Alpha cell autoantibodies: immunological and metabolic follow-up study

We studied glucagon responses to OGTT and insulin and arginine stimulation in 12 out of 21 patients who were found positive for alpha cell autoantibodies (ACA) during routine screening procedures for autoimmunity in a group of 4080 individuals. The study was repeated in 8 subjects after an average observation period of 42 months. In both studies glucagon plasma levels were normal and independent of ACA titres, ACA ability to fix complement and ACA ability to cross-react with duodenal alpha cells. The clinical significance of ACA remains to be elucidated.

Critical evaluation of serum thyroglobulin (Tg) levels during thyroid hormone suppression therapy versus Tg levels after hormone withdrawal and total body scan: results in 291 patients with thyroid cancer

Serum thyroglobulin (Tg) levels were measured during thyroid-hormone suppressive therapy in 291 patients who had been treated for well-differentiated thyroid carcinoma. The findings were compared with those of a subsequent total body scan (TBS) and with Tg levels measured after thyroid-hormone withdrawal. Of the patients with low Tg levels during suppressive therapy, 91.6% were subsequently shown to be free of disease or to have only remnants in the thyroid bed, whereas 8.4% had metastases (false-negative). Of the patients with false-negative findings, 89.3% had nodal metastases; 60.8% of the patients with nodal metastases exhibiting radioiodine uptake and only 23% of those with nonfunctioning nodal metastases had low Tg levels during suppression therapy. After thyroid-hormone withdrawal, all but 1 of the patients with nodal metastases had high Tg levels. All but 2 of the patients with distant metastases had high Tg levels during suppression therapy; 1 of these 2 patients exhibited high Tg levels after T3 withdrawal. No differences between Tg levels in patients with functioning and non-functioning metastases were found. Our study indicates that Tg assays performed during suppressive therapy have a fairly good predictive value and can be used as a general guide in the follow-up of thyroid cancer. However, since most differentiated metastases produce Tg only when stimulated by thyroid-stimulating hormone, measurements of Tg levels after the discontinuation of suppressive therapy would also seem to be necessary.

Localization of met-enkephalin on human spermatozoa and evidence for its physiological role

Pro-opio-melano-cortino-derived peptides have been identified in rat testicular extracts and in human seminal plasma, but their physiological role is still unknown. We report that met-enkephalin is localized on human spermatozoa, by means of an indirect immunofluorescent technique. Furthermore, we demonstrate that a met-enkephalin analog (D-Ala2-Mephe4-Met-(o)-ol-enkephalin, FK 33-824, Sandoz, Basel, Switzerland: DAMME) inhibits in a dose-dependent manner the acrosome reaction induction. The hypothesis of a physiological role of seminal met-enkephalin on human spermatozoa fertilizing ability is briefly discussed.

Demonstration and characterization of anti-human mitochondria autoantibodies in idiopathic hypoparathyroidism and in other conditions

We studied 32 patients with idiopathic hypoparathyroidism (IHP), 19 patients with organ-specific autoimmune diseases (OSAD) without IHP, 50 normal controls and a known serum with anti-mitochondrial autoantibodies (AMA). Patients' sera were tested by the classical indirect immunofluorescent technique and by the indirect immunofluorescent complement fixation technique on unfixed cryostat sections of normal human parathyroid, pancreas, thyroid, stomach, kidney, and rat kidney. Five out of 32 patients with IHP, three out of 19 patients with OSAD without IHP and one out of 50 normal controls revealed a bright reactivity against oxyphil cells and a weak reactivity against chief cells of normal parathyroid. These sera also brightly reacted with mitochondria-rich cells and weakly with the remaining cells of only human tissues. The absorption of positive sera with human mitochondria completely abolished this positivity but the absorption with rat mitochondria failed to prevent this reaction. This reactivity was due to an anti-human mitochondrial autoantibody (AHMA) of IgG class. By non-competitive ELISA and Western blot we also demonstrated that every AHMA-positive serum mainly reacted against a human mitochondrial membrane-bound protein of approximate mol. wt. of 46 kd, while the AMA-positive serum reacted against different mitochondrial antigens. The present study shows that a specific parathyroid autoantibody was not detectable in patients with IHP.

