Lymphocytopenia, T-lymphocyte subsets, and colorectal polyps in automotive pattern and model makers

Several studies have found pattern and model makers to be at increased risk for colorectal polyps and colorectal cancers. One study found an increased prevalence of lymphocytopenia. The association of total lymphocyte, CD4 (T-helper cell), CD8 (T-suppressor cell), CD2 (total T-cell), and CD16 (natural killer cell) counts with biopsy-proved colorectal polyp status was investigated in 70 patternmakers participating in one or more of four sequential screenings. In logistic regression analyses after adjusting for age or trade years, pack-years smoked, and material worked with most, a history of any type of polyp was significantly associated with total lymphocyte count (odds ratio of 2.01 for a 500 cell/cc decrease, P = 0.03), and somewhat associated with decreased CD4 and CD2 counts (P values of 0.06 and 0.07, respectively). In linear regression models adjusted for age, pattern and model makers had (regardless of polyp status) significantly lower CD4, CD8, CD2, and CD16 counts than did laboratory reference controls (P value less than 0.01 for each comparison). These findings appear consistent with a sequence of carcinogenesis initiated by pattern and model makers' work-place exposures that depress immune surveillance thus promoting the development of colorectal polyps as a precursor of carcinoma.