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.

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.

[Newborn screening for severe combined immunodeficiencies (SCID) in Germany]

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.

[Hepatolienal candidosis as a rare differential diagnosis of disseminated small parenchym lesions]

HISTORY

We report about a 17-year-old patient with the secondary malignancy of acute myeloid leukemia (AML). He developed fever of unclear origin during the hematopoietic stem cell transplantation.History We report about a 17-year-old patient with the secondary malignancy of acute myeloid leukemia (AML). He developed fever of unclear origin during the hematopoietic stem cell transplantation.

EXAMINATIONS

In the focus search, the routine sonography of the abdomen showed disseminated hypoechoic small- parenchymal lesions of the liver. In the complementary MRI, disseminated small lesions of the liver parenchyma and the spleen were demarked after contrast agent administration.

DIAGNOSIS

Imaging revealed suspicion of hepatolienal candiasis.Diagnosis Imaging revealed suspicion of hepatolienal candiasis.

THERAPY

Empirical therapy with amphotericin B was used. A sonographic punch biopsy of the liver was performed. The pathological examination showed oval particles in the PAS staining in the sense of an opportunistic mycosis of the Candida infection type.

CONCLUSION

The case shows that in immunosuppressed patients, candidiasis must always be considered as a differential diagnosis with simultaneous parenchymal changes in the liver and/or spleen. In addition, in the screening situation, a suitable linear transducer should be used when asking about fungal lesions in the liver and spleen. Alternatively, if suspected hepato-lienal candidiasis could be diagnosed by a contrast-enhanced MRI of the upper abdomen/abdomen.

NK Cells from RAG- or DCLRE1C-Deficient Patients Inhibit HCMV

The recombination-activating genes (RAGs) and the DNA cross-link repair 1C gene (DCLRE1C) encode the enzymes RAG1, RAG2 and Artemis. They are critical components of the V(D)J recombination machinery. V(D)J recombination is well known as a prerequisite for the development and antigen diversity of T and B cells. New findings suggested that RAG deficiency impacts the cellular fitness and function of murine NK cells. It is not known whether NK cells from severe combined immunodeficiency (SCID) patients with defective RAGs or DCLRE1C (RAGs⁻/DCLRE1C⁻-NK) are active against virus infections. Here, we evaluated the anti-HCMV activity of RAGs⁻/DCLRE1C⁻-NK cells. NK cells from six SCID patients were functional in inhibiting HCMV transmission between cells in vitro. We also investigated the expansion of HCMV-induced NK cell subset in the RAG- or DCLRE1C-deficient patients. A dynamic expansion of NKG2C⁺ NK cells in one RAG-2-deficient patient was observed post HCMV acute infection. Our study firstly reveals the antiviral activity of human RAGs⁻/ DCLRE1C⁻-NK cells.

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).

The German National Registry of Primary Immunodeficiencies (2012-2017)

Introduction: The German PID-NET registry was founded in 2009, serving as the first national registry of patients with primary immunodeficiencies (PID) in Germany. It is part of the European Society for Immunodeficiencies (ESID) registry. The primary purpose of the registry is to gather data on the epidemiology, diagnostic delay, diagnosis, and treatment of PIDs. Methods: Clinical and laboratory data was collected from 2,453 patients from 36 German PID centres in an online registry. Data was analysed with the software Stata® and Excel. Results: The minimum prevalence of PID in Germany is 2.72 per 100,000 inhabitants. Among patients aged 1-25, there was a clear predominance of males. The median age of living patients ranged between 7 and 40 years, depending on the respective PID. Predominantly antibody disorders were the most prevalent group with 57% of all 2,453 PID patients (including 728 CVID patients). A gene defect was identified in 36% of patients. Familial cases were observed in 21% of patients. The age of onset for presenting symptoms ranged from birth to late adulthood (range 0-88 years). Presenting symptoms comprised infections (74%) and immune dysregulation (22%). Ninety-three patients were diagnosed without prior clinical symptoms. Regarding the general and clinical diagnostic delay, no PID had undergone a slight decrease within the last decade. However, both, SCID and hyper IgE- syndrome showed a substantial improvement in shortening the time between onset of symptoms and genetic diagnosis. Regarding treatment, 49% of all patients received immunoglobulin G (IgG) substitution (70%-subcutaneous; 29%-intravenous; 1%-unknown). Three-hundred patients underwent at least one hematopoietic stem cell transplantation (HSCT). Five patients had gene therapy. Conclusion: The German PID-NET registry is a precious tool for physicians, researchers, the pharmaceutical industry, politicians, and ultimately the patients, for whom the outcomes will eventually lead to a more timely diagnosis and better treatment.

