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Human leukocyte antigens (HLA) have been reported to associate with the risk of aneurysmal subarachnoid hemorrhage (SAH) and poor outcome after SAH. Our aim was to identify HLA antigens that associate with the risk of fatal SAH in the Finnish population. Medical records of 600 cadaveric organ donors were reviewed to find organ donors that succumbed to SAH (n = 232) or brain trauma (n = 151). HLA antigen frequencies in these groups were compared with HLA frequencies in a reference population of 10,000 bone marrow donors. Chi-Square test with Bonferroni correction and multiplicative logistic regression models were used and false positive result probabilities (FPRP) were calculated. Alpha-level was 0.01. HLA-A3 associated with fatal SAH (p = 0.0014, OR 1.3 and 95%CI 1.1-1.6) and HLA-DR7 inversely associated with fatal SAH (p = 0.0040, OR 0.3 and 95%CI 0.2-0.6). HLA-A3 but not HLA-DR7 showed also a positive trend in donors with brain trauma. FPRP was below 0.5 for HLA-A3, but clearly above 0.5 for HLA-DR7. HLA-A3 seems to associate with fatal SAH in the Finnish population. Further studies are needed to reveal the pathobiologic mechanisms for how HLA-A3 associates with the risk of fatal SAH in Finns.

Tumor-specific CD8(+) T cells can potentially be activated by two distinct mechanisms of major histocompatibility complex class I-restricted antigen presentation as follows: direct presentation by tumor cells themselves or indirect presentation by professional antigen-presenting cells (APCs). However, controversy still exists as to whether indirect presentation (the cross-priming mechanism) can contribute to effective in vivo priming of tumor-specific CD8(+) T cells that are capable of eradicating cancer in patients. A clinical trial of vaccination with granulocyte macrophage-colony stimulating factor-transduced pancreatic cancer lines was designed to test whether cross-presentation by locally recruited APCs can activate pancreatic tumor-specific CD8(+) T cells. Previously, we reported postvaccination delayed-type hypersensitivity (DTH) responses to autologous tumor in 3 out of 14 treated patients. Mesothelin is an antigen demonstrated previously by gene expression profiling to be up-regulated in most pancreatic cancers. We report here the consistent induction of CD8(+) T cell responses to multiple HLA-A2, A3, and A24-restricted mesothelin epitopes exclusively in the three patients with vaccine-induced DTH responses. Importantly, neither of the vaccinating pancreatic cancer cell lines expressed HLA-A2, A3, or A24. These results provide the first direct evidence that CD8 T cell responses can be generated via cross-presentation by an immunotherapy approach designed to recruit APCs to the vaccination site.

During pregnancy, the non-classical major histocompatibility complex (MHC) class I HLA-G molecule is specifically expressed in trophoblast cells at the materno-fetal interface and may exert a local control of the immune response against viral infections. Human cytomegalovirus (HCMV) infection, which is the major cause of congenital defects, encodes multiple glycoproteins (US2, US3, US6, US10 and US11) that interrupt the MHC class I pathway of antigen presentation. The effect of some of these unique short (US) proteins on HLA-G expression has been previously studied, but little is known about the modulation of HLA-G cell surface expression during the course of HCMV infection which ensures expression of all of these US proteins. Using flow cytometry analysis, HLA-G cell surface expression was evaluated in HCMV-infected U373-HLA-G transfectant cells and compared with the modulation of the endogenous classical HLA-A2 molecules. The results indicated that HCMV infection down-modulated HLA-G cell surface expression, but later after infection and to a lesser extent than HLA-A2. Using various HLA-G/HLA-A2 chimeras, we showed that the unique structure of HLA-G cytoplasmic tail was partly involved in the resistance of HLA-G to viral down-modulation. Such limited down-modulation of HLA-G may have functional consequences in term of innate immunity against congenital HCMV infection.

