressive therapy for allograft rejection). Risk factors in HSCT recipients are allogeneic transplantation from an unrelated donor; chronic graft-versus-host disease treated with corticosteroids; unrelated or mismatched allograft; pretransplant conditioning using total body irradiation, busulfan, or cyclophosphamide; and type and stage of primary hematological disorder. Transplant recipients with evidence of prior exposure to M. tuberculosis should receive treatment appropriate for latent TB infection. Optimal management of active TB disease is particularly challenging due to significant drug interactions between the anti-TB agents and the immunosuppressive therapy. In this chapter, we address the epidemiology, clinical presentation, diagnostic considerations, and management strategies for TB in SOT and HSCT recipients.

Elderly kidney transplant recipient with intermittent fever: a case report of leishmaniasis with acute kidney injury during liposomal amphotericin B therapy

We present a case report of visceral leishmaniasis in an elderly kidney transplant recipient (age, 73 years) with high intermittent fever in the 2 months before admission. Symptoms started 16 years after transplant. The patient received appropriate treatment with liposomal amphotericin and experienced transient increases in serum creatinine levels. Progression to dialysis was avoided with short duration of therapy (5 consecutive days, plus 1 more dose 1 week apart, a schedule alternative to 15-21 days [supported by the literature]) and a temporary reduction in tacrolimus exposure. After 4 months, recurrence of symptoms without other explanation required a second bone marrow aspirate; it revealed the persistence of amastigote forms. Visceral leishmaniasis is a potentially life-threatening infection; to the best of our knowledge, this is the oldest transplanted patient with a case of leishmaniasis described in the literature.

Old and new challenges in Chagas disease

Chagas disease, caused by the parasite Trypanosoma cruzi, is a neglected disease, which can lead to cardiomyopathy, arrhythmias, megaviscera, and more rarely, polyneuropathy in up to 30-40% of patients around 20 to 30 years after acute infection. Although it is endemic in the Americas, global population movements mean that it can be located wherever migrants from endemic areas settle. The disease was first described 100 years ago and still challenges clinicians worldwide, since diagnostic, therapeutic, and prognostic methods remain insufficient. Furthermore, factors such as HIV co-infection, immunosuppressive drugs, transplantation, and neoplastic disease can alter the natural course of the infection. We present the case of a Bolivian woman with chronic T cruzi infection diagnosed at our clinic in Madrid, Spain, who subsequently developed non-Hodgkin lymphoma. Our report illustrates the challenges of an increasingly common infection seen in non-endemic countries, and highlights both daily management dilemmas and associated difficulties that arise.

An approach to the management of Trypanosoma cruzi infection (Chagas' disease) in immunocompromised patients

The epidemiology of Chagas disease has changed in the last decades due to migration movements, population ageing and the emergence of new transmission routes. In endemic countries, health facilities and access to healthcare are improving and T. cruzi infected patients are also benefiting from medical advances. The HIV epidemic has spread to both endemic and non-endemic areas for T. cruzi, organ transplant rates have increased recently, especially in Latin America, and other medical conditions affecting the immune system are increasing their global burden. The natural course of Chagas disease is mainly determined by the host's cellular immune response. These conditions may therefore overlap with T. cruzi infection and alter the disease's natural history which may present with atypical clinical forms and a higher associated morbidity and mortality in immunocompromised patients. The present review aims to contribute to the management of immunosuppressed patients with T. cruzi infection.

Parasitic infections in solid organ transplant recipients

Parasitic diseases are rare infections after a solid organ transplant (SOT). Toxoplasmosis, Trypanosoma cruzi, and visceral leishmanias are the 3 main opportunistic protozoal infections that have the potential to be lethal if not diagnosed early and treated appropriately after SOT. Strongyloides stercoralis is the one helminthic disease that is life-threatening after transplant. This review addresses modes of transmission, methods of diagnosis, and treatment of the most serious parasitic infections in SOT. The role of targeted pretransplant screening of the donor and recipient for parasitic diseases is also discussed.