The HL-A7 histocompatibility antigen in sarcoidosis in relation to tuberculin sensitivity

[Human leukocyte antigens A and B in Turkish patients with sarcoidosis]

OBJECTIVE

Associations between human leukocyte antigens (HLA) and sarcoidosis have been reported in several studies. We aimed to investigate these associations in Turkish patients.

PATIENTS AND METHOD

We performed HLA-A, HLA-B, HLA-C, and HLA-D typing in 83 patients with sarcoidosis and in 250 healthy controls using a microlymphocytotoxicity method to investigate genetic susceptibility to the disease.

RESULTS

Because of significant violation of Hardy-Weinberg equilibrium at HLA-C and HLA-DQB1 loci, only results obtained at other HLA loci were used. Although HLA-A9, HLA-B5, and HLA-B8 allele frequencies were significantly higher in the patient group compared to the controls (odds ratio [OR]= 21.8, P= .015; OR= 9.34, P= .049; OR= 2.26, P= .031, respectively), none of the differences remained significant after applying the Bonferroni correction. HLA-A24, HLA-A26, and HLA-B62 alleles were significantly less frequent in the patient group compared to the controls (OR= 0.48, P= .018; OR= 0.19, P= .003; OR= 0.11, P= .044, respectively). However, the differences also failed to remain significant after Bonferroni correction.

CONCLUSIONS

These results suggest that both HLA may play significant roles (either increasing or reducing risk) in the pathogenesis of sarcoidosis and in its distinct clinical forms and laboratory findings.

Tuberculosis in patients with various HLA phenotypes

Tuberculosis patients and healthy subjects from six ethnic groups of the Soviet Union were HLA-A, -B, -C, and DR typed. The frequencies of the HLA-A, -B and -C antigens differed amongst the ethnic groups. With all groups, however, patients with tuberculosis showed a significantly increased frequency of HLA-DR2 and a reduced frequency of HLA-DR3 type. Unfavourable dynamics of tuberculosis was significantly associated with an increased incidence of B15 and DR2 and a reduced incidence of B27 and DR3. Family studies revealed that the inheritance of susceptibility to tuberculosis (from parent to offspring) is associated with the inheritance of certain HLA haplotypes. Tuberculosis patients bearing the DR2 antigen had increased levels of IgG antibodies to PPD and the frequency of B7 and, more particularly, DR2 was higher in anergic patients.

Association of HLA-DR with sarcoidosis. Correlation with clinical course

HLA-DR typing was performed in 58 Japanese patients with sarcoidosis. We found a significantly increased frequency of HLA-DRw52 (p less than 0.0007; pc less than 0.009) and DR5J (p less than 0.004; pc less than 0.05). (Corrected probability value is given as pc.) In 34 of 58 patients the disease resolved spontaneously. There was no significant difference between the frequency of DRw52 and the resolution rate of disease. The frequency of DR5J was increased significantly in the unresolved cases. Our results also suggest that DRw52 is concerned with onset of sarcoidosis and DR5J antigen has an effect on the clinical course of this disease.

High prevalence of familial sarcoidosis in an Irish population

Previous studies in the Republic of Ireland have demonstrated a high national prevalence of sarcoidosis. Observations in our sarcoid clinic suggested a high prevalence of the disease among siblings and prompted a survey to quantify this phenomenon. The study group comprised 114 index patients with biopsy proved sarcoidosis and a total sibling pool of 534 individuals. Eleven of the index patients (9.6%) were found to have at least one sibling with sarcoidosis. Of the 13 siblings thus identified, eight had biopsy proof of the disease, while the remaining five showed highly suggestive clinical and radiological evidence of sarcoidosis. There was no significant difference in the mode of presentation between the sibling pairs or between familial and non-familial cases and there was an equal distribution of like sex and unlike sex pairs. In only two instances was the temporal profile of onset of the disease suggestive of intrafamilial spread of a transmissible agent. The high prevalence of sarcoidosis among siblings reported here (2.4%) suggests that genetic factors significantly predispose to the development of sarcoidosis and that family members of affected patients should be screened for this disease.

