Langerhans' cell histiocytosis diagnosed due to dermatological perianal lesion / Histiocitose de células de Langerhans diagnosticada por lesão perianal dermatológica

Abstract Langerhans' cell histiocytosis is a rare disease characterized by proliferation of Langerhans cells in the body. It affects mainly males, predominantly in childhood. Ulcerated plaques are one of the cutaneous forms of presentation. Diagnostic confirmation is done through immunohistochemistry. As therapeutic options, topical corticosteroids and chemotherapy are good choices. The case is reported of a male patient, aged 14, with perianal ulceration. He consulted a coloproctologist, who performed a biopsy of the region and started local triamcinolone applications. Immunohistochemistry diagnosed Langerhans' cells histiocytosis. Further investigation revealed diabetes insipidus, osteolytic lesions in the skull and lower limbs, enlarged liver, and encephalic alterations. Chemotherapy was started with Vinblastine, with significant improvement of the lesions.

Resumo A histiocitose de células de Langerhans é uma doença rara caracterizada pela proliferação de células de Langerhans no corpo. A doença afeta principalmente os homens, predominantemente na infância. Placas ulceradas são uma das formas cutâneas de apresentação. A confirmação diagnóstica é feita através de análise imuno-histoquímica. Como opções terapêuticas, corticosteroides tópicos e quimioterapia são boas escolhas. O caso aqui relatado é de um paciente do sexo masculino, com idade de 14 anos, com ulceração perianal. Ele consultou um coloproctologista, que realizou uma biópsia da região e iniciou o tratamento com aplicações locais de triancinolona. A análise imunohistoquímica diagnosticou histiocitose de células de Langerhans. Outros exames revelaram diabetes insipidus, lesões osteolíticas no crânio e nos membros inferiores, aumento do fígado e alterações encefálicas. A quimioterapia foi iniciada com vimblastina, com melhora significativa das lesões.

Histiocitose de células de Langerhans: relato de um caso / Langerhans cell histiocytosis: case report

A histiocitose de células de Langerhans corresponde a um grupo heterogêneo de desordens caracterizadas pela proliferação monoclonal de células dendríticas. Predomina na infância e pode afetar qualquer órgão. Relata-se caso de paciente, sexo feminino, 44 anos, apresentando placas espessas, exsudativas, com escamas aderentes aos pelos, localizadas no couro cabeludo, semelhantes a dermatite seborreica, além de fístulas nas axilas, regiões inframamárias e inguinais de evolução há 16 anos. Realizou-se biópsia da lesão cutânea seguida de imunohistoquímica que concluiu diagnóstico de Histiocitose de células de Langerhans. Investigação sistêmica evidenciou acometimento pulmonar concomitante. Até o presente momento existem poucas publicações sobre envolvimento cutâneo em adultos, assim como não há protocolos de tratamento para os mesmos, necessitando maiores estudos para melhor manejo desses pacientes.

Langerhans cell histiocytosis corresponds a heterogeneous group of disorders characterized by monoclonal dendritic cells proliferation, it predominates in childhood which may affect any organ of the body. The case reports of a female patient, aged 44, presenting thick plates with scales adhering to the hairs, scalp located, similar to seborrheic dermatitis, besides fistulas in axillas, inguinal and infra mammary regions. The hypothesis of Langerhans cell histiocytosis was confirmed by cutaneous biopsy and immunohistochemistry. Systemical investigation accused pulmonary involvement. Until now are few publications about adult cutaneous cases, so none treatment protocols are avaible for them. More specific studies are demanded for better management of these patients.

