Suppressor-cell dysfunction in children with histiocytosis-X

Langerhans cell histiocytosis of the sternum

We report a rare case of Langerhans cell histiocytosis involving the sternum. The patient was a 12-year-old girl presenting with anterior chest pain and swelling. Radiographs and computed tomography showed an osteolytic lesion in the sternum. Technetium bone scintigraphy revealed increased uptakes in the sternum, the greater trochanter of the right femur, and the right distal tibia. Incisional biopsy for the sternum lesion was performed, and the histopathologic diagnosis was Langerhans cell histiocytosis. She was treated with chemotherapy and the symptoms disappeared.

Langerhans cell histiocytosis patients have HLA Cw7 and DR4 types associated with specific clinical presentations and no increased frequency in polymorphisms of the tumor necrosis factor alpha promoter

BACKGROUND

Current theory on the etiology of Langerhans cell histiocytosis (LCH), formerly Histiocytosis-X, is that abnormality(ies) of the immune system are responsible for dysregulation of Langerhans cells (LC) in patients' lesions. Among the known abnormalities in LCH patients are increased amounts of tumor necrosis factor alpha (TNF-alpha) and other cytokines in the lesions.

PROCEDURE

We investigated the human leukocyte antigen (HLA) phenotypes of 29 patients and 37 healthy family members to determine if any haplotypes segregate with the presence or locations of the disease. The lymphocyte subsets for 22 patients and 11 family members were also determined.

RESULTS

Patients with single bone, multiple bone, or multi-system LCH had different relative proportions of HLA types. Patients presenting with single bone disease had an especially high frequency of the DR4 type. In this patient group, every Caucasian patient had either Cw7 or DR4. Lymphopenia was documented in patients who had been off therapy as well as those who only had surgical curetage of their lesions. Family members also had low numbers of T lymphocytes. There were fewer mutations of the TNF-alpha promoter in patients than in the general population.

CONCLUSIONS

Although there is an increased percentage of LCH patients with DR4 and/or Cw7 there was also an increased prevalence of this antigen as well as lymphopenia among unaffected family members. Additional genetic and/or environmental factors are necessary to explain this association. TNF-alpha promoter mutations are not responsible for the increased production of this cytokine.

Immunogenetic heterogeneity in single-system and multisystem langerhans cell histiocytosis

Langerhans cell histiocytosis is a rare disease with an unknown etiology and poorly understood pathogenesis. Immunologic, viral, and proliferative clonality causes have all been considered. To determine whether Langerhans cell histiocytosis and its two main subgroups, single-system and multisystem disease, are associated with HLA-A, -B, -Cw, or -DR alleles, a total of 84 patients <15 y of age at the time of diagnosis and of Nordic origin were analyzed, 82 for HLA class I and 76 for HLA class II. Stratification of the patients into two subgroups, single-system disease (skin only, and monostotic and polyostotic disease) and multisystem disease with or without organ dysfunction, showed that patients with single-system disease (17 of 45, 38%) more often (p = 0.00018 and, after correction, p = 0.029) had the phenotype HLA-DRB1*03 compared with patients with multisystem disease (1 of 31, 3%). In the patients with multisystem disease a nonsignificant reduction of the frequency of this phenotype was seen compared with controls (p = 0.02, uncorrected). In 14 of the patients with single-system disease, but none with multisystem disease, the deduced haplotype HLA-A*01, B*08, DRB1*03 was found. High-resolution typing, performed in nine patients, revealed that all had the HLA-A*0101, B*0801, DRB1*0301, DQB1*0201 alleles. Our findings suggest an immunogenetic heterogeneity in the two clinical entities of Langerhans cell histiocytosis and indicate that HLA-DRB1*03 may play a protective role against developing multisystem disease. Further studies to confirm these findings are desired.

Eosinophilic granuloma of the bilateral temporal bone

An unusual presentation of eosinophilic granuloma (EG) of the bilateral temporal bone in a 2-year-old male child is discussed with the literature review. Involvement of the temporal bone is relatively uncommon and otorrhea or symptoms resembling mastoiditis are nonspecific. This rare condition should be kept in mind in differential diagnosis of otitis media refractory to medical therapy.

The epidemiology of Langerhans cell histiocytosis

Little progress has been made in finding the causes of LCH. Epidemiologic studies are difficult because of the rarity of this disease. Although several associations have been demonstrated in case-control studies, particularly that with thyroid disease, no causal relationships have been documented. Additional case-control studies may uncover the to-date missing lead that may prove fruitful for epidemiologic investigation.

