Improved outcome with immunosuppressive monotherapy after renal transplantation in Schimke-immuno-osseous dysplasia

Clinical course of post-kidney transplant Schimke immuno-osseous dysplasia

BACKGROUND

Schimke immuno-osseous dysplasia (SIOD) is a rare systemic disease characterized by short stature, proteinuria, and recurrent infections. Patients usually have spondyloepiphyseal dysplasia, and progressive steroid-resistant nephropathy that leads to kidney failure. However, their clinical course after kidney transplantation (KT) is not yet well known. Here, we present our experience with cases of SIOD treated at our institute.

CASE PRESENTATION

Since 2014, three children have been diagnosed with nephropathy resulting from SIOD. They presented with proteinuria in the nephrotic range at 7, 5, and 3 years of age. Focal segmental glomerulosclerosis was confirmed and progressed to kidney failure approximately 2 years after proteinuria was detected. These patients underwent living-donor KT from their parents. After KT, Case 1 lost his graft within 7 months due to multi-organ failure caused by disseminated adenovirus infection and died. Case 2 experienced graft failure 5 years after KT due to acute rejection from poor compliance. In Case 3, the allograft was still functioning 6 years after KT with low-dose tacrolimus single medication (trough level < 5 ng/mL). Extra-renal manifestations progressed regardless of KT, namely, right renal vein thrombosis and pulmonary hypertension in Case 1, severe bilateral hip dysplasia and Moyamoya syndrome in Case 2, and neutropenia and thrombocytopenia in Case 3, in addition to recurrent infection.

CONCLUSION

In SIOD patients, KT is complicated with recurrent infections due to their inherent immune dysfunction. Additionally, extra-renal symptoms may render the patients morbid despite the recovery of kidney function.

Schimke immuno-osseous dysplasia. A case report in Colombia

Background

Schimke immune-osseous dysplasia (SIOD) is an ultra-rare multisystemic, monogenic, and autosomal recessive inherited disease caused by biallelic mutations in the SMARCAL1 gene. Approximately 100 cases have been reported worldwide. The disease is characterized by skeletal, renal, and immunological abnormalities.

Case description

This is a 6-year-old female patient who debuted with nephrotic syndrome at five years of age, with a switch to corticosteroid resistance and poor response to immunosuppressive treatment received. The patient was admitted and referred to our institution due to convulsive status. During her hospitalization, thrombosis was found in the left renal vein, and a renal biopsy report of Collapsing Focal and Segmental Glomerulosclerosis (FSGS) was obtained. The patient had multiple infections during hospitalization, with T lymphocyte lymphopenia and severe IgG hypogammaglobulinemia. Additionally, given dysmorphic facies, delayed weight-height development, and spondyloepiphyseal dysplasia, exome sequencing was performed, finding an homozygous pathogenic variant c.1933C > T p.Arg645Cys in SMARCAL1, compatible with the diagnosis of SIOD.

Discussion

We present the case of a patient that exhibited a severe phenotype of the disease, with skeletal, renal, severe combined immunological compromise and cerebrovascular involvement during follow-up, and the available proposed mechanisms of the disease focused on the clinical manifestations of this patient. It is the first case of SIOD reported in Colombia and the first comprehensive characterization reported in the literature of a patient with homozygosity of the known variant c.1933C > T p.Arg645Cys.

Conclusion

A severe phenotype of the disease with cerebrovascular involvement by homozygosity of the known variant c.1933C > T p.Arg645Cys in the SMARCAL1 gene can be expected.

Successful low-dose immunotherapy after kidney transplantation in a 10-year-old girl with Schimke immuno-osseous dysplasia

BACKGROUND

This case report highlights a successful steroid-free, low-dose immunosuppressive protocol for renal transplantation in a pediatric patient with Schimke immuno-osseous dysplasia with excellent 7-year patient and graft survival. Schimke immuno-osseous dysplasia is a rare multisystem disorder involving the kidney. Renal transplantation is a therapeutic option, but posttransplant mortality is high due to severe infections and posttransplant lymphoproliferative disease.

