Scrapie is a transmissible degenerative disease of the central nervous system occurring naturally in sheep. It belongs to the group ofprion diseases also affecting man in which an abnormal isoform of the host-encoded prion protein (PrP) accumulating in the brain is responsible for neuronal death. Three main polymorphisms have been described in the sheep PrP gene, at positions 136, 154 and 171. A strong association between susceptibility/resistance to natural scrapie and a dimorphism at codon 136 of the ovine PrP gene has been reported in several breeds, including Romanov. This dimorphism, however, is not found in all scrapie-affected breeds. We have compared the PrP genotypes of Lacaune sheep obtained from enzootically affected flocks with those of apparently healthy sheep. A third variant at codon 171 was also evidenced. The results were compared with those obtained in a single experimental Romanov flock orally challenged with nematode parasites in which scrapie suddenly appeared and killed 80 % of the sheep. We present evidence that, even in different epizootological circumstances, the major genetic factor controlling the susceptibility/resistance to natural scrapie in sheep, is represented by codon 171 genotype of the PrP gene. We also suggest that a modification of the allelic effects of codon 136 can occur in heavily infected animals.

We explored simultaneously 14-3-3 protein, neuron-specific enolase (NSE), and one astroglial protein, S-100, recently proposed as Creutzfeld-Jakob disease (CJD) markers, in the cerebrospinal fluid (CSF) of 129 patients with suspected CJD. Cutoff values for NSE and S-100 were established at 25 and 2.5 ng/ml, respectively. The highest sensitivity was observed for S-100 (94.2%) followed by 14-3-3 (89.8%) and NSE (79.7%), while the highest specificity in CJD diagnosis was obtained with 14-3-3 protein (100%) as compared with NSE (91.5%) and S-100 (85.4%). No influence of sex, genotype at codon 129 of the prion protein gene, time between sampling, and death or disease duration has been found. Based on 90 cases initially referred as ‘probable’ or ‘possible’ CJD, with 14-3-3, NSE, or S-100 we could correctly discriminate between ‘CJD’ or ‘non-CJD’ categories in 94.4, 86.5, and 90% of the cases, respectively. When limited to ‘possible CJD’ cases, diagnosis based on one of the three CSF proteins was accurate in 98, 90.7 and 87.3%, respectively. In view of the fact that the CSF 14-3-3 protein test alone has the highest specificity and good sensitivity, it appears that there is no additional advantage at the moment to include NSE and/or S-100 protein in the exploration of clinically suspected CJD cases.

Summary. Systemic mastocytosis (SM) is characterized by proliferation of mast cells in various organs, which may release a wide variety of mediators, thereby explaining the broad clinical spectrum of disease manifestations. The potentially life-threatening systemic symptoms and tumoral proliferation are poorly controlled despite the use of several cytotoxic chemotherapies and/or symptomatic treatments. Twenty consecutive adult SM patients with histologically confirmed bone marrow (BM) involvement received interferon-a subcutaneously (1-5 million units/m 2 /d, with progressive dose intensification over the first month of treatment) and were evaluated after 6 months of therapy. Seven of them had previously received symptomatic treatments, including steroids, which were ineffective. Among the 13 patients treated for at least 6 months, seven partial and six minor responses, mainly concerning vascular congestion and skin lesions, were obtained, while BM infiltration remained unchanged in 12 patients. The significant reduction of mast-cell mediator levels after 6 months of treatment was not predictive of clinical remission. The rate of depression was unexpectedly high (seven patients; 35%). Two patients died soon after starting therapy (one myocardial infarction, one septic shock). Six months of interferon-a may relieve vascular congestion in adults with SM, probably by inhibiting mast-cell degranulation.

Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). As the other sporadic or infectious prion disease forms, they are almost all characterized by the accumulation in the brain of an abnormal misfolded form of the patient's PrP. Brain extracts can often transmit the disease once inoculated in a recipient animal. Inherited prion diseases with Creutzfeldt‐Jakob disease (CJD) phenotype are autosomal forms, although sporadic cases have been reported. We report three novel mutations of the PRNP gene in unrelated patients with clinical and histopathologic features of CJD. The three mutations were missense: c635G>A (E196K), c656G>A (V203I) and c680G>C (E211Q). Familial history of neurologic disorders was evidenced for patients carrying the E196K and E211Q mutations. E196K would be predicted to have more severe effects on protein stability than V203I and E211Q. These mutations expand the spectrum of mutations in PRNP and reduce the proportion of CJD patients in whom genetic alterations have not been found. Hum Mutat 15:482, 2000. © 2000 Wiley‐Liss, Inc.

Human prion diseases are characterized by the accumulation in the brain of an abnormal form of the prion protein. Prion protein polymorphisms seem to play a key role in the pathogenesis of these diseases, probably by enhancing the amyloidogenic properties of the protein. We performed prion protein gene (PRNP) coding sequence analysis in 57 French subjects with Creutzfeldt-Jakob disease (CJD) and found a mutation of the PRNP coding sequence in nine subjects (15.8%); the mutation corresponded with a known family history of CJD in only three of these subjects. In 41 definite and probable cases without known PRNP mutations, codon 129 genotyping revealed an excess of the homozygous 129Met/Met genotype corresponding to a 3.4-fold increased risk of developing CJD when compared with the two other genotypes. We also found that the 129Val/Val genotype, which mainly governs susceptibility to iatrogenic CJD, does not seem to predispose to sporadic CJD.