Letizia Vitali

Celiac disease and type I (insulin-dependent) diabetes mellitus in childhood: follow-up study.

To ascertain the specificity of IgA and IgG antigliadin (IgA-AGA, IgG-AGA), IgA-antireticulin (R1-ARA), and antiendomysial (AEA) antibodies for the diagnosis of celiac disease, we evaluated 133 type I diabetic children aged 1.4-28.4 years (mean 14.1 +/- 6.6), with diabetes from onset to 20.5 years. Fifty-three patients were considered at onset and 49 of these also during follow-up. IgA-AGA and IgG-AGA were determined by enzyme-linked immunosorbent assay (ELISA), R1-ARA and AEA by indirect immunofluorescence. IgA-AGA were positive in 20 of 133 (15%), IgG-AGA were positive in seven of 133 (5.26%), while R1-ARA and AEA were positive in three patients. At the onset of disease we found elevated IgA-AGA in 17 of 53 (32%) patients, IgG-AGA in four (7.55%) patients, three of them with IgA-AGA as well; R1-ARA and AEA were present in three (5.66%) patients, all with high IgA-AGA levels. During 1-10 year follow-up IgA-AGA decreased to within the normal range in 13 patients, with elevated IgA-AGA at onset but without R1-ARA and AEA; in four patients with high IgA-AGA at onset, IgA-AGA remained constantly elevated as did R1-ARA and AEA in three of them; and two patients, without IgA-AGA, R1-ARA, and AEA at onset, became positive for all three antibodies. Intestinal biopsy confirmed a diagnosis of celiac disease in five of these with IgA-AGA, R1-ARA, and AEA, but not in one patient with persistent IgA-AGA but no AEA and R1-ARA, suggesting that R1-ARA and AEA are more reliable markers for the screening of celiac disease in type I diabetic patients.

Cytotoxic activity in children with insulin-dependent diabetes mellitus

We determined the percentage of circulating natural killer (NK) cells, using the monoclonal antibodies anti-CD57 and anti-CD16, NK cytotoxic activity (lytic units/10(6)) and lymphokine-activated killer (LAK) activity in 25 IDDM patients aged 3-23 years, 12 with disease for < 1 year (Group I) and 13 with disease for > 3 years (Group II). Nine age-matched healthy subjects served as controls. The percentage of CD57+ cells was similar in IDDM patients and controls, while the percentage of CD16+ cells was lower in IDDM patients (P < 0.05) than in controls. NK cell cytotoxic activity was lower in IDDM patients than in controls (P < 0.01), in Group I and II compared with controls (P < 0.005). LAK activity was similar in IDDM patients and in controls. No correlation was found between NK cytotoxic activity and metabolic control, HLA typing, while a negative correlation was found between NK cytotoxic activity and insulin requirement (P < 0.05). The decreased NK cytotoxic activity observed in our patients, in particular in long-standing diabetics, with normal NK cell number, could be due to a qualitative defect of the NK cells, or to a deficient IL-2 and/or TNF-alpha production, or to a immunomodulatory or immunosuppressing effect of insulin.

Low Serum Levels of Tumor Necrosis Factor-Alpha in Insulin-Dependent Diabetic Children

We measured serum levels of tumor necrosis factor-alpha (TNF-alpha) in 48 children with insulin-dependent diabetes mellitus (IDDM), divided into two groups according to disease duration (group I < 6 months and group II > 3 years): group I 15 patients, aged 2.2-13.7 years, and group II 33 patients, aged 4.5-25.5 years. Thirty-six age- and sex-matched healthy subjects served as controls. TNF-alpha levels were measured by immunoradiometric assay. We found that TNF-alpha levels were lower in all IDDM patients (29.65 +/- 3.83 pg/ml) than in controls (74.74 +/- 10.17 pg/ml) (p < 0.0001), as well as in group I (24.07 +/- 3.65 pg/ml) and group II (32.16 +/- 5.29 pg/ml) as compared to controls (p < 0.001). TNF-alpha levels were significantly lower in patients with antibodies than in those without antibodies and in controls. Similar results were found in longstanding IDDM patients. No correlation was found between serum TNF-alpha and chronologic age, duration of disease, metabolic control, insulin requirement and HLA typing. During a 1-year follow-up study in 12 group I patients no significant variations in TNF-alpha levels were observed. It has been reported that the administration of exogenous TNF suppresses the development of diabetes in nonobese diabetic mice, low producers of endogenous TNF. The results suggest that aberrant TNF-alpha synthesis may contribute to immune dysregulation thus favoring the development of autoimmune diseases.

Central motor conduction time in children and adolescents with insulin-dependent diabetes mellitus (IDDM)

Measurement of central motor conduction time (CMCT) after percutaneous magnetic stimulation of the brain is an electrophysiological method that may discover subclinical impairment of central nervous system (CNS). In order to detect an impairment of CNS, we measured CMCT right (R) and left (L) after percutaneous stimulation of the brain in 34 patients affected by insulin-dependent diabetes mellitus (IDDM) (16 males and 18 females), aged 16.4 +/- 4.1 years (7.3-23.2 years), with duration of disease 7.6 +/- 4.9 years (7/12-16 years), and HbA1c annual mean 7.41 +/- 1.1% (n.v. 5.14 +/- 0.84%). Twenty-three sex- and age-matched healthy subjects served as controls. In our IDDM patients we observed a delay of CMCT R (P < 0.0005) and L (P < 0.0005) as compared to controls. No correlation was found between CMCT (R and L) and chronologic age, duration of disease, peroneal motor nerve conduction velocity. No association was observed between CMCT (R and L) and HLA antigens. On the basis of IDDM duration, patients were divided into 2 groups (G): G I (9 pts) with IDDM < 2 years and G II (25 pts) with IDDM > 5 years, 12 of them with precocious signs of one or more microangiopathic complications. No difference in CMCT (R and L) was observed between the 2 groups and between G I and controls; G II patients had a longer delay of CMCT R (P < 0.0001) and L (P < 0.0001) than controls. In G II patients, a positive correlation between CMCT R and HbA1c of the 5 years before the test (P < 0.025) was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Final height attainment in girls and boys with insulin-dependent diabetes mellitus

