Mycophenolate mofetil immunosuppressive therapies increase the incidence of cytomegalovirus infection in renal transplantation

The Expanding Field of Secondary Antibody Deficiency: Causes, Diagnosis, and Management

Antibody deficiency or hypogammaglobulinemia can have primary or secondary etiologies. Primary antibody deficiency (PAD) is the result of intrinsic genetic defects, whereas secondary antibody deficiency may arise as a consequence of underlying conditions or medication use. On a global level, malnutrition, HIV, and malaria are major causes of secondary immunodeficiency. In this review we consider secondary antibody deficiency, for which common causes include hematological malignancies, such as chronic lymphocytic leukemia or multiple myeloma, and their treatment, protein-losing states, and side effects of a number of immunosuppressive agents and procedures involved in solid organ transplantation. Secondary antibody deficiency is not only much more common than PAD, but is also being increasingly recognized with the wider and more prolonged use of a growing list of agents targeting B cells. SAD may thus present to a broad range of specialties and is associated with an increased risk of infection. Early diagnosis and intervention is key to avoiding morbidity and mortality. Optimizing treatment requires careful clinical and laboratory assessment and may involve close monitoring of risk parameters, vaccination, antibiotic strategies, and in some patients, immunoglobulin replacement therapy (IgRT). This review discusses the rapidly evolving list of underlying causes of secondary antibody deficiency, specifically focusing on therapies targeting B cells, alongside recent advances in screening, biomarkers of risk for the development of secondary antibody deficiency, diagnosis, monitoring, and management.

Emerging trends in infections among renal transplant recipients

Outcomes following renal and simultaneous kidney-pancreas transplants have improved significantly due to better surgical techniques and improved modalities of antirejection therapy. However, infection remains a significant cause of morbidity and mortality. The use of new modalities of immunosuppression and routine use of antimicrobial prophylaxis has changed the pattern of infections post-transplantation. Cytomegalovirus remains a significant problem and BK virus has emerged as an important pathogen. New antimicrobial agents are now available to treat infection, however, antimicrobial resistance remains a concern.

[Risk factors for cytomegalovirus in solid organ transplant recipients]

Cytomegalovirus (CMV) is the most important opportunistic pathogen in patients undergoing solid organ transplantation and increases mortality due to both direct and indirect effects. The most important risk factor for the development of CMV disease is discordant donor-recipient CMV serology (positive donor and negative recipient), which confers more than 50% risk of developing CMV disease if no prophylaxis is given. The use of highly potent antiviral agents for CMV prophylaxis in high-risk patients has changed the characteristics of CMV disease in this population. Other classical risk factors for CMV disease include acute graft rejection, the type of organ transplanted, coinfection with other herpesviruses and the type of immunosuppressive agents employed. New risk factors for this complication have recently been described, including variations in the CMV genotype between donor and recipient and genetic alterations in the recipient's innate immunity. The present review discusses classical risk factors and the latest findings reported on the development of CMV in organ transplant recipients.

[Lights and shadows of cytomegalovirus infection in solid organ transplantation]

Cytomegalovirus (CMV) develops in 30-80% of patients undergoing solid organ transplantation (SOT). The incidence and presence of symptomatic disease varies depending on the type of transplant, the presence of associated risk factors, the intensity of immunosuppression, and the prevention strategies used. The impact of CMV on SOT is due not only to the effects of CMV disease per se, but also to its multiple indirect effects resulting from its immunomodulatory role and immunoactivation caused by viral latency. The two prophylactic strategies used (universal prophylaxis and preemptive therapy) are equally useful. Both strategies have advantages and disadvantages, and uncertainties remain on the populations that should receive prophylaxis and for how long. Viral monitoring to detect CMV infection is important for diagnosis, prognosis and evaluation of treatment response. The new real-time polymerase chain reaction techniques have provided numerous advantages but standardization remains an issue and common reference values are required. Specific anti-CMV drugs are available but issues such as the role of valganciclovir versus ganciclovir, the development of resistances and optimal treatment length are still being debated. Complementary therapy with mTOR inhibitors and vaccine strategies against CMV are alternatives for which conclusive data are lacking.

