Kaposi's Sarcoma After Autologous Stem-Cell Transplantation and Rituximab Treatment

Hematopoietic stem cell transplantation and the noncytomegalovirus herpesviruses

Although hematopoietic stem cell transplantation (HSCT) and other cellular therapies have significantly improved outcomes in the management of multiple hematological and nonhematological malignancies, the resulting impairment in humoral and cellular response increases the risk for opportunistic infection as an undesirable side effect. With their ability to establish latent infection and reactivate when the host immune system is at its weakest point, the Herpesviridae family constitutes a significant proportion of these opportunistic pathogens. Despite recent advancements in preventing and managing herpesvirus infections, they continue to be a common cause of significant morbidity and mortality in transplanted patients. Herein, we aim to provide and update on herpesvirus other than cytomegalovirus (CMV) affecting recipients of HSCT and other cellular therapies.

Rituximab-Induced Kaposi Sarcoma in HIV-Negative Patients: A Narrative Review

Kaposi sarcoma (KS) is a low-grade mesenchymal angioproliferative disorder that requires infection with human herpes virus 8 (HHV-8) for it to develop. It is commonly seen in HIV-positive patients and rarely in immunosuppressed HIV-negative patients. Rituximab is a monoclonal anti-CD20 chimeric murine/human immunoglobulin G antibody used to treat B cell lymphoproliferative diseases as well as a variety of autoimmune disorders. Several cases of iatrogenic Kaposi sarcoma (iKS) have been described after rituximab treatment. The purpose of this narrative review is to identify the presence of common clinical characteristics among rituximab-induced KS patients that could facilitate better management of this rare condition.

Kaposi's sarcoma, biologics and small molecules: Navigating the complex interplay between host immunity and viral biology. A case series with focused review of the literature

The consequences of cytokine-specific immune modulation in the development and course of Kaposi's sarcoma (KS) are poorly understood. A retrospective chart review of patients treated with biologic/small molecule drugs and followed at the dedicated KS outpatient service of our Dermatology Unit was performed. The literature on biologic and small molecule drug use in KS patients was also reviewed. Data concerning 12 KS patients treated with biologic/small molecule drugs were collected. After a median delay of 6 months following biologic or small molecule drug introduction, nine patients experienced either KS onset or reactivation. Drugs associated with KS onset or flaring were: rituximab, infliximab, ruxolitinib apremilast (1), mirikizumab, abatacept (1). After a median follow-up of 25 months, all cases achieved persistent complete response through culprit drug discontinuation or drug withdrawal plus treatment. No effect on KS course was recorded with tocilizumab and vedolizumab. Based on our experience with the largest case series reported to date as well as the available literature, tocilizumab and ustekinumab seem to exert an overall neutral effect on KS. On the other hand, rituximab, infliximab, and ruxolitinib have been associated with the development or worsening of pre-existing KS and should be carefully pondered before use. Due to limited and partly controversial evidence, no definitive conclusions can be drawn on vedolizumab, apremilast, mirikizumab, abatacept.

Human herpesvirus 8 and Kaposi sarcoma: how should we screen and manage the transplant recipient?

PURPOSE OF REVIEW

HHV-8-associated diseases are rare but potentially fatal in transplant recipients. Important differences exist in the distribution of HHV-8 seroprevalence, which might contribute to the lack of uniform approach to HHV-8. The aim of this review was to discuss recent updates in screening and management of HHV-8 after transplant.

RECENT FINDINGS

Increasing attention has been given to the nonmalignant but potentially fatal inflammatory syndrome caused by HHV-8 in solid organ transplant (SOT) recipients. At-risk groups include HHV-8-IgG D+/R- transplant and HHV-8-positive recipients. Severe cases of donor-derived HHV-8 disease, mainly Kaposi sarcoma, frequently without skin involvement and some diagnosed at autopsy, highlight the need to increase clinicians' awareness, to implement effective preemptive strategies and to perform rapid diagnosis. In HSCT setting, HHV-8-associated disorders are very rare.

SUMMARY

Identification of SOT recipients at risk through reliable serology is warranted and the utility of preemptive management and HHV-8-DNA monitoring should be studied. Clinicians should be aware of severe nonmalignant disorders and of early post-SOT Kaposi sarcoma cases with lymph node or transplanted organ involvement in order to provide prompt diagnosis and treatment. No screening for HHV-8 is warranted after HSCT but rapid diagnosis and reduction of immunosuppression remain fundamental.