NKp46 is a diagnostic biomarker and may be a therapeutic target in gastrointestinal T-cell lymphoproliferative diseases: a CELAC study.

OBJECTIVES: Primary GI T-cell lymphoproliferative diseases (T-LPD) are heterogeneous entities, which raise difficult diagnosis and therapeutic challenges. We have recently provided evidences that lymphomas complicating coeliac disease (CD) arise from innate-like lymphocytes, which may carry NK receptors (NKRs). DESIGN: NKRs expression was compared by flow cytometry in intraepithelial lymphocytes (IEL) from CD, type I or type II refractory CD (RCD). NKp46 was next assessed by immunohistochemistry in paraffin-embedded biopsies from 204 patients with CD, RCDI, RCDII or GI T-cell lymphomas and from a validation cohort of 61 patients. The cytotoxic properties of an anti-NKp46 monoclonal antibody conjugated to pyrrolobenzodiazepine (PBD) was tested ex vivo in human primary tumour cells isolated from fresh duodenal biopsies. RESULTS: NKp46 (but not CD94, NKG2A, NKG2C, NKG2D) was significantly more expressed by malignant RCDII IEL than by normal IEL in CD and RCDI. In paraffin biopsies, detection of >25 NKp46+ IEL per 100 epithelial cells discriminated RCDII from CD and RCDI. NKp46 was also detected in enteropathy-associated T-cell lymphomas (EATL, 24/29) and in monomorphic epitheliotropic intestinal T-cell lymphomas (MEITL, 4/4) but not in indolent T-LPD (0/15). Treatment with anti-NKp46-PBD could efficiently and selectively kill human NKp46+ primary IEL ex vivo. CONCLUSION: NKp46 is a novel biomarker useful for diagnosis and therapeutic stratification of GI T-LPD. Strong preclinical rationale identifies anti-NKp46-PBD as a promising therapy for RCDII, EATL and MEITL.

Addition of high-dose cytarabine to immunochemotherapy before autologous stem-cell transplantation in patients aged 65 years or younger with mantle cell lymphoma (MCL Younger): a randomised, open-label, phase 3 trial of the European Mantle Cell Lymphoma Network.

BACKGROUND: Mantle cell lymphoma is characterised by a poor long-term prognosis. The European Mantle Cell Lymphoma Network aimed to investigate whether the introduction of high-dose cytarabine to immunochemotherapy before autologous stem-cell transplantation (ASCT) improves outcome. METHODS: This randomised, open-label, parallel-group, phase 3 trial was done in 128 haemato-oncological hospital departments or private practices in Germany, France, Belgium, and Poland. Patients aged 65 years or younger with untreated stage II-IV mantle cell lymphoma were centrally randomised (1:1), with computer-assisted random block selection, to receive either six courses of R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by myeloablative radiochemotherapy and ASCT (control group), or six courses of alternating R-CHOP or R-DHAP (rituximab plus dexamethasone, high-dose cytarabine, and cisplatin) followed by a high-dose cytarabine-containing conditioning regimen and ASCT (cytarabine group). Patients were stratified by study group and international prognostic index. The primary outcome was time to treatment failure from randomisation to stable disease after at least four induction cycles, progression, or death from any cause. Patients with stage II-IV mantle cell lymphoma were included in the primary analysis if treatment was started according to randomisation. For safety analyses, patients were assessed according to the treatment actually started. This study is registered with ClinicalTrials.gov, number NCT00209222. FINDINGS: Of 497 patients (median age 55 years [IQR 49-60]) randomised from July 20, 2004, to March 18, 2010, 234 of 249 in the control group and 232 of 248 in the cytarabine group were included in the primary analysis. After a median follow-up of 6.1 years (95% CI 5.4-6.4), time to treatment failure was significantly longer in the cytarabine group (median 9.1 years [95% CI 6.3-not reached], 5 year rate 65% [95% CI 57-71]) than in the control group (3.9 years [3.2-4.4], 40% [33-46]; hazard ratio 0.56; p=0.038). During induction immunochemotherapy, patients who received high-dose cytarabine had increased grade 3 or 4 haematological toxicity (haemoglobin 71 [29%] of 241m vs 19 [8%] of 227 controls; platelets 176 [73%] of 240 vs 21 [9%] of 225), grade 3 or 4 febrile neutropenia (39 [17%] of 230 vs 19 [8%] of 224), and grade 1 or 2 renal toxicity (creatinine 102 [43%] of 236 vs 22 [10%] of 224). The number of ASCT-related deaths was similar (eight [3.4%]) in both groups. INTERPRETATION: Immunochemotherapy containing high-dose cytarabine followed by ASCT should be considered standard of care in patients aged 65 years or younger with mantle cell lymphoma. FUNDING: European Commission, Lymphoma Research Foundation, and Roche.