Incidence, risk factors, and outcomes associated with cytomegalovirus disease in small bowel transplant recipients

Despite improved prophylaxis, monitoring, and more efficient immunosuppression, CMV infection remains a common opportunistic infection in transplant recipients. We assessed the incidence of CMV disease in pediatric SBT recipients, the timing of CMV disease after transplantation, and its impact on patient outcome. The medical records of 98 SBT recipients were reviewed. We performed descriptive analysis, regression analysis, and Kaplan-Meier curves to determine the time-to-event after transplantation. Fifty-three percent patients were male and 47% female, with a mean age of 38.3 months. Thirty-five percent of patients received prophylactic VGC, 55% GCV, 10% a combination of GCV/VGC, and 99% CMV immunoglobulins. A total of 24.5% recipients were CMV D+/R- (CMV serostatus donor positive/recipient negative). Seven (c. 7%) patients developed CMV disease. CMV disease was associated with 2.5 times (0.52-12.1; p = 0.25) higher rate of CMV mismatch and 11.1 times (1.3-95.9; p = 0.03) higher risk of death. CMV prophylaxis increased time-to-death (p = 0.074). Time-to-CMV disease was shorter in patients with enteritis (p < 0.0001), and CMV disease was associated with shorter time-to-death after transplantation (p = 0.001). CMV disease in SBT recipients was associated with an 11-fold mortality increase and a fourfold faster time-to-death. Time-to-death was significantly shorter with CMV enteritis.

Cytomegalovirus disease in renal transplant recipients: a single-center experience

Cytomegalovirus (CMV) is the most common viral infection following kidney transplant, has been recognized as a major factor for graft loss and increased incidence of acute rejection. Different studies have reported a variable incidence of CMV disease with the use of Mycophenolate mofetil (MMF). We retrospectively analyzed our renal transplant recipients to review the results of CMV disease and to compare CMV disease in patient on Azathioprine and MMF for this purpose we retrospectively reviewed 521 live related kidney transplant recipients at our institute. 74 (14.2 %) live related allograft recipients developed CMV disease after a median interval of 7.18 ± 4.35 months from transplantation. The mean age was 36.15 ± 10.7 years. 63 of the patients were male. Malaise, fever and diarrhea were among most common symptoms. 20 (27.02 %) of the 74 recipients developed transaminitis, 13 (17.2 %) developed CMV gastritis, 5 (9.13 %) recipients developed pneumonia, and 3 (4.05 %) patient developed colitis. 59 (80 %) patients had leucopenia and 41 (56.5 %) developed thrombocytopenia. Mean serum creatinine level was 1.5 ± 0.4 (0.9-2.4) mg/dl before the disease, 1.9 ± 0.6 (1.3-3.6) mg/dl at the time of the diagnosis, and 1.7 ± 0.06 (0.8-4.2) mg/dl at the end of the treatment. CMV disease developed in 9 (36 %) of recipients who received basiliximab as induction therapy and 13 (30.24 %) of recipients who received ATG (p > 0.05). The incidence of CMV disease was similar in cyclosporine based regimen (13.2 %) and Tacrolimus based regimen 27 (16.16 %) (p = 0.137) and was also similar in Azathioprine 41 (9.5 %) and MMF group 33 (14.3 %) (p = 0.163). There was no significant difference in severity of CMV disease in both groups, except a higher incidence of leucopenia in Azathioprine group (86 vs. 74 %, p < 0.05) as compared to MMF group. 51 (68.91 %) patient developed graft dysfunction during CMV disease. In conclusion we report a low incidence (14.2 %) and milder form of cytomegalovirus disease at our center. Use of universal cytomegalovirus prophylaxis was associated with a low incidence and milder form of the disease. Incidence of CMV disease was similar between Azathioprine and MMF groups.

Impact of CMV infection on acute rejection and long-term renal allograft function: a systematic analysis in patients with protocol biopsies and indicated biopsies

BACKGROUND

Higher rates of acute rejection (AR) and reduced graft survival have been reported in patients with cytomegalovirus (CMV) infection, but an association between these factors remains controversial.

METHODS

In this study, serial protocol biopsies (PBs) and clinically indicated biopsies (IBs) from a large cohort of renal allograft recipients (n &frac14; 594) were analyzed to examine the relation between CMV and AR.

RESULTS

Patients with CMV were more likely to receive IB (85 of the 153 patients; 56%) compared to patients without CMV (138 of 441 patients; 32%; P = 0.003). However, this did not translate into a greater number of patients with episodes of acute cellular rejection on histopathology in IBs. Analysis of PBs revealed a significantly higher number of episodes of rejection per patient with CMV infection (P = 0.04), but only in a subgroup of patients with triple immunosuppression. Long-term graft function post-transplantation was analyzed in four different subgroups according to CMV infection and/or AR. Differences in renal function were apparent within the first 6 weeks after transplantation and persisted during follow-up, with the best renal function in patients without AR or CMV, whereas patients with both AR and CMV had the worst (P < 0.012 at 1 year; P < 0.001 at 2 years). On average, the latter group had significantly older donors and more often delayed graft function.