We compared in an inducible expression system the individual effect of US2, US6 and US11 human cytomegalovirus (HCMV) proteins on HLA-E and HLA class Ia surface expression, assessing in parallel their influence on target susceptibility to NK cell clones. To this end, the RPMI 8866 B lymphoma cell line (HLA-A2, HLA-A3, HLA-B7, HLA-Cw7, HLA-E(R), HLA-E(G)) was stably cotransfected with the ecdysone receptor, together with the US sequences under the control of an ecdysone-inducible promoter. Biosynthesis of viral proteins was turned on by incubating transfectants with Ponasterone A. US6 down-regulated expression of all class I molecules, hampering target resistance to NK cell clones controlled by the CD94/NKG2A, KIR2DL2 and/or CD85j (ILT2 or LIR-1) inhibitory receptors. By contrast, US11 reduced the surface levels of class Ia molecules but preserved HLA-E; this rendered US11(+) cells sensitive to NK clones under the control of KIR2DL2 and/or CD85j, while their resistance to CD94/NKG2A(+)KIR2DL2(-) effector cells was maintained. US2 preserved as well HLA-E expression but selectively targeted class Ia molecules; in fact, HLA-A and HLA-C allotypes were down-modulated whereas HLA-B7 remained unaltered. US2(+) targets became sensitive to KIR2DL2(+) cells but remained resistant to CD94/NKG2A(+)CD85j(+) NK clones. The differential effects of US proteins on HLA class Ia and HLA-E likely reflect the evolutionary adaptation of HCMV to counteract NK-mediated surveillance.

No monoclonal antibodies (mAbs) are presently available to measure the total amount of beta2-microglobulin-free HLA class I heavy chain (FHC) in sera. The available ELISA-based double determinant immunoassay (DDIA), established to measure FHC, uses two mAbs (TP25.99 and HC-10) that recognize a monomorphic determinant expressed on all HLA-B/C FHC products and a determinant expressed only on some HLA-A FHC products. This restricted reactivity implies that, in addition to HLA-B/C, HLA-A FHC products are also detected in individuals bearing HLA A3 and/or A30 allotypes. The aim of this study was to establish whether such restriction results in the detection of low FHC levels in individuals lacking HLA A3 and/or A30 allospecificities. The FHC mean concentration (+/- SD) in 294 healthy blood/bone marrow donors (HBDs) was 0.24 (+/- 0.2) mg/l. The grouping of HBDs according to their HLA-A FHC product reactivity with one, both or no mAbs did not result in any statistically significant differences (Mann-Whitney test: P > 0.05) between their median FHC concentrations. Since the absence of differences in their FHC levels was not attributable to a difference in the percentage distribution of HLA allotypes associated with high or low HLA-B/C FHC expression, our results indicate that FHC HLA A3 and/or A30 products detected in DDIA by these two mAbs only minimally contribute to FHC serum expression and that the assay is not limited by the failure to detect HLA-A FHC products in A3- and/or A30- individuals.

Purpose: Spondyloarthropathy includes the subcategory of reactive arthritis (ReA). Spondyloarthropathies are commonly associated with certain human leukocyte antigen (HLA) alleles. Because we identified bacteria associated with ReA within the temporomandibular joint (TMJ), we now evaluate the frequency of HLA alleles in patients with TMJ pathology., Patients and Methods: HLA typing of 129 patients (121 females and 8 males) performed by standard microcytotoxicity technique. Thirty patients had only class I (HLA-A and -B loci) evaluated. Ninety-nine patients had both class I and class II (HLA-DR loci) evaluated. Identification of alleles at the C locus was not performed. The antigenic frequency in the study group was compared to US white control subjects using a 2-tailed Fisher's exact test with a Bonferroni multiple comparison adjustment., Results: The following class I HLA alleles, -A1 (32%), -A2 (50%), -A3 (33%), -B7 (23%), -B14 (14%), -B35 (20%), and -B44 (36%), including the B7 cross-reactive group (CREG) (49%) and class II alleles -DR1 (25%) and -DR4 (34%), were found to have an increased frequency in our patient group., Conclusions: Our study shows an increased frequency of several alleles that have been previously associated with arthropathy, and the alleles of the B7 CREG, in patients with TMJ pathology. Patients with these alleles may have an increased risk for the development of internal derangement of the TMJ as a consequence of the bacterial/infectious agents and host interactions with the subsequent cytokine/inflammatory response being influenced by their HLA phenotype., (Copyright 2002 American Association of Oral and Maxillofacial Surgeons)