The Implication and Significance of Beta 2 Microglobulin: A Conservative Multifunctional Regulator / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>This review focuses on the current knowledge on the implication and significance of beta 2 microglobulin (β2M), a conservative immune molecule in vertebrate.</p><p><b>DATA SOURCES</b>The data used in this review were obtained from PubMed up to October 2015. Terms of β2M, immune response, and infection were used in the search.</p><p><b>STUDY SELECTIONS</b>Articles related to β2M were retrieved and reviewed. Articles focusing on the characteristic and function of β2M were selected. The exclusion criteria of articles were that the studies on β2M-related molecules.</p><p><b>RESULTS</b>β2M is critical for the immune surveillance and modulation in vertebrate animals. The dysregulation of β2M is associated with multiple diseases, including endogenous and infectious diseases. β2M could directly participate in the development of cancer cells, and the level of β2M is deemed as a prognostic marker for several malignancies. It also involves in forming major histocompatibility complex (MHC class I or MHC I) or like heterodimers, covering from antigen presentation to immune homeostasis.</p><p><b>CONCLUSIONS</b>Based on the characteristic of β2M, it or its signaling pathway has been targeted as biomedical or therapeutic tools. Moreover, β2M is highly conserved among different species, and overall structures are virtually identical, implying the versatility of β2M on applications.</p>

Clinical and pathologic characteristics of Erdheim-Chester disease / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore the clinicopathologic features, immunophenotype, differential diagnosis and gene mutation status of the Erdheim-Chester disease (ECD).</p><p><b>METHODS</b>Clinical and pathologic findings of 3 ECD cases were examined by gross, microscopic, immunohistochemical methods and BRAF V600E mutation. Related literatures were reviewed.</p><p><b>RESULTS</b>Two male patients and one female patient presented clinically with multiple skin nodules, bone pain and bony lesions by imaging study. Microscopically, the lesions were composed of spindle-shaped fibroblasts, foamy histiocytes and scattered Touton-type giant cells embedded in reactive fibrous tissue. Lymphocytes, plasma cells, and multinucleated giant cells were also found. Immunohistochemically, all histiocytes were positive for CD68, none of which expressed CD1a, although 2 cases focally expressed weak S-100 stain. In 2 cases,BRAF V600E mutation was detected.</p><p><b>CONCLUSIONS</b>ECD is a rare disease of xanthogranulomatous histiocytosis.Its diagnosis relies on pathological and immunohistochemical findings, but correlation with clinical information, especially radiographic findings should be performed.No effective treatment of the disease is currently available.</p>

Colonic Langerhans Cell Histiocytosis Presenting as an Isolated Polyp / 대한내과학회지

A 56-year-old male underwent a screening colonoscopy. An 8-mm sessile polyp was removed from the descending colon using snare polypectomy. Histology showed Langerhans cells and eosinophil infiltration of the submucosa. Immunohistochemical staining was positive for S-100 protein and CD1a antigen, which confirmed the diagnosis of Langerhans-cell histiocytosis. On further workup, there was no evidence of involvement of any other organs. Here, we report a very rare case of colonic Langerhans-cell histiocytosis presenting as an isolated polyp.

Langerhans cell histiocytosis: a clinicopathologic and immunohistochemical analysis of 258 cases / 中华病理学杂志

<p><b>OBJECTIVES</b>To observe the clinicopathologic features of Langerhans cell histiocytosis (LCH), and to evaluate the values of langerin, CD1a and S-100 protein expression in diagnosis of the tumor.</p><p><b>METHODS</b>Total 258 cases of Langerhans cell histiocytosis in the past 18 years (from 1992 to 2008) were collected, morphologic review and immunohistochemical staining were performed.</p><p><b>RESULTS</b>In all 258 cases, the ages of patients older than 16 years or younger than 2 years were 126 (48.8%) and 37 (14.3%), respectively, in the remaining 95 (36.8%) of the cases, the age of the patients ranged from 2 to 16 years. For all of 258 cases, there were 364 diseased sites. Bony lesions accounted for 77.2% (281 cases), especially the skull (112 cases, 39.9%), followed by lymph node (25 cases, 6.9%) and skin (14 cases, 3.8%). Clinically, unisystem or unifocal disease was predominant (201 cases, 77.9%), followed by unisystem and multifocal disease (21 cases, 8.1%), multi-system disease (26 cases, 10.1%), isolated pulmonary LCH (2 cases, 0.8%), and unclassified (8 cases, 3.1%). Histologically, variable number of Langerhans cells was present in 265 samples of 258 cases. Multinucleated giant cells were found in 166 (62.6%) of the samples. Eosinophils were the major infiltrating non-neoplastic cells, and eosinophilic abscess was seen in 57 cases (21.5%). Coagulative necrosis and dead bone were detected in 29 (10.9%) and 124 (46.8%) of the cases, respectively. Immunohistochemically, the expression of S-100 protein, CD1a and langerin was 99.1% (209/211), 100% (206/206) and 98.5% (193/196), respectively, and the sensitivity of them had no statistical difference.</p><p><b>CONCLUSIONS</b>In this group of LCH cases, the ratio of adult patients is high, but the proportion of multi-organ lesion is low. No significant difference of the sensitivity is found among langerin, CD1a and S-100 expression in diagnosis of LCH.</p>