The localisation of the apical Par/Cdc42 polarity module is specifically affected in microvillus inclusion disease.

BACKGROUND INFORMATION: Microvillus inclusion disease (MVID) is a genetic disorder affecting intestinal absorption. It is caused by mutations in MYO5B or syntaxin 3 (STX3) affecting apical membrane trafficking. Morphologically, MVID is characterised by a depletion of apical microvilli and the formation of microvillus inclusions inside the cells, suggesting a loss of polarity. To investigate this hypothesis, we examined the location of essential apical polarity determinants in five MVID patients. RESULTS: We found that the polarity determinants Cdc42, Par6B, PKCζ/ι and the structural proteins ezrin and phospho-ezrin were lost from the apical membrane and accumulated either in the cytoplasm or on the basal side of enterocytes in patients, which suggests an inversion of cell polarity. Moreover, microvilli-like structures were observed at the basal side as per electron microscopy analysis. We next performed Myo5B depletion in three dimensional grown human Caco2 cells forming cysts and found a direct link between the loss of Myo5B and the mislocalisation of the same apical proteins; furthermore, we observed that a majority of cysts displayed an inverted polarity phenotype as seen in some patients. Finally, we found that this loss of polarity was specific for MVID: tissue samples of patients with Myo5B-independent absorption disorders showed normal polarity but we identified Cdc42 as a potentially essential biomarker for trichohepatoenteric syndrome. CONCLUSION: Our findings indicate that the loss of Myo5B induces a strong loss of enterocyte polarity, potentially leading to polarity inversion. SIGNIFICANCE: Our results show that polarity determinants could be useful markers to help establishing a diagnosis in patients. Furthermore, they could be used to characterise other rare intestinal absorption diseases.

Subcutaneous Panniculitis-like T-cell Lymphoma: Immunosuppressive Drugs Induce Better Response than Polychemotherapy.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare condition usually considered to have a favourable prognosis. However, it is not known whether polychemotherapy or immunosuppressive-based therapy is the best approach for treating SPTCL. Using data collected between 2000 and 2012 in France, we analysed clinical, biological and pathological data of 27 patients with SPTCL. Medical history revealed that 40% of patients had been previously diagnosed with an autoimmune disorder and 22% with inflammatory panniculitis. Haemophagocytic syndrome was present in 37% of cases. Autoantibodies were positive in 65% of cases. Complete remission (CR) was reached in 74% of cases. Immunosuppressive drug treatment was given in 69.5% of patients (group 1) and polychemotherapy in 30.5% (group 2). CR was 81.2% and 28.5% (p?=?0.025), respectively. Progression rate was 6.2% and 42.8% (p?=?0.067), respectively. This study suggests that immunosuppressive drugs should be considered as the first-line treatment for SPTCL.

Defective anti-polysaccharide response and splenic marginal zone disorganization in ALPS patients.

Autoimmune lymphoproliferative syndrome (ALPS) caused by impaired FAS-mediated apoptosis of lymphocytes is characterized by lymphoproliferation, autoimmunity, but also an increased risk of invasive bacterial infection, notably following splenectomy. We surveyed a cohort of 100 ALPS patients (including 33 splenectomized) and found that 12 (10 splenectomized) had experienced 23 invasive bacterial infections mainly caused by Streptococcus pneumoniae. This vulnerability was associated with evidence of defective B-cell function characterized by low serum immunoglobulin (Ig) M, low IgM antibody production in response to S pneumoniae following nonconjugated immunization, and low blood memory B-cells counts (including marginal zone [MZ] B-cell counts). This immunodeficiency strongly correlated with intensity of lymphoproliferation. Spleen sections from 9 ALPS patients revealed double-negative T-cell (DN-T) infiltration of the MZ, which was depleted of B cells. MZ in ALPS patients contained an abnormally thick layer of MAdCAM-1((+)) stromal cells and an excess of DN-Ts. DN-Ts were shown to express MAdCAM-1 ligand, the α4ß7 integrin. These observations suggest that accumulating DN-Ts are trapped within stromal cell meshwork and interfere with correct localization of MZ B cells. Similar observations were made in spleens of fas-deficient mice. Our data revealed an unexpected mechanism by which ALPS results in anti-polysaccharide IgM antibody production-specific defect. Splenectomy should be avoided.