Background: The blood vessels of a transplanted organ are the interface between donor and recipient. The endothelium in the blood vessels is thought to be the major target for graft rejection. Endothelial cells of a transplanted organ are believed to remain of donor origin after transplantation. We aimed to verify this concept., Methods: We studied biopsy samples from 12 renal transplants for the presence of endothelial cells of recipient origin. We used three different techniques: immunohistochemistry for MHC class-I antigens, immunohistochemistry for ABO-blood-group antigens, and in-situ hybridisation for X and Y chromosomes. After we had confirmed that these techniques did identify endothelial cells of recipient origin, tests were done in a second group of 26 patients to find out whether endothelial chimerism correlated with graft rejection., Findings: We found a strong correlation between the percentage of recipient endothelial cells in the peritubular capillaries and the type of graft rejection (r = 0.71, p < 0.0001). These cells were found mainly in grafts of patients who had had rejection, especially among patients with vascular rejection. In grafts of patients without rejection only sporadically recipient endothelial cells were detectable., Interpretation: Our data show that endothelial cells of the recipient can replace those of the donor. This replacement is associated with graft rejection. We postulate that endothelium that is damaged by vascular rejection is repaired by endothelial cells of the recipient.

Uveitis is a general term that refers to the inflammation of uveal tract, which is an important cause of blindness in young people. It is well known that uveitis can be the initial manifestation of a systemic disease (S.D.), and may appear years before the diagnosis of the primary disease. Uveitis should be integrated in a systemic study with proper testing. Therefore, the diagnosis is a matter for the ophthalmologist and the Specialist in internal medicine. We have made a retrospective study of 71 patients with chronic uveitis or panuveitis. We found 54.9% of primary uveitis and 45.1% of S.D. associated uveitis, most of them with Behçet's disease (16/71) and Ankylosing Spondilytis (7/71). HLA typing of the patients showed a decreased frequency of HLA A1 and HLA A3 antigens and an increased frequency of the HLA B27 antigen, when compared to a Portuguese control population. We confirmed the important role of HLA B27 as an independent susceptibility factor for anterior uveitis. The lowest HLA A3 frequency was observed in the group of S.D. associated uveitis, which could suggest that this antigen may play a role as a factor of resistance to uveitis.

Aims: A case report is presented in which an unexpected pathological diagnosis raised the possibility that biopsies of two patients were mixed-up. Since these biopsies were obtained from kidney transplant patients, the HLA-typings of both patients were known., Methods and Results: We developed an immunohistochemical method using HLA-class I specific monoclonal antibodies to recognize the donor and recipient antigens in these biopsies. Using this method we could confirm the identity of the patients of whom the biopsies had been taken., Conclusions: This method, which uses the highly polymorphic HLA-system, is potentially useful for rapid and easy verification of the identity of specimens if a mix-up is suspected.

