Lymphocytic Subpopulation Profiles in Bronchoalveolar Lavage Fluid and Peripheral Blood From Tobacco and Marijuana Smokers: Cellular Analysis of PB

Table 4 displays the mean percentages and concentrations of PB lymphocytic phenotypes in the four study groups. The percentage of PB CD4 cells and the PB CD4:CD8 ratio (Fig 1) were significantly higher in MS and MTS compared with NS and TS. Marijuana, but not tobacco use, had a significant effect in increasing the percentage of PB CD4 cells, decreasing the percentage of CD8 cells, and increasing the PB CD4:CD8 ratio (two-way ANCOVA). No dose-response relationship of current or accumulated amount of marijuana or tobacco smoked with any of the bronchoalveolar or PB results could be demonstrated.
In addition to the chemical compounds responsible for its psychoactive effects, marijuana smoke contains many of the same respiratory toxins and irritants as tobacco. Previous studies have suggested that habitual use of marijuana produces many of the same effects as tobacco in causing respiratory symptoms and local inflammatory changes. Thus, the possibility that marijuana use could cause alterations of pulmonary immune and effector cells like those reported in tobacco smokers was a practical concern. Buy inhalers online read only This study was designed to compare the effect of heavy, habitual marijuana versus tobacco use on the profile of lymphocytic phenotypes in BAL fluid and PB. We examined four groups of carefully screened volunteers, who were comparable except for the history of habitual marijuana and/or tobacco use. Our findings indicate that tobacco and marijuana have different effects on lower respiratory tract and circulating T-lymphocyte subpopulations.
Analysis of our data confirms previous reports that both tobacco and marijuana use are associated with the accumulation of inflammatory cells in the lower respiratory tract. Increased concentrations of AM, lymphocytes, and neutrophils were observed among TS, and were particularly high in the MTS group. Marijuana use was associated with increased concentrations of AM, although the increase was less pronounced than with tobacco smoking. The light microscopic appearance of AM, many being particulate laden, was similar among TS, MS, and MTS. Among the subjects studied, heavy, habitual exposure to marijuana smoke was not associated with the alterations of bronchoalveolar T-lymphocyte subpopulations observed in TS. Significantly lower bronchoalveolar CD3 and CD4 cell percentages, higher bronchoalveolar CD3 and CD8 cell concentrations, and lower bronchoalveolar CD4:CD8 ratios were associated with tobacco, but not marijuana use. These results confirm a previous report of altered bronchoalveolar T-cell subpopulations among TS. Our findings suggest that the accumulation of lymphocytes in the lower respiratory tract predominantly involves CD8 cells, leading to little increase in concentration of CD4 cells, so that the percentage of CD4 cells and the CD4:CD8 ratio are reduced.

Table 4—Peripheral Blood Lymphocytic Phenotypes in the Four Subgroups (Data Expressed as Mean ± SEM)