CHOP and DHAP plus rituximab followed by autologous stem cell transplantation in mantle cell lymphoma: a phase 2 study from the Groupe d'Etude des Lymphomes de l'Adulte.

Treatment of mantle cell lymphoma (MCL) in younger patients remains a challenge. We report results of a phase 2 trial using cytarabine and rituximab as induction regimen before autologous stem cell transplantation. Patients younger than 66 years with stage 3 or 4 MCL were included. Treatment consisted of 3 courses of CHOP(21) with rituximab at the third one and 3 of R-DHAP. Responding patients were eligible for autologous stem cell transplantation with TAM6 or BEAM. Sixty patients were included. Median age was 57 years. Characteristics of patients were: BM involvement 85%, leukemic disease 48%, gastrointestinal involvement 52%, Performance Status > 16%, lactate dehydrogenase > 1N 38%, Mantle Cell Lymphoma International Prognostic Index (low 55%, intermediate 38%, high 13%). The overall response rate was 93% after (R)-CHOP and 95% after R-DHAP. Although uncommon after (R)-CHOP (12%), 57% of patients were in complete response after R-DHAP. With median follow-up of 67 months, median event-free survival is 83 months, and median overall survival is not reached. Five-year overall survival is 75%. Comparison with a previous study without rituximab shows improvement of outcome (median event-free survival, 51 vs 83 months). No toxic death or unexpected toxicities were observed. This study confirms that induction with rituximab and cytarabine-based regimens is safe and effective in MCL patients. This regimen is currently compared with R-CHOP(21) induction in a multicentric European protocol.

A Mendelian predisposition to B-cell lymphoma caused by IL-10R deficiency.

Monogenic interleukin-10 (IL-10) and IL-10 receptor (IL-10R) deficiencies cause very early onset severe inflammatory bowel disease. Here, we report that 5 patients with an IL-10R1 (n = 1) or IL-10R2 (n = 4) deficiency developed B-cell non-Hodgkin lymphoma between the ages of 5 and 6 years (which was recurrent in 1 patient). These lymphomas had some of the characteristics of diffuse large B-cell lymphomas and contained monoclonal, Epstein-Barr virus-negative germinal center B cells. The tumors displayed a remarkably homogeneous signature, with original activation of the nuclear factor κB pathway and a decrease in intratumor T-cell infiltration. Hence, IL-10R deficiency is associated with a high risk of developing B-cell lymphoma. Our results revealed an unexpected role of the IL-10R pathway in lymphomagenesis.

Immune deficiency-related enteropathy-lymphocytopenia-alopecia syndrome results from tetratricopeptide repeat domain 7A deficiency.

BACKGROUND: Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases, but the underlying molecular mechanisms remain largely unknown. Studies of monogenic diseases can provide insight into the pathogenesis of IBD. OBJECTIVE: We thought to determine the underlying molecular causes of IBD occurring in 2 unrelated families in association with an immune deficiency. METHODS: We performed genetic linkage analysis and candidate gene sequencing on 13 patients from a large consanguineous family affected by early-onset IBD, progressive immune deficiency, and, in some cases, autoimmunity and alopecia, a condition we named enteropathy-lymphocytopenia-alopecia. The candidate gene was also sequenced in an unrelated patient with a similar phenotype. We performed histologic analysis of patients' intestinal biopsy specimens and carried out functional assays on PBMCs. Gut organoids derived from a patient's biopsy specimen were analyzed. RESULTS: We identified biallelic missense mutations in tetratricopeptide repeat domain 7A (TTC7A) in all patients from both families. The resulting TTC7A depletion modified the proliferation, adhesion, and migratory capacities of lymphocytes through inappropriate activation of the RhoA signaling pathway. Normal function was restored by wild-type TTC7A expression or addition of a RhoA kinase inhibitor. The growth and polarity of gut epithelial organoids were also found to be dependent on the RhoA signaling pathway. CONCLUSIONS: We show that TTC7A regulates the actin cytoskeleton dynamics in lymphocytes through the RhoA signaling pathway and is required in both lymphocytes and epithelial cells for maintaining equilibrium between cell proliferation, migration, polarization, and cell death. Our study highlights variability in the phenotypic expression resulting from TTC7A deficiency and outlines that impairment of both epithelial cells and lymphocytes cooperatively causes IBD.