Background: To determine the extent to which major histoincompatibilities are recognized after bone marrow transplantation, we characterized the specificity of the cytotoxic T lymphocytes isolated during graft-versus-host disease. We studied three patients transplanted with marrow from donors who were histoincompatible for different types of HLA antigens., Methods: Patient 1 was mismatched for one "ABDR-antigen" (HLA-A2 versus A3). Two patients were mismatched for antigens that would usually not be taken into account by standard selection procedures: patient 2 was mismatched for an "HLA-A subtype" (A*0213 versus A*0201), whereas patient 3 was mismatched for HLA-C (HLA-C*0501 versus HLA-C*0701). All three HLA class I mismatches were detected by a pretransplant cytotoxic precursor test., Results: Analysis of the specificity of the cytotoxic T lymphocyte clones isolated after transplantation showed that the incompatibilities detected by the pretransplant cytotoxic precursor assay were the targets recognized during graft-versus-host disease., Conclusions: Independent of whether the incompatibility consisted of a "full" mismatch, a "subtype" mismatch, or an HLA-C mismatch, all clones recognized the incompatible HLA molecule. In addition, some of these clones had undergone antigen selection and were clearly of higher specificity than the ones established before transplantation, indicating that they had been participating directly in the antihost immune response.

The aim of this study was to describe the histologic pattern of iron distribution in end-stage cirrhosis due to various causes and to test the reliability of the hepatic iron index (equal to hepatic iron concentration divided by age) in excluding or confirming associated hemochromatosis in such a condition. Large slices of the resected livers of 30 patients transplanted for alcoholic and/or viral end-stage cirrhosis were assessed histologically for iron distribution and biochemically for hepatic iron concentration in the least and the most iron-overloaded nodules of each case. HLA-A3 was used as the marker for the hemochromatosis gene in the population studied. Intranodular parenchymal siderosis was found in 23 cases (12 spotty, 11 diffuse) with diffuse intrabiliary iron deposits apparent in only two cases. Although in 14 patients the hepatic iron index was significantly high (> 1.9) so as to suggest hemochromatosis, these cases did not correspond to homozygous hemochromatosis with respect to the prevalence of HLA-A3 antigen. End-stage cirrhosis arising from different causes is frequently complicated by parenchymal siderosis that may mimic hemochromatosis, including a hepatic iron index greater than 1.9. The diagnosis of hemochromatosis in patients with end-stage cirrhosis, even those with a hepatic iron index greater than 1.9, should rely mainly on clinical and histologic data.

Background: We investigated patients who had unexplained hepatic iron overload and normal transferrin saturation., Methods: 65 patients with a median liver iron concentration of 65 mumol/g dry weight of liver (normal < 36 mumol/g), hyperferritinaemia (566 micrograms/L; normal < 400 micrograms/L), and normal transferrin saturations (32%) were compared with genetic haemochromatosis (GH) controls including homozygous (matched for sex and serum ferritin concentration) and heterozygous individuals. Relatives of patients who had ratios of liver iron concentration to age greater than 1.9 were also studied., Findings: The 65 patients were significantly older and had significantly less hepatic iron overload than individuals with genetic haemochromatosis. The frequency of HLA-A3 antigen was significantly lower in these patients than in individuals with homozygous (p < 0.0001) or heterozygous (p < 0.0002) GH. Five HLA-identical siblings of the patients had normal serum ferritin concentrations. Most of the patients (95%) had one or more of the following conditions; obesity, hyperlipidaemia, abnormal glucose metabolism, or hypertension., Interpretation: We have found a new non-HLA-linked iron-overload syndrome which suggests a link between iron excess and metabolic disorders. The current diagnostic criteria for genetic haemochromatosis should be reviewed.

Background/aims: Mild to moderate iron overload is found in most patients with porphyria cutanea tarda. This study aimed to evaluate whether iron overload in patients with porphyria cutanea tarda is related to the presence of a coexistent genetic hemochromatosis gene., Methods: A cohort study of 94 Italian patients with porphyria cutanea tarda (90 men and 4 women) and 20 relatives of five patients with iron overload were studied. Diagnosis of iron overload was assessed by transferrin saturation, serum ferritin and iron removed by phlebotomy to reach depletion. HLA typing by microlymphocytotoxicity test and duodenal ferritin analysis by immunohistochemistry were performed in a smaller number of patients. The chi square test was used to compare means and prevalences., Results: Iron overload was present in 62% of the patients. HLA-A3 prevalence was significantly higher (p < 0.01) in subjects with iron overload than in those without. A lack of duodenal ferritin was observed in 14/18 patients with and in 6/12 without iron overload. Family studies showed the presence of iron overload but not of porphyria cutanea tarda in HLA identical or semi-identical relatives of the patients., Conclusions: Italian patients with porphyria cutanea tarda and iron overload appear to have one or even two genes for genetic hemochromatosis.