Association of HLA B8 with spontaneous resolution in sarcoidosis

HLA may influence the natural history of some diseases. HLA frequencies have been compared in 164 healthy control subjects, 50 patients with sarcoid lung fibrosis, and 37 patients with sarcoidosis that resolved spontaneously. B8 was increased significantly in the resolved group compared to both healthy control subjects (p less than 0.001) and the fibrotic group (p less than 0.01). The results support the findings of other investigators, and are consistent with the hypothesis that inherited host factors, perhaps related to immune response, influence the clinical expression of sarcoidosis.

Chromosome analysis in patients with sarcoidosis

Chromosome analysis of lymphocytes from the peripheral blood of 20 patients with sarcoidosis and 10 healthy controls showed a significantly greater number of hypomodal cells among the patients. Two patients receiving systemic treatment with glucocorticoids had many chromosomal aberrations.

The genetic hypothesis for susceptibility to lepromatous leprosy

Evidence for genetic influence of the host response to infection with Mycobacterium leprae is reviewed. A complex segregation analysis is performed on data for 91 families from Mactan, Philippines, in each of which at least one offspring developed lepromatous leprosy. The data are not found to be inconsistent with an autosomal recessive hypothesis for susceptibility to lepromatous leprosy. Heritability estimates in the range of 80% were calculated for sib-sib pairs under the multifactorial hypothesis for susceptibility. It is argued that the multifactorial hypothesis is more in keeping with available immunologic, epidemiologic, and demographic data than is the single gene hypothesis.

Cellular immunity in Guamanians with amyotrophic lateral sclerosis and Parkinsonism-dementia

To test the hypothesis that host resistance factors may be abnormal in Guamanians in whom amyotrophic lateral sclerosis and Parkinsonism-dementia develop, cellular immunity was evaluated in both diseases and compared to that of Guamanians with other nervous-system diseases, normal adult Guamanians and non-Guamanians with amyotrophic lateral sclerosis and Parkinsonism. Diminished responses to skin-test antigens, lymphopenia, diminished per cent and total T cells and, less frequently, decreased mitogen responses were seen in Guamanian patients with amytorophic lateral sclerosis and Parkinsonism-dementia but not in the other patient or normal groups. Guamanian patients with amyotrophic lateral sclerosis and diminished cellular immunity had an increased frequency of HLA-Bw35 (P less than 0.005) and shorter mean duration of disease (P less than 0.05) than those with normal cellular immunity. In Parkinsonism dementia diminished cellular immunity was less strongly associated with HLA-BW35 (P less than 0.05) and was not associated with differences in duration of disease. Normal Guamanians and those with other nervous-system diseases showed no association of diminished cellular immunity with HLA-Bw35. The association appeared disease-related, with onset concomitant with the neurologic expression of Guamanian amyotrophic lateral sclerosis and Parkinsonism-dementia.

The HLA system and leprosy in Thailand

To investigate immunogenetics of leprosy, 205 leprosy patients (26 with tuberculoid, 57 with borderline-tuberculoid, 21 with borderline, 31 with borderline-lepromatous, and 70 with lepromatous leprosy) have been typed for HLA antigens, and compared with 183 healthy controls from the same region (Northern Thailand). There was no significant difference between the overall group of leprosy patients or the three borderline classes and the controls. The two polar forms, tuberculoid and lepromatous leprosy, however, showed significant associations: HLA-A2 is decreased and HLA-Bw17 is increased in tuberculoid leprosy; HLA-B7 is increased in lepromatous leprosy. When both polar forms are compared with each other, HLA-A2 is significantly higher, HLA-Bw40 lower in patients with lepromatous than in those with tuberculoid leprosy. The results are discussed with respect to the different immune responsiveness in the two polar forms of leprosy.

HLA association studies in black sarcoidosis patients

The frequencies of HLA antigens were determined in 32 black sarcoidosis patients and in 89 normal black controls. Aw23 was found in 23.6% of controls as compared with a lower frequency (6.2%) in patients (P = 0.06). No other associations were found.

Association between HLA-B7 and allergic reactions to insulin in insulin-dependent diabetes mellitus

Forty-four cases of insulin-dependent diabetes mellitus with cutaneous allergic reactions to insulin were typed for HLA-A and -B antigens. HLA-B7, which commonly is negatively associated with insulin-dependent diabetes mellitus, showed a positive association with insulin allergy. A second antigen, HLA-Bw21 may also be positively associated with local insulin allergy. These data were discussed in relation to heterogeneity of insulin-dependent diabetes mellitus and to the existence of B7-associated immune response genes for allergic-immunoreactivity to insulin.