Autoimmune Lymphoproliferative Syndrome Masquerading as Posttransplant Lymphoproliferative Disorder

Diagnostic and management roles of FDG PET/CT imaging in post-transplant lympho-proliferation in pediatric heart transplantation

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of pediatric heart transplant (PHTx). 18F-FDG PET/CT has been used to differentiate early lympho-proliferation from more advanced PTLD. We report our experience with PET/CT in the management of PTLD following PHTx.

METHODS

This was a retrospective study of 100 consecutive PHTx recipients at our institution between 2004 and 2018. Patients who underwent PET/CT or conventional CT scans to evaluate for PTLD or high Epstein-Barr viral load were included.

RESULTS

Males, eight females. Median age at transplant was 3.5 months (IQR = 1.5-27.5). Median age at PTLD diagnosis was 13.3 years (IQR = 9.2-16.1). Median time between transplant and PTLD diagnosis was 9.5 (IQR = 4.5-15) years. Induction agents were used in 12 patients (50%): Thymoglobulin (N = 9), anti-IL2 (N = 2), and Rituximab (N = 1). Eighteen patients (75%) had PET/CT, of whom 14 had 18FDG-avid PTLD. Six had conventional CT. Nineteen patients (79.2%) had diagnostic biopsy confirmation of PTLD, and 5 (20.8%) had excisional biopsies. Two patients had Hodgkin's lymphoma; nine had monomorphic PTLD; eight had polymorphic PTLD; five were classified as other. Nine patients had monomorphic PTLD, including seven with diffuse large cell lymphoma (DLBC) and one with T cell lymphoma. The majority (16/24) had multi-site involvement at PTLD diagnosis, and PET/CT showed that 31.3% (5/16) had easily accessible subcutaneous nodes. Seventeen patients (overall survival 71%) underwent successful treatment without recurrence of PTLD. Of seven deaths (7/24, 29%), five had DLBC lymphoma, one had polymorphic PTLD and one had T-cell lymphoma.

CONCLUSION

PET-CT allowed simultaneous anatomical and functional assessment of PTLD lesions, while guiding biopsy. In patients with multiple lesions, PET/CT revealed the most prominent and active lesions, improving diagnostic accuracy.

Clinical, immunological, and genetic features in 780 patients with autoimmune lymphoproliferative syndrome (ALPS) and ALPS-like diseases: A systematic review

BACKGROUND

Autoimmune lymphoproliferative syndrome (ALPS) is a group of genetic disorders characterized by early-onset lymphoproliferation, autoimmune cytopenias, and susceptibility to lymphoma. The majority of ALPS patients carry heterozygous germline mutations in the TNFRSF6 gene. In this study, we conducted a systematic review of patients with ALPS and ALPS-like syndrome.

METHODS

The literature search was performed in Web of Science, Scopus, and PubMed databases to find eligible studies. Additionally, the reference list of all included papers was hand-searched for additional studies. Demographic, clinical, immunological, and molecular data were extracted and compared between the ALPS and ALPS-like syndrome.

RESULTS

Totally, 720 patients with ALPS (532 genetically determined and 189 genetically undetermined ALPS) and 59 cases with ALPS-like phenotype due to mutations in genes other than ALPS genes were assessed. In both ALPS and ALPS-like patients, splenomegaly was the most common clinical presentation followed by autoimmune cytopenias and lymphadenopathy. Among other clinical manifestations, respiratory tract infections were significantly higher in ALPS-like patients than ALPS. The immunological analysis showed a lower serum level of IgA, IgG, and lymphocyte count in ALPS-like patients compared to ALPS. Most (85%) of the ALPS and ALPS-like cases with determined genetic defects carry mutations in the FAS gene. About one-third of patients received immunosuppressive therapy with conventional or targeted immunotherapy agents. A small fraction of patients (3.3%) received hematopoietic stem cell transplantation with successful engraftment, and all except two patients survived after transplantation.

CONCLUSION

Our results showed that the FAS gene with 85% frequency is the main etiological cause of genetically diagnosed patients with ALPS phenotype; therefore, the genetic defect of the majority of suspected ALPS patients could be confirmed by mutation analysis of FAS gene.