We compared final height to height at diagnosis (expressed as a standard deviation score, SDS), predicted adult height (according to the Bayley and Pinneau method) and target genetic height (expressed as mean parental height in cm, +6.5 for males and -6.5 for females) in 37 patients (15 males, 22 females) with insulin-dependent diabetes mellitus (IDDM), aged 20.6 +/- 3.3 years (16.6-27), with 11.8 +/- 3.7 years (5.2-19.2) mean duration of disease. In the 22 females, final height (162.4 +/- 5.7 cm; range, 150-174 cm) was higher than predicted (161.5 +/- 7.8 cm; range, 146-176.2 cm) and target genetic height (159.7 +/- 3.8 cm; range, 152.8-167.3 cm), although not significantly. Female patients showed a positive correlation between final height and both predicted (P < 0.05) and target genetic height (P < 0.005). No difference was observed in final height between patients diagnosed in the prepubertal or pubertal phase (162.2 +/- 4.6 cm vs. 163.4 +/- 6.2 cm; P-value n.s.). In the 15 males, final height (173.4 +/- 4.4 cm; range, 166.5-181 cm), lower than predicted (175.4 +/- 4.9 cm; range, 166-183 cm), was higher than target genetic height (169.9 +/- 4.8 cm; range, 162.4-177 cm) (P < 0.05). Male patients showed a positive correlation between final height and target genetic height (P < 0.05). No difference was found in final height between patients diagnosed in the prepubertal or pubertal phase (173.6 +/- 3.5 cm vs. 172.7 +/- 5.5 cm; P-value n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Rejection of Islets Differing by a Single Antigen Is Dependent on Donor MHC

To study the effect of expression of a single foreign antigen on the outcome of otherwise compatible mouse islet grafts, we have used transgenic mice expressing the human complement receptor 2 (CR2, CD21, C3d/EBV receptor) on their pancreatic (β-cells (RIPCR2 mice). Donors were RIP-CR2 mice, typed at the major histocompatibility complex (MHC) as H-2k, H-2b, or H-2bxk, and recipients were streptozotocintreated nontransgenic B6 × CBA Fl mice (H-2bxk). H-2b or H-2bxk CR2-expressing islets were not rejected (mean survival time [MST] >100 days) but induced a peri-insulitis and an antibody response to CR2. In contrast, H-2k CR2-expressing islets were rejected in 80% of the cases with a MST of 65 ± 23 days and were massively infiltrated by a destructive insulitis. In both cases, the infiltrate was mainly made of CD4+ cells, with few CD8+ cells. The isotype of IgG antibody response to CR2 was studied: recipients of H-2k grafts had a predominantly IgGl response, while recipients of H-2b grafts had a balanced IgG2a and IgGl response. To further evaluate the mechanism of differential rejection of the two types of grafts, recipients were immunized with CR2-expressing rat insulinoma cells before transplantation. Preimmunization with CR2 did not affect the outcome of H-2b grafts but greatly accelerated the rejection of H-2k grafts. These experiments indicate that expression of a single foreign antigen on β-cells triggers an immune response leading to rejection or to peri-insulitis, depending on the MHC of donor islets.

Enhancement of soluble CD23 serum levels and cell-surface CD23-expression in subjects at increased risk of type 1 diabetes mellitus and in diabetic patients.

The low affinity receptor for IgE, CD23, is expressed on lymphocytes among other cell types. The purpose of the present study was to assess serum sCD23 levels and CD23 expression on peripheral blood mononuclear cells (PBMC) in people at increased risk of developing Type 1 diabetes mellitus and in diabetic patients. Serum sCD23 levels were significantly higher in first‐degree relatives of Type 1 patients (median: 3.2 U ml−1) (p < 0.001) and in newly diagnosed (median: 3.3 U ml−1) (p < 0.001) and long‐standing (median: 2.5 U ml−1) (p = 0.01) Type 1 diabetic patients than in controls (median: 1.2 U ml−1). Newly diagnosed patients showed higher levels than those with long‐standing disease (p = 0.026). Moreover the percentage of B cells expressing CD23 were significantly higher in first‐degree relatives (median: 48.6 %) (p < 0.001) and in newly diagnosed (median: 58 %) (p < 0.001) and long‐standing (median: 44.8 %) (p = 0.03) Type 1 diabetic patients than in controls (median: 28.5 %). The increased sCD23 levels and the increased number of cells expressing CD23 observed in subjects at increased risk of Type 1 diabetes and diabetic patients may be indicators of Th2 activity in Type 1 diabetes.

HLA-DR3 and DR4 Allele Segregation in IDDM Families and in Controls

Segregation distortion of HLA alleles in IDDM families is still a matter of discussion. Some evidence for preferential transmission of DR3 and DR4 from parents to both diabetic and non-diabetic progenies has been given.1 However, other studies investigating the same issue have not confirmed this differential mode of inheritance.2