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M Martinetti

Publications and source records attributed to M Martinetti.

88 records · Page 5Linked to original sources
PubMed1988

Immunogenetic heterogeneity of uveal melanoma.

Investigations have been performed to identify genetic markers in uveal melanoma (UM) patients. The immunogenetic heterogeneity of the histologically different forms of UM until now has been little analyzed. We subdivided our UM patients, all typed for class I and II HLA antigens and for Bf polymorphism, into two groups: 1) those with a high degree of malignancy (with nonspindle cells) and 2) those with a low degree of malignancy (with spindle cells). The deviated frequencies of class I HLA antigens (A32, B27) seem to be involved in the predisposition to spindle cell melanoma, while HLA class II (DR3, DR7) and class III (Bf F) strongly mark the worst form of UM. Different Gm allotype distributions between the two histological types of UM were also found.

Gene Frequency↗
PubMed1988

Report of one case of familial sarcoidosis.

Familial sarcoidosis is a quite unusual occurrence. We describe two affected sisters, in which the clinical features of the disease were fairly similar. Interestingly, the two patients and two unaffected siblings share an HLA haplotype [A10 (26); CW7; B16 (38); DRW6; DQW1] rare in Caucasians.

Adult↗
PubMed1988

Decreased in vitro lymphocyte stimulation and reduced sensitivity to IL-2 in patients with alopecia areata.

The response to the T-cell growth factor interleukin-2 (IL-2) and to phytohemagglutinin (PHA) and concanavalin A (Con-A) were investigated in 63 patients with alopecia areata (AA) and in control subjects. The proliferative response to mitogens and to IL-2 determined by measuring [3H]-thymidine incorporation 72 h after stimulation is generally decreased in AA patients. The response to mitogens and to IL-2 was related to the response to the topical sensitizer SADBE (squaric acid dibutylester) and patients with no allergic reaction to this substance showed a marked reduction in lymphocyte stimulation, especially with IL-2. HLA typing of 34 of the 63 AA patients was performed in order to investigate the immunogenetic basis of hyporesponsiveness to topical sensitization. The relationship between reduced in vitro response to mitogens and particularly to IL-2, and in vivo response to sensitization to SADBE and the presence of HLA-DR5 are discussed.

Administration, Cutaneous↗
PubMed1987

Human leukocyte antigen region involvement in the genetic predisposition to alopecia areata.

Human leukocyte antigens (HLA) of classes I and II were studied in 127 patients with alopecia areata (AA). The patients were subdivided into different groups depending on hair loss area, sex, pathogenesis, response to topical immune modulators (squaric acid dibutylester and diphencyprone) and age of onset of the disease. The frequencies of class I HLA markers (loci A, B, C) were not significantly different from the controls. However, among the class II antigens (loci DR, DQ), the frequency of DR5 was increased in both alopecia areata and alopecia universalis when compared with the control group. In particular, DR5 was strongly linked to the early-onset form. The highest DR5 frequency (62%) was found in the group of patients which presented both the early onset and the most severe form of the disease (p less than 0.01; RR = 3.14). A decrease of the HLA-B8 phenotype frequency was found in the alopecia areata group versus the alopecia universalis one. No significant deviation was found between the female patients and the control group. However, an increase of CW3 and a decrease of DR1 was seen in the males. In the group including 'combined', 'prehypertensive', 'atopic' alopecia of Ikeda's classification the frequency of HLA-A28 and DR5 was increased and that of DR1 was decreased in comparison with the 'common' type of alopecia and the controls. It was not possible to find any relationship between these genetic markers and the response to topical immune modulators.

Adolescent↗
PubMed1987

Human MHC class III genes, BF and C4. Polymorphism, complotypes and HLA class I and II associations in the Lombardy population (Italy).

