Infectious Complications in the Renal Transplant Recipient

Practical Applications in Immunohistochemistry: Evaluation of Rejection and Infection in Organ Transplantation

CONTEXT

-Immunohistochemical analysis of tissue biopsy specimens is a crucial tool in diagnosis of both rejection and infection in patients with solid organ transplants. In the past 15 years, the concept of antibody-mediated rejection has been refined, and diagnostic criteria have been codified in renal, heart, pancreas, and lung allografts (with studies ongoing in liver, small intestine, and composite grafts), all of which include immunoanalysis for the complement split product C4d.

OBJECTIVES

-To review the general concepts of C4d biology and immunoanalysis, followed by organ-allograft-specific data, and interpretative nuances for kidney, pancreas, and heart, with discussion of early literature for lung and liver biopsies. Additionally, practical applications and limitations of immunostains for infectious organisms (Polyomavirus, Adenoviridae [adenovirus], and the herpes virus family, including Herpes simplex virus, Cytomegalovirus, Human herpes virus 8, and Epstein-Barr virus) are reviewed in the context of transplant recipients.

DATA SOURCES

-Our experience and published primary and review literature.

CONCLUSIONS

-Immunohistochemistry continues to have an important role in transplant pathology, most notably C4d staining in assessment of antibody-mediated rejection and assessment of viral pathogens in tissue. In all facets of transplant pathology, correlation of morphology with special studies and clinical data is critical, as is close communication with the transplant team.

Pneumocystis jirovecii pneumonia in patients with end-stage renal disease: a comparison with the general population

BACKGROUND

Data on occurrence and risk factors for pneumocystis pneumonia (PCP) in patients with end-stage renal disease (ESRD) are sparse.

METHODS

This was a nationwide population-based study assessing occurrence and risk factors for PCP among patients with ESRD and population controls over a 21-year period (1/1 1990 to 31/12 2010). Using Danish registry data, first-time diagnoses of PCP were identified.

RESULTS

We identified 13 296 adult patients with ESRD and 244 255 controls, yielding 63 560 and 2 223 660 person-years of follow-up (PYFU), respectively. Fifty-eight first-time diagnoses of PCP were recorded in the ESRD group. Forty-six episodes occurred among renal transplant recipients (RTx) and 12 among haemodialysis patients (HD), yielding incidence rates of 181 (136-242) and 43.1 (24.5-75.9) per 100 000 PYFU. Compared to population controls, we found incidence rate-ratios of 125.9 (78.4-204) among RTx and 29.9 (14.1-59.7) among HD patients. Risk factors for PCP in RTx were age 50-65 years, age > 65 years, diabetes, polycystic kidney disease and hypertensive kidney disease/nephrosclerosis with an IRR of 2.22 (1.14-4.31), 3.12 (1.35-7.21), 3.44 (1.16-10.2), 4.25 (1.55-11.7) and 3.87 (1.49-10.0), respectively, and more than 36 months of dialysis before transplantation with an IRR of 1.99 (1.03-3.84). Among RTx the risk of PCP was highest during the first 6 months post-transplantation and increased from the beginning (IR1990-94 = 111 (46.3-267) per 100 000 PYFU) towards the end of the study period (IR2005-10 = 299 (203-439)).

CONCLUSION

The PCP risk is substantial in RTx within the first 6 months of transplantation, emphasizing the potential benefit of prophylactic treatment in the early post-transplant period. Importantly, we identified subgroups within the RTx group that require more attention.

Prospective, comprehensive, and effective viral monitoring in Cuban children undergoing solid organ transplantation

PURPOSE

In Cuba, viral monitoring in the post-transplant period was not routinely performed. The aim of this research is to identify the most frequent viruses that affect transplanted Cuban children, by implementing a viral follow-up during the post-transplant period.

METHODS

The study population included all Cuban pediatric patients who underwent solid organ transplantation (SOT) between November 2009 and December 2012. A total of 34 transplanted pediatric patients of kidney (n = 11) and liver (n = 23) were prospectively monitored during a 34-week period for viral DNAemia and DNAuria by simultaneous detection of cytomegalovirus (CMV), Epstein-Barr virus, herpes simplex virus type 1 and 2, varicella zoster virus, human herpesvirus 6, human adenovirus, and polyomaviruses (BKV and JCV) using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Viral genome of at least one virus was detected in 21 of 34 recipients, 18 patients excreted virus in urine while 12 presented DNAemia. CMV (41.2%) and BKV (35.3%) were the most frequent viruses detected during the follow-up. CMV was the virus mainly associated with clinical symptoms and DNAemia. Its excretion in urine (with cut off value of 219 copies/mL) was associated with detection in plasma (p < 0.001); furthermore, CMV viruria was predictive of CMV viremia (OR:8.4, CI:2.4-29.1, p = 0.001). There was no association between high viral load and clinical complications, due to the prompt initiation of preemptive ganciclovir.

