Chemotherapy for a secondary malignancy nearly restores complete chimerism in an SCID-patient after HSCT.

For patients with inborn errors of immunity (IEI) and other inborn diseases, mixed donor chimerism is a well-accepted outcome of hematopoietic stem cell transplantation (HSCT). Cytoreductive chemotherapy for a secondary malignancy is a potential challenge for the stability of the graft function after HSCT. We report on a boy with X-SCID who developed Ewing sarcoma ten years after HSCT which was successfully treated with cytoreductive chemotherapy, surgery and local radiation. Surprisingly, this treatment had a positive impact on mixed chimerism with an increase of donor-cell proportions from 40% for neutrophils and 75% for non-T-mononuclear cells (MNCs) to >90% for both. T-cell counts remained stable with 100% of donor origin. This is -to our knowledge- the first report on the impact of cytoreductive chemotherapy on post-HSCT mixed chimerism and provides an important first impression for future patients.

Survival in primary hemophagocytic lymphohistiocytosis, 2016 to 2021: etoposide is better than its reputation.

ABSTRACT: Primary hemophagocytic lymphohistiocytosis (pHLH) is a life-threatening hyperinflammatory syndrome that develops mainly in patients with genetic disorders of lymphocyte cytotoxicity and X-linked lymphoproliferative syndromes. Previous studies with etoposide-based treatment followed by hematopoetic stem cell transplantation (HSCT) resulted in 5-year survival of 50% to 59%. Contemporary data are lacking. We evaluated 88 patients with pHLH documented in the international HLH registry from 2016-2021. In 12 of 88 patients, diagnosis was made without HLH activity, based on siblings or albinism. Major HLH-directed drugs (etoposide, antithymocyte globulin, alemtuzumab, emapalumab, ruxolitinib) were administered to 66 of 76 patients who were symptomatic (86% first-line etoposide); 16 of 57 patients treated with etoposide and 3 of 9 with other first-line treatment received salvage therapy. HSCT was performed in 75 patients; 7 patients died before HSCT. Three-year probability of survival (pSU) was 82% (confidence interval [CI], 72%-88%) for the entire cohort and 77% (CI, 64%-86%) for patients receiving first-line etoposide. Compared with the HLH-2004 study, both pre-HSCT and post-HSCT survival of patients receiving first-line etoposide improved, 83% to 91% and 70% to 88%. Differences to HLH-2004 included preferential use of reduced-toxicity conditioning and reduced time from diagnosis to HSCT (from 148 to 88 days). Three-year pSU was lower with haploidentical (4 of 9 patients [44%]) than with other donors (62 of 66 [94%]; P < .001). Importantly, early HSCT for patients who were asymptomatic resulted in 100% survival, emphasizing the potential benefit of newborn screening. This contemporary standard-of-care study of patients with pHLH reveals that first-line etoposide-based therapy is better than previously reported, providing a benchmark for novel treatment regimes.

[Newborn screening for severe combined immunodeficiencies (SCID) in Germany]. / Neugeborenenscreening auf schwere kombinierte Immundefekte (SCID) in Deutschland.

Patients with a severe combined immunodeficiency (SCID) harbor genetic mutations disrupting T cell immunity and hence suffer severe, life-threatening infections or manifestations of immune dysregulation within the first months of their life. The only cure is to correct their immune system, usually by means of hematopoietic stem cell transplantation (HSCT). Pilot studies and national programs in the United States and in European countries have shown that patients can be identified at an early asymptomatic stage through newborn screening. This allows treatment before the occurrence of severe complications, which improves the outcome of curative strategies like HSCT.After assessment by the Federal Joint Committee (G-BA), the SCID screening was implemented into newborn screening in Germany in 2019. The first results of the screening (dry blood spot cards from around 2 million newborns between August 2019 and February 2022) were recently published. As expected, in addition to classic SCID diseases (incidence 1:54,000), infants with syndromic disorders and T cell lymphopenia were also identified. All patients with classic SCID were scheduled for curative treatment. Of the 25 patients with classic SCID, 21 were already transplanted at the time of data analysis. Only one of 21 transplanted patients died due to pre-existing infections. A comparison of the recent screening data with historical data suggests that SCID newborn screening has been successfully implemented in Germany. Patients with SCID are routinely identified very early and scheduled for curative therapy.

Prospective Newborn Screening for SCID in Germany: A First Analysis by the Pediatric Immunology Working Group (API).

