Gian Franco Gaetani

Influenza vaccine in chronic lymphoproliferative disorders and multiple myeloma.

Objective: Vaccination against influenza in patients with chronic lymphoproliferative disorders (CLPD) and multiple myeloma (MM) is still a matter of clinical uncertainty. The aim of this study was to determine the safety, immunogenicity and clinical response to a commercially available vaccine against influenza in a group of such patients.

Incompletely processed N-glycans of serum glycoproteins in congenital dyserythropoietic anaemia type II (HEMPAS)

Congenital dyserythropoietic anaemia type II, or HEMPAS (hereditary erythroblastic multinuclearity with positive acidifed serum lysis test) is a genetic disease caused by membrane disorganization of erythroid cells. The primary defect of this disease lies in the gene encoding enzyme(s) which is responsible for the biosnythesis of Asn‐linked oligosacharides chains of glycoproteins (Fukuda et al. 1990). In order to know whether this gene defect affects the glycosylation in the cells other than the erythroid cells, the carbohydrate structures of the transferrin isolated from the sera of HEMPAS patients were analysed. Fast atom bombardment mass spectrometry analysis showed the presence of high mannose type and hybrid type oligosaccharides in the HEMPAS transferrin which is in contrast to the complex‐type oligosac charides found in the normal transferrin. The results strongly suggest that biosynthesis of Asn‐linked oligosaccharide chains in HEMPAS hepatocytes is disturbed. As a result, the serum glycoproteins with incompletely processed carbohydrates are circulating in the plasma in HEMPAS patients. but they must have been absorbed by the cells in the liver and the reticuloendothelial cells. Upon intravenous infusion into rats, as much as 30% of the HEMPAS transferrin was cleared from the plasma circulation. The majority of the HEMPAS transferrins was taken up by the liver, and transferrin was distributed both in the hepatocytes and the Kupffer cells. The presence of enormous amounts of aberrantly glycosylated serum glycoproteins may lead to the liver cirrhosis and secondary tissue siderosis seen in HEMPAS patients.

Polyclonal origin of medullary carcinoma of the thyroid in multiple endocrine neoplasia type 2

Abstract Multiple endocrine neoplasia type 2 (MEN 2) is a dominantly inherited cancer syndrome characterized by medullary thyroid carcinoma (MTC) and other tumors. Since MTC can also occur in a sporadic form and as familial medullary thyroid carcinoma, this neoplasm offers a unique opportunity to investigate the difference of origin, if any, between the sporadic and the hereditary forms of a tumor. While sporadic malignancies have usually been found to result from a mutational event occurring at the single-cell level and are therefore monoclonal, studies on hereditary neoplasms have been scarce and often produced conflicting results. In order to determine the clonal origin of sporadic MTCs and of those occurring in MEN 2 syndromes we used a clonality assay based on a polymorphic trinucleotide repeat of the X-linked human androgen-receptor gene. We found that 10 out of 11 MTCs expressed a polyclonal pattern of X inactivation, including a significant percentage of the cases clinically defined as sporadic.

Familial Hodgkin's disease: a disease of young adulthood?

Abstract Familial Hodgkins disease (FHD) is estimated to represent approximately 4.5% of all cases of Hodgkins disease (HD). Shared environmental factors, such as Epstein-Barr virus and other viral agents, and genetic determinants have all been proposed to explain familial aggregation of HD. In order to compare the characteristic features of FHD with those of the much more common sporadic form, we reviewed 28 articles on FHD, published between 1972 and 1995, and analyzed in further detail data from 18 papers, reporting on a total of 328 patients. The male-to-female ratio of the FHD population examined was 1.5, similar to that reported for sporadic HD, and lower than the one suggested for FHD by some authors. On the other hand, a significant difference was found between sporadic and familial HD according to age at diagnosis; that is, only one major peak between 15 and 34 years was present in the group of patients with FHD. Further investigation of FHD in young adulthood may provide insight into the hypothesis of a genetic or infectious etiology of the disease.

A novel NADPH:(bound) NADP + reductase and NADH:(bound) NADP + transhydrogenase function in bovine liver catalase

Many catalases have the shared property of containing bound NADPH and being susceptible to inactivation by their own substrate, H2O2. The presence of additional (unbound) NADPH effectively prevents bovine liver and human erythrocytic catalase from becoming compound II, the reversibly inactivated state of catalase, and NADP+ is known to be generated in the process. The function of the bound NADPH, which is tightly bound in bovine liver catalase, has been unknown. The present study with bovine liver catalase and [14C]NADPH and [14C]NADH revealed that unbound NADPH or NADH are substrates for an internal reductase and transhydrogenase reaction respectively; the unbound NADPH or NADH cause tightly bound NADP+ to become NADPH without becoming tightly bound themselves. This and other results provide insight into the function of tightly bound NADPH.