Increased proportions of γδ T lymphocytes in atypical SCID associate with disease manifestations

Severe combined immunodeficiencies (SCID) comprise a group of genetic diseases characterized by abrogated development of T lymphocytes. In some case reports of atypical SCID patients elevated proportions of γδ T lymphocytes have been reported. However, it is unknown whether these γδ T cells modulate or reflect the patient's clinical phenotype. We investigated the frequency of elevated γδ T cell proportions and associations with clinical disease manifestations in a cohort of 76 atypical SCID patients. Increased proportions of γδ T lymphocytes were present in approximately 60% of these patients. Furthermore, we identified positive correlations between elevated proportions of γδ T cells and the occurrence of CMV infections and autoimmune cytopenias. We discuss that CMV infections might trigger an expansion of γδ T lymphocytes, which could drive the development of autoimmune cytopenias. We advocate that atypical SCID patients should be screened for elevated proportions of γδ T lymphocytes, CMV infection and autoimmune cytopenias.

Key findings to expedite the diagnosis of hyper-IgE syndromes in infants and young children

BACKGROUND

Hyper-IgE syndromes (HIES) are primary immunodeficiency disorders characterized by elevated serum IgE, eczema, and recurrent infections. Despite the availability of confirmatory molecular diagnosis of several distinct HIES entities, the differentiation of HIES particularly from severe forms of atopic dermatitis remains a challenge. The two most common forms of HIES are caused by mutations in the genes STAT3 and DOCK8.

METHODS

Here, we assess the clinical and immunologic phenotype of DOCK8- and STAT3-HIES patients including the cell activation, proliferation, and cytokine release after stimulation.

RESULTS

Existing HIES scoring systems are helpful to identify HIES patients. However, those scores may fail in infants and young children due to the age-related lack of clinical symptoms. Furthermore, our long-term observations showed a striking variation of laboratory results over time in the individual patient. Reduced memory B-cell counts in concert with low specific antibody production are the most consistent findings likely contributing to the high susceptibility to bacterial and fungal infection. In DOCK8-HIES, T-cell lymphopenia and low IFN-gamma secretion after stimulation were common, likely promoting viral infections. In contrast to STAT3-HIES, DOCK8-HIES patients showed more severe inflammation with regard to allergic manifestations, elevated activation markers (HLA-DR, CD69, CD86, and CD154), and significantly increased inflammatory cytokines (IL1-beta, IL4, IL6, and IFN-gamma).

CONCLUSION

Differentiating HIES from other diseases such as atopic dermatitis early in life is essential for patients because treatment modalities differ. To expedite the diagnosis process, we propose here a diagnostic workflow.

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.

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.

Successful haploidentical hematopoietic stem cell transplantation in a patient with SCID due to CD3ε deficiency: need for IgG-substitution 6 years later

BACKGROUND

The CD3 co-receptor complex is essential for signal transduction after specific binding of the T-cell receptor (TCR). CD3E encodes the CD3ε chain, one of the protein components (γ-, δ-, ε- and ζ-chain) of the CD3 co-receptor. As previously reported in one family CD3ε deficiency causes SCID.

PATIENT

We report on a patient with SCID due to CD3ε deficiency treated by HLA-haploidentical stem cell transplantation (SCT) (donor: mother) 15 years ago which resulted in development of normal T- and B-cell immunity. Despite conditioning donor cell engraftment was confined to T cells, while all other blood cell lineages remained of patient origin (split chimerism). In spite of normal functions, T-cell numbers never reached normal levels and naïve CD45+RA+ T-cells remained low. At 6 years after SCT the patient developed signs of humoral immunodeficiency, requiring regular substitution of IgG.

RESULTS

In a retrospective genetic work up 11 years after SCT, a homozygous splice site mutation in CD3E was identified resulting in the loss of CD3ε protein. The loss of B-cell function as observed in the patient was reflected by a lack of switched memory B cells. To rule out a primary role of CD3ε in B-cell function we studied expression of CD3E in B-cells which was found not to be expressed.

DISCUSSION

The clinical presentation of a secondary loss of specific humoral immunity in this constellation of split chimerism after allogeneic haploidentical SCT is unusual and unexpected in a patient with a primary T-cell defect. A most likely explanation is the gradual loss of T-helper-cell function.

[Interdisciplinary AWMF guideline for the treatment of primary antibody deficiencies]

BACKGROUND

Currently, management of antibody deficient patients differs significantly among caregivers. Evidence and consensus based (S3) guidelines for the treatment of primary antibody deficiencies were developed to improve the management of these patients.

