CD1 genotyping of patients with Mycobacterium malmoense pulmonary disease

Mycobacterium malmoense is an opportunistic mycobacterium that occasionally causes disease in non-immunosuppressed individuals. As only a few individu als exposed to these organisms actually develop clinical disease, it is pos sible there is a genetic component to susceptibility. CD1 molecules are Cap able of presenting antigens from more virulent mycobacteria to T cells; the refore, we were interested in discovering whether recently described polymo rphisms in CD1 molecules modulated susceptibility to M malmoense pulmonary disease. The CD1 system comprises five genes (CD1A, -B, -C, -D, and -E) loc ated on chromosome 1 (1q22-23). CD1 molecules are structurally and function ally related to major histocompatibility complex (MHC) class I molecules an d are expressed on dedicated antigen-presenting cells. The primary function of CD1 molecules is to present lipid and glycolipid antigens to T cells. W e have developed an allele-specific polymerase chain reaction-sequence-spec ific primer (PCR-SSP) method of CD1 genotyping. Using this method, we compa red the allele and haplotype frequencies of CD1 in 49 MV-negative patients with M malmoense pulmonary disease with those in 342 normal controls. The C D1A and CD1E alleles were nominally identified as CD1A*01, CD1A*02, CD1E*01 and CD1E*02, and the control gene frequencies were found to be 5%, 95%, 67 % and 33%, respectively. No significant difference was observed between the patient and control cohorts. Positive linkage disequilibrium values of 0.7 3 were observed between CD1A*02 and CD1E*01 (P<0.0001; <chi>(2) test), and 0.94 between CD1A*01 and CD1E*02 (p<0.0001; <chi>(2) test). Typing was also performed for two previously described CD1D alleles (CD1D*01 and CD1D*02) although only CD1D*01 was detected.