We postulated that the severity of iron overload in homozygous hemochromatosis probands is related to the expression of HLA-A3 or D6S105 allele 8. Therefore, we used these markers to characterize Alabama hemochromatosis probands and normal control subjects. We then quantified the blood removed by phlebotomy to exhaust body iron stores and maintain normal serum ferritin concentrations in our hemochromatosis probands. Induction and maintenance phlebotomy requirements were significantly greater in presumed HLA-A3 homozygotes or in D6S105 allele 8 homozygotes than in homozygous probands lacking these markers. Intermediate values were observed in probands who were HLA-A3 or allele 8 heterozygotes, respectively. We also analyzed data from males and females separately. Among subjects of the same sex, the induction and maintenance phlebotomy requirements in subjects presumed to be HLA-A3 homozygotes or in allele 8 homozygotes were greater than those of other groups. Our results support the hypothesis that the severity of iron overload in hemochromatosis is determined predominantly by genetic factors, and provide evidence that two or more mutations for hemochromatosis exist. However, the design of our study does not permit a distinction to be made between allelic and locus heterogeneity for the hemochromatosis gene(s).

Gene-therapy of blood-borne disorders may be best achieved using hematopoietic stem cells (HSC) which have extensive self renewal potential as well as multilineage repopulating potential as a cellular target. The human HSC, which is CD34+Thy-1+Lin- has been isolated from fetal, adult bone marrow and cytokine-mobilized peripheral blood (MPB) (1-3). Results presented in this study show that the degree of mobilization of HSC into peripheral blood of cancer patients is highly variable and that the combined use of high dose chemotherapy and GM-CSF as a mobilization strategy is superior to the use of G-CSF with regard to the mobilization of true HSC. A multistep cell isolation procedure has been developed which utilizes high speed flow-cytometric cell sorting and allows the isolation of sufficient numbers of HSC from MPB to permit their use as an hematopoietic graft for clinical transplantation. Hematopoietic stem cells isolated from MPB are capable of self-renewal and differentiation into multiple hematopoietic lineages as shown by their behavior in both in vitro and in vivo assays. Mobilized PB mononuclear cells isolated from cancer patients are frequently contaminated with tumor cells. Using this cell isolation procedure, HSC preparations from patients with multiple myeloma have been created with greatly reduced tumor cell burdens. These CD34+Thy-1+Lin- cells are capable of being stably transduced at high efficiency (32-75%) by co-culture on a cell line producing recombinant retroviruses containing the neomycin-resistant gene. These HSC cell populations are likely ideal targets for hematopoietic cell-based gene therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

It is well established that relationships exist between the frequencies of certain HLA antigens and various disease entities. In an earlier study we found a significant correlation between the frequency of HLA-A2 and HLA-A3 and recurrent acute otitis media (rAOM). Of 34 HLA antigens analysed, HLA-A2 occurred in 80.0% and HLA-A3 in only 11.1% of children with rAOM as compared to 55.9% and 27.5%, respectively, in healthy controls. In the present study we investigated the frequencies of the same 34 HLA antigens in 40 children who had been regularly controlled at our clinic for chronic secretory otitis media (SOM) for at least 6 years. HLA-A2 was found in 52.0% (21/40) and HLA-A3 in 27.5% (11/40) of these children, figures on a par with those of healthy controls. The HLA-A2 frequency was significantly lower in chronic SOM patients than in rAOM children. Some other non-significant differences were also found between these two groups. The results indicate a difference in hereditary influence on the pathogenesis of rAOM and that of chronic SOM.