Retículo-histiocitose congênita autolimitada em recém-nascido (Hashimoto- Pritzker) / Congenital self healing reticulohistiocytosis in a newborn (Hashimoto Pritzker)

A retículo-histiocitose congênita autolimitada é o espectro benigno das histiocitoses de células de Langerhans, caracterizada pela presença de lesões cutâneas ao nascimento ou no período neonatal, ausência de manifestações sistêmicas e resolução espontânea do quadro clínico. Apesar do curso benigno e frequente autorresolução na maior parte dos pacientes, estudos mostram que, em alguns casos, pode haver disseminação ou recaída da doença, enfatizando que o curso clínico é variável, havendo necessidade de seguimento em longo prazo. O acompanhamento do paciente por longo período é importante para detectar possível envolvimento sistêmico, pois existe relato de recorrência, envolvendo pele, mucosa, ossos e glândula pituitária.

Congenital self-healing reticulohistiocytosis is the benign spectrum of Langerhans Cell Histiocytosis, characterized by cutaneous lesions at birth or in the neonatal period, absence of systemic manifestations and spontaneous resolution of clinical status. Despite the benign and often self-resolving course in most patients, studies show that in some cases there may be metastasis or recurrence of the disease, emphasizing that the clinical course is variable, requiring long-term follow-up. The monitoring of the patient for a long period is important to detect possible systemic involvement, as there is a report of recurrence involving the skin, mucosa, bone and pituitary gland.

Immunological study of expression of CD1 in preimplantation and midgestation mouse embryo cells and placental trophoblasts and the role of decidual natural killer T cells at the feto-maternal interface

Expression of major histocompatibility complex molecules in the preimplantation embryo is important for control of development and immune recognition of the embryo by the mother. Four types of major histocompatibility complex class I molecules that have been identified are as follows: class Ia, class Ib, class Ic, and class Id. Expression of class Ic and class Id antigens in preimplantation embryos has not yet been fully evaluated. Cluster of differentiation 1 [CD1] molecule is a member of class Id antigen. Localization and regulation of CD1 expression remain unclear. The aim of this study was to detect expression of the CD1 molecule in a preimplantation mouse embryo at two-cell, four-cell, eight-cell, and blastocyst stages and in the embryo cells and placental trophoblasts at 10 days of gestation. Detection of invariant natural killer T [iNKT] cells in the decidua at the site of attachment of the placenta was also investigated. Mice of the C57BL/6 genetic background were used. Forty-eight female and 16 male mice of 10-12 weeks of age were divided into two groups. Group 1 included 24 female and eight male mice. Eight breeding colonies were constructed in which each cage contained one male and three female mice. The pregnant female mice were killed at 36, 48, 60, and 80 h of appearance of the vaginal plug to collect two-cell, four-cell, eight-cell, and blastocyst stages of embryos, respectively. The embryos were then processed for immunohistochemistry. Group 2 animals included 24 female and eight male mice. Eight breeding colonies were constructed in which each cage contained one male and three female mice. The pregnant female mice were killed at 10 days of gestation when embryo cells, placental cells, and decidual cells were isolated and processed for culturing and immunohistochemistry. This study showed no expression of CD1 molecules in any of the preimplantation mouse embryo stages till the blastocyst stage, but were detected on the cell surface and inside the cytoplasm of embryo cells and placental trophoblasts at 10 days of gestation. A high proportion of iNKT cells was also detected in the decidua at the site of attachment of the placenta. The CD1 molecule is not actively involved in the regulation of early development of embryo till the blastocyst stage, and the true biological role of CD1 in preimplantation development remains to be determined. However, it may play a role in the placenta and in embryo development during midgestation by preventing lysis of fetal and placental cells through an interaction with decidual iNKT cells at the feto-maternal interface

