DISSEMINATED BACILLUS-CALMETTE-GUERIN INFECTIONS IN PATIENTS WITH PRIMARY IMMUNODEFICIENCIES

The pathologic findings from biopsy or autopsy material in four patien ts, who were vaccinated with bacillus Calmette-Guerin (BCG) at birth i n Chile, are presented. Two patients had severe combined immunodeficie ncy, and two had more restricted cellular (T-cell) immunodeficiency wi th no evidence of human immunodeficiency virus infection. The patients had distinct skin nodules and nodular lesions in systemic organs and bone marrow. Three patients had regional BCG lymphadenitis. One patien t with severe combined immunodeficiency, however, had disseminated BCG without any local reaction. In all cases BCG strains of Mycobacterium were identified in a reference mycobacteriology laboratory. The histo logic lesions in most patients usually consisted of diffuse histiocyti c infiltrates with poorly formed granulomas and variable or no necrosi s. Histiocytes were plump and engorged with numerous acid-fast bacilli (AFB). In some areas the massive histiocytosis resembled a spindle ce ll neoplasm. Other histologic findings supported the underlying immuno deficiency. The pattern of histiocytic response and degree of microbia l killing depend on the host's immunocompetence. In the later stages o f disease or in severe immunodeficiency, there is a lack of granuloma formation and unimpeded proliferation of AFB. These findings are remin iscent of nontuberculous mycobacterial infections in AIDS patients. Ba cillus Calmette-Guerin dissemination has to be considered in immunocom promised individuals when the patient comes from other countries in wh ich such vaccinations are practiced.