The polymorphisms of the fourth component of human serum complement and factor B (BF) (controlled by class III MHC genes) was investigated in a panel of 250 unrelated individuals from the Lombardy population, previously HLA typed (A, B, C, DR, DQ antigens) and in 25 families. Nine different alleles at the C4A and eight at the C4B loci were detected. At both loci, alleles without a gene product (i.e. "null alleles") were observed with high frequency: 8.2% for C4A "nulL" and 10% C4B "null". As expected from allele frequencies the most common haplotype was C4A*3, C4B*1 (52%). The most common BF alleles, BF*S and BF*F had a frequency of 77.7% and 17.7% respectively, while the gene frequencies of SO.7 and F1 were 2.9 and 0.9% respectively. The association of complotypes and HLA haplotypes was analysed in 50 chromosomes. The most common combination, defined by class I, II and III alleles was B35-S31-DR5 (11%) followed by B16(38)-S31-DR5 with a frequency of 6.5%. Two duplications at the C4B locus were detected. A new variant (C4A*X) strikingly faster than that of the C4A*6 product was identified in two related individuals (aunt and nephew). The practical advantages of complotype determination in disease association studies and in healthy population is discussed.

Alleles↗
PubMed1986

Genetic heterogeneity in uveitis.

Eighty-nine unrelated patients with ocular inflammation (uveitis) were investigated for the HLA class I and class II genetic markers, We subdivided our patients according to: 1. the anatomical location of the lesion; 2. the temporal course of the disease; 3. the aetiology. We eliminated from our sample of patients the individuals with other systemic diseases. We could not find an association with B27, as previously described, but we did note statistically significant differences between the class II antigen distribution in the different anatomical subgroups. HLA-DR3 seems a marker of the intermediate form of uveitis (p, uncorrected 0.03); the absence of DR1 in the patient group with posterior uveitis may be a protecting factor (p. uncorrected less than 0.01); the presence of DR4 in all cases of panuveitis is statistically significant (p, uncorrected = 0.0006).

Adolescent↗
PubMedDate not supplied

Sharing at the major histocompatibility complex affects the secondary sex ratio in differing ways.

We analysed the effect of HLA loci on the secondary sex ratio, and investigated whether allele sharing between parents and between mother and child, or child homozygosity, affected the viability of male embryos, which are generally less resistant to unfavourable conditions during pregnancy. The sharing conditions at the B and DR loci showed significantly differing effects: HLA-B seemed to favour female births, while, in pregnancies subsequent to the first, HLA-DR seemed to favour male births. Both HLA-B and DR loci seemed to work through immunological mechanisms.

Alleles↗
PubMedDate not supplied

HLA and hypocomplementemia: the disadvantage of carrying the HLA-B35 and the silent alleles of the C4 complement component.

Hypocomplementemia is an extremely complex phenomenon: we devoted our attention to its immunogenetic basis, particularly to the HLA haplotypes involved and to the study of C4 polymorphic genes. With this in mind we analyzed a group of unrelated patients with hypocomplementemia and 15 families suffering from specific C4 deficiency. Firstly, we performed a population analysis in order to identify a statistically significant association: HLA-B35 and C4BQ0 alleles, in the total group of hypocomplementemic individuals, seem to be associated with the primary disease. Secondly, we defined HLA haplotypes clear-cut segregation in the hypocomplementemic families and we identified the most common HLA haplotypes carrying B35 and C4 null allele associated with this condition. With the aid of correspondence analysis and the Transmission Disequilibrium Test (TDT), we measured the strength of this association. In this work, mainly through family analysis, we envisaged a potentially interesting genomic trait, within HLA, close to B locus, that seems to be involved in hypocomplementemia itself and perhaps in hypocomplementemia-related disorders.

Algorithms↗
PubMedDate not supplied

Hierarchy of baby-linked immunogenetic risk factors in the vertical transmission of hepatitis C virus.

Mother-to-infant transmission of Hepatitis C Virus (HCV) represents the major cause of pediatric HCV infection today. Immunogenetic influence has been poorly investigated and mainly confined to HLA-class II serological polymorphisms. Among 290 parities, 135 from Pavia and 155 from Bergamo, of HCV-RNA-infected Italian women, 21 babies (7.24%) were HCV-RNA positive at birth and steadily positive over 20 months of life. All the 21 infected babies and 44 randomly selected uninfected ones, born to HCV-RNA+ mothers but steadily negative for HCV-RNA during a follow-up of 2 years, and their mothers were investigated for HLA-G, -C, -DRB1, -DQA1 and -DQB1 genomic polymorphisms. Among the different covariates, HLA-Cw*07, -G*010401, -DRB1*0701, -DRB1*1401 and homozygosity for HLA-G 14bp deletion can be considered as risk factors for HCV vertical transmission. On the contrary, protection was conferred by the HLA-DQB1*06, -G*0105N, -Cw*0602, DRB1*1104 and -DRB1*1302 alleles. Our initial question was: has the immunogenetic profile any role in the protection of the fetus growing in an infected milieu and, if so, is it independent from the other non-immunogenetic parameters? The answer to both questions should be yes.