Serum thyroglobulin levels in patients with well-differentiated thyroid cancer during suppression therapy: study on 429 patients

Serum thyroglobulin (Tg) was measured in 429 patients with well-differentiated thyroid carcinoma, during thyroid hormone suppression therapy. 324 patients out of 429 were considered free of disease; 44 had only remnants in the thyroid bed; 61 had metastases, of them 40 were detected by TBS and 21 were nonfunctioning and were detected by other diagnostic procedures. Tg was measured by a RIA method in 257 patients and by an IRMA method in 277 patients. The correlation between the two methods was very good (r = 0.914) for values higher than 25 ng/ml with the RIA method. The cut-off limit to distinguish pathological from nonpathological values was considered the mean value found in the patients free of disease plus 2SD. The cut-off limit for the RIA method was 24.2 ng/ml and 3.0 ng/ml for the IRMA method. Of patients with high Tg levels 92% had metastases, either nodal or distant; only 8% had remnants in the thyroid bed. Tg levels were high in 80% of the patients with metastases, all but two of the patients with metastases and low Tg levels had nodal metastases. Moreover, Tg levels were high in 76% of the patients with metastases unable to take up radioiodine.

IN CONCLUSION

patients with low levels of serum Tg during suppression therapy have a high probability of being free of disease, even though the presence of tumors cannot be excluded. On the other hand a value greater than the cut-off limit suggests the presence of metastases despite a negative scan.

Incidence and significance of organ-specific autoimmune disorders (clinical, latent or only autoantibodies) in patients with vitiligo

The frequency of autoimmune disorders was determined in 373 vitiligo patients and in controls matched for sex, age and race. Vitiligo patients had an increased frequency of clinical autoimmune diseases of thyroid (7.5%), stomach (0.8%), parathyroid (1%), adrenal gland (1.3%). Vitiligo patients, without clinical signs of overt autoimmune diseases, also had a statistically significant increase in the frequency of gastric parietal cell (p less than 0.001), thyroid microsomal (p less than 0.05) and adrenal autoantibodies (p less than 0.05). This increased incidence of autoimmune manifestations was correlated with the duration of vitiligo. Furthermore in 94% of the patients with parietal cell autoantibodies a gastric biopsy showed atrophic gastritis. In addition, in 48% of the patients with thyroid microsomal autoantibodies and in 2 out of 6 patients with adrenal autoantibodies without overt diseases at the beginning of the study, the functional investigation of the target organs during the follow-up allowed the detection of the presence or that of the subsequent development of clinical or subclinical dysfunction.

Clinical and subclinical organ-specific autoimmune manifestations in type 1 (insulin-dependent) diabetic patients and their first-degree relatives

Studying 239 Type 1 (insulin-dependent) diabetic patients and 144 of their first-degree relatives, we found a significant prevalence of autoimmune manifestations in both groups, compared with sex- and age-matched control subjects (p less than 0.001). In particular, in diabetic patients we found a high frequency of autoimmune thyroid disease and idiopathic Addison's disease and also a significant prevalence of thyroid (p less than 0.001), parietal cell (p less than 0.05) and adrenal antibodies (p less than 0.05). In the relatives a high frequency of thyroid disease, thyroid, parietal cell and adrenal antibodies and a significant prevalence of islet cell antibodies (p less than 0.05) were detected. In both groups functional glandular tests and gastric biopsies performed on the basis of autoantibody positivity revealed 13 examples of subclinical hypothyroidism, two cases of reduced adrenocortical reserve and five of atrophic gastritis. Autoantibody screening in diabetic patients and their relatives permitted the early diagnosis of the underlying endocrine disorders.

Anti-ribosomal ribonucleoprotein autoantibodies in systemic lupus erythematosus

Sera from systemic lupus erythematosus (SLE) patients giving a fluorescent ribosomal pattern on tissue and cell preparations also showed precipitating autoantibodies against purified rat liver ribosomes. Ribosomal antigen is also present in rabbit thymus cellular extract (RTE), since the same sera gave precipitin lines against RTE in identity with ribosomes. Immunofluorescent staining was completely inhibited by serum absorption with ribosomes or with RTE. However ribosomal RNA and RNase or trypsin-treated ribosomes failed to react with these autoantibodies as demonstrated in immunoabsorption and immunodiffusion studies. These data suggest that these sera contain autoantibodies directed against some antigenic site composed of a portion of both RNA and ribosomal protein. Ribosomal autoantibodies were detectable at a low frequency in SLE patients characterized by an active disease and renal involvement.

Autoantibodies against Leydig cells in patients after spermatic cord torsion

This study is aimed at searching for the presence of circulating antibodies against frozen sections of human testis, ovary and trophoblast in patients that had spermatic cord torsion. Sixty-eight sera samples were studied. Nine patients (13.2%) were positive for organ specific anti-testis autoantibodies. Six patients were positive for antibodies against Leydig cells: five were positive only with the indirect immunofluorescence technique of complement fixing (ITT/CF), the sixth patient was positive only with the indirect immunofluorescence technique (ITT). The other three patients were positive for antibodies against germ line cells: two patients were positive with both techniques, the third was positive only with indirect immunofluorescence technique. Eight of these patients were negative for antibodies against adrenal cortex while only one case was positive with indirect immunofluorescence technique both on adrenal cortex and Leydig cells. Human lyophilized testis absorbed the reactive antibodies against Leydig cells and germ line cells, while adrenal cortex and lyophilized testosterone were ineffective. This study shows the identification of a specific antibody against Leydig cells and germ line cells in patients after spermatic cord torsion.

