ańczak M

Strong association of HLA-Cw6 allele with juvenile psoriasis in Polish patients

Association of psoriasis vulgaris with HLA-C is not equally strong in different human populations. It has not yet been studied in Polish patients at DNA level, but only by serology that is inadequate for HLA-C. Therefore, we examined the distribution of HLA-C alleles by means of low resolution PCR-SSP in 102 Polish psoriatics and 123 healthy controls. We have found significantly higher representation of HLA-Cw*06 (odds ratio, 18.73; P(cor)<0.001) and significantly lower representation of HLA-Cw*07 (odds ratio, 0.41; P(cor)<0.038) in patients than in controls. Association of HLA-Cw*06 with psoriasis was even stronger in early age at onset (0-20 years) group: odds ratio, 77.71; P(cor)<0.001. Therefore, our population seems to belong to those with strong association of psoriasis with HLA-Cw*06.

Distribution of LILRA3 (ILT6/LIR4) deletion in psoriatic patients and healthy controls

The leukocyte immunoglobulinlike receptor (LILRA3; ILT6) gene is localized on human chromosome 19 in the region 19q13.4, in the leukocyte receptor complex that encodes leukocyte receptors LILR (ILT/LIR), killer cell immunoglobulinlike receptors (KIR), LAIR, Fc IgA receptor, and others. The biologic role of the LILRA3 molecule and the nature of its ligand are not known. Comparison of LILRA3 gene sequence with those of other LILRs suggests LILRA3 is a soluble molecule. If LILRA3 binds human leukocyte antigen (HLA) class I molecules like other LILRs whose ligands are known, then it might block recognition of HLA by these receptors, influencing immune response and susceptibility to HLA class I associated disease. A deletion of LILRA3 gene was found in a minority of British population. We typed 108 healthy individuals from the Low Silesia region and 103 patients diagnosed with psoriasis vulgaris (a disease associated with HLA class I antigen, HLA-Cw6) for LILRA3 to examine whether LILRA3 deletion was distributed differently in patients affected with the disease. No differences in frequencies of the LILRA3 deletion were found between controls and patients or between HLA-Cw6(+) and HLA-Cw6(-) controls or patients, suggesting that LILRA3 has no role in psoriasis.

Are Single Nucleotide Polymorphisms of the Immunoglobulin A Fc Receptor Gene Associated with Allergic Asthma

Background: Eosinophils are important components of allergic inflammation. The immunoglobulin A (IgA) Fc receptor (FcαRI), encoded by the FCAR gene, is a possible candidate for eosinophil activation at mucosal surfaces, where IgA is abundant. Both elevated cell surface expression of FcαRI and increased avidity for IgA were described on eosinophils from allergic subjects. The aim of our study was to examine the possible association of FCAR gene polymorphisms with allergic asthma. Methods: We screened three regions of the FCAR gene: (1) the promoter region, (2) exon 3, encoding the first extracellular domain (EC1), and (3) exon 5, coding for the transmembrane and cytoplasmic domain, for new and published polymorphisms using a sensitive temperature gradient gel electrophoresis technique and compared their frequencies in 112 patients diagnosed with allergic asthma and 100 healthy controls. Results: Six polymorphisms, including two novel ones, were detected. No differences between patients and controls were found in the distribution of any of these polymorphisms. Conclusion: FcαRI polymorphism does not seem to be a risk factor in allergic asthma. Nevertheless, this is the first report on the distribution of 6 single nucleotide polymorphisms of the FCAR gene in a human population and the first study on FCAR polymorphism in allergic asthma.

Studies on binding of HIV-1 p24gag peptide to HLA-Cw3+ cells.

Human major histocompatibility complex class I antigens, HLA-C, are expressed on the cell surface at approximately a tenfold lower level than HLA-A and -B. We hypothesized that the expression of HLA-C is limited by the quantity of high affinity peptides which bind to these molecules, thus allowing only a small fraction of HLA-C molecules to be transported and/or to remain stable on the cell surface. If this assumption is correct, then the addition of exogenous peptide should increase cell surface HLA-C expression. To verify the hypothesis, we pulsed lymphoblastoid cell line PAJ (HLA-Cw3+) with synthetic HIV-1 p24gag 145-152 peptide, known to be presented to T-lymphocytes by HLA-Cw3 molecule. PAJ (HLA-Cw3+) cells bound approximately two times more of the peptide than HAJ (HLA-Cw3-), and four times more than 500/C9 (HLA-Cw3-) cells. Accordingly, overnight pulsing of PAJ cells with the p24gag 145-152 peptide caused an increase in class I HLA expression detected on the cell surface by flow cytofluorimetric analysis with anti-HLA-B,C monoclonal antibodies but not by anti-HLA-A antibody. In contrast, HLA-Cw3- cells treated in the same manner did not show any increase of HLA class I expression. Our data suggest that low concentration of high affinity peptides within the cell may be one of the factors limiting cell surface expression of HLA-C molecules.

Allelic distribution of complement components BF, C4A, C4B, and C3 in Psoriasis vulgaris.

Psoriasis vulgaris is a multifactorial disease; the strongest association was established with the HLA complex. The actual disease-predisposing gene(s) has not been identified yet, but several genes from this region were examined in addition to HLA-C and -B. However, HLA-linked complement component polymorphic genes were not extensively studied. Therefore, we typed 67 psoriatic patients for alleles of the HLA-linked complement components BF, C4A and C4B. Alleles of C3, encoded on another chromosome, were established in parallel as a negative control. Frequencies in patients were compared with those in unrelated healthy controls, 100 individuals for C4A and C4B, 890 for BF and 4719 for C3 We found no association of BF alleles with disease, similarly to C3. Among C4 alleles, C4B*3 was present in 13.4% of patients as compared with 1% of controls (OR, 15.36; 95% CI, 1.897-124.42; P=0.0009), and C4A*6 was present in 19.4% of patients versus 7% of controls (OR, 3.20; 95% CI, 1.202-8.508; P=0.0155). The high frequency of C4B*3 in psoriatics has not been described so far. These results suggest a contribution of C4 genes themselves or a closely linked gene to the susceptibility to psoriasis.

Human in vitro cell lines verification by minisatellite DNA restriction fragment length polymorphism

Four families of human in vitro cell lines were tested for minisatellite restriction fragment length polymorphism (RFLP) using multilocus probes MZ1.3 and/or 33.15 after digestion of DNA with restriction enzymes HinfI or HaeIII. These results confirmed that (i) the RFLP pattern is relatively stable in established cell lines and, therefore, could be used as a specific marker of a cell line identity, (ii) the use of MZ1.3 and 33.15 probes permits the identification of hybridomas and (iii) one of the cell lines tested, a lymphoblastoid cell line HAJ, may possess a hot spot of mutation.