Adult↗
PubMedDate not supplied

A first study of cytokine genomic polymorphisms in CFS: Positive association of TNF-857 and IFNgamma 874 rare alleles.

OBJECTIVE: In the past two years we have developed a biological bank of genomic DNA, cDNA, serum and red blood cells of Italian patients with certified CFS from the two Italian referral centers for the syndrome. Recent studies have shown an imbalance in cytokine production in disease states similar to Chronic Fatigue Syndrome (CFS), such as sickness behavior, both in animals and in humans. However we notice that serum cytokine concentrations are often inconstant and degrade rapidly. With this in mind, we investigated cytokine gene polymorphisms in 80 Italian patients with CFS in order to ascertain whether in this group of patients it is possible to describe a genetic predisposition to an inflammatory response. METHODS: We analyzed the promoter polymorphisms of IL-10, IL-6 and the IFNgamma 874 T/A polymorphism in intron 1 with a PCR-SSP method (Cytogen One Lambda Inc. Canoga Park, CA, U.S.A) in 54 patients and TNF-308 G/A and -857 C/T promoter polymorphisms with a PCR-RFLP method (in 54 and 80 patients respectively). RESULTS: There is a highly significant increase of TNF -857 TT and CT genotypes (p = 0.002) among patients with respect to controls and a significant decrease of IFN gamma low producers (A/A) (p = 0.04) among patients with respect to controls. CONCLUSIONS: We hypothesize that CFS patients can have a genetic predisposition to an immunomodulatory response of an inflammatory nature probably secondary to one or more environmental insults of unknown nature.

Adolescent↗
PubMedDate not supplied

Factors leading to the appearance, after BMT, of cytotoxic antibodies against T, B and activated T lymphocytes: critical appraisal.

In order to investigate the role of lymphocytotoxic antibodies, acquired after allogeneic and autologus bone marrow transplantation, we studied 309 sera from 42 transplanted patients (16 adults and 26 children). We tried to correlate antibody elicitation towards T, B and activated T lymphocytes with the following parameters: genetic (recipient's and donor's sex, HLA profile), clinical (recipient's primary disease, GvHD, transplant outcome) and technical (bone marrow purging, auto-or allotransplant). There is evidence that anti-T and -B cytotoxic antibodies appear earlier than anti-activated T antibodies. Anti-HLA specific antibodies seem to be produced by the transfusional stimulus: they appear early after BMT and wane after the first year. Humoral responsiveness seems to be age related (adults are more responsive than children) and conditioned by GvHD (the level of cytotoxic antibodies decreases when GvHD is prevented by bone marrow purging). The level of cytotoxicity is significantly lower in the sera of autotransplanted patients compared with the allotransplanted ones. It appears that anti-activated T antibodies are produced by cell activation at different times in adults and children: in adults this occurs during GVHD and in children during the relapse of disease.

Adolescent↗
PubMedDate not supplied

Possible interaction between HLA and Ig light chain markers in susceptibility to uveitis.

We detected and analysed the Gm and Km allotype markers of Ig in 57 patients affected by uveitis, an ocular inflammation with multifactorial etiology. The aim of the present study has been to investigate the possibility that different immunogenetic factors predispose to the various forms of the disease. We found a statistically significant alteration of Km(1) allele frequency (relative risk = 2.65). That seems to predispose to anterior uveitis, especially when associated with a blank at HLA-A locus (RR = 7.83) but predispose to the posterior form when in combination with HLA-B38 (RR = 19.24). Moreover, a high frequency of Km(1)/A blank phenotypic association was noticed in uveitis with infectious aetiology (RR rising to 10.44). The Km(1) genotype may itself predispose to uveitis and its combination with different HLA alleles could enhance the susceptibility to one particular form rather than to another.

Adolescent↗