Five-year Follow-up ofMicropolyspora faeniAntibody in Smoking and Nonsmoking Farmers

Abstract

To examine factors that influence changes in Micropolyspora faeni (MF) antibody titer in farmer's lung disease (FLD), we followed for 5 yr the prevalence of serum MF antibody and the epidemiologic factors (years on farm, hours in barn, and hay-handling time) among 92 dairy farmers in Hokkaido, Japan. The prevalence of MF antibody among nonsmokers was significantly higher than that among smokers: 27.1% versus 7.7% in 1979, 31.3% versus 2.9% in 1984. There was no remarkable change in overall prevalences of MF antibody between 1979 and 1984 (18.5 and 19.6%, respectively). However, out of 17 seropositive farmers, six (35%) became seronegative, and out of 75 seronegative farmers, seven (9.3%) became seropositive after 5 yr. The nonsmoking farmers who remained seronegative throughout the follow-up period were older and had worked longer on farms than the farmers with seroconversion. These results suggest that in addition to smoking habits, age and exposure time to MF influence the immune response to MF in dairy farmers. Out of 11 farmers who remained seropositive throughout the 5-yr period, two (18.2%) developed FLD. Therefore, continuously positive MF antibody is one of the risk factors in the development of FLD.

Longitudinal Changes of Sensitization to Farming-Related Antigens among Young Farmers

“…None of the sensitizations found at the first study reverted to negative. This observation seems to contradict previous studies [6, 7], postulating a fluctuating nature of precipitin positivity. The reason for this discrepancy is not obvious but may in part result from the small number of individuals tested.…”

“…Two observers agree that the persistence of precipitins over time may be a risk factor for farmers’ lung [6, 7]. The actual incidence of this disease, however, is low even in precipitin-positive individuals [6].…”

“…In summary, young farmers in the Tyrol have a high probability of becoming sensitized to thermophilic actinomycetes and fungi already during their first years of work. The persistence of antibodies over time may place them at a higher risk of contracting farmers’ lung [6, 7]. The relationship between workplace-related factors, especially the presence of moldy hay and the lack of a hay dryer, and allergic sensitization has been confirmed [4].…”

“…In a recent investigation, we could demonstrate that the prevalence of allergic sensitization to farming-related antigens is high even at young age and that a clear-cut association to workplace conditions can be found [4]. The impact of these findings for the long-term outcome is unknown, especially so as the pattern of sensitization may change with time [5, 6, 7]. We have therefore undertaken to reexamine allergic sensitization in young Tyrolean farmers and its relationship with workplace conditions, and to study changes in lung function as a possible indicator of allergy-mediated respiratory disease.…”

Elevated Soluble lnterleukin-2 Receptors in Young Healthy Cigarette Smokers: Lack of Association with Atopy or Airways Hyperresponsiveness

“…However, cigarette smokers also have decreased natural killer cell number and function, lower serum IgG levels and a diminished immunoglobulin response to certain aeroantigens, suggesting a suppressive effect of tobacco smoke [1,4,5].…”