BACKGR OUND: T-cell receptor excision circle (TREC)-based newborn screening (NBS) for severe combined immunodeficiencies (SCID) was introduced in Germany in August 2019. METHODS: Children with abnormal TREC-NBS were referred to a newly established network of Combined Immunodeficiency (CID) Clinics and Centers. The Working Group for Pediatric Immunology (API) and German Society for Newborn Screening (DGNS) performed 6-monthly surveys to assess the TREC-NBS process after 2.5 years. RESULTS: Among 1.9 million screened newborns, 88 patients with congenital T-cell lymphocytopenia were identified (25 SCID, 17 leaky SCID/Omenn syndrome (OS)/idiopathic T-cell lymphocytopenia, and 46 syndromic disorders). A genetic diagnosis was established in 88%. Twenty-six patients underwent hematopoietic stem cell transplantation (HSCT), 23/26 within 4 months of life. Of these, 25/26 (96%) were alive at last follow-up. Two patients presented with in utero onset OS and died after birth. Five patients with syndromic disorders underwent thymus transplantation. Eight syndromic patients deceased, all from non-immunological complications. TREC-NBS missed one patient, who later presented clinically, and one tracking failure occurred after an inconclusive screening result. CONCLUSION: The German TREC-NBS represents the largest European SCID screening at this point. The incidence of SCID/leaky SCID/OS in Germany is approximately 1:54,000, very similar to previous observations from North American and European regions and countries where TREC-NBS was implemented. The newly founded API-CID network facilitates tracking and treatment of identified patients. Short-term HSCT outcome was excellent, but NBS and transplant registries will remain essential to evaluate the long-term outcome and to compare results across the rising numbers of TREC-NBS programs across Europe.

Successful hematopoietic stem cell transplantation in a 4-1BB deficient patient with EBV-induced lymphoproliferation.

Complete remission from recurrent EBV-positive lymphoma is not mandatory before HSCT to achieve long-term cure in a patient suffering from a recently described immunodeficiency affecting the T-cell coactivation molecule 4-1BB.

Dataset of clinical, immunohistopathological and laboratory features of patients with MHC II deficiency suffering from enteropathy.

Major histocompatibility complex class II (MHC II) is essential for adaptive immune response. We recently reported on disturbed adaptive mucosal immunity due to MHC II deficiency and prolonged enteropathy. Here, we share medical history, flow cytometric analysis of blood lymphocytes, immunohistopathology, and fecal analysis of seven genetically confirmed patients with MHC II deficiency suffering from enteropathy. Data on flow cytometric analysis of HLA-DR expression on monocytes and B cells before hematopoietic stem cell transplantation (HSCT) and after in-vitro stimulation is shown. The course of immune reconstitution after HSCT of MHC II deficient patients in comparison to severe combined immunodeficiency (SCID) patients is described. In addition, immunohistopathology illustrating CD4 and CD8 T cell infiltration, absence of B lymphocytes and plasma cells, and disturbed immunoglobulin expression in the gut as well as absent HLA-DR expression in the liver is shown. Furthermore, data from fecal analysis such as stool fat, nitrogen, and water fraction as well as faecal markers such as alpha-1-antitrypsin, pancreas specific elastase 1, eosinophilic protein X (EPX), and beta defensin 2 are presented. Altogether this data demonstrates the complex phenotype of MHC II deficiency. The data can be valuable for researchers interested in mucosal immunity. For further interpretation of the data presented in this article, please see the research article "Persisting enteropathy and disturbed adaptive mucosal immunity due to MHC class II deficiency" (Posovszky et al., 2019).

Persisting enteropathy and disturbed adaptive mucosal immunity due to MHC class II deficiency.

Intestinal epithelial cells (IECs) form a fundamental mucosal barrier and actively participate in tolerance and immunity against intestinal contents. Major histocompatibility complex class II (MHC II) and invariant chain (Ii) molecules are essential for adaptive immune response. MHC II deficiency often presents with gastrointestinal disorders. Intestinal biopsy samples revealed an absence of HLA-DR, Ii, and local immunoglobulins in both hematopoietic immune cells and IECs accompanied by a lack of faecal sIgA. After successful hematopoietic stem cell transplantation (HSCT) absent HLA-DR and Ii expression persisted in IECs and faecal stool analysis indicated inflammation and high microbial activity. We describe multifaceted disturbance of adaptive mucosal immunity in MHC II deficient patients suffering from enteropathy. HLA-DR and Ii expression on enterocytes is not restored by HSCT. This may account for increased susceptibility to enteric infections and intestinal inflammation leading to prolonged enteropathy reported in MHC II deficient patients.

Human RIPK1 deficiency causes combined immunodeficiency and inflammatory bowel diseases.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in RIPK1 presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in RIPK1 were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.