To determine the biological significance of high concentrations of non-haem iron in the livers of infants dying from sudden infant death syndrome (SIDS), liver samples were obtained at necropsy from 66 infants who died from SIDS and 28 control infants who died before 2.5 years of age. All were full term deliveries. Liver iron concentrations decreased rapidly with age in the two groups. Liver iron concentrations in the SIDS infants and controls were compared for those infants who died between 1 month and 1 year of age. The median liver iron concentration in the SIDS infants was 296 micrograms/g wet weight; significantly higher than the median of 105 micrograms/g in controls. There was an inverse relation between iron concentration and age in the two groups, but an analysis of covariance confirmed the significantly lower values in controls. The frequency (22%) of HLA-A3 in SIDS infants was similar to that expected for the United Kingdom population (25%) and does not implicate the gene for haemochromatosis as a cause of high liver iron concentrations. These findings show that the peak incidence of SIDS occurs when mean concentrations of iron in liver tissue are higher than at any other time of life. Although a primary causal connection seems unlikely, high tissue iron concentrations may lower resistance to infection and enhance free radical formation, leading to tissue damage.

Cytomegalovirus infection, a common complication in immunosuppressed graft recipients, bears an adverse impact on graft survival. Cytomegalovirus enhances the expression of the monotypic determinants of the class I major histocompatibility complex molecule by the endothelium, possibly rendering the endothelial cells more immunogenic and prone to attack by the allogeneic lymphocytes. In the present study, we focused on the effect of cytomegalovirus on the endothelial cell expression of different class I genes, on the relation between the extent of endothelial cell infection and the class I effect, and on the time course of the class I changes induced by the cytomegalovirus infection. Cytomegalovirus infection of primary cultures of human umbilical vein endothelial cells augmented the expression of the A2, A3, and B7 class I major histocompatibility complex genes when compared with uninfected cells. beta 2 microglobulin upregulation by the infected cells paralleled the changes in specific class I expression; this effect was significant only after 7 days after infection. Double immunocytochemical staining and fluorescence-activated cell sorter analysis revealed that the class I enhancement was uniform throughout the umbilical vein endothelial cell monolayer and not restricted to the cells that expressed cytomegalovirus early or late antigens. Ultraviolet-inactivated supernatants from infected umbilical vein endothelial cell did not increase class I expression on uninfected cells. In conclusion, cytomegalovirus might affect graft survival by amplifying the changes in class I expression beyond the sites of viral replication.

We investigated the iron status of 33 pyruvate kinase (PK) deficient patients, most of the cases reported in Italy. Serum ferritin (SF) was higher than the upper limit of the range of matched controls in 15/25 (60%) non-transfused patients (median 228 micrograms/l, range 58-3160 v 43, 22-310). Liver siderosis and fibrosis were found in 8/9, and cirrhosis in two who died at age 39 and 42 of complications of iron overload. SF was independent of age, sex, or severity of haemolysis. The prevalence of HLA-A3 antigen in PK deficient patients was not significantly different from that of our healthy population (29.6% v 23%). The HLA-A3 positive, non-transfused patients had significantly higher SF values than the HLA-A3 negative ones (median 675 micrograms/l, range 340-3160 v 145, 58-400). A pedigree study of six high SF-probands indicated that iron overload has a multifactorial pathogenesis. In particular, the association of PK deficiency-induced haemolysis, splenectomy and an additional factor (heterozygosity for idiopathic haemochromatosis, ineffective erythropoiesis) leads to severe iron accumulation. We suggest that monitoring iron status would be useful in PK deficient patients, particularly in splenectomized and HLA-A3 positive ones, to identify those at risk of iron overload and prevent the clinical consequences of iron accumulation.