METHODS

Based on a thorough analysis of current evidence (systematic literature search in PubMed; deadline November 2011) 14 recommendations were finalized during a consensus meeting in Frankfurt in November 2011 using structured consensus methods (nominal group technique). Experts were nominated by their scientific societies/patient initiatives (Tab. 1).

RESULTS

The guidelines focus on indication, practical issues and monitoring of immunoglobulin replacement therapy as well as on different routes of administration. Furthermore recommendations regarding supportive measures such as antiinfective therapy, vaccinations and physiotherapy are given. Combining literature evidence and experience of caregivers within this evidence and consensus based guidelines offers the chance to improve the quality of care for anti-body deficient patients.

Regulated expression of nuclear receptor RORγt confers distinct functional fates to NK cell receptor-expressing RORγt(+) innate lymphocytes

Whether the recently identified innate lymphocyte population coexpressing natural killer cell receptors (NKRs) and the nuclear receptor RORγt is part of the NK or lymphoid tissue inducer (LTi) cell lineage remains unclear. By using adoptive transfer of genetically tagged LTi-like cells, we demonstrate that NKR⁻RORγt(+) innate lymphocytes but not NK cells were direct progenitors to NKR(+)RORγt(+) cells in vivo. Genetic lineage tracing revealed that the differentiation of LTi-like cells was characterized by the stable upregulation of NKRs and a progressive loss of RORγt expression. Whereas interleukin-7 (IL-7) and intestinal microbiota stabilized RORγt expression within such NKR-LTi cells, IL-12 and IL-15 accelerated RORγt loss. RORγt(+) NKR-LTi cells produced IL-22, whereas RORγt⁻ NKR-LTi cells released IFN-γ and were potent inducers of colitis. Thus, the RORγt gradient in NKR-LTi cells serves as a tunable rheostat for their functional program. Our data also define a previously unappreciated role of RORγt⁻ NKR-LTi cells for the onset or maintenance of inflammatory bowel diseases.

Patients with early relapse of primary hemophagocytic syndromes or with persistent CNS involvement may benefit from immediate hematopoietic stem cell transplantation

Primary hemophagocytic syndromes represent a group of rare immunodeficiencies, which are characterized by development of life-threatening systemic inflammatory manifestations, so-called accelerated phases. Immunosuppressive therapies are only temporarily effective to control this complication and the prognosis is dismal unless treated by hematopoietic SCT (HSCT). At present, optimal modalities of this potentially curative approach remain incompletely defined. In this study, we analyzed our experience in 18 patients with primary hemophagocytic syndromes treated since 1984 in our center by HSCT. Ten of these patients had previously developed accelerated phases and were in remission at the time of HSCT, whereas five patients had findings of active disease, with two cases in early phases of recurrences of less than 2 weeks duration and three cases with persistent central nervous system disease, whereas three patients had never experienced accelerated phases. In the group with active disease, four of five patients are long-term survivors and are well, whereas one patient died of CMV pneumonia. This outcome compares favorably with results in patients transplanted in remission, where 6 of 10 are long-term survivors. Our findings indicate that HSCT can have a favorable prognosis even in patients with active disease of primary hemophagocytic syndrome.

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.

Patients with adenosine deaminase deficiency surviving after hematopoietic stem cell transplantation are at high risk of CNS complications

Adenosine deaminase (ADA) deficiency is a systemic metabolic disease that causes an autosomal recessive variant of severe combined immunodeficiency (SCID) and less consistently other complications including neurologic abnormalities. Hematopoietic stem cell transplantation (HSCT) is able to correct the immunodeficiency, whereas control of nonimmunologic complications has not been extensively explored. We applied HSCT in 15 ADA-deficient patients consecutively treated at our institutions since 1982 and analyzed long-term outcome. Seven patients received transplants without conditioning from HLA-matched family donors (MFDs); the other 8 patients received conditioning and were given transplants either from HLA-mismatched family donors (MMFDs; n = 6) or from matched unrelated donors (MUDs; n = 2). At a mean follow-up period of 12 years (range, 4-22 years), 12 patients are alive with stable and complete immune reconstitution (7 of 7 after MFD, 4 of 6 after MMFD, and 1 of 2 after MUD transplantation). Six of 12 surviving patients show marked neurologic abnormalities, which include mental retardation, motor dysfunction, and sensorineural hearing deficit. We were unable to identify disease or transplantation-related factors correlating with this divergent neurologic outcome. The high rate of neurologic abnormalities observed in long-term surviving patients with ADA deficiency indicates that HSCT commonly fails to control CNS complications in this metabolic disease.