METHODS

A 10-year-old girl diagnosed with Schimke immuno-osseous dysplasia and end-stage renal disease underwent an AB0-compatible living-related kidney transplantation, with no donor-specific antibodies. Our standard immunosuppression protocol was modified due to the risk of infection. Basiliximab was used as induction therapy, and a reduced dose of mycophenolate mofetil and tacrolimus was initiated following transplantation, maintaining the patient on a low tacrolimus target (3-5 μg/L). Mycophenolate mofetil was discontinued after 8 weeks due to neutropenia and the patient was kept on tacrolimus as monotherapy. Five years posttransplant the patient developed acute onset of neurological symptoms, consisting of ataxia, lack of voluntary coordination, balance, aphasia and dysphagia, and diplopia. She recovered without neurological deficits within 6 weeks. Extensive evaluation revealed no pathology. To avoid a possible a component of tacrolimus-induced cerebral vasoconstriction, the immunosuppressive therapy was changed to everolimus.

RESULTS

Seven years posttransplant, the patient has experienced no serious infections, no rejections, and had excellent graft function, and no de novo donor-specific antibodies.

CONCLUSIONS

The present results indicate that low-dose immunosuppressive therapy after renal transplantation with low immunological risk should be considered for patients with Schimke immuno-osseous dysplasia.

Schimke immunoosseous dysplasia: an ultra-rare disease. a 20-year case series from the tertiary hospital in the Czech Republic

BACKGROUND

Schimke immunoosseous dysplasia (SIOD) is an ultra-rare inherited disease affecting many organ systems. Spondyloepiphyseal dysplasia, T-cell immunodeficiency and steroid resistant nephrotic syndrome are the main symptoms of this disease.

CASE PRESENTATION

We aimed to characterize the clinical, pathological and genetic features of SIOD patients received at tertiary Pediatric Nephrology Center, University Hospital Motol, Prague, Czech Republic during the period 2001-2021. The mean age at diagnosis was 21 months (range 18-48 months). All patients presented with growth failure, nephropathy and immunodeficiency. Infections and neurologic complications were present in most of the affected children during the course of the disease.

CONCLUSIONS

Although SIOD is a disease characterized by specific features, the individual phenotype may differ. Neurologic signs can severely affect the quality of life; the view on the management of SIOD is not uniform. Currently, new therapeutic methods are required.

Sequential Stem Cell-Kidney Transplantation in Schimke Immuno-osseous Dysplasia

Lifelong immunosuppression is required for allograft survival after kidney transplantation but may not ultimately prevent allograft loss resulting from chronic rejection. We developed an approach that attempts to abrogate immune rejection and the need for post-transplantation immunosuppression in three patients with Schimke immuno-osseous dysplasia who had both T-cell immunodeficiency and renal failure. Each patient received sequential transplants of αβ T-cell-depleted and CD19 B-cell-depleted haploidentical hematopoietic stem cells and a kidney from the same donor. Full donor hematopoietic chimerism and functional ex vivo T-cell tolerance was achieved, and the patients continued to have normal renal function without immunosuppression at 22 to 34 months after kidney transplantation. (Funded by the Kruzn for a Kure Foundation.).

Eltrombopag (thrombopoietin-receptor agonist) and plasmapheresis as rescue therapy of acute post-renal transplant immune thrombocytopenia in a child with Schimke immuno-osseous dysplasia-case report

SIOD is rare disorder related to SMARCAL1 or SMARCAL2 gene mutation, including (among other comorbidities) T-cell immunodeficiency, nephrotic syndrome, and renal failure. Up to 22% of primary patients may develop various autoimmune disorders. We report the case of 11-year-old male with SIOD, who presented ITP at 2 years after renal transplantation with decrease in platelet count (from normal) to 56 000/μL and then (gradually) to 2000/μL. There was no effect of iv. methylprednisolone/dexamethasone. As the presence of antibodies against GPIIb/IIIa, GPIb, and GPIaIIa platelet glycoproteins was confirmed, patient was given 50 g of IVIG and then was put on plasmapheresis; however, both showed poor direct effect. As we were afraid to give rituximab (due to expected overimmunosuppression), we prescribed the oral TPO-receptor agonist (eltrombopag). Patient responded after 17 days of therapy, to the final dose of 50 mg/d (approx. 2 mg/kg). The antiplatelet antibodies disappeared after four plasmapheresis. Overall, the therapy was continued for 7 weeks and was stopped at platelet count of 433 000/μL. Platelet count remained stable in 8-month follow-up. Combination of plasmapheresis and TPO-receptor agonist was effective in post-renal transplant acute ITP in patient with SIOD.