Circulating antibodies in malignant melanoma patients

Sera from 46 patients with malignant melanoma (MM) in different clinical stages and from 25 healthy blood donors were studied by an indirect conventional immunofluorescent technique (IIT) and by an immunofluorescent complement-fixation test (ICFT). No specific and reliable serological reactivity could be demonstrated against autologous and homologous MM and other nonmalignant pigmented tissues. An increased incidence of diffused antinuclear (ANA; 41%) and cytoplasmic epidermal cell autoantibodies (A-CYT; 71%) was observed in the patients by IIT. Statistical evaluation of the results gave significant values in the chi 2 test in patients for ANA (chi 2 = 5.2061; p less than 0.05) and for A-CYT (chi 2 = 8.9176; p less than 0.01) versus age-matched controls. Thyroid microsomal, gastric parietal cell, smooth muscle and mitochondria autoantibodies were, respectively, detected in 4.3, 4.3, 4.3 and 0% of patients' sera.

Incidence and significance of islet-cell autoantibodies in different types of diabetes mellitus

Islet-cell (ICA) and organ-specific autoantibodies (OSA) were determined by the indirect immunofluorescence technique in 920 diabetics, 1,159 nondiabetic patients, and 100 young and 100 adult healthy controls with normal glucose tolerance. In control subjects ICA were not detected, and only 20 miscellaneous patients with normal glucose tolerance showed ICA (1.7 per cent). ICA were present in 45.4 per cent of patients with juvenile insulin-dependent diabetes (IDD) during the first six months of disease and in 29.1 per cent of patients between 6 and 12 months of disease onset; ICA presence decreased to 19.2 per cent and 20.6 per cent after one and five years of duration of diabetes.

In patients with maturity-onset IDD, ICA incidence was 19.4 per cent in the first year, 20 per cent between one and five years, and 12.2 per cent after five years of disease. In this group, 64 per cent of ICA-positive patients showed clinical and/or serologie evidence of thyroid, gastric, or adrenal autoimmune disorders.

In sera from young patients with non-insulin-dependent diabetes (J-NIDD), ICA were not detected. In adult patients with the same type of diabetes (M-NIDD) ICA incidence was 9.8, 7, and 8.9 per cent and was not related to the duration of diabetes. Patients with chemical diabetes were divided into two groups (younger and older than 35 years), and ICA incidence was 18.9 and 12.9 per cent, respectively. In two nondiabetic patients, glucagon cell autoantibodies were detected. ICA titers were variable in juvenile IDD of recent onset. Persistent ICA titers, frequently associated with OSA, were observed in the other types of diabetes, with the exception of J-NIDD. ICA may be considered markers of severe beta-cell alteration, with consequent reduction of insulin secretion, even though insulin dependency is sometimes delayed in a few patients.

Insulin and glucagon secretion in diabetic and non-diabetic patients with circulating islet cell antibodies

Thirty-nine patients (14 non-diabetics, 8 chemical diabetics, and 17 overt diabetics) with circulating islet cell antibodies (ICA) were studied. Insulin and glucagon secretion after oral (100 g) and intravenous glucose loading (200 mg/kg bolus injection followed by an infusion of 20 mg/min over 60 min) and arginine infusion (25 g over 30 minutes) were evaluated in these patients and in non diabetic and diabetic ICA-negative controls. In the non-diabetic groups with or without ICA, insulin and glucagon responses to glucose were similar. Moreover, in ICA positive patients the response of these hormones to arginine infusion was reduced. Similar alterations in insulin and glucagon secretion were observed in the CIA positive and negative patients with chemical or overt diabetes. In particular, fasting hyperglucagonaemia and glucagon hyperresponse to arginine are associated with a lack of insulin secretion in the patients with overt diabetes. Hormonal differences between diabetics with and without ICA could not be detected.

Epidermal cytoplasmic antibodies. (Incidence and clinical significance)

Antibodies to epidermal cytoplasmic antigens were detected by the indirect immunofluorescence (IF) technique in 36% of 100 adult healthy subjects and in 17.6% of 17 normal newborn infants. This type of autoantibody occurred in 33% of 100 cases with vitiligo, in 32.5% of 40 cases with psoriasis, in 55.3% of patients with malignant tumours and in 72.7% of subjects with malignant melanoma. The frequency of the autoimmune reactions was statistically significant only in patients with malignant neoplasms. In the majority of positive cases the IF pattern involved the upper layers of the epidermal cells (U-CYT). The basal layer was generally negative. Only a few cases showed a pattern involving both the upper and the basal layers (G-CYT). However, a wide variation in staining was noted when sera were tested on different skin specimens or different sections of the same skin. To identify the nature of the target antigen(s), absorption experiments of sera were attempted with lyophilized and particulate antigens. Animal and human blood cells and lyophilized homogenates of malignant tumours failed to absorb the autoimmune activity of positive sera. Only a powder preparation of keratin induced a decrease in antibody titres. It is postulated that they are the result of an antigenic stimulation by exogenous substances commonly present in the environment.

Clotting factors and platelets. Immunofluorescence evidence that fibrinogen and factor VIII are present in human washed platelets, whereas prothrombin complex factors and factor XIII are lacking

Factor I (fibrinogen) and factor VIII were shown, by an indirect immunofluorescence technique, to be present in human washed platelets. In the case of fibrinogen, the immunofluorescent pattern had a 'clod distribution' up to a 1:128 dilution of the antiserum. Factor VIII showed a 'speckled' pattern up to the 1:64 dilution. Cross-absorption studies confirmed the presence of such factors. Factor II, VII, IX, X and XIII, however, were not found in washed platelets. A diffuse fluorescence was noted using normal rabbit sera, but this was due to a cross-reaction, since it disappeared using a 1:32 diluted sera.

Heterologous specificity of reticulin RS antibodies

Reticulin antibodies were detected by the indirect immunofluorescence technique in 1450 sera from miscellaneous patients. R1 pattern on human and rat tissues was found only in 2 cases with adult coeliac disease. Reticulin Rs staining, involving intrasinusoidal cells of rat liver as well as interstitial and endothelial structures of various rat tissues, was demonstrated in 3.7% of cases, without correlation with gastro-intestinal or skin disorders. Rs pattern, due to IgG antibodies, could be absorbed by rat erythrocytes. Only Rs positive sera showed high titres of anti-rat IgG-type hemoagglutinins. Rat RBC agglutinating activity was demonstrated by a modified indirect Coomb's test. Heterologous Rs antibodies appear unrelated to particular diseases and should not be mistaken for the R1 and R2 patterns, which may be useful for diagnostic procedures.