In situ hybridization

Papular follicular eruptions in human immunodeficiency virus-positive patients in South Africa

BACKGROUND

Papular and follicular eruptions, such as papulopruritic eruption, eosinophilic folliculitis, and infective folliculitis, are relatively common disorders in patients infected with the human immunodeficiency virus (HIV). These conditions may show considerable clinical overlap.

OBJECTIVE

To assess the relative proportion of pruritic papular cutaneous eruptions in South Africans with HIV-associated dermatoses, and to correlate the clinical and histologic features of these lesions.

METHODS

The clinical and histologic features of papular follicular eruptions were correlated in 40 consecutive black HIV-positive patients who underwent skin biopsy.

RESULTS

The clinical features were similar in all patients and consisted of widespread papules and pustules involving the face, limbs, and trunk. The most common histologic finding was acute suppurative folliculitis, seen in 27 patients (67.5%). In most cases, no cause was found for the suppuration. Papulopruritic eruption of HIV was diagnosed in six patients (15%), HIV-associated eosinophilic folliculitis in four (10%), Pityrosporum folliculitis in two (5%), and acne in one (2.5%). Concordance between the initial clinical diagnosis and the final histopathologic diagnosis was achieved in only 27.5% of cases.

CONCLUSION

Skin biopsy remains an important adjunct to the correct diagnosis and classification of papular and follicular eruptions in HIV-positive patients.

Transgenic models of human immunodeficiency virus type-1

Transgenic models have provided significant insights into HIV-1 pathogenesis, particularly with regards to Kaposi's sarcoma. HIV-associated nephropathy, the tissue-restricted expression of CNS strains of HIV-1, and the function of Nef in vivo. Both multigenic and single gene constructs have contributed to our understanding of HIV-1-induced diseases. While failing to provide models suitable for vaccine development, these transgenic models have provided great insight into HIV pathogenesis and may yet provide a means for the development and testing of molecular based therapies for AIDS.

The molecular diagnosis of cutaneous infection

Molecular biologic techniques are having an impact on many different aspects of medicine. In the realm of infectious agents, they are enhancing our diagnostic capabilities, allowing earlier detection of infection, avoiding the need of culturing infectious agents for the purpose of diagnosis, and broadening our concepts to include the presence of infection in the absence of a culturable agent or serologic evidence of infection. As one might expect, the applicability of these techniques varies with the type of infectious agent being considered. For example, in most bacterial infections the infectious agent can be cultured and accurately identified within 48 hours. It is therefore unlikely that molecular diagnostic techniques will replace the "gold standard" of culture in instances of bacterial infection. Mycobacterial and spirochetal agents, by contrast, do not fall into this category. Although the rapid growers (Mycobacterium fortuitum and Mycobacterium chelonae) pose little problem because they can be cultured within 1 week, M. tuberculosis, M. leprae and the slow growing mycobacteriae require long intervals to culture and/or identify. These organisms may in the future be identified with molecular diagnostic techniques. In the group of spirochetal pathogens, Treponema pallidum infection is, for the most part, easily diagnosed with serologic studies. In early seronegative cases, spirochetes can be detected in primary inoculation lesions by darkfield microscopy or in tissue sections with appropriate stains. Conversely, detection of Borrelia burgdorferi is currently fraught with difficulties. Tissue sections stained for these spirochetes are difficult to interpret, and serologic studies have shown widely variable results. The polymerase chain reaction has already been applied to the study of Borrelia infection with encouraging early results.(ABSTRACT TRUNCATED AT 250 WORDS)