CONCLUSIONS

Our data suggests that the link between CMV and AR is far less significant than previously thought. Outcome in patients with CMV may be more determined by coexisting conditions like high donor age and delayed graft function.

Changing treatment protocol from azathioprine to mycophenolate mofetil: decrease in renal dysfunction, increase in infections

INTRODUCTION

Immunosuppression for renal transplantation has shifted from azathioprine (AZA) regimens to those containing mycophenolate mofetil (MMF). This study investigated the impact of this change on the causes for rehospitalization as well as on graft and patient survival.

METHODS

In this retrospective cohort study, we reviewed long-term patient and graft survivals as well as the causes of posttransplant admissions for 893 kidney recipients. Data on survival and readmissions were available for 811 subjects, who were divided to into the AZA cohort (n=289, transplantation between 1998 and 1999) and the MMF cohort (n=567, transplantation between 2000 and 2001). Survival, the cause for readmission, time interval between transplantation and readmission, intensive care unit (ICU) admission, mortality, and graft loss were compared between the two cohorts.

RESULTS

Five-year patient and graft survival rates were 85% and 67% for the AZA cohort and 91% and 68% for the MMF cohort (P=.013). There were 202 (71%) and 371 (72%) readmissions registered for the AZA and MMF groups, respectively. In comparison with the AZA cohort, while readmissions secondary to graft rejection showed a significant decrease in the MMF cohort (62% vs 35%, P=.000), readmissions secondary to infections exhibited a significant increase (37% vs 50%, P=.002). A marginally significant increased mortality rate (2% vs 5%, P=.087) and ICU admission rate (3% vs 6%, P=.062) were also observed in the MMF cohort by comparison with the AZA cohort.

CONCLUSION

The shift in the immunosuppression protocol from AZA to MMF, albeit advantageous in many instances, can sometimes undermine the outcome by giving rise to such complications as high infection rates.

Does mycophenolate mofetil increase the incidence of cytomegalovirus disease compared with azathioprine after cadaveric kidney transplantation?

Although most of the published papers had not found increase in the incidence of CMV disease in kidney transplant recipients treated with mycophenolate mofetil (MMF), we had feeling from everyday practice that after its introduction number of patients with CMV disease has increased. To test this hypothesis, we performed retrospective analysis of our database, comparing the incidence of CMV disease in patients treated with azathioprine (AZA) and patients treated with MMF. CMV disease was defined as CMV antigenemia (positive CMV pp65 determined by ELISA test) plus any of the following: decrease leucocytes or platelets, increased transaminases, increase in serum creatinine. The azathioprine treated group (AZA group) included 280 patients (132 female) treated for 17,672 months with AZA + Cyclosporine A (CyA) + steroid, or AZA + steroid, while the MMF group included 219 patients (112 female) treated for 5079 months with MMF + CyA + steroid, or MMF + steroid. There was no difference in acute rejection episodes between the AZA and the MMF group. The AZA group had 51 CMV disease episodes (1 episode per 346.5 treatment months), and the MMF group experienced 43 episodes (1 per 118.1 months) (P < .01). Mean onset of CMV disease was 32.65 +/- 47.69 (SD) months after transplantation in the AZA group, and 3.72 +/- 4.43 in the MMF group. There was no difference between two treatment groups regarding the donor-recipient CMV status mismatch. Despite having the increased incidence of CMV disease, MMF group had less severe disease compared to AZA group with decrease in leukocyte count in 11.6% vs 15.7% of episodes, decrease in platelet count in 20.9% vs 21.6%, elevation of transaminases in 18.6% vs 29.4% respectively, and finally increase in serum creatinine greater than 20% in 51.2% in MMF vs 74.5% in AZA group. Five patients from the AZA group experienced CMV pneumonitis with the mortality rate of 80%. Only one patient from the MMF group had CMV pneumonitis, and he survived. According to our results, patients treated with MMF have increased risk for development of CMV disease. However, the disease course is less severe, and less frequently accompanied with deterioration of renal function in comparison to the AZA group.

