First I have to remind you that I am not a doctor (I know you know this but the habit comes from working with attorneys for so many years) but I am going to try and shed some light on some things for you. The different tests are done to try and pinpoint which, if any, autoimmune diseases a person may have.
1. The homogeneous, or smooth pattern is found in a variety of connective tissue diseases, as well as in people taking particular drugs, such as certain antiarrhythmics, anticonvulsants or antihypertensives.
2. As for the titer of 1:160 is really borderline or very low on the "high" end.
The detection of autoantibodies against centromere protein B is of great diagnostic and prognostic importance for progressive systemic scleroderma (PSS).
Patients with Raynaud’s phenomena who test positive for anticentromere antibodies are more likely than patients with negative anticentromere antibody test results to develop limited scleroderma. Patients with any features of CREST syndrome are also likely to have anticentromere antibodies before all of the features emerge. To assist with diagnosis, patients suspected of having scleroderma should also be tested for anti-Scl-70 antibodies. These antibodies are seen in up to 40 percent of patients with diffuse scleroderma although they are usually not seen in limited scleroderma.
Besides systemic sclerosis, anticentromere antibodies are seen in a number of different conditions including drug-induced lupus, systemic lupus erythematosus (SLE), rheumatoid arthritis, Sjogren’s syndrome, and in overlap syndromes including lupus overlap syndromes, and conditions of systemic sclerosis/Sjogren’s syndrome overlap and systemic sclerosis/primary biliary cirrhosis overlap.