Crohn disease: susceptibility and disease heterogeneity revealed by HLA genotyping.

Predisposition to Crohn disease (CD) seems to be genetically determined but, though several reports on the matter, the association between HLA antigens and the disease is still controversial. PCR-SSP high resolution typing in 107 CD patients, and in subgroups selected according to clinical features, showed a positive association with the rare haplotype DRB1*07, DQB1*0303 both in the overall patients (p = 0.002; pc = ns) and in the subgroup of nonfistulized patients (p = 0.0008; pc = 0.032). Moreover, the protective role of the haplotype DRB1*03, DQB1*0201 (p = 0.029) was confirmed also in Italian patients, whereas no strong association with HLA class I alleles has been found. In addition, variability of the HLA alleles frequency in CD subgroups was observed, supporting the hypothesis of a genetic heterogeneity of the disease and suggesting that HLA alleles distribution in selected groups may allow to identify patients with probably different prognosis or associated complications.

Common human leukocyte antigen alleles in pemphigus vulgaris and pemphigus foliaceus Italian patients.

Pemphigus refers to a group of autoimmune blistering skin diseases, mainly identified as pemphigus vulgaris and pemphigus foliaceus, both characterized by the presence of autoantibodies against keratinocyte adhesion molecules, leading to loss of cell-cell adhesion with consequent blister formation. Pemphigus vulgaris is reported to be associated with human leukocyte antigen DR4 and/or DR6 whereas no data are available on pemphigus foliaceus, except for the endemic Brazilian form (fogo selvagem), which is reported to be associated with DR1 and DR4. We here report human leukocyte antigen molecular typing on a total of 87 patients, 61 with pemphigus vulgaris and 26 with pemphigus foliaceus, versus 128 healthy matched controls. Generic typing showed an increase of DRB1*04 and DRB1*14 and a decrease of DRB1*07 in both pemphigus vulgaris and pemphigus foliaceus patients. Molecular subtyping of DR4+ and DR14+ subjects showed a highly significant association between the DRB1*1401 and both pemphigus vulgaris (p < 0.0001) and pemphigus foliaceus patients (p < 0.0001) together with a significant increase of the linked DQB1*0503 (pemphigus vulgaris p < 0.0001; pemphigus foliaceus p < 0.0001). Moreover, whereas the association between DRB1*0402 and pemphigus vulgaris (p < 0.0001) has been confirmed, no significant association between a specific allele of the DR4 group and pemphigus foliaceus, has been found. Therefore, at least in Italian patients, pemphigus vulgaris and pemphigus foliaceus share DRB1*1401 and DQB1*0503, as susceptible human leukocyte antigen alleles, whereas DRB1*0402 is only found associated with pemphigus vulgaris. The observation that both diseases, pemphigus vulgaris and pemphigus foliaceus, carry the same susceptible human leukocyte antigen alleles has been interpreted as a common genetic background predisposing to pemphigus as, like in other autoimmune disorders, it is not sufficient to explain the onset of the disease on the basis of the sole aforementioned alleles. Other linked genes and/or environmental factors should play a facilitating role in the outbreak of pemphigus, either pemphigus vulgaris or pemphigus foliaceus.

Molecular analysis of HLA DRB1 and DQB1 polymorphism in Italian melanoma patients.

Several studies have reported association between a variety of malignancies and human leukocyte antigens (HLA) genes. However, conflicting data have been reported on HLA association and melanoma. We report here serologic and molecular analysis by polymerase chain reaction sequence-specific primers (PCR-SSP) and PCR sequence-specific oligonucleotides (PCR-SSO) of HLA class II DRB1 and DQB1 loci in 132 patients with melanoma and 102 ethnically matched controls. Molecular typing of DQB1 polymorphism showed a significant increase of DQB1 *0501 (25.0% versus 14.7%; p = 0.038). Moreover, an increase of DQB1*0301, which was present in 62.8% of patients and 54.9% of controls (p = 0.136), was noted. Because DQB1*0501 and DQB1*0301 are strongly linked to DRB1*01 and DRB1*11, respectively, both found increased in patients with melanoma, to look for a more stringent association with a particular allele specificity of the DR locus, we performed PCR-SSP high-resolution typing of DR1 and DR11 positive subjects. Results showed no significant difference between the frequencies of the alleles found in patients with respect to controls. Analysis of the distribution of DQB1*0501 and DQB1*0301 according to the AJCC clinical stage of the disease showed no significant difference in the frequency of these alleles between the localized and the metastatic form of the disease. However, none of the HLA class II alleles showed significant association after correction of the p value. These results indicate that HLA class II alleles may not contribute to a strong susceptibility to melanoma, at least in Italian patients.

JURL-MK1 (c-kit(high)/CD30-/CD40-) and JURL-MK2 (c-kit(low)/CD30+/CD40+) cell lines: 'two-sided' model for investigating leukemic megakaryocytopoiesis.

Two novel cell lines (JURL-MK1 and JURL-MK2) have been established from the peripheral blood of a patient in the blastic phase of chronic myelogenous leukemia. The cells grow in a single cell suspension with doubling times of 48 h (JURL-MK1) and 72 h (JURL-MK2). Cytogenetic analysis has shown that JURL-MK1 is hypodiploid whereas JURL-MK2 is near triploid and that both cell lines retain t(9;22). Moreover, JURL-MK1 and JURL-MK2 have a bcr/abl-fused gene with the same junction found in the patient's fresh cells, and both cell lines express the b3/a2 type of hybrid bcr/abl mRNA. The morphology and immunophenotype of these cell lines are reminiscent of megakaryoblasts. In both lines, a limited but consistent percentage of cells expresses gpIIbIIIa (CD41a), gpIIIa (CD61) and CD36, with no expression of gplb (CD42b), glycophorin A, hemoglobin and CD34. Both cell lines are clearly positive for CD33, CD43, CD45RO and CD63, while CD13, CD44, CD54, CD30 and CD40 are specific features of JURL-MK2. Among cytokine receptors, CD117/SCF-R is strongly displayed by a large fraction of JURL-MK1 cells but is hardly detectable on about 20% JURL-MK2 cells. Both cell lines are clearly positive for CD25/IL2R alpha, while a marked expression of CD116/GM-CSF-R and CDw123/IL3R alpha is restricted to JURL-MK2. Induction of cell differentiation in vitro has demonstrated that TPA is able to modulate the JURL-MK1 phenotype, causing an increased expression of platelet-associated antigens. The JURL-MK2 phenotype is easily modulated by both TPA and DMSO, which cause an increased expression of CD41a and CD117 accompanied by a decreased expression of CD30. Proliferation studies demonstrated that JURL-MK1 cell growth is enhanced by stem cell factor, while JURL-MK2 proliferation is unaffected by this cytokine. JURL-MK1 and JURL-MK2 are two novel cell lines with divergent biological features, representing a 'two-sided' model for investigating new aspects of megakaryocytopoiesis.