Lymphocytic colitis is a newly described chronic diarrheal disorder. Although its etiology is unknown, the possibility has been raised that autoimmunity may play a role in both lymphocytic and collagenous colitis, a similar clinicopathologic illness. The frequencies of HLA class I and class II antigens were examined in 24 white patients with lymphocytic colitis and in 47 white patients with collagenous colitis. Frequencies in these two disorders were compared to control white populations and to each other. An increased frequency of HLA-A1 was noted in 16 of 24 lymphocytic colitis patients (66.6%) compared with 1089 of 3942 controls (27.6%) (P less than 0.005; relative risk 5.2). Furthermore, HLA-A3 was found in decreased frequency in lymphocytic colitis patients: 0 of 24 (0%) compared with 1017 of 3942 controls (25.8%) (P less than 0.05; relative risk 0.0). Collagenous colitis patients had no significant deviation from control frequencies of HLA antigens. In lymphocytic colitis, there was no significant increase in B8 or DR3 antigens, which are found in linkage disequilibrium with A1 and associated with many autoimmune diseases. Moreover, the frequency of autoimmune-associated class I HLA antigens was not increased in lymphocytic colitis. Statistically significant differences existed between lymphocytic and collagenous colitis in HLA-A1, A3, Bw6, and B7 antigen frequencies. The HLA patterns noted previously in other gastrointestinal disorders, including ulcerative colitis and Crohn's disease, were not apparent in lymphocytic or collagenous colitis. HLA typing provides further evidence that lymphocytic colitis is a distinct form of chronic intestinal inflammatory disease associated with HLA class I phenotypes.

The frequencies of a number of HLA antigens were investigated in 45 individuals with clinical recurrent acute otitis media (rAOM), defined as six or more episodes of AOM during a 12-month period, and were compared to those in a control group from the same district. HLA-A2 was found to occur in 80% of the rAOM group, as compared to 55.9% of controls (p less than 0.01). HLA-A3 antigen occurred in only 11.1% of the rAOM group in contrast to 27.5% of controls (p less than 0.05). Among 22 prospectively followed children without any AOM during their first 3 years of life, the frequencies of HLA-A2 and HLA-A3 antigens were comparable with those among controls.

Clinical data suggest the involvement of hereditary factors in children susceptible to recurrent acute otitis media. That relationships of varying degree exist between the frequencies of certain HLA antigens and various disease entities is well established. In the present study, we investigated the frequencies of a number of HLA antigens in 45 patients with clinical recurrent acute otitis media and compared these frequencies with those in a control group from the same district. The HLA-A2 antigen occurred in 80% (36/45) of the group with recurrent acute otitis media, as compared with 56% of controls. Of a subgroup of 11 children with recurrent acute otitis media who were prospectively followed up, 10 (91%) were HLA-A2 positive. The HLA-A3 antigen occurred in only 11% (5/45) of the group with recurrent acute otitis media as a whole (n = 45) in comparison with 28% of controls. Among 22 prospectively followed up children without any episode of acute otitis media during the first 3 years of life, the frequency of HLA-A2 was 45% (10/22) and that of HLA-A3, 32% (7/22). The results indicate the existence of a relationship between recurrent acute otitis media and the HLA-A locus, suggesting the involvement of genetic factors in the disease.

Thirteen unrelated patients with idiopathic haemochromatosis (eight men, five women) were studied. The diagnosis was based on clinical, biological, and histochemical findings. HLA typing was performed in all 13 and in all of their available first degree relatives (n = 31). HLA A3 was present in nine of 13 probands (69.2% compared with 18.8% in the group of 53 healthy blood donors and 22.4% in a selected Hungarian population (n = 1910). HLA B7 was present in five of 13 probands (38.4% compared with 11.3% and 14.6%). An A3B7 antigen association was found in five of 13 patients. The A3B7 haplotype was found in three, A2B12 and A2B38 haplotypes were found twice in 10 genotyped probands. Pedigree studies showed that there was one unaffected homozygote, 24 heterozygotes, and six non-carriers. Extended family and population studies are necessary to establish the prevalence of the gene in Hungary and an association with haplotypes other than A3B7.