CONCLUSION

This comprehensive viral monitoring program effectively prevents the development of critical viral disease, thus urge the implementation of qRT-PCR as routine for viral monitoring of transplanted Cuban organ recipients.

Atypical presentation of exophytic herpes simplex virus type 2 with concurrent cytomegalovirus infection: a significant pitfall in diagnosis

We report 3 unusual cases of atypical exophytic cutaneous herpes simplex virus (HSV) type 2 with concurrent cytomegalovirus (CMV) infection in immunosuppressed patients and raise awareness to the significant clinical and pathologic challenges in establishing the correct diagnosis. In all the 3 cases, the lesions presented as fungating plaques and nodules with areas of superficial erosion. Initial clinical differential included genital warts, syphilis, versus cutaneous malignancy. All the 3 patients were referred to the dermatology clinic where a combination of cutaneous biopsies, viral cultures of the lesions, polymerase chain reaction, CMV antigenemia, and immunoperoxidase stains for CMV and HSV confirmed the diagnosis of HSV type 2 with concurrent CMV infection. All the 3 patients were treated with oral valganciclovir with significant improvement noted at the follow-up visit. In addition, we review the previously reported HSV/CMV cutaneous coinfection cases.

Delay of adequate empiric antibiotic therapy is associated with increased mortality among solid-organ transplant patients

Empiric antibiotic therapy is often prescribed prior to the availability of bacterial culture results. In some cases, the organism isolated may not be susceptible to initial empiric therapy (inadequate empiric therapy or IET). In solid-organ transplant recipients, the overall incidence and clinical importance of IET is unknown. We performed a retrospective cohort study of patients admitted from 2002 to 2004. Multiple logistic regression analyses were conducted to determine associations between potential determinants and mortality. IET was administered in 169/312 (54%) patients, with a hospital mortality rate that was significantly greater than those receiving adequate therapy (24.9% vs. 7.0%; relative risk [RR] 3.55; 95% confidence interval [CI], 1.85-6.83; p < 0.001). Regression analysis demonstrated that an increasing duration of IET (adjusted odds ratio [OR] at 24 h: 1.33; 95% CI: 1.15-1.53; p < 0.001), ICU-associated infections (adjusted OR: 6.27; 95% CI: 2.79-14.09; p < 0.001), prior antibiotic use (adjusted OR: 3.56; 95% CI: 1.51-8.41; p = 0.004) and increasing APACHE-II scores (adjusted OR: 1.26; 95% CI: 1.16-1.34; p < 0.001) were independently correlated with hospital mortality. IET is common and appears to be associated with an increased hospital mortality rate in the solid-organ transplant population.

Infectious complications after kidney transplantation: a single-center experience

Infectious complications after renal transplantation are associated with significant morbidity and mortality. The prevalence of infections in transplant recipients varies from country to country. This study sought to assess the overall incidence of post-transplant infectious complications at our research center in Iran, compared with other centers in the world. Between 2002 and 2004, 179 renal transplantations were performed in our center. Of these, 142 were studied and followed for 1 year. Immunosuppressive regimens were cyclosporine, mycophenolate mofetil, and prednisolone. The overall incidence of infections was 54.2%. The most common sites of infections were the urinary tract (41.5%) and the respiratory tract (6.3%). The most frequent causes of infections were Klebsiella (24%) and cytomegalovirus (CMV) (17.6%). Wound infection occurred in 4.9% of the patients. Three (2.1%) patients developed hepatitis C and 2 (1.4%) had mycobacterial infections. There was no case of Pneumocystis pneumonia. Overall mortality was 7.7%. Infection-related mortality was 3.5%. In conclusion, this study identifies infections as the cause of morbidity and mortality in the post-transplant period. There was a low incidence of tuberculosis (<2% yearly) and a high incidence of CMV disease in our recipients.