Ras activation in myelodysplastic syndromes: clinical and molecular study of the chronic phase of the disease

We studied N‐ras and Ki‐ras point mutations respectively at codons 12–13 and 12 in 15 patients with myelodysplastic syndromes (MDS) using the polymerase chain reaction (PCR) method for DNA amplification, and slot blot hybridization to allele specific oligonucleotide (ASO) probes. We analysed peripheral blood and bone marrow samples collected at diagnosis and repeatedly during the chronic phase of the disease to define when the activation occurred and in which haemopoietic cell populations, in order to establish possible relationships between clinical and molecular features. In three cases the N‐ras oncogene was mutated at codon 12 in every cell population, both at diagnosis and throughout the chronic phase. Point mutations were not seen at the 12 codon of the Ki‐ras oncogene. In patients lacking activated ras oncogene at diagnosis, mutations were not discovered during the entire period of observation. Therefore in our cases disease progression and leukaemic transformation did not correlate with the presence of the activated N‐ras. Our data suggest that ras activation occurs early in the pathogenesis of MDS and involves a haemopoietic progenitor with multiple differentiative capacity, without however conferring an apparent proliferative advantage on its progeny.

Favism: Erythrocyte Metabolism during Haemolysis and Reticulocytosis

Summary. The reduced activity of glucose‐6‐phosphate dehydrogenase (d‐glucose‐6‐phosphate; NADP+ i‐oxidoreductase; G6PD) in Mediterranean erythrocytes explains the precarious equilibrium of the hexose monophosphate pathway (HMP) and the susceptibility of these cells to haemolytic agents. G6PD‐deficient erythrocytes, in steady‐state conditions, have a low NADPH/NADP+ ratio, thus allowing the HMP to operate at its maximal intracellular rate and to compensate the intrinsic erythrocyte enzyme deficiency. Studies started soon after accidental intake of fava beans by sensitive G6PD‐deficient subjects demonstrate a decrease of both NADPH/NADP+ ratio and reduced glutathione. The metabolic effects induced by fava beans may be attributed to oxidative stress probably associated with an inhibitor effect of some unknown metabolite on the HMP. The availability of erythrocytes from subjects recovering from haemolysis with high reticulocyte counts and increased G6PD activity, provides new information on the rate of synthesis as well as on the in vivo decay of the mutant enzyme. Correlation of G6PD activity to reticulocyte count and extrapolation to an ideally homogenous population of reticulocytes reveal that the mutant enzyme is synthesized at a nearly normal rate. Furthermore, the present correlation allows an estimate of the in vivo half‐life of Mediterranean G6PD. The rate of decline of about 8 d observed in this study well correlates to the intracellular metabolic aspects of G6PD Mediterranean erythrocytes.

Histological subtypes of Hodgkin's disease in the setting of HIV infection

Abstract. The relative incidence of Hodgkins disease (HD) has been found to have increased approximately seven times in HIV-infected patients. We analyzed the histological distribution of HIV-associated HD with the aim of clarifying purported difference(s) from de novo HD. References on HIV/AIDS-associated HD were retrieved from the most complete databases. Nineteen articles were the subject of our analysis. Seventeen of them reported data on the histological type of HIV/AIDS-associated HD patients; the route of infection and age of the patients were also considered when available. According to the Petos methodology, histological types were compared with those from two large studies in the United States on de novo HD: 3,245 cases from the Surveillance, Epidemiology, and End Results (SEER) and 1,140 from Stanford University. The analysis of the two groups showed statistically significant differences (p<0.001) in the percentage of all histological types and odds ratios (OR) of the pooled effect of 0.4 (95% CI: 0.3–0.6) for lymphocyte predominance (LP), 0.3 (95% CI: 0.2–0.4) for nodular sclerosis (NS), 3.2 (95% CI: 2.6–3.8) for mixed cellularity (MC), and 6.3 (95% CI: 4.5–8.8) for lymphocyte depletion (LD). Comparison with the Stanford University series yielded similar results. Whilst retrospective and based on a limited number of cases, our data confirm a higher incidence of unfavorable histological subtypes in HIV-infected patients and show a reduction in the observed cases of good prognosis subtypes. Prospective studies, with careful histological observations, are required to better evaluate the characteristics of the LP subtype in the special setting of HIV infection.

Heterogeneity of clonal development in chronic myeloproliferative disorders

Recent reports have suggested a previously unexpected variability in the expression of the dominant neoplastic clone in myeloproliferative disorders (MPD). We evaluated 49 female patients with MPD and informative at the X‐linked androgen receptor (AR) locus to establish the X chromosome inactivation pattern of hemopoietic cells. Whereas in chronic myelogenous leukemia (CML) the granulocytes (PMN) were uniformly of monoclonal origin, a striking heterogeneity of clonal development was found in PMN from patients with other MPD, with up to 50% of them expressing a polyclonal pattern of X inactivation. Am. J. Hematol. 60:158–160, 1999.

Bound and unbound pyridine dinucleotides in normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes

We have measured, by a sensitive cycling assay, the concentration of bound and unbound dinucleotides in normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes. Measurement of free NADP in ultrafiltrates confirms that in normal erythrocytes almost all NADP is bound to cytosolic proteins. In glucose-6-phosphate dehydrogenase-deficient erythrocytes unbound NADP is significantly higher than in normal red cells and the NADP+/NADPH ratio is largely in favor of the oxidized form. In normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes essentially all NAD (bound and unbound) is in the oxidized state. About 50% of the total amount of NAD (NAD+ + NADH) is free in the cytosol, with a NAD+/NADH ratio greater than 100.