Mycosis fungoides, a rare form of cutaneous T cell leukemia/lymphoma, is suspected of having a viral etiology on the basis of certain similarities to adult T cell leukemia, which is associated with human T cell leukemia/lymphoma virus type I (HTLV-I) infection. Cell lines were established from peripheral blood mononuclear cells (PBMC) of an HTLV-I-seronegative patient with mycosis fungoides. DNA hybridization analysis revealed the presence of HTLV-I-related sequences with unusual restriction endonuclease sites. Sequence analysis of subcloned fragments demonstrated the presence of a monoclonally integrated provirus with a 5.5-kilobase deletion involving large regions of gag and env and all of pol. Additional evidence for the presence of deleted proviruses was found by polymerase chain reaction (PCR) amplification of DNA from cutaneous lesions of five other HTLV-I-seronegative patients. The findings suggest that HTLV-I infection may be involved in the etiology of at least certain cases of mycosis fungoides.

The urinary excretion of histamine and its main metabolite, 1-methyl-4-imidazoleacetic acid (MeImAA), was determined in 30 adult patients with the clinical diagnosis of urticaria pigmentosa (UP). Clinical and laboratory investigations including skin histology, bone marrow examination, and scintigraphy of the skeleton, liver, and spleen revealed systemic manifestations in 14 cases. Among the 16 cases with dermal proliferation of mast cells only 3 cases classified as telangiectasia macularis eruptiva perstans (TMEP). All patients with systemic mastocytosis and UP excreted increased amounts of MeImAA in the urine while normal amounts were found in 2 of the patients with TMEP. A significant correlation existed between MeImAA excretion and the extent of mast cell infiltration in skin and internal organs. No such correlation was found for urinary histamine. Urinary MeImAA but not histamine is therefore considered a useful indicator of systemic involvement by reflecting the size of the mast cell histamine pool. The main symptom of the patients was pruritus, which was moderate to severe in 17 and mild or absent in 13 cases. Gastrointestinal symptoms were present in 14 patients. However, there was no obvious correlation between the excretion of MeImAA and any of the symptoms recorded. Neither was the severity of pruritus correlated to the histamine content of the skin, which was measured in both lesional and unaffected skin in 23 of the patients. Thus, symptoms possibly caused by histamine in mastocytosis patients are not directly related to urinary histamine metabolite excretion or tissue histamine content.

Between 1977 and October 1989, 445 patients have been treated with bone-anchored skin-penetrating titanium implants for anchorage of facial prostheses or bone-conducting hearing aids, at the Ear, Nose and Throat Department at Sahlgren's Hospital in Gothenburg. The majority of patients had no adverse skin reactions, while a few patients were responsible for the majority of the adverse reactions. The aim of our study was to analyse differences between these groups. We started a clinical study on 9 patients with a clinical history of adverse skin reactions around the titanium implants and 9 patients without adverse skin reactions were used as controls. None of the patients had delayed hypersensitivity to titanium. Microbiological analyses showed that when there was clinical irritation, Staphylococcus aureus could be isolated.

We examined the association between severity of disease in mastocytosis and skeletal manifestation and bone markers in 16 patients varying in extent of mastocytosis as determined by the urine excretion of methylimidazoleacetic acid. Both osteoporosis and osteosclerosis were found. Bone density in the hip was significantly higher (p < 0.05) in both men and women with an enhanced histamine metabolite excretion. Patients with only moderately increased mast cell mass had low bone mineral density in the hip, osteoporosis and vertebral fractures. The different skeletal disease patterns in mastocytosis might be the effect on osteoblasts and osteoclasts of biologically active substances. Mast cells release a number of vasoactive substances, including histamine which promotes osteoblasts and heparin and prostaglandin D2 which induce bone resorption by activation of osteoclasts. Systemic mastocytosis is a rare disease characterized by multi-organ infiltration by mast cells and with varying skeletal manifestations including osteoporosis. Treatment with bisphosphonates may be beneficial in arresting osteoporosis in this disorder.

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