Immune dysfunction in Australian Aborigines.

An examination of the prevalence and phenotype of immune disorders in different ethnic groups may provide important clues to the etiopathogenesis of these disorders. Whilst still conjectural the restricted and somewhat unique polymorphisms of the MHC (and other genetic loci involving host defences) of the Australian Aborigines may provide an explanation for their apparent heightened susceptibility to newly encountered infections and their resistance to many (auto) immune and allergic disorders. In comparison with non-Aboriginal Australians, Australian Aborigines have heightened frequencies of rheumatic fever, systemic lupus erythematosus, various infections and post-streptococcal glomerulonephritis. In contrast various autoimmune disorders (e.g. rheumatoid arthritis, multiple sclerosis, CREST, biliary cirrhosis, coeliac disease, pernicious anaemia, vitiligo), B27 related arthropathies, psoriasis, lymphoproliferative disorders and atopic disorders appear infrequent or absent. Similarly various autoantibodies occur with increased or diminished frequency. With continuing racial admixture, social deprivation and deleterious lifestyles of these people it is likely that further changes in both the frequencies and phenotype of these immune disorders will occur. It is only with a full understanding of the pathogenic mechanisms involved in these immune disorders that meaningful and clinical relevant interventions will be possible.

Decreased nailfold capillary density in limited scleroderma with pulmonary hypertension.

Approximately 20% of patients with the limited form of scleroderma will develop pulmonary hypertension which is generally a late stage fatal complication. Why pulmonary hypertension occurs in this subset of patients is unknown and it has not been possible to predict which patients are at risk. Nailfold capillary dilatation, distortion and drop occurs universally in patients with scleroderma and is generally an early finding. The present study was conducted to investigate whether quantitative nailfold capillaroscopy could distinguish those limited scleroderma patients who have established pulmonary hypertension. Quantitative nailfold capillaroscopy was performed by Visual Image Analysis in 10 healthy subjects and 20 patients with limited scleroderma (18 centromere +ve), of whom 8 had established pulmonary hypertension. It was found that scleroderma patients with pulmonary hypertension had a significant reduction in capillary density compared with patients lacking this complication (p < 0.01). Patients with scleroderma have significantly more dilated capillaries than controls although no significant differences were observe between the two patient subgroups. The finding of reduced nailfold capillary density in scleroderma patients with established pulmonary hypertension has possible pathogenic significance and may allow detection of this subgroup at an early stage in their disease progression.

The abnormalities of nailfold capillaries in scleroderma as assessed by video image analysis and photomicroscopy.

Scleroderma is a systemic connective tissue disease in which the diagnosis in supported by morphological changes in nailfold capillary size and density. These changes are open to observer bias. In this paper we describe 2 objective methods that allow quantitative definition of capillary changes, video image analysis (VIA) and photomicroscopy. VIA was used to assess 15 healthy control subjects and 22 patients with scleroderma. Scleroderma patients had a significantly larger capillary diameter (43 microns versus 20 microns, p = 0.0001) and capillary density was reduced by a mean factor of 0.5. Image stored on computer will facilitate serial assessments of nailfold capillary changes and possibly provide information on disease progression.