Characterization of Crohn disease in X-linked inhibitor of apoptosis-deficient male patients and female symptomatic carriers.

BACKGROUND: Crohn disease is an inflammatory bowel disease (IBD) with a complex mode of inheritance. Although nucleotide binding and oligomerization domain containing 2 (NOD2) is the strongest risk factor, the cause of Crohn disease remains unknown in the majority of the cases. X-linked inhibitor of apoptosis (XIAP) deficiency causes X-linked lymphoproliferative syndrome type 2. IBD has been reported in some XIAP-deficient patients. OBJECTIVE: We characterize the IBD affecting a large cohort of patients with mutations in XIAP and examine the possible pathophysiologic mechanisms. METHODS: We performed a phenotypical and histologic analysis of the IBD affecting 17 patients with hemizygous mutations in XIAP, including 3 patients identified by screening 83 patients with pediatric-onset IBD. The X chromosome inactivation was analyzed in female carriers of heterozygous XIAP mutations, including 2 adults with IBD. The functional consequences of XIAP deficiency were analyzed. RESULTS: Clinical presentation and histology of IBD in patients with XIAP deficiency overlapped with those of patients with Crohn disease. The age at onset was variable (from 3 months to 41 years), and IBD was severe and difficult to treat. In 2 patients hematopoietic stem cell transplantation fully restored intestinal homeostasis. Monocytes of patients had impaired NOD2-mediated IL-8 and monocyte chemoattractant protein 1 (MCP-1) production, as well as IL-10, in response to NOD2 and Toll-like receptor 2/4 costimulation. Nucleotide binding and oligomerization domain containing 1 (NOD1)-mediated IL-6 and IL-8 production was defective in fibroblasts from XIAP-deficient patients. The 2 heterozygous female carriers of XIAP mutations with IBD displayed abnormal expression of the XIAP mutated allele, resulting in impaired activation of the NOD2 pathway. CONCLUSION: IBD in patients with XIAP deficiency is similar to Crohn disease and is associated with defective NOD2 function in monocytes. Importantly, we report that it is not restricted to male patients because we identified 2 symptomatic female heterozygous carriers of XIAP mutations.

Genetic characterization of congenital tufting enteropathy: epcam associated phenotype and involvement of SPINT2 in the syndromic form.

Congenital tufting enteropathy (CTE) is a rare and severe enteropathy recently ascribed to mutations in the epcam gene. Here we establish SPINT2, previously ascribed to congenital sodium diarrhea, as a second gene associated with CTE and report molecular and immunohistochemistry data in 57 CTE patients. Inclusion criteria were early onset diarrhea and intestinal insufficiency with the typical histological CTE abnormalities. The clinical phenotype was registered, the entire coding regions of epcam and SPINT2 sequenced, and immunostaining of EpCAM and SPINT2 performed on intestinal biopsies. An epcam mutation was involved in 41 patients (73 %) who mainly displayed isolated digestive symptoms. Mutations severely affected gene expression since the EpCAM signal on intestinal tissues was either undetectable or low and irregular. Twelve other patients (21 %) carried mutations in SPINT2, and were phenotypically characterized by systematic association with keratitis (p < 10(-4)) and, for half of them, with choanal atresia (p < 10(-4)). Dependency on parenteral nutrition (PN) was comparable in patients with epcam or SPINT2 mutations, but the frequent epcam mutation c.556-14A>G (abnormal splicing) was significantly associated with a better outcome (p = 0.032) with milder PN dependency to weaning in some cases. Finally, four patients (7 %) with isolated digestive symptoms had no detectable epcam or SPINT2 mutation. Two candidate genes, Elf3 and Claudin7, were excluded from this population. Our study allows us to separate CTE patients into at least three genetic classes, each with specific phenotypes. The genetics approach raises the question of the distinction between two congenital enteropathies. Our findings should help improve the diagnosis of CTE, guide toward strategies of long-term PN management, and limit indications for intestinal transplantation to life-threatening PN complications.