The expression of S-100 protein, CD1a, CD83 and Ki-67 in oral Langerhans cell histiocytosis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study clinicopathological features, diagnosis, differential diagnosis of oral Langerhans cell histiocytosis (LCH), retrospective clinicopathologic study was carried on and a variety of immune phenotype were detected.</p><p><b>METHODS</b>The clinicopathological features of 29 cases of oral LCH were analyzed. The immunohistochemical staining of S-100 protein, CD1a, CD83 and Ki-67 were used in above cases by immunohistochemical streptavidin-biotin peroxidase (SP) and Elivison two-step method. Statistical analysis was adopted for the results.</p><p><b>RESULTS</b>Of the 29 cases of LCH, the expression of S-100 protein and CD1a were positive in 24 cases and negative in 5 cases, so 5 cases were excluded from the diagnosis of LCH. Among 24 cases of LCH, 15 patients were male and 9 were female. The median age was 7.50 years. 14 lesions were in the mandible, 5 were in the maxilla and 5 involved the mandible and maxilla. 9 cases were in stage I, 13 in stage II and 2 in stage III, according to Bartnick classification. Immunohistochemistry showed all 24 cases staining for S-100 protein and CD1a were positive. Comparing with maxillofacial lesions involved soft tissue, Ki-67 positive rate was lower and CD83 positive rate was higher in maxillofacial single bone lesion.</p><p><b>CONCLUSION</b>The immunohistochemical staining of S-100 protein and CD1a are important for the diagnosis of LCH. Maxillofacial bone single LCH might have lower proliferative activity and a higher state of maturity. Maxillofacial LCH involved soft tissue might have a higher proliferative activity and a lower state of maturity.</p>

Langerhans Cell Sarcoma Arising in a Lymph Node: A Case Report and Review of the Literature

We report a case of Langerhans cell sarcoma presented as a solitary mass in the left supraclavicular area in a 31-year-old woman. Computed tomography revealed a relatively well-defined and lightly enhancing mass in the left supraclavicular area, measuring 5.5x4.5x3.2 cm. Excision was subsequently performed. Microscopically, the specimen consisted of an enlarged and partially effaced lymph node. Nests of different size composed of atypical tumor cells were located in the paracortex and the medulla of the lymph node. The tumor cells exhibited abundant eosinophilic or clear cytoplasm and displayed marked nuclear atypia and increased mitotic figures. Infiltration of many eosinophils was identified in the periphery and between the tumor cells. The tumor cells were reactive for CD1a and S100 protein. Ultrastructually, they were found to have Birbeck granules in the cytoplasm.

E-cadherin and CD1a expression in gingival epithelium in periodontal health, disease and post-treatment.

Background: Epithelial integrity is important for maintenance of periodontal health. It is not fully known if non-surgical periodontal therapy is capable of recreating the epithelial barrier in its functional state. Patients and Methods: Sixty-five patients (31 males and 34 females) were included in the study. They were divided into group A (healthy gingiva 16 patients), group B (gingivitis 17 patients), group C (periodontitis 17 patients), and group D (post-treatment 15 patients). Gingival samples were collected and immunohistochemical study was done using E-cadherin and CD1a antibody. Statistical analysis was done using analysis of variance (ANOVA), followed by Tukey-Kramer multiple comparison test for CD1a and Tukey's highly significant difference (HSD) test for E-cadherin. Result: There was a statistically significant difference (P<0.001) in the expression of E-cadherin between healthy (1.846±0.555), gingivitis (1.100±0.994), and periodontitis group (0.700±0.483). Similarly, there was a statistically significant difference (P<0.001) in the expression of CD1a between healthy (75.70±3.09), gingivitis (42.53±3.09), and periodontitis group (29.07±3.08). However, the expression of E-cadherin (1.242±0.653) and CD1a in post-treatment samples (52.18±2.90) was lower with no statistically significant difference when compared to health. Discussion: The significant reduction in E-cadherin and CD1a levels in periodontal disease when compared to health could possibly be a result of invasion by the periodontopathogens and its subsequent sequel. Although, the post-treatment samples showed significant improvement when compared to disease, the reduction in E-cadherin and CD1a levels when compared to gingival health suggests that the epithelial barrier was not yet fully established in its functional state.