Effects of mycophenolate mofetil on donor-specific antibody formation in renal transplantation

BACKGROUND

Mycophenolate mofetil (MMF) is a routinely used immunosuppressive agent that selectively blocks T- and B-lymphocyte proliferation. The present study was designed to investigate the effects of this drug on human leukocyte(HLA) antibody production in general and donor-specific antibody (DSA) formation in particular in 154 recipients of renal allografts.

PATIENTS AND METHODS

Renal allograft recipients were subdivided into three groups. Group 1 patients (n = 60) had received MMF since transplantation in combination with either cyclosporin A or tacrolimus and steroids. Group 2 patients (n = 29) had received an MMF-free immunosuppressive regimen initially followed by addition of MMF some time later. Group 3 patients (n = 65) had received no MMF. Cyclosporin A or tacrolimus in combination with azathioprine and/or steroids were used for immunosuppression. DSA were demonstrated by enzyme-linked immunosorbent assay (ELISA) for detection of panel-reactive antibodies of HLA class I and II specificity.

RESULTS

The HLA antibodies were found in 16.7%, 27.6% and 30.8% of transplant recipients in groups 1, 2 and 3, respectively. DSA were found in 8.3%, 17.2% and 20.0%, and non-DSA in 10.0%, 20.7% and 24.6%, of patients in groups 1, 2 and 3, respectively.

CONCLUSION

The MMF reduces anti-HLA class I and II antibody production and consequently DSA production in renal allograft recipients. Our data indicate this effect to be more pronounced in patients given MMF immediately after transplantation than in those in whom MMF is introduced some time later. The presence of DSA in the serum of renal allograft recipients is associated with poorer graft function (higher serum creatinine and more rejection episodes).

Ex vivo lymphocyte proliferative function is severely inhibited in renal transplant patients on mycophenolate mofetil treatment

Mycophenolate mofetil (MMF) is a recently introduced immunosuppressive drug. Its active form is mycophenolic acid (MPA). MPA specifically inhibits de novo purine synthesis, which is vital for T and B lymphocyte proliferation. We measured lymphocyte subset numbers and mitogen induced proliferation in kidney transplant recipients on different combinations of MMF, cyclosporin A (C), azathioprine (A) and prednisolone (P) (C+A n=70; C+A+P n=15; C+MMF n=45; C+MMF+P n=37) and normals (n=73). Patients on MMF had severely reduced phytohaemagglutinin A (PHA) induced proliferation compared to normals (Nml 2766+/-926 CPM/1000 lymphocytes [mean+/-S.D.]; C+MMF 282+/-406; C+MMF+P 195+/-496); non-MMF patients did not differ from normal. Similar inhibition of Poke Weed Mitogen and Staphylococcal enterotoxin B induced proliferation was observed. Cell cycle studies established that MMF patients had a significantly higher proportion of lymphocytes in the G0/G1 phase following PHA stimulation than the non-MMF patients. All transplant groups had significantly lower B cell numbers than the normal controls but no differences in CD4 and CD8 T cell numbers. All but the C+MMF group had significantly lower CD16+NK cell numbers than normal, while only the non-MMF groups had significantly lower CD56+NK cell numbers. The proliferation assay used was an ex vivo diluted whole blood technique. Removal of residual MPA by washing the plasma out prior to mitogen stimulation led to a significant increase in proliferation in six out of seven cases. In summary we have found that MMF treatment has a strikingly inhibitory effect on patient ex vivo lymphocyte mitogenic function.

Blood cyclosporine C0 and C2 concentrations and cytomegalovirus infections following lung transplantation

The aim of this study was to determine whether cyclosporine levels predose (C0) and at two hours postdose (C2) were higher among patients presenting with cytomegalovirus (CMV) infection or disease. Between days 40 and 365 posttransplantation serial C0 and C2 levels were measured in 15 lung transplant recipients. Nine developed 13 episodes of CMV infection or disease. Both C0 and C2 levels were higher during CMV infection or disease episodes. Eleven of the 13 CMV episodes (84%) displayed C0 >220 ng/mL and none had C0 <200 ng/mL. For C2, 11 of 13 CMV episodes (84%) showed C2 >1200 ng/mL and none had C2 <1000 ng/mL. Among determinations that did not coincide with a CMV episode, 7 of 21 (33%) showed C0 >220 and 9 of 21 (42%) showed C2 >1200, respectively (P<.05). In conclusion, cyclosporine blood levels are higher among patients presenting with CMV infection or disease.