[Pulmonary infections following solid organ transplantation]

Solid organ transplantation is the standard of care for selected patients with severe vital organ dysfunction. The need for immunosuppression to prevent organ rejection is a common characteristic of recipients. Immunosuppression increases the risk of infections, especially with low virulence opportunistic pathogens. Infections following solid organ transplantation mainly affect the lungs and the airways. Establishing the diagnosis includes a wide spectrum of pulmonary diagnostics, high standard microbiological analysis and various imaging methods. With the improvement of treatment options, the number of kidney, liver, heart and lung transplant recipients is increasing and, therefore, more and more physicians may meet pulmonary complications in these patients.

Cytomegalovirus infection after kidney transplantation, susceptibility to CMV-infection in association with HLA-genotype — Doctoral dissertation summary

Cytomegalovirus infection is a major infectious complication of transplant recipients, causing significant morbidity and mortality. It is possible to treat this infection effectively only if we know the direct and indirect effects of it, if we take the risk-factors into account, and use sensitive and reliable diagnostic methods for early establishment of diagnosis. In order to avoid severe CMV-infection, it is possible to administer prophylactic therapy. For prophylaxis planning it is important to know the CMV-seroprevalence of Hungarian population and its characteristics. Our results have shown that the seroprevalence of Hungarian population is high: 86%. The primary CMV-infection in Hungary occurs in childhood or in early adulthood, till age of 20 years the seroprevalence is 72%. CMV-seronegative recipients should be transplanted using organs of seronegative donors, however, the chance obtaining the graft from a CMV-seronegative donor was shown to be 2% only. Since such seromatching is rear, we have to know that the constellation of negative recipient and positive donor is the highest risk-factor for developing severe primary CMV-infection. While investigating data of 147 CMV-seronegative recipients from high-risk group it has been established that CMV-infection prophylaxis is essential for high risk patients in the early post-transplant period of 3 months, the administration of any of investigated prophylactic protocols is advantageous in comparing with prophylaxis free management of those patients (P=0.006). The study has also proven that monoprophylaxis with ganciclovir or valganciclovir is the most effective and cost-effective procedure as compared to other protocols (P=0.006). It is important to take into consideration that in prophylactic groups the “late-onset” CMV-infection occurred often (25.4%), and that there were no signs of seroconversion after the primary CMV-infection in 14% of the patients. For the first time it has been found and proven that the female sex is a risk factor for CMV-infection (P=0.0006). Genetic variability influences susceptibility to infectious diseases and HLA-molecules are critical for viral antigen uptaking, processing and presenting. Our data of 129 of high-risk patients suggest that recipients positive for HLA-DQ3 are more susceptible to CMV-infection than a comparable group of patients negative for this HLA-type. This result was not due to rejection and/or treatment for rejection and was not influenced by induction therapy or number of HLA-mismatches. The multivariate Cox Regression analysis has shown that HLA-DQ3 positivity is an independent predictor of primary CMV-infection in CMV-seronegative recipients with seropositive donor grafts (P=0.001). The cognition of HLA-DQ3 is useful in the prediction of acute CMV-infection in high-risk patients, and should influence the planning of the patients' management.

Gastrointestinal cytomegalovirus infections in organ transplant patients

A cytomegalovirus (CMV) az immunszupprimált szervtranszplantált betegek egyik veszélyes fertőzése. A transzplantáltak 80-90%-ánál a fertőzés inaktív; a tünetekkel járó CMV-betegség gyakorisága 30-40%-os. Gastrointestinalis CMV-betegség a szervátültetettek mintegy 10%-ában fordul elő, a kórkép a tápcsatorna bármelyik szakaszát érintheti. A CMV-betegség leggyakrabban a nyálkahártya károsodásával, fekélyekkel, eróziókkal, vérzésekkel jár, oka lehet a tápcsatorna motilitási zavarának, ritkábban gastrointestinalis gyulladásos teriméknek, perforációknak. A diagnosztika alapja az endoszkópos vizsgálat biopsziás mintavétellel. A biopsziás minta szövettani vizsgálatakor keresni kell a CMV-fertőzésre jellemző cytomegaliás sejteket intranukleáris („bagolyszem”) és intracitoplazmatikus zárványokkal. A vírus kimutatására számos mikrobiológiai, immunhisztokémiai és molekuláris biológiai módszer létezik. Igazolt kórkép esetén a kezelés kettős: az elváltozásoknak, tüneteknek megfelelő gasztroenterológiai kezelés mellett meg kell kezdeni az antivirális terápiát általában intravénás ganciclovirrel és/vagy orális valganciclovirrel. Lényeges a betegség kialakulásának megelőzése is: a magas rizikójú betegcsoportban általános profilaxis javasolt per os valganciclovirrel, speciális esetekben hiperimmunglobulinnal; közepes kockázat esetén a mikrobiológiai surveillance eredménye alapján preemptív kezelés kezdhető.