Discovery of Human Immunodeficiency Virus Infection by Immunohistochemistry on Lymph Node Biopsies From Patients With Unexplained Follicular Hyperplasia

Immunohistochemical diagnosis of human infectious diseases: a review

BACKGROUND

Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.

MAIN BODY

Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.

CONCLUSION

IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.

The Usefulness of HIV-1p24 in Detecting the Presence of HIV Infection in Histopathology Tissue Specimens

Introduction HIV (human immunodeficiency virus)-associated immunodeficiency is the single most important acquired immunodeficiency in humans, underlying several diseases. The presence of HIV infection may be unsuspected or undetected in tissues due to latency or failure of the consulting physician to document it on the requisition form. HIV-1p24 protein is a component of the HIV particle capsid that can be exploited serologically and immunohistochemically to detect the presence of HIV infection. This study aimed to assess the usefulness of HIV-1 p24 immunohistochemistry in detecting the presence of HIV infection in histopathology tissues in a resource-challenged setting.

Materials and Methods HIV-1p24 immunohistochemical expression was evaluated in 59 cases from the archives of both Nnamdi Azikiwe University Teaching Hospital (NAUTH) and Pathocon Specialist Clinic and Research Institute over a 10-year period. Pathology consult forms of all clinically and morphologically suspected cases of Kaposi sarcoma and their blocks were retrieved, recut, and reviewed using hematoxylin and eosin, and then subjected to HIV-1p24 immunohistochemical staining.

Results Of the 59 cases, 38 expressed p24, whereas 21 were negative. Fifteen of the positive cases had no prior documented evidence of HIV infection. Five cases with clinically known statuses, four positive and one negative, were found to be negative and positive, respectively, following HIV-1p24 immunohistochemical staining, probably due to usage of ELISA (enzyme-linked immunosorbent assay) detection kit only and long term antiretroviral therapy. HIV infection was commoner in the third and fourth decades of life.

Conclusion HIV-1p24 is a useful low-cost immunohistochemical marker in detecting the presence of HIV infection in histopathology specimens, even in previously unsuspected cases.

Identifying HIV infection in diagnostic histopathology tissue samples--the role of HIV-1 p24 immunohistochemistry in identifying clinically unsuspected HIV infection: a 3-year analysis

AIMS

Because of the clinical difficulty in identifying the early stages of human immunodeficiency virus (HIV) infection, the histopathologist often has to consider the diagnosis of HIV in tissue samples from patients with no previous suspicion of HIV infection. The aim was to investigate the practicality and utility of routine HIV-1 p24 immunohistochemistry on tissue samples received at a London histopathology laboratory.

METHODS AND RESULTS

Over a 3-year period, HIV-1 p24 was evaluated immunohistochemically on 123 cases. Of these, 37 (30%) showed positive expression of p24 in lesional follicular dendritic cells (FDCs). Of these 37 cases, 11 were not clinically suspected to be HIV+ and had no prior serological evidence of HIV infection. These cases represented lymph node biopsies, tonsillar and nasopharyngeal biopsies and a parotid excision. In addition to expression on FDCs, in 22 cases (60%), p24 also highlighted mononuclear cells and macrophages. p24 was also useful in confirming the presence of HIV in lymphoid tissue in non-lymphoid organs such as the lung, anus, salivary gland and brain. Immunonegativity occurred in occasional known HIV+ cases, probably related to treatment or tissue processing.

CONCLUSIONS

This study confirms the usefulness of this technique in detecting unsuspected HIV infection in lymphoid and non-lymphoid organs on histopathological material and should be part of routine evaluation of lymph nodes and lymphoid tissue in other organs if morphological or clinical features suggest HIV infection.

Cystic lymphoid hyperplasia of the parotid gland in HIV-positive and HIV-negative patients: quantitative immunopathology

BACKGROUND

Benign lymphoepithelial lesions of the parotid include a spectrum of disorders ranging from lymphoepithelial sialadenitis (LESA) of Sjögren syndrome to lymphoepithelial cysts (LEC) and both human immunodeficiency virus (HIV)-related and -unrelated cystic lymphoid hyperplasia (CLH). They share a common microscopic appearance characterized by epimyoepithelial islands and/or epithelial lined cysts in a lymphoid stroma. However, they differ greatly regarding their etiology, clinical presentation, and management.

OBJECTIVE

The purpose of this study was to establish specific immunophenotypic profiles for these diverse disease entities.

STUDY DESIGN

Four cases of HIV+ CLH, 5 cases of HIV- CLH, 3 cases of LESA of Sjögren syndrome, and 3 cases of sporadic LEC were quantitatively analyzed for distribution of lymphoreticular cell subpopulations, using antibodies against CD20, CD45RO, CD4, CD8, CD57, and CD68.

RESULTS

The cystic lesions in both the HIV+ and HIV- cases were microscopically analogous. However, a marked decrease in the interfollicular CD4:CD8 ratio was observed in all HIV+ CLH cases, which was statistically significant when compared with the HIV- cases (P = .02) and cases of LESA of Sjögren syndrome (P = .03). No significant differences regarding the distribution of CD20+ B lymphocytes in epithelial cyst lining or the interfollicular or follicular distribution of CD20+, CD45RO+, CD57+, and CD68+ cells were present among the different groups.

CONCLUSION

Analysis of the interfollicular CD4:CD8 ratio may offer a simple immunophenotypic approach in the distinction of HIV+ from other lymphoepithelial lesions of the parotid gland, when HIV status is unknown and p24 immunohistochemistry is not readily available.

Postinfection passive transfer of KD-247 protects against simian/human immunodeficiency virus-induced CD4+ T-cell loss in macaque lymphoid tissue

BACKGROUND

Preadministration of high-affinity humanized anti-HIV-1 mAb KD-247 by passive transfer provides sterile protection of monkeys from heterologous chimeric simian/human immunodeficiency virus infection.

METHODS

Beginning 1 h, 1 day, or 1 week after simian/human immunodeficiency virus-C2/1 challenge (20 50% tissue culture infective dose), mature, male cynomolgus monkeys received multiple passive transfers of KD-247 (45 mg/kg) on a weekly basis for approximately 2 months. Concentrations and viral loads were measured in peripheral blood, and CD4 T-cell counts were examined in both peripheral blood and various lymphoid tissues.

RESULTS

Pharmacokinetic examination revealed similar plasma maintenance levels ranging from 200 to 500 microg/ml of KD-247 in the three groups. One of the six monkeys given KD-247 could not maintain these concentrations