The role of human leucocyte antigen genes in the development of malignant disease

Mycosis fungoides: HLA class II associations among Ashkenazi and non-Ashkenazi Jewish patients

BACKGROUND

An immunogenetic mechanism has been suggested to play a role in the pathogenesis of mycosis fungoides (MF). While results of studies on HLA class I associations haveproved inconsistent, two previous studies showed that certain HLA class II alleles were significantly increased among North American caucasian patients with MF: HLA-DRB1*11 and DQB1*03.

OBJECTIVES

To investigate the possible HLA class I and class II associations with MF among Jewish patients.

METHODS

The patient group comprised 68 Jewish patients with MF: 38 Ashkenazi and 30 non-Ashkenazi. The control group comprised 252 healthy Jewish volunteers: 132 Ashkenazi and 120 non-Ashkenazi. Tissue typing for HLA class I (A and B) was performed using the National Institutes of Health microlymphocytotoxicity technique. DNA-based low-medium resolution analysis for DRB1* and DQB1* alleles was performed using polymerase chain reaction (PCR) amplification with sequence-specific primers. For those alleles found to have significantly increased frequency, high-resolution analysis was done by means of PCR sequence-specific oligotyping.

RESULTS

The allele frequency of HLA-DRB1*11 was found to be significantly increased but only among Ashkenazi patients with MF (30% vs. 19% in the controls; P = 0.034). High-resolution analysis for DRB1*11, not previously performed, suggested that its greater frequency is due to the increased number of Ashkenazi MF patients with the DRB1*1104 allele (P corrected = 0.036). Analysed together, DQB1*03 alleles (DQB1*0301-0304) had a significantly greater frequency in MF as a group as compared with controls (47% vs. 33%, P = 0.003). DQB1*0301 was demonstrated to be the specific allele associated with MF in Jewish patients (allele frequency of 36% vs. 23% in controls; P corrected = 0.0068), which was not the case for North American caucasian patients with MF. No greater frequencies of any of the HLA class I A or B antigens were found.

CONCLUSIONS

Our findings further demonstrate the 'universality' of MF HLA class II susceptibility alleles, i.e. HLA-DRB1*11 and HLA-DQB1*03, suggesting that HLA polymorphism is likely to be important in the pathogenesis of MF in Jewish patients, as it is in North American caucasian patients. Not previously reported is our finding that HLA-DRB1*1104 is the specific allele more prevalent among patients with MF. Our study also underscores some differences in HLA profiles between non-Jewish and Jewish patients with MF and between Ashkenazi and non-Ashkenazi Jewish patients, indicating the possibility of diverse HLA disease associations in populations with different genetic backgrounds. Our study provides further evidence for the lack of association between HLA class I and MF.

HLA-DQB1*0303 and *0301 alleles influence susceptibility to and prognosis in cutaneous malignant melanoma in the British Caucasian population

The presence of lymphocytic infiltrates within primary cutaneous malignant melanoma (CMM), documented spontaneous tumour regression and genetic linkage with chromosome six in familial cases all suggest that immunogenetic factors may modulate disease progression. An association has been suggested between HLA DQB1*0301 and CMM in US patients but no such investigation has been performed in the UK population. Polymerase chain reaction-based HLA class II DRB1, DQA1 and DQB1 typing of 99 UK-based CMM patients was performed using DNA extracted from archival formalin-fixed and paraffin wax-embedded surgical biopsies, enabling retrospective access to clinical follow-up data. An increase in frequency of the HLA DQB1*0303 genotype among CMM patients was identified compared to control subjects (19.2% vs 5.8%; Pc=0.003; RR=3.9) while HLA DQB1*0301 was associated with more advanced and therefore poorer prognosis primary tumours (e.g. HLA DQB1*0301 allele frequency: 20.1% vertical growth phase vs 4.0% horizontal growth phase; Pc=0.03; RR=6.1). These findings suggest that the HLA DQB1 locus, and in particular the HLA DQB1*0303 and *0301 alleles, may play an important role in determining the risk of development and the prognosis of CMM within the UK population.