Small intestinal CD4+ T-cell lymphoma is a heterogenous entity with common pathology features.

BACKGROUND & AIMS: Little is known about intestinal CD4+ T-cell lymphoma; this rare malignancy is misdiagnosed frequently. We evaluated diagnostic criteria and factors that might affect its development and outcome. METHODS: In a retrospective analysis, we analyzed medical records and intestinal specimens from 10 patients diagnosed with intestinal CD4+ T-cell lymphoma among 115 consecutive patients examined for severe enteropathy with villous atrophy. Samples were analyzed by histology, flow cytometry, and comparative genomic hybridization. RESULTS: Small-intestine epithelial and lamina propria tissues from patients who presented with chronic diarrhea and malnutrition had variable levels of infiltration of CD3+ CD4+ T cells. Flow cytometry showed a high frequency of CD4+ intraepithelial cells, which frequently expressed a specific Vß chain. T-cell receptor ß clonality was confirmed by DNA sequencing. Two patients had HLA and serology results compatible with celiac disease and autoimmune enteropathy, respectively. Two patients were found to have antibodies against human T-cell leukemia virus and 2 patients had signs of a recent infection with the herpes viruses. Comparative genomic hybridization analyses showed heterogeneous chromosomal abnormalities. Symptoms were reduced in patients treated with steroids (n = 5), but not in patients given purine analogues or chemotherapy. Antibodies against CD52 produced clinical and histologic responses in 2 of 2 patients, whereas severe adverse effects developed in 1 patient. At the latest follow-up evaluation, all patients were alive. CONCLUSIONS: There is much heterogeneity in the onset and genetic features of intestinal CD4+ T-cell lymphomas, despite their common presentation as indolent lymphoproliferations of the intestinal mucosa. Patients should be treated with steroids, and possibly antibodies against CD52 (for the most aggressive forms of this disorder).

High prevalence of BRAF V600E mutations in Erdheim-Chester disease but not in other non-Langerhans cell histiocytoses.

Histiocytoses are rare disorders of unknown origin with highly heterogeneous prognosis. BRAF mutations have been observed in Langerhans cell histiocytosis (LCH). We investigated the frequency of BRAF mutations in several types of histiocytoses. Histology from 127 patients with histiocytoses were reviewed. Detection of BRAF(V600) mutations was performed by pyrosequencing of DNA extracted from paraffin embedded samples. Diagnoses of Erdheim-Chester disease (ECD), LCH, Rosai-Dorfman disease, juvenile xanthogranuloma, histiocytic sarcoma, xanthoma disseminatum, interdigitating dendritic cell sarcoma, and necrobiotic xanthogranuloma were performed in 46, 39, 23, 12, 3, 2, 1, and 1 patients, respectively. BRAF status was obtained in 93 cases. BRAF(V600E) mutations were detected in 13 of 24 (54%) ECD, 11 of 29 (38%) LCH, and none of the other histiocytoses. Four patients with ECD died of disease. The high frequency of BRAF(V600E) in LCH and ECD suggests a common origin of these diseases. Treatment with vemurafenib should be investigated in patients with malignant BRAF(V600E) histiocytosis.

Enteropathy-associated T-cell lymphoma complicating an autoimmune enteropathy.

Enteropathy-associated T-cell lymphoma (EATL) is a rare non-Hodgkin lymphoma frequently associated with celiac disease. We report a case of EATL complicating adult autoimmune enteropathy (AIE). Analysis of phenotype, rearrangements in T-cell receptor genes, and chromosome alterations by high-resolution comparative genomic hybridization identified features distinct from those described for types I and II EATL. Furthermore, EATL arose from a single T-cell clone that had been present for several years in AIE-associated, oligoclonal, intestinal T-cell infiltrate. Emerging T-cell clones should be monitored in patients with AIE who receive long-term immunosuppressive therapy.

Loss of p19Arf in a Rag1(-/-) B-cell precursor population initiates acute B-lymphoblastic leukemia.

