Limited usefulness of antithyroperoxidase and antithyroglobulin assays in Jamaicans with Graves' disease

The clinical usefulness of commercially prepared haemagglutination kits for thryro peroxidase (TPO) antibody and thyroglobulin (TG) antibody was evaluated in 145 consecutive Jamaicans with Graves' disease. Sixty two (43 percent) of the patients were newly diagnosed, 12 (8 percent) were in remission and 71 (49 percent) had relapsed. Sera from 65 (45 percent) patients were positive for thyroid antibodies. The TPO antibodies were found in 43 percent (63/145), thyroglobulin antibodies in 12 percent (17/145) fifteen (10 percent) patients had both anti-TPO and TG antibodies. Similar prevalences of TPO antibody were found in newly diagnosed patients and those who had relapsed (44 percent v. 41 percent) but the prevalence in the patients in remission was significantly higher (75 percent; X2 = 4.8, P <0.05). The prevalence of TPO antibody increased significantly with age at onset before age 35 years compared to later onset (56 percent v. 32 percent; X2 = 8.09, P <0.005). The presence of both TPO antibody (64 percent v. 31 percent; X2 = 13.1, P <0.001) and TG antibody (22 percent v. 6 percent; X2 = 8.8, P <0.005) correlated positively with Graves' opthalmopathy. Neither of the tests was adequately sensitive in detecting GD in Jamaicans. (AU)

The significance of immune disorder in tropical spastic paraparesis

The reports of the occurrence of HTLV-1 infection and/or HTLV-1 associated myelopathy (HAM)/tropical spastic paraparesis (TSP) in patients with certain organ-specific and nonorgan-specific autoimmune diseases prompted us to assess the relationship between TSP and humoral autoimmunity. Blood samples from 76 TSP patients, 60 asymptomatic HTLV-1 carriers and 100 HTLV-1 seronegative blood donors were examined for the presence of organ-specific and nonorgan-specific autoantibodies, reactive serological tests for syphilis, immunoglobulin and complement concentrations as well as immunecomplexes. High prevalences of autoantibodies (39/76, 51 percent), reactive serological tests for syphilis (23/76; 30 percent), hypergammaglobulinaemia (69/76, 90 percent) and the complement fixing immune complexes (44/76, 58 percent) were found in the TSP patients. These indicators of immunological disorder were found in statistically significantly lower prevalences in asymptomatic HTLV-1 carriers (12/60, 20 percent; p < 0.001; 6/60, 10 percent; p < 0.05; 32/60, 53 percent; p < 0.001 and 8/60, 13 percent; p < 0.001, respectively) and HTLV-1 seronegative blood donors (8/100, 8 percent; p < 0.001; 3/100, 3 percent; p < 0.001; 15/100, 15 percent p < 0.001 and 5/100, 5 percent; p < 0.001, respectively). The profiles of autoimmune phenomena observed in the patient and control groups revealed that they were associated with TSP rather than mere HTLV-1 infection and consequently pathogenic significance. The array of immunological features present in TSP was suggestive of autoimmune disease resulting from immune dysfunction. Studies which explore the possible existence of HTLV-1 induced autoantibodies with specificity for antigens of the spinal cord in TSP might be useful in elucidating its pathogenesis.(Au)

Seroprevalence of autoantibodies in selected and unselected populations in Jamaica

Various serological techniques were used to investigate the prevalence and distribution of autoantibodies in healthy Jamaicans and patients with autoimmune and non-autoimmune disease. Low concentrations of autoantibodies were found in healthy Jamaicans, including thyroid (1.5 percent), gastric parietal cell (1.4 percent) and smooth muscle (11.3 percent). There was no significant age or sex predominance in the distribution of autoantibodies in the healthy population though autoimmune disease was more prevalent in females. Serological overlaps occurred but the comparative distributions and concentrations of autoantibodies in patients with autoimmune disease and non-autoimmune disease, and health subjects indicate that currently available methods of autoantibody determination may be used successfully in diagnosis in Jamaica. Failure to detect circulating pancreatic islet cell antibodies in insulin-dependent diabetic patients as well as in healthy Jamaicans questions the pathogenicity of these antibodies and diminished their diagnostic usefulness in this population. (AU)

Autoantibodies and autoimmune disease in Jamaica

This study investigated the repertoire of autoantibodies found in normal healthy Jamaicans as it relates to the efficacy of laboratory diagnosis of autoimmune disease. Clinical, immunological and genetic features of certain autoimmune diseases as they occur in Jamaicans were also examined. A number of immunological techniques were applied. There was no marked female preponderance of thyroid autoantibodies in the normal population although autoimmune thyroid disease was found predominantly in females. This indicates that gonadal hormones may be important in the development of disease. The low frequency and concentrations in which islet cell autoantibodies occur in Jamaican type 1 diabetics (3.2 percent) supports a non-pathogenetic role for these antibodies (Chapter 6). The bimodal clinical distribution of myasthenia gravis found elsewhere was not observed in Jamaicans (Chapter 10). There was no female preponderance in the ocurrence of rheumatoid factors. The frequency of certain ARA criteria were statistically significantly lower in Jamaican systemic lupus erythematosus (SLE) patients compared with American patients. Several HLA associations were found with myasthenia gravis, SLE and rheumatoid arthritis although these were mostly weak. The data obtained herein will contribute to the improvement in diagnosis and management of autoimmune diseases in Jamaica and the lack of understanding of the pathogenesis of autoimmune diseases

Absence of islet cell autoantibodies in Jamaican Blacks with diabetes mellitus

Forty-two patients, mainly of Black ancestry, attending the Diabetic Clinic, University Hospital of the West Indies, were studied for the frequency of autoantibodies against pancreatic islet cells (ICA), thyroid microsomes (TMA) and gastric parietal cells (PCA). There were 24 men and 18 women with an age range of 6-77 years and a mean age of 56.3 ñ 16.5 years. They had had diabetes for periods ranging from 1 to 40 years with a mean duration of 12.3 yearsñ 7.9 years. Sixty per cent had had insulin therapy for periods ranging from 0.25 to 25 years with a mean duration of 7.6 ñ 6.4 years. The mean body mass index was 24.0 ñ 2 with a range of 16.5 - 32.1. No patient had ICA. Of the insulin-treated patients, 17 percent were TMA positive. No patient had both TMA and PCA positivity. Amongst black populations, there is less evidence for autoimmune pathogenesis of insulin-requiring diabetes. The results suggest geographic as well as racial heterogeneity for black populations with diabetes, and emphasize the limitations of Caucasian Euro-American classifications of the disease, (AU)