Association Between Mycophenolate Mofetil Use and Subsequent Infections Among Hospitalized Patients with Systemic Lupus Erythematosus: A Nested Case-Control Study

Mycophenolate mofetil: an update on its mechanism of action and effect on lymphoid tissue

Introduction

Mycophenolate mofetil (MMF) is an immunosuppressive drug administered in the management of both autoimmune diseases and organ transplantation. The main aims of the study were: (a) to obtain information regarding the safety of using MMF in respect of its effect on normal T and B cells in lymphoid tissues; (b) to investigate whether the generation of inducible Foxp3-expressing regulatory T cells (Treg) might constitute additional mechanisms underlying the immunosuppressive properties of MMF.

Methods

The effect of MMF (in vivo studies) and its active metabolite, mycophenolic acid, (in vitro studies) on murine CD4+ and CD8+ T cells as well as B cells was determined, regarding: (a) absolute count, proliferation and apoptosis of these cells (in vitro studies); (b) absolute count of these cells in the head and neck lymph nodes, mesenteric lymph nodes and the spleen (in vivo studies).

Results

The study found that the treatment of mice with MMF induced depletion of CD4+ and CD8+ T cells and B cells in lymph nodes and the spleen, and the magnitude of these effects should be considered as clinically relevant. The study demonstrated the following actions of the drug: (a) proapoptotic action on effector CD4+ and CD8+ T (Teff) cells, and B cells; (b) the down-regulation or prevention of activation-induced expression of CD25 on CD4+ and CD8+ Teff cells; (c) the generation of Foxp3+CD25+CD4+ and Foxp3+CD25+CD8+ T cells resulting in the shift of the Treg cell/activated Teff cell balance toward an increased proportion of Treg cells.

Conclusion

The depletive effect of MMF on CD4+ and CD8+ T cells and B cells in lymphoid tissues should be taken into account when assessing the benefit-risk ratio of using MMF in patients with microbial infections and undergoing vaccination. The study contributed new insight into this mechanism, indicating that MMF effectively prevents the proliferation of T and B cells, but may be less effective against already proliferating cells. Moreover, the findings of the study strongly suggest the existence of additional mechanisms that may be responsible for the clinical efficacy of the drug, including the induction of Foxp3-expressing CD4+ and CD8+ Treg cells.

Tacrolimus- and Mycophenolate-Mediated Toxicity: Clinical Considerations and Options in Management of Post-Transplant Patients

Tacrolimus and mycophenolate are important immunosuppressive agents used to prevent organ rejection in post-transplant patients. While highly effective, their use is associated with significant toxicity, requiring careful management. Tacrolimus, a calcineurin inhibitor, is linked to nephrotoxicity, neurotoxicity, metabolic disturbances such as diabetes mellitus and dyslipidemia, and cardiovascular complications such as hypertension and arrhythmias. Mycophenolate, a reversible inhibitor of inosine monophosphate dehydrogenase, frequently causes gastrointestinal disturbances, including diarrhea and colitis, as well as hematologic side effects like anemia and leukopenia, which increase infection risk. Therapeutic drug monitoring (TDM) and pharmacogenomics have emerged as essential strategies for mitigating these toxicities. TDM ensures tacrolimus trough levels are maintained within a therapeutic range, minimizing the risks of nephrotoxicity and rejection. Pharmacogenomic insights, such as CYP3A5 polymorphisms, allow for personalized tacrolimus dosing based on individual metabolic profiles. For mycophenolate, monitoring inosine monophosphate dehydrogenase activity provides a pharmacodynamic approach to dose optimization, reducing gastrointestinal and hematologic toxicities. Emerging tools, including dried blood spot sampling and pharmacokinetic modeling, offer innovative methods to simplify monitoring and enhance precision in outpatient settings. Despite their utility, the toxicity profiles of these drugs, including those of early immunosuppressants such as cyclosporine and azathioprine, necessitate further consideration of alternative immunosuppressants like sirolimus, everolimus, and belatacept. Although promising, these newer agents require careful patient selection and further research. Future directions in immunosuppressive therapy include integrating individual pharmacogenetic data to refine dosing, minimize side effects, and improve long-term graft outcomes. This narrative review underscores the importance of personalized medicine and advanced monitoring in optimizing post-transplant care.

Risk factors for initial and recurrent severe infections in first hospitalized patients with systemic lupus erythematosus: A retrospective study of a Chinese cohort

OBJECTIVE

To evaluate the incidence and associated factors of initial and recurrent severe infections in hospitalized patients with systemic lupus erythematosus (SLE).

METHODS

SLE patients that first hospitalized between 2010 and 2021 were studied retrospectively and divided into SLE with and without baseline severe infection groups. The primary outcome was the occurrence of severe infection during follow-up. Cox regression models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for initial and recurrent severe infections.

RESULTS

Among 1051 first hospitalized SLE patients, 164 (15.6%) had severe infection on admission. During a median follow-up of 4.1 years, 113 (10.8%) patients reached severe infection outcomes, including 27 with reinfection and 86 with initial severe infection (16.5% vs. 9.7%, p = .010). Patients with baseline severe infection had a higher cumulative incidence of reinfection (p = .007). After adjusting for confounding factors, renal involvement, elevated serum creatinine, hypoalbuminemia, cyclophosphamide, and mycophenolate mofetil treatment were associated with an increased risk of severe infection, especially initial severe infection. Low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use significantly increased the risk of recurrent severe infection, with adjusted HR (95% CI) of 3.15 (1.22, 8.14), 3.60 (1.56, 8.28), and 2.14 (1.01, 5.76), respectively. Moreover, baseline severe infection and low immunoglobulin had a multiplicative interaction on reinfection, with adjusted RHR (95% CI) of 3.91 (1.27, 12.09).

CONCLUSION

In this cohort of SLE, patients with severe infection had a higher risk of reinfection, and low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use were independent risk factors for recurrent severe infection.