In human B-acute lymphoblastic leukemia (B-ALL), RAG1-induced genomic alterations are important for disease progression. However, given that biallelic loss of the RAG1 locus is observed in a subset of cases, RAG1's role in the development of B-ALL remains unclear. We chose a p19Arf(-/-)Rag1(-/-) mouse model to confirm the previously published results concerning the contribution of CDKN2A (p19ARF /INK4a) and RAG1 copy number alterations in precursor B cells to the initiation and/or progression to B-acute lymphoblastic leukemia (B-ALL). In this murine model, we identified a new, Rag1-independent leukemia-initiating mechanism originating from a Sca1(+)CD19(+) precursor cell population and showed that Notch1 expression accelerates the cells' self-renewal capacity in vitro. In human RAG1-deficient BM, a similar CD34(+)CD19(+) population expressed p19ARF. These findings suggest that combined loss of p19Arf and Rag1 results in B-cell precursor leukemia in mice and may contribute to the progression of precursor B-ALL in humans.

Long-term follow up of the FL2000 study comparing CHVP-interferon to CHVP-interferon plus rituximab in follicular lymphoma.

Anti-CD20-containing chemotherapy regimens have become the standard of care for patients with follicular lymphoma needing cytotoxic therapy. Four randomized trials demonstrated a clinical benefit for patients treated with rituximab. However, no long-term follow up (i.e. > 5 years) of these trials is yet available. Between May 2000 and May 2002, 358 newly diagnosed patients with high tumor burden follicular lymphoma were randomized to receive cyclophosphamide, adriamycin, etoposide and prednisolone plus interferon-α2a or a similar chemotherapy-based regimen plus rituximab, and outcome was up-dated. With a median follow up of 8.3 years, addition of rituximab remained significantly associated with prolonged event-free survival (primary end point) (P=0.0004) with a trend towards a benefit for overall survival (P=0.076). The Follicular Lymphoma International Prognostic Index score was strongly associated with outcome for both event-free and overall survival in univariate analysis and its prognostic value remained highly significant after adjusting for other significant covariates in multivariate models (P<0.0001 and P=0.001, respectively). Considering long-term toxicity, the addition of rituximab in the first-line setting was confirmed as safe with regards to development of secondary malignancies. Long-term follow up of patients with follicular lymphoma treated in the FL2000 study confirms the sustained clinical benefit of rituximab without long-term toxicity.

Late-onset post-transplantation lymphoproliferative disorders after kidney transplantation: a monocentric study over three decades.

BACKGROUND: Late-onset post-transplantation lymphoproliferative disorders (PTLDs) occur 1 year after transplantation and are associated with poor prognosis. Initial treatment usually involves a reduction in immunosuppressive treatment. While early-onset PTLDs have a good prognosis following RI, this approach is generally inadequate for late-onset PTLDs. We assessed the specific outcome of late-onset PTLDs after kidney transplantation during the past three decades. METHODS: We reviewed the clinical and biological data of 52 kidney transplant recipients who developed late-onset PTLDs at our centre between 1980 and 2010. We compared clinical features, long-term outcome and renal prognosis of late-onset PTLDs both before and after the era of rituximab. RESULTS: Before 2000, 38% of the patients underwent surgery and 76% received chemotherapy either immediately or after surgery. After 2000, rituximab was administrated to 70% of the patients either alone (23%) or in combination with chemotherapy (77%). Chemotherapy alone was administrated in 26% of the cases. Before and after 2000, complete remission was achieved in 38 and 87% of the cases, respectively (P = 0.0005). The 5-year overall survival (OS) was 33.3 and 69% (P = 0.003), and 5-year disease-free survival was 37.5 and 80%, respectively (P = 0.19). Renal function was preserved in 70% of the cases at the end of the follow-up. CONCLUSIONS: This study shows an increase in OS and low graft loss for patients with late-onset PTLDs during the last decade, which may be attributed to multiple changes in clinical practice, including a more standardized treatment and the use of rituximab in combination with chemotherapy.

Severe cutaneous bacillus Calmette-Guérin infection in immunocompromised children: the relevance of skin biopsy.