CD4+ T cell-derived IL-21 and deprivation of CD40 signaling favor the in vivo development of granzyme B-expressing regulatory B cells in HIV patients.

IL-21 can induce both plasma cells and regulatory B cells. In this article, we demonstrate that untreated HIV patients display CD4(+) T cells with enhanced IL-21 expression and high in vivo frequencies of regulatory B cells overexpressing the serine protease granzyme B. Granzyme B-expressing regulatory B cells (GraB cells) cells from HIV patients exhibit increased expression of CD5, CD43, CD86, and CD147 but do not produce IL-10. The main functional characteristic of their regulatory activity is direct granzyme B-dependent degradation of the TCR-ζ-chain, resulting in significantly decreased proliferative T cell responses. Although Th cells from HIV patients secrete IL-21 in a Nef-dependent manner, they barely express CD40L. When culturing such IL-21(+)CD40L(-) Th cells with B cells, the former directly induce B cell differentiation into GraB cells. In contrast, the addition of soluble CD40L multimers to T cell/B cell cultures redirects B cell differentiation toward plasma cells, indicating that CD40L determines the direction of IL-21-dependent B cell differentiation. As proof of principle, we confirmed this mechanism in a patient lacking intact CD40 signaling due to a NEMO mutation. The majority of peripheral B cells from this patient were GraB cells and strongly suppressed T cell proliferation. In conclusion, GraB cells represent potent regulatory B cells in humans that are phenotypically and functionally distinct from B10 cells and occur in early HIV infection. GraB cells may contribute significantly to immune dysfunction in HIV patients, and may also explain ineffective Ab responses after vaccination. The use of soluble CD40L multimers may help to improve vaccination responses in HIV patients.

DOCK8 deficiency: clinical and immunological phenotype and treatment options - a review of 136 patients.

Mutations in DOCK8 result in autosomal recessive Hyper-IgE syndrome with combined immunodeficiency (CID). However, the natural course of disease, long-term prognosis, and optimal therapeutic management have not yet been clearly defined. In an international retrospective survey of patients with DOCK8 mutations, focused on clinical presentation and therapeutic measures, a total of 136 patients with a median follow-up of 11.3 years (1.3-47.7) spanning 1693 patient years, were enrolled. Eczema, recurrent respiratory tract infections, allergies, abscesses, viral infections and mucocutaneous candidiasis were the most frequent clinical manifestations. Overall survival probability in this cohort [censored for hematopoietic stem cell transplantation (HSCT)] was 87 % at 10, 47 % at 20, and 33 % at 30 years of age, respectively. Event free survival was 44, 18 and 4 % at the same time points if events were defined as death, life-threatening infections, malignancy or cerebral complications such as CNS vasculitis or stroke. Malignancy was diagnosed in 23/136 (17 %) patients (11 hematological and 9 epithelial cancers, 5 other malignancies) at a median age of 12 years. Eight of these patients died from cancer. Severe, life-threatening infections were observed in 79/136 (58 %); severe non-infectious cerebral events occurred in 14/136 (10 %). Therapeutic measures included antiviral and antibacterial prophylaxis, immunoglobulin replacement and HSCT. This study provides a comprehensive evaluation of the clinical phenotype of DOCK8 deficiency in the largest cohort reported so far and demonstrates the severity of the disease with relatively poor prognosis. Early HSCT should be strongly considered as a potential curative measure.

Comparison of outcomes of hematopoietic stem cell transplantation without chemotherapy conditioning by using matched sibling and unrelated donors for treatment of severe combined immunodeficiency.

BACKGROUND: Patients with severe combined immunodeficiency disease who have matched sibling donors (MSDs) can proceed to hematopoietic cell transplantation (HCT) without conditioning chemotherapy. OBJECTIVE: We sought to determine whether the results of HCT without chemotherapy-based conditioning from matched unrelated donors (URDs), either from volunteer adults or umbilical cord blood, are comparable with those from MSDs. METHODS: We performed a multicenter survey of severe combined immunodeficiency transplantation centers in North America, Europe, and Australia to compile retrospective data on patients who have undergone unconditioned HCT from either URDs (n = 37) or MSDs (n = 66). RESULTS: Most patients undergoing URD HCT (92%) achieved donor T-cell engraftment compared with 97% for those with MSDs; however, estimated 5-year overall and event-free survival were worse for URD recipients (71% and 60%, respectively) compared with MSD recipients (92% and 89%, respectively; P < .01 for both). URD recipients who received pre-HCT serotherapy had similar 5-year overall survival (100%) to MSD recipients. The incidences of grade II to IV acute and chronic graft-versus-host disease were higher in URD (50% and 39%, respectively) compared with MSD (22% and 5%, respectively) recipients (P < .01 for both). In the surviving patients there was no difference in T-cell reconstitution at the last follow-up between the URD and MSD recipients; however, MSD recipients were more likely to achieve B-cell reconstitution (72% vs 17%, P < .001). CONCLUSION: Unconditioned URD HCT achieves excellent rates of donor T-cell engraftment similar to that seen in MSD recipients, and reconstitution rates are adequate. However, only a minority will have myeloid and B-cell reconstitution, and attention must be paid to graft-versus-host disease prophylaxis. This approach might be safer in children ineligible for intense regimens to spare the potential complications of chemotherapy.