Density of Langerhans cells in the keratocystic odontogenic tumor / Densidade das células de Langerhans no tumor odontogênico queratocístico

INTRODUCTION: Keratocystic odontogenic tumors (KOTs) are distinct odontogenic lesions commonly affecting the mandible bones. Langerhans cells (LCs) are specialized dendritic cells responsible for the presentation of antigens to T lymphocytes in mucosal and cutaneous surfaces. OBJECTIVE: This study analyzed the immunohistochemical expression of LCs in KOTs. MATERIALS AND METHODS: Fifteen cases of KOTs were studied using the anti-CD1a marker. Results: LCs were observed in all 15 cases analyzed. They were found to be concentrated in areas of cystic epithelial hyperplasia, mainly in those areas presenting higher concentration of inflammatory cells. Furthermore, a significant association between the number of LCs and areas of cystic epithelium presenting hyperplasia (Mann-Whitney test, p = 0.0223) was observed. The shape and location of these cells in KOTs epithelium were variable. CONCLUSION: The lower number of LCs observed on atrophic cystic epithelium of KOTs may be due to decreased epithelial immunosurveillance and this may result in locally aggressive invasiveness.

INTRODUÇÃO: Tumor odontogênico queratocístico (TOQ) é uma lesão odontogênica de caráter distinto que afeta frequentemente ossos maxilares. Células de Langerhans (CLs) são células dendríticas especializadas, responsáveis pela apresentação de antígenos aos linfócitos T nas superfícies cutânea e mucosa. OBJETIVO: Este estudo analisou a expressão imuno-histoquímica das CLs em lesões de TOQ. MATERIAIS E MÉTODOS: Quinze casos de TOQ foram estudados utilizando o marcador anti-CD1a. RESULTADOS: As CLs foram observadas em todos os 15 casos analisados. Essas células estavam concentradas em áreas de hiperplasia do epitélio cístico, especialmente naquelas que apresentavam alta concentração de células inflamatórias. Em adição, foi encontrada associação significativa entre número de CLs e áreas do epitélio cístico que apresentavam hiperplasia (Mann-Whitney test, p = 0.0223). O formato e a localização dessas células no epitélio dos TOQs foram variáveis. CONCLUSÃO: O menor número de CLs encontrado no revestimento cístico atrófico dos TOQs pode ser atribuído à imunovigilância deficiente e isso pode resultar em comportamento biológico localmente agressivo.

Quantitative differentiation of dendritic cells in lung tissues of smokers with and without chronic obstructive pulmonary disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Chronic obstructive pulmonary disease (COPD) is thought to be an inflammatory immune response disease. In most cases, the disease is caused by cigarette smoke, but it has been demonstrated that only 10% to 20% of smokers will definitely suffer from COPD. Dendritic cells (DCs) are considered to be the promoter of immune responses. However, the underlying mechanisms involved are still unrevealed. In this study, we aimed to investigate the quantitative differentiation of pulmonary DC in smokers with or without COPD to explore the possible role of DCs in smokers suffering COPD.</p><p><b>METHODS</b>Peripheral lung specimens from non-smokers without airflow obstruction (control group, n = 7), smokers without airflow obstruction (smoker group, n = 7) and patients with COPD (COPD group, n = 7) were investigated to detect the quantity of S-100 and CD1a positive cells by immunohistochemical or immunofluorescent assay.</p><p><b>RESULTS</b>In smokers with COPD, the number of S-100(+) DCs was higher than in the controls and smokers without COPD (P < 0.01 and P < 0.05) and there was a higher number of S-100(+) DCs in smokers with COPD than in smokers without COPD, but without a significant difference (P > 0.05). An inverse correlation was found between the number of DCs and forced expiratory volume in the first second (FEV(1))% pred (r = -0.75, P < 0.05), which was also found between the number of DCs and FEV(1)/forced vital capacity (FVC) (r = -0.72, P < 0.05). The mean number of CD1a(+) DCs, increased from non-smokers to non-COPD smokers to COPD patients, with significant differences between each group (P < 0.01).</p><p><b>CONCLUSIONS</b>The quantity of DCs significantly increased in smokers with COPD compared with non-smokers or smokers without COPD. The results suggest that DCs may play an important role in the pathogenesis of smoking-induced COPD, and the upregulation of DCs may be a potential maker to identify the smokers who have more liability to suffer from COPD.</p>