Complement-fixing adrenal autoantibodies as a marker for predicting onset of idiopathic Addison's disease

In a prospective investigation of the role of adrenal autoantibodies (AA) in predicting the onset of idiopathic Addison's disease, 9 initially non-addisonian AA-positive autoimmune subjects were followed for 42 months. In 4 of these subjects Addison's disease developed within 1-31 months. A fifth had reduced adrenocortical reserve at the start and at the end of the investigation. An AA capable of fixing the membrane attack complex of complement [(C5-C9) F-AA] was detected before onset of the disease in the sera of the 4 patients in whom Addison's disease developed. (C5-C9) F-AA may be involved in the pathogenesis of idiopathic Addison's disease and may be regarded as a marker for individuals in whom idiopathic adrenal insufficiency is likely to develop.

Detection of immunoglobulins G and A on the cell membrane of hepatocytes from patients with alcoholic liver disease

The presence of immunoglobulins (Ig) G, A, and M and of complement fractions (C3-C4) on the liver cell surface was investigated by direct immunofluorescence in 40 patients with alcoholic liver disease. IgG was detected on the liver cell membrane with a linear staining pattern in 29 patients. The percentage of IgG-positive hepatocytes correlated with transaminase activities, independently of the histological findings. IgA was demonstrable with a coarse granular staining pattern in 11 of the 14 cases with established cirrhosis. The finding of IgG bound to the hepatocyte surface in patients with alcohol-induced liver damage suggests that alcohol could be responsible for antigenic modifications of hepatocyte membrane with consequent triggering of a humoral immune response.

Immunohistochemical identification of factor X-like antigen in the A cells of the normal human pancreas

An indirect immunofluorescence technique using two rabbit anti-human factor X sera was used to investigate the presence of factor X in various human tissues. Of all tissues studied only the cytoplasm of some islet cells of the six human pancreases illustrated specific reactivity for factor X-like material. No reaction was seen in the exocrine pancreas. Cross-absorption studies with factor X-deficient plasma, glucagon or alpha-1-antitrypsin did not modify the pattern. On the contrary, cross-absorption with factor X Friuli or with normal plasma eliminated the positivity. No factor X-like material was seen in rat or guinea pig pancreas. The double-immunofluorescence technique demonstrated that the reactivity was localized only in the cytoplasm of the A cells.

Immunological and clinical study of patients after spermatic cord torsion

We studied 25 patients with spermatic cord torsion occurring after puberty. The elapsed time between the onset of symptoms and observation varied from 6 months to 7 years. We evaluated the semen of these patients and found that the number of spermatozoa was lower in patients with an atrophic testis (13 patients) than in those with a normal testis or, in those with torsion treated by orchidectomy. Moreover, the number of spermatozoa was lower in patients who had torsion for more than 2 years before being checked (12 patients) than in patients who had a more recent torsion (13 patients). Agglutinating antibodies were present in 20% of the patients but, they are not correlated fertility or sterility. Immunofluorescent antibodies also were not correlated with the changes found by semen analysis. They are not present in patients with a normal testis at the time of observation. On the other hand, immobilizing antibodies were significantly correlated with sterility and, particularly with changes of motility. These data suggest that sterility after spermatic cord torsion is correlated with an autoimmune mechanism. It may occur particularly in those patients with atrophic testes and has a slow onset taking more than 2 years to evolve completely.

Lymphocyte subpopulations in insulin-dependent diabetics with and without serum islet-cell autoantibodies

The lymphocyte subpopulations of 26 insulin-dependent diabetics were studied. Thirteen of them had persistent pancreatic islet-cell serum antibodies (ICA) (mean (+/- SD) duration of diabetes 11 +/- 8 years). The others were ICA-negative (mean duration of diabetes 10 +/- 8 years). The mean fasting blood glucose in the week before the lymphocyte count was 1..37 +/- 0.45 g/l (two specimens for every patient). As controls 19 healthy volunteers, sex and age matched, were investigated. The T-lymphocyte count was no different in diabetics compared to controls. B-cells were significantly raised (p less than 0.01) in the ICA-positive group, when tested with anti-human gammaglobulin sera (IgG + IgA + IgM), anti-human IgM, while no difference was observed between ICA-negative patients and normal subjects. IgA-bearing lymphocytes were equally raised in both diabetic groups (p less than 0.05). These data show an altered immunological balance in type IB (autoimmune) diabetes, characterized by an increased number of B-lymphocytes.