Stem cell transplantation in children with infantile osteopetrosis is associated with a high incidence of VOD, which could be prevented with defibrotide

Malignant infantile osteopetrosis (MIOP) is a rare hereditary disorder of osteoclast function, which can be reversed by hematopoietic stem cell transplantation (SCT). We observed a high incidence of hepatic veno-occlusive disease (VOD) in transplanted patients and explored the prevention of this complication by using defibrotide (DF) as a prophylaxis. Twenty children with MIOP were consecutively transplanted in our center between 1996 and 2005. Eleven of these patients were transplanted between 1996 and 2001 and experienced an overall incidence of VOD of 63.6% (7/11). VOD was severe in three patients and one patient succumbed to VOD-related multi-organ failure. Owing to this very high incidence of VOD, DF prophylaxis was initiated in nine patients consecutively transplanted between 2001 and 2005. In this group, only one patient (11.1%) was diagnosed with moderate VOD. We report here a very high risk in patients with MIOP to develop VOD after transplantation. Prophylactic DF was implemented in our current transplant protocol and reduced the VOD rate significantly in this high-risk population.

Omenn syndrome: a lack of tolerance on the background of deficient lymphocyte development and maturation

PURPOSE OF REVIEW

Omenn syndrome is a rare inherited primary immunodeficiency characterized by severe combined immunodeficiency in combination with autoimmune features leading to squamous erythrodermia, alopecia, lymphadenopathy, hepatosplenomegaly, and intractable diarrhea. Recent advances include characterizing the genetic basis of the syndrome and integrating the genetic defects into knowledge of tolerance induction.

RECENT FINDINGS

Molecular studies have shown that besides the well-known hypomorphic recombination activating gene defects, mutations in the nonhomologous end-joining factor Artemis and in the interleukin-7 receptor alpha chain can contribute to the development of Omenn syndrome. These investigations established that Omenn syndrome is a genetically heterogeneous condition. Whereas the majority of patients with Omenn syndrome bear hypomorphic gene alterations, some exhibit somatic mosaicism due to second-site reversions of null alleles. A lack of central tolerance contributes to the autoimmune pathology of the disease.

SUMMARY

Research has begun to clarify the genetic defects and the conditions underlying the lack of tolerance enforcement that predispose to Omenn syndrome. Clinical applications of this research include the identification of the causative genetic defect in the majority of Omenn syndrome cases and the use of this genetic knowledge in family and prenatal analyses and in difficult differential autoimmune diagnoses.

[Nitinol stent implantation in benign esophagotracheal fistula]

The self-expanding nitinol stent is easy to handle and well tolerated. It offers an improved method in the treatment of perforations of the upper aerodigestive tract. It is easily implantable with rigid and flexible endoscopes. A 45-year-old female patient developed a tracheal necrosis after polytrauma and protracted intubation and ventilation. The permanent cuff pressure caused a 5-cm long fistula located at the posterior trachea 3 cm above the carina. After stabilization of the general condition and spontaneous reduction of the fistula length to 2 cm, we implanted the silicon-covered esophageal stent. Daily bronchoscopic examination was done before and after implantation of the stent. Two days after implantation, we were able to remove the blocked tracheostomy tube. Immediately oral nutrition was possible without complications. Because of its easy and fast application without any complications, the new type of nitinol stent is a promising alternative for ear, nose, and throat patients in bad general condition to provide fast and safe treatment in benign tracheoesophageal fistulas.

Synovial PMN show a coordinated up-regulation of CD66 molecules

Changes in the expression of various activation-dependent surface markers have been reported for polymorphonuclear neutrophils (PMN) isolated from synovial fluid of patients with inflammatory joint diseases. We extend these findings to the expression of CD66 molecules and several other surface markers. Three members of the CD66 family, namely CD66a, CD66b, and CD66c, showed an up to fourfold up-regulation on synovial fluid PMN compared with peripheral blood PMN (PBG) of the same patients; CD59 was increased twofold, the expression of CD16 did not change, whereas CD62L was reduced by more than 50% on synovial fluid PMN. It is interesting that CD66a, CD66b, and CD66c showed a coordinated expression on PBG of patients and controls and a coordinated up-regulation on synovial neutrophils. In contrast, after in vitro stimulation of peripheral blood PMN with phorbol myristate acetate, CD66c was much less up-regulated compared with CD66a and CD66b. All samples of synovial fluid PMN exhibited an additional increase in the expression of CD66a, CD66b, and CD66c when stimulated with phorbol myristate acetate in vitro. Prostaglandins are known to inhibit various responses of neutrophils to inflammatory stimuli. We could show that prostaglandins inhibit N-formyl-methionyl-leucyl-phenylalanine-induced up-regulation of CD66 on peripheral blood PMN in a concentration-dependent manner.

