CD4 and tuberculosis: CD4 values from the TB–HIV+ group have been linked to the approximately similar CD4 values from the TB+HIV+ group, with the following maximum differences in CD4 counts between the two matched subjects for each of four pre-established ranges: maximum difference of 20 cells for CD4 counts < 100 cells/mm3, maximum difference of 40 cells between 100 and 200 cells/mm3, maximum difference of 60 cells between 200 and 500 cells/mm3 and maximum difference of 120 cells for CD4 counts > 500 cells/mm3.