Subacute thyroiditis is thought to be virally induced in genetically predisposed individuals because a strong association has been suggested recently between HLA-B35 and patients in whom subacute thyroiditis has developed. Two identical twin brothers were seen at our clinic with the same symptoms and date of onset of hyperthyroidism and enlargement and tenderness of the thyroid, which gave us a unique opportunity to study the genetic predisposition and treatment of this thyroid disease. Diagnostic criteria for subacute thyroiditis were met in both twins, including hyperthyroxinemia, suppression of thyroidal 123I uptake, increased erythrocyte sedimentation rate, transient painful goiter, and absence of antimicrosomal antibodies. Twin B was treated with corticosteroids, and a nonsteroidal anti-inflammatory agent was prescribed for Twin A. The mode of treatment used did not make a difference in affecting the course of the disease. The erythrocyte sedimentation rate was normal after 2 months from onset of symptoms. Results of viral studies were inconclusive. The same HLA typing was found in each twin: A3, B18, B35, Cw4, DR2, DRw10, DQw1. Thus, each was heterozygous for HLA-B35. We reviewed the literature and found a strong association between HLA-B35 and subacute thyroiditis in various ethnic groups tested. Our experience with these identical twins provides additional evidence to suggest that HLA-35 and perhaps Cw4 confer genetic susceptibility in acquiring subacute painful thyroiditis in a possible dominant mode of inheritance.

Associations between HLA types and serum antibodies to native and denatured type II collagen were sought in 105 patients with rheumatoid arthritis (RA). Antibodies were measured using a solid phase radioimmunoassay. There were no significant associations between any HLA antigen (A, B, or DR) and a high antibody titre to native collagen. There were significant associations, however, between HLA antigens and high antibody titres to denatured collagen. Although DR4 did not show an association, the phenotype A2+DR4+ did; this was not related to A2 as A2+DR- was not associated with a high antibody titre. No single B locus antigen showed an association, but several B locus antigens, B12, B15, and B40, were included in phenotypes with A2 and DR4 which were associated with a high antibody titre to denatured collagen. These HLA associations with anticollagen type II are best explained by a gene other than DR4 (but in linkage with it) which may regulate the antibody response to denatured collagen. If so, this would represent an HLA gene in addition to DR4 that is active in RA.

Multiple sclerosis has been shown to be associated with the presence of certain major histocompatibility (MHC) tissue antigens which are coded on chromosome 6. There are racial differences in the antigens associated with MS. The strength of the associations vary in different communities in Western Europe. We have investigated the association between MS and MCH antigens in Northern Ireland in a group of 104 patients. There is a particularly strong association between MS and HLA-DR2, 65.4% compared with 25.5% in 184 controls. A weaker association has been demonstrated with HLA-A3 (44.2% vs 26.5% in controls). There have been conflicting reports concerning an association of HLA-DW2 and HLA-DR2 with a rapidly progressive form of MS. Our data do not support that hypothesis.

HLA-A and HLA-B antigens were determined in 16 unrelated subjects orginating from Veneto affected by idiopathic haemochromatosis (IH). HLA-A3 was found in 13/16 patients vs. 300/1,348 controls (p less than 0.00005). Prevalences of A3,B35 haplotype were 0.4375 in patients vs. 0.0816 in controls (p less than 0.0005). Linkage disequilibrium analysis proved the existence of a positive third-order linkage disequilibrium among IH, HLA-A3 and HLA-B35 alleles. Our data confirm the close association of IH and HLA-A3 and prove the peculiar association of the disease with A3,B35 haplotype in north-eastern regions of Italy. The positive third-order linkage disequilibrium suggests a remote event (mutation, recombination or immigration) as origin for IH and A3,B35 association.