Treatment of recurrent respiratory papillomatosis with argon plasma coagulation

Extension of recurrent respiratory papillomatosis (RRP) to the lower airway in children is life-threatening and an extremely difficult condition to treat. We present the case of a seven-year-old girl with progressive RRP since the age of two. Repeated CO2 laser treatment and interferon-alpha treatment could not prevent tracheotomy and spread to the trachea. We used argon plasma coagulation (APC) with flexible endoscopy for the first time for the treatment of RRP. APC gives a controlled limited penetration into the tissue and good control of bleeding. There is no carbonization or vaporization which makes it a suitable method for the treatment of lower airway RRP. After a few treatments with APC, we gained very good control of the disease with no side-effects or complications. The described application of APC seems to be a promising way to treat lower airway RRP.

Response of mouse oral mucosa to repeated doses of bleomycin

Bleomycin (BLM) applied at systemically tolerable doses induces denudation of tongue mucosa in the C3H-Neuherberg mouse strain. The dose-incidence curve after single injections has a sigmoid shape with an ED50 of 17.5 mg/kg. In contrast, the dose-response curves to repeated (two, five and 10) drug injections follow triphasic shapes and show dose-effect inversions. The effect initially increases with dose to a maximum of 70-100% at 2 x 7, 5 x 2, and 10 x 0.9 mg/kg. A marked decrease in response is observed at higher doses with a nadir of 10-30% after 2 x 11 mg/kg, 5 x 4 to 5 x 5 mg/kg and 10 x 2 mg/kg, followed by a second rise when dose is further increased. These clinical results were confirmed in a histological study. Variation of the time interval between two drug injections caused marked fluctuations in the treatment efficacy. A clear increase in drug response was induced by splitting total drug doses of 6, 14 or 22 mg/kg, the maximum effect (100%) was seen at intervals of 2 h, 0.5-1 h and 0.25 h between two injections of 3, 7 or 11 mg/kg, respectively. At longer intervals of up to 6 h, a dose-dependent decrease in drug efficacy resulted in an inverse dose-effect. Original tissue tolerance to BLM was restored only in the 2 x 3 mg/kg arm but was still elevated in the other arms after 96 h. The results can be plausibly explained by the dose-dependent induction of detoxifying processes.

Response of mouse tongue epithelium to single doses of bleomycin and radiation

Both bleomycin (BLM) and local X-irradiation (25 kV) induce denudation in the tongue epithelium of the C3H-Neuherberg mouse in a dose-dependent manner. In the present study the effect of BLM alone and of combined single doses of drug and radiation were studied using the incidence of epithelial denudation as the end-point. In 'time-line' experiments, 8 mg/kg BLM were given before or after graded doses of X-rays. BLM treatment required a reduction of the radiation dose (ED50) from 15 Gy to 5-7 Gy, independent of sequence or time interval. In contrast, the time course of the response was clearly dependent on the treatment interval. Latency decreased when the drug was injected less than 2 h before irradiation with minimum latency observed at 30 min. Isobologram analysis of experiments with varying combinations of X-rays and BLM demonstrated that small drug doses were relatively more effective than larger doses, suggesting an upward concavity of the BLM dose-effect curve in vivo, i.e. a 'negative shoulder' of the curve in the low dose region. In contrast to the response to X-rays alone, which has a constant latent time to ulcer of 10 days, the latency in combined treatment was clearly shortened with increasing drug dose and at high doses eventually approximated the epithelial turnover time of 5 days. The data suggest that BLM both as a single agent and in combination with X-rays reduced the probability of abortive divisions and through this effect shortened the latent time to epithelial denudation.

Different actions of neomychin and metronidazole on breath hydrogen (H2) exhalation

Purpose of this investigation was to characterize the effect of antibiotics as a possible limiting factor for the evaluation of hydrogen (H2) breath analysis tests which depend on bacterial carbohydrate fermentation. Breath H2-excretion following ingestion of the non-absorbable disaccharide lactulose was monitored in healthy subjects before and after pretreatment with the aminoglycoside neomycin or with metronidazole. Metronidazole decreased the amount of hydrogen exhaled by 39 % (p<0.05) and peak H2-excretion by 42.1 % (p<0.01), because it suppresses anaerobe H2 producing microorganisms. Neomycin intensified nonsignificantly the integrated (0-6 hours) breath hydrogen response to lactulose (+43 %) and the maximal H2-concentration by 29.8 %, probably because it interferes with intestinal bacteria which are important for H2-consumption.