Three groups of people with different clinical histories and manifestations to house dust were skin tested with Dermatophagoides pteronyssinus extracts. The results showed close correlation between positive skin tests and clinical sensitivity to dust. The correlation was not, however, perfect and, although D. pteronyssinus is a major factor in house dust allergy, it does not appear to be the sole antigen involved.
The response to lepromin and Kveim antigens was compared and studied in 15 leprosy patients who were tuberculin negative. Of the 11 lepromin positive tuberculoid patients, 4 were Kveim positive, 1 was equivocal, and the rest were negative. Of the four lepromin negative lepromatous patients, one gave a positive Kveim test while the other three were negative. It has been shown that false-positive Kveim reactions are found in a higher percentage of South Indian leprosy patients than in those of other backgrounds, such as Japanese and Malaysian Chinese patients. It is also suggested that no definite relationship exists between the reaction of leprosy patients to lepromin and Kveim antigens. We further suggest that the anergy exhibited by lepromatous patients to the antigen of M. leprae is specific, as evidenced by the positive Kveim response in one lepromatous patient.
Kveim tests using a validated material have been undertaken in Malaysia on 39 patients (32 Chinese; 4 Malay and 3 Aboriginal) with lepromatous or tuberculoid leprosy. All the patients had been treated for leprosy, most for two or more years. The tests were read microscopically. Of the 21 lepromatous patients one gave a weak positive and two an equivocal Kveim test whereas four of the nine tuberculoid patients gave equivocal or weak Kveim positivity. Only the tuberculoid form elicits a higher proportion of granulomas than might be expected in a comparable normal population. Of nine patients (8 lepromatous; 1 tuberculoid ) who failed to sensitize well to tuberculin
following two BCG vaccinations, two gave equivocal Kveim tests similar in appearance to those in the other groups.
A survey of 227 patients from 5-60 years of age revealed the presence of positive histoplasmin skin tests in 10.5 per cent. and positive complement-fixation tests in 19-8 per cent. Sputum from 13 of the 37 patients who had a positive complement-fixation test were cultured for H. capsulatum but with negative results. Exposure to infection by the fungus is equally distributed among the different race and age groups. A careful and constant watch should be kept for histoplasmosis in all chest hospitals as a certain number of cases may be present. It tends to elude diagnosis unless specially sought as it resembles the clinical picture of tuberculosis or other granulomatous disease. It presents a field for further investigation and research in Malaya.