role of GM-CSF in the generation of CD1a positive cells in vitro by JMML patients

Juvenile myelomonocytic leukemia [JMML] is a rare myeloproliferative disorder of childhood. It was recently demonstrated that mononuclear cells from spleen, peripheral blood and bone marrow of the patients with JMML proliferate in vitro and population of the cells differentiate within 7 days to the CD1a positive dendritic cells. In the present study, the role of GM-CSF in the proliferation and differentiation of the JMML cells in vitro was investigated. MNC from patients with JMML was cultured for 7 days in RPMI/10%FCS and 1% penicillin-streptomycin. The phenotype of the cultured cells was determined at day 7 using antibodies against Ki-67, CD1a, CD14 and CD68. GM-CSF concentration was first measured at days 1, 3, 5 and 7 in the supernatants of the cultured mononuclear cells from two patients with JMML. To study the roll of GM-CSF in JMML cultures, GM-CSF activity was neutralized using monoclonal antibody [Ab] against human GM-CSF in different concentrations [0.05 micro g/ml, 0.5 micro g/ml, 5 micro g/ml and 10 micro g/ml]. The effect of neutralizing antibody was determined at day 7 in treated and untreated cultures by immunostaining using antibodies against Ki-67, CD68, CD1a and CD14. The expression of GM-CSF, GM-CSFR, TNF-alpha, IFN-alpha and SCF was also determined at day 7 in mononuclear cells treated and untreated cultures by RT-PCR. GM-CSF neutralization led to decrease of the total cell number. Additionally, neutralization of GM-CSF decreased in dose dependent manner the number of CD1a, CD14 and Ki-67 positive cells in JMML cultures, whereas the percentage of CD68 remained unchanged. The expression of GM-CSF, GM-CSFR, TNF-alpha and SCF could be demonstrated at the mRNA level in the antibody treated and untreated culture as well. GM-CSF plays an important role in the proliferation and differentiation of JMML cells into the CD1a and CD14 positive cells

Expressions of CD1a and CD83 of Langerhans cells in the local lesions of epidermodysplasia verruciformis patients / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the expressions of CD1a and CD83 of Langerhans cells (LC) in the lesions of epidermodysplasia verruciformis (EV) patients.</p><p><b>METHODS</b>We used immunohistochemical method to detect the expressions of CD1a and CD83 in the lesions of 10 patients with EV lesions and in the skins of 10 normal subjects.</p><p><b>RESULTS</b>No CD83 + LCs was detected in all EV patients and normal controls, but CD1a + LC was found in all cases. The quantity of CD1a + LCs in the lesions of EV patients was significantly lower than that in the normal skin (P < 0.01); furthermore, the distribution of LCs in EV lesions was uneven.</p><p><b>CONCLUSION</b>The functions of LCs may be inhibited in EV patients.</p>

Effect of simian vacuolating virus 40 on development and differentiation of dendritic cells from Rhesus macaque / 病毒学报