Langerhans cell histiocytosis: an exploratory epidemiologic study of 177 cases

There is little information available regarding epidemiologic risk factors for Langerhans cell histiocytosis (LCH). An exploratory investigation was conducted using information obtained from parents of 177 cases of LCH diagnosed before 21 years of age (median 2 years). Utilizing data available from the Children's Cancer Group, LCH cases were compared to two matched control groups including 614 patients diagnosed with a variety of childhood cancers and 318 community controls. Questionnaire data included information on demographics, prenatal and perinatal factors, complications in the neonatal period, environmental exposures, family medical history, and childhood exposures. Factors found to be statistically significantly associated with an increased risk of LCH included: maternal urinary tract infection during the index pregnancy, feeding problems during infancy, and blood transfusions during infancy. Use of supplemental vitamins was associated with a significantly decreased risk of LCH. Results from this exploratory study provide a basis for speculation on potential etiologic risk factors for LCH. Future epidemiologic investigations of LCH need to consider the presenting disease characteristics in assessing possible etiologic factors.

Interferon-alpha in childhood haematological malignancies

The application of cytostatics has brought about a breakthrough in the treatment of childhood haematological malignancies in the past 20 years. Chemotherapy appears to be least successful in the rare, low and very high mitotic index diseases, which often have an enormous tumour-burden. The suitability of chemotherapy in minimal residual leukaemia is also of some doubt. In these situations a 'conservative' treatment may be more appropriate. Because interferon-alpha has a distinct mechanism of action, and a broad-spectrum haematopoietic inhibitory activity, it is relatively nontoxic and noncancerogenic, and it may have a role in the treatment of malignant haematological disorders, either as a mono- or combination therapy. The exact indications and dosages for interferon in childhood malignancies are far from clear. Up to now, it has proved to be most efficacious in small tumour masses, providing a theoretical basis for application in minimal residual disease. Controlled clinical data, however, are not yet available. It remains to be determined whether or not interferon can be added to current chemotherapy protocols without a significant reduction of dose. Hopefully, a deeper understanding of the activities of interferon will allow us to plan better trials with combination treatments.

The histiocytoses of childhood

The histiocytoses of childhood include Langerhans' cell histiocytosis, haemophagocytic syndrome (familial and reactive), sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease), juvenile xanthogranuloma and malignant histiocytosis. These disorders show wide variation in their clinical presentation, prognosis and genetic implications. All are characterized by localized or generalized proliferation of histiocytes, but they differ in their morphology, histochemical and immunochemical staining patterns and electronmicroscopical features. On the basis of a comprehensive clinical history and critical interpretation of morphology and immunocytochemistry using an appropriately selected panel of antibodies, a diagnosis can be reached in the majority of cases.

Con A-induced suppressor cell function depends on the activation of the CD4+CD45RA inducer T cell subpopulation

Human T cells incubated for 48 hr with Con A suppress B cell Ig production. We sought to define the interactions between CD4+ T cells and CD8+ T cells in the generation of suppressor cell activity following Con A stimulation. Con A-activated CD4+ inducer T cells suppressed Ig production in autologous cocultures of T cells and B cells by 84%, while PHA-activated CD4+ T cells could not. However, Con A-activated CD4+ T cells are not themselves suppressors. When Con A-activated CD4+ T cells were added to coculture of B cells plus T cells depleted of CD8+ T cells, no suppression of Ig production was observed. Furthermore, these Con A-activated CD4+ T cells were able to provide excellent help for Ig production. Therefore, Con A-induced suppressor cell function requires a CD4+ suppressor/inducer acting on a CD8+ suppressor/effector ultimately resulting in the down regulation of B cell Ig synthesis. Human CD4+ inducer T cells can be functionally dissected into helper/inducer or suppressor/inducer T lymphocytes based on their expression of either the CDw29 or CD45RA surface molecules, respectively. Following incubation with Con A the expression of CD45RA on CD4+ T cells increased from 34 to 80% (P = 0.001) while CDw29 expression was unchanged. Incubating lymphocytes with PHA resulted in a non-specific increase in both CD45RA and CDw29 expression by CD4+ T cells. The increase in CD4+CD45RA expression was a result of active proliferation by the Con A-stimulated T cells. Suppression of Ig secretion was directly correlated with the enhanced CD45RA expression following Con A activation. We demonstrate that enhanced suppressor/inducer function is unique to Con A stimulation and was not observed following activation by PHA. Furthermore, short-term culture with Con A results in the selective expansion of the CD4+CD45RA T cell subpopulation.

Eosinophilic granuloma of the temporal bone: radiological approach in the pediatric patient

Eosinophilic granuloma is one of the three clinical variants of Histiocytosis-X (eosinophilic granuloma, Hand-Schüller-Christian and Letterer-Siwe disease). Involvement of the temporal bone is relatively rare and initially silent. However, it can erode the mastoid cortex, destroy the tegmen and extend into the cranial vault, as well as erode the semicircular canals or cochlea. It usually presents as an aural polyp or postauricular swelling. Chronic otorrhea is what brings the patient to the ORL-Clinic. It is frequently confused with infectious diseases or neoplastic conditions of the temporal bone. In this paper we report 6 cases of eosinophilic granuloma in the temporal bone, discuss the plain radiological and CT findings and review the literature.