Outcome of hematopoietic stem cell transplantation for adenosine deaminase-deficient severe combined immunodeficiency.

Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed outcome of HCT in 106 patients with ADA-SCID who received a total of 119 transplants. HCT from matched sibling and family donors (MSDs, MFDs) had significantly better overall survival (86% and 81%) in comparison with HCT from matched unrelated (66%; P < .05) and haploidentical donors (43%; P < .001). Superior overall survival was also seen in patients who received unconditioned transplants in comparison with myeloablative procedures (81% vs 54%; P < .003), although in unconditioned haploidentical donor HCT, nonengraftment was a major problem. Long-term immune recovery showed that regardless of transplant type, overall T-cell numbers were similar, although a faster rate of T-cell recovery was observed after MSD/MFD HCT. Humoral immunity and donor B-cell engraftment was achieved in nearly all evaluable surviving patients and was seen even after unconditioned HCT. These data detail for the first time the outcomes of HCT for ADA-SCID and show that, if patients survive HCT, long-term cellular and humoral immune recovery is achieved.

Long-term outcome and lineage-specific chimerism in 194 patients with Wiskott-Aldrich syndrome treated by hematopoietic cell transplantation in the period 1980-2009: an international collaborative study.

In this retrospective collaborative study, we have analyzed long-term outcome and donor cell engraftment in 194 patients with Wiskott-Aldrich syndrome (WAS) who have been treated by hematopoietic cell transplantation (HCT) in the period 1980- 2009. Overall survival was 84.0% and was even higher (89.1% 5-year survival) for those who received HCT since the year 2000, reflecting recent improvement of outcome after transplantation from mismatched family donors and for patients who received HCT from an unrelated donor at older than 5 years. Patients who went to transplantation in better clinical conditions had a lower rate of post-HCT complications. Retrospective analysis of lineage-specific donor cell engraftment showed that stable full donor chimerism was attained by 72.3% of the patients who survived for at least 1 year after HCT. Mixed chimerism was associated with an increased risk of incomplete reconstitution of lymphocyte count and post-HCT autoimmunity, and myeloid donor cell chimerism < 50% was associated with persistent thrombocytopenia. These observations indicate continuous improvement of outcome after HCT for WAS and may have important implications for the development of novel protocols aiming to obtain full correction of the disease and reduce post-HCT complications.

HLA-haploidentical donor transplantation in severe combined immunodeficiency.

Curative treatment of Severe Combined Immunodeficiency (SCID) by Hematopoietic Cell Transplantation (HCT) remains a challenge, in particular in infants presenting with serious, poorly controllable complications. In the absence of a matched family donor, HLA-haploidentical transplantation from parental donors represents a uniformly and readily available treatment option, offering a high chance to be successful. Concerning outcomes of HCT in SCID, other important parameters beside survival need to be taken into consideration, in particular the stability and robustness of the graft and its function, as well as potential late complications, related either to the disease or to the treatment.

Multicenter survey on the outcome of transplantation of hematopoietic cells in patients with the complete form of DiGeorge anomaly.

Seventeen patients transplanted with hematopoietic cells to correct severe T lymphocyte immunodeficiency resulting from complete DiGeorge anomaly were identified worldwide, and retrospective data were obtained using a questionnaire-based survey. Patients were treated at a median age of 5 months (range, 2-53 months) between 1995 and 2006. Bone marrow was used in 11 procedures in 9 cases: 6 from matched unrelated donors, 4 from human leukocyte antigen (HLA)-identical siblings, and one haploidentical parent with T-cell depletion. Unmobilized peripheral blood was used in 8 cases: 5 from HLA-identical siblings, one from a matched unrelated donor, one from an HLA-identical parent, and one unrelated matched cord blood. Conditioning was used in 5 patients and graft-versus-host disease prophylaxis in 11 patients. Significant graft-versus-host disease occurred in 9 patients, becoming chronic in 3. Median length of follow-up was 13 months, with transplantation from HLA-matched sibling showing the best results. Median survival among deceased patients (10 patients) was 7 months after transplantation (range, 2-18 months). The overall survival rate was 41%, with a median follow-up of 5.8 years (range, 4-11.5 years). Among survivors, median CD3 and CD4 counts were 806 (range, 644-1224) and 348 (range, 225-782) cells/mm(3), respectively, CD4(+)/CD45RA(+) cells remained very low, whereas mitogen responses were normalized.