To study the effect of simian vacuolating virus 40 (SV40) on development and differentiation of dendritic cells (DC) from rhesus macaque, the peripheral blood-derived dendritic cells from rhesus monkey were pulsed with inactivated SV40 and infective SV40, respectively at the 5th day post DC cultivation. Expressions of CD1a, HLA-DR, CD86 and CD83 on the cell surface at the 7th, 9th day post DC cultivation were analyzed by flow cytometry (FCM). The results showed that expressions of CD1a, HLA-DR, CD86 and CD83 on the cell surface in the inactivated SV40-pulsed experimental group were higher than those in the infective SV40-pulsed experimental group (P < 0.05). These cell surface molecules represented characteristic development and differentiation phase of DC. Down-regulation of expressions of these cell surface molecules indicated that infective SV40 might hamper differentiation and maturation of dendritic cells from rhesus monkey.

Juvenile myelomonocytic leukemia [JMML] cells spontaneously differentiate into dendritic cell like populations in vitro

Juvenile myelomonocytic leukemia [JMML] is a rare myelodysplastic/ myeloproliferative malignancy of early childhood, characterized by monocytosis, hepatosplenomegaly and an aggressive clinical course. semi-solid culture JMML progenitor cells proliferate spontaneously into colony forming units. In order to study the mechanisms of proliferation and differentiation of JMML cells we developed a suspension culture system without additional exogenous growth factor supplement. Mononuclear cells [MNC] from peripheral blood, bone marrow or spleen of 14 patients with JMML and 24 controls were studied. JMML cells expressed higher levels of the proliferation marker Ki67 [median 24% [7-39%] vs a median of 3.5% in controls]. 90% of JMML cells were CD68-positive [vs 35% in controls] and by day 7 all JMML samples contained CD1a- positive cells. Electron microscopy demonstrated cytoplasmic vesicular structures resembling multilamellar MHC II compare-timents, which together with the expression of CD1a - support a dendritic cell [DC]-phenotype. Differentiation into CD1a-positive DC seems to be a frequent phenomenon in cultured JMML MNC, which in vivo may contribute to clinical characteristics such as skin and organ infiltration

Generalized asymptomatic red nodules in a 21-year old Filipino male

A 21 year old Filipino male presented with swelling of the second right hand digit unresponsive to antibiotics. Amputation revealed chronic inflammation and negative cultures. He developed sterile conjunctivitis and a generalized eruption of asymptomatic red papules and nodules. First skin biopsy revealed a diffuse infiltrate of epithelioid and foamy histiocytes, diagnosed as "juvenile xanthogranuloma." The second biopsy revealed large histiocytes with a "ground-glass" eosinophilic cytoplasm, multinucleated giant cells, and mixed cell infiltrate. Immunohistochemistry showed histiocytes staining with (+)S100 and (+)CD68, and (-)CD1a. Final diagnosis was "multicentric reticulohistocytosis." Despite treatment with oral prednisone, methotrexate and alendronate, lesions were progressive. CONCLUSION: This fascinating case manifests with overlapping features of both juvenile xanthogranuloma and multicentric reticulohistiocytosis, and lead the authors to suggest considering the spectrum of diseases called the non-Langerhans cells histiocytosis when presented with a generalized nodular eruption.

Interstitial and Langerhans' dendritic cells in chronic periodontitis and gingivitis

The aim of the present study was to compare quantitatively the distribution of dendritic cell subpopulations in chronic periodontitis and gingivitis. Fourteen biopsies from patients with chronic periodontitis and fifteen from patients with gingivitis were studied. An immunoperoxidase technique was used to quantify the number of Langerhans' cells (CD1a) and interstitial dendritic cells (factor XIIIa) in the oral and sulcular and junctional/pocket epithelia and in the lamina propria. A greater number of factor XIIIa+ dendritic cells in the lamina propria and CD1a+ dendritic cells in the oral epithelium were observed in gingivitis compared to the periodontitis group (p = 0.05). In the sulcular and junctional/pocket epithelia and in the lamina propria, the number of CD1a+ dendritic cells was similar in the gingivitis and periodontitis groups. In conclusion, the number of Langerhans' cells in the oral epithelium and interstitial dendritic cells in the lamina propria is increased in gingivitis compared to periodontitis, which may contribute to the different pattern of host response in these diseases.