Disseminated bacillus Calmette-Guérin infection (BCGitis) is an uncommon condition which is usually associated with primary immunodeficiency. Skin histopathology findings have been described in rare cases only. A retrospective clinicopathological study was performed to assess the potential utility of skin biopsies in the diagnosis, prognosis and follow-up of these patients. Four cases of disseminated BCGitis in children with Severe Combined ImmunoDeficiency were biopsied before and after Haematopoietic Stem Cell Transplantation (HSCT). The results were compared to the clinical and immunological status of the children. Early skin biopsies revealed either dense dermal infiltration by foamy macrophages filled with acid fast bacilli (AFB) or mycobacterial spindle-cell pseudotumors rich in AFB. There were no granulomas. These patterns led to the diagnosis of disseminated BCGitis potentially caused by severe immunodeficiency. After HSCT, repeated skin biopsies were performed on persistent or new cutaneous lesions to rule out immune reconstitution inflammatory syndrome and to check for tuberculoid granulomas. One patient died of BCGitis combined with graft versus host disease. The 3 others presented with progressive-onset well differentiated granulomas over a long period and recovered. Skin biopsy is a useful part of the diagnostic workup for disseminated BCGitis, directing the clinician toward severe immunodeficiency. Moreover, skin biopsy may be a useful means of monitoring immune restoration for prognostic purposes.

Primary T-cell immunodeficiency with immunodysregulation caused by autosomal recessive LCK deficiency.

BACKGROUND: Signals emanating from the antigen T-cell receptor (TCR) are required for T-cell development and function. The T lymphocyte-specific protein tyrosine kinase (Lck) is a key component of the TCR signaling machinery. On the basis of its function, we considered LCK a candidate gene in patients with combined immunodeficiency. OBJECTIVE: We identify and describe a child with a T-cell immunodeficiency caused by a homozygous missense mutation of the LCK gene (c.1022T>C) resulting from uniparental disomy. METHODS: Genetic, molecular, and functional analyses were performed to characterize the Lck deficiency, and the associated clinical and immunologic phenotypes are reported. RESULTS: The mutant LCK protein (p.L341P) was weakly expressed with no kinase activity and failed to reconstitute TCR signaling in LCK-deficient T cells. The patient presented with recurrent respiratory tract infections together with predominant early-onset inflammatory and autoimmune manifestations. The patient displayed CD4(+) T-cell lymphopenia and low levels of CD4 and CD8 expression on the T-cell surface. The residual T lymphocytes had an oligoclonal T-cell repertoire and exhibited a profound TCR signaling defect, with only weak tyrosine phosphorylation signals and no Ca(2+) mobilization in response to TCR stimulation. CONCLUSION: We report a new form of T-cell immunodeficiency caused by a LCK gene defect, highlighting the essential role of Lck in human T-cell development and responses. Our results also point out that defects in the TCR signaling cascade often result in abnormal T-cell differentiation and functions, leading to an important risk factor for inflammation and autoimmunity.

Cutaneous hematologic disorders in children.

BACKGROUND: To determine and list the clinical and pathological features of cutaneous hematologic diseases in childhood. PROCEDURE: We retrospectively analyzed the data for 51 patients up to 15 years of age, who presented with primary cutaneous hematologic disorders according to the WHO-EORTC classification, at Necker-Enfants Malades Hospital, Paris, France, over a 17-year period. The cases were classified into the following diagnostic categories: CD30+ T-cell lymphoproliferative disorders (24) all consisting of lymphomatoid papulosis (LyP, 24), lymphoblastic lymphoma (LL, 7), acute leukemias (AL, 7), mycosis fungoides (MF, 5), Epstein-Barr virus-related lymphoproliferative disorders (EBV-related LPD, 5), T/NK-cell lymphoma, nasal type (1), γ/δ T-cell lymphoma (1), and panniculitis-like T-cell lymphoma (1). RESULTS: We encountered a majority of LyP. No secondary lymphoma was found in LyP patients with a median follow-up of 8 years. 29% and 80% of LyP and MF patients, respectively, presented with pityriasis lichenoides chronica (PLC) before onset of disease. Owing to a frequently misleading clinicopathological presentation, MF patients were first underdiagnosed. Clinicopathological features of LL and AL were highly stereotypical, leading to the diagnosis being suspected and confirmed more promptly. In the latter patients and in EBV-related LPD patients, skin lesions usually led to the discovery of systemic disease. CONCLUSION: Distribution of cutaneous hematologic diseases seems to be different in adults and in children aged <15-year old. PLC was strongly correlated with MF and LyP. Physicians must be made aware of the stereotypical clinical presentations of LL and AL to allow prompt diagnosis and treatment.