HLA-haploidentical donor transplantation in severe combined immunodeficiency.

Curative treatment of Severe Combined Immunodeficiency (SCID) by Hematopoietic Cell Transplantation (HCT) remains a challenge, in particular in infants presenting with serious, poorly controllable complications. In the absence of a matched family donor, HLA-haploidentical transplantation from parental donors represents a uniformly and readily available treatment option, offering a high chance to be successful. Concerning outcomes of HCT in SCID, other important parameters beside survival need to be taken into consideration, in particular the stability and robustness of the graft and its function, as well as potential late complications, related either to the disease or to the treatment.

Reticular dysgenesis (aleukocytosis) is caused by mutations in the gene encoding mitochondrial adenylate kinase 2.

Human severe combined immunodeficiencies (SCID) are phenotypically and genotypically heterogeneous diseases. Reticular dysgenesis is the most severe form of inborn SCID. It is characterized by absence of granulocytes and almost complete deficiency of lymphocytes in peripheral blood, hypoplasia of the thymus and secondary lymphoid organs, and lack of innate and adaptive humoral and cellular immune functions, leading to fatal septicemia within days after birth. In bone marrow of individuals with reticular dysgenesis, myeloid differentiation is blocked at the promyelocytic stage, whereas erythro- and megakaryocytic maturation is generally normal. These features exclude a defect in hematopoietic stem cells but point to a unique aberration of the myelo-lymphoid lineages. The dramatic clinical course of reticular dysgenesis and its unique hematological phenotype have spurred interest in the unknown genetic basis of this syndrome. Here we show that the gene encoding the mitochondrial energy metabolism enzyme adenylate kinase 2 (AK2) is mutated in individuals with reticular dysgenesis. Knockdown of zebrafish ak2 also leads to aberrant leukocyte development, stressing the evolutionarily conserved role of AK2. Our results provide in vivo evidence for AK2 selectivity in leukocyte differentiation. These observations suggest that reticular dysgenesis is the first example of a human immunodeficiency syndrome that is causally linked to energy metabolism and that can therefore be classified as a mitochondriopathy.

Results and long-term outcome in 39 patients with Wiskott-Aldrich syndrome transplanted from HLA-matched and -mismatched donors.

In this report, we present an analysis in 39 WAS patients treated by hematopoietic stem cell transplantation (HSCT) in our center since 1983. Fifteen patients received transplants from HLA-identical unrelated donors, 15 from nonidentical parental donors, and 9 from matched siblings. The overall survival rate is 90% in patients with matched donors and 50% in patients after nonidentical transplantation, with a mean follow-up time of 11 years. Treatment failures in the latter group were mainly related to graft rejections and to GvHD and infections following repeat transplants. Long-term survivors in both patient groups remain with few exceptions free of late complications and with stable graft function and complete donor cell chimerism. Based on our findings, we recommend early and prompt treatment of each diagnosed WAS patient if an HLA-matched, related or unrelated, donor can be identified. If this is not the case, HLA-nonidentical donor transplantation represents an alternative to be considered early in patients with severe disease.

Long-term follow-up in patients with severe combined immunodeficiency treated by bone marrow transplantation.

Immune reconstitution was studied in 31 long-term surviving patients after bone marrow transplantation for severe combined immunodeficiency. Donors in 7 cases were HLA-identical and in 25 cases HLA-haploidentical family members, and in 13 of these latter cases cytoreductive conditioning had been used prior to transplantation. At a mean follow-up of 15 years after transplantation (range 10 to 22 years), T cell numbers and functions had remained stable and within normal limits in the majority of patients. Marked variability however was observed with regard to reconstitution of B cell immunity. Furthermore numbers of circulating naïve CD4+ T cells were variable and markedly diminished in a substantial proportion of patients at recent evaluations. Normal B cell immunity and persistently normal naïve T cell numbers were strongly correlated with the continued detection of donor type CD34+ precursor cells in the patients marrow, which were absent in non conditioned patients. These findings indicate that stable donor precursor cell engraftment in the marrow may be of relevance for complete and stable long-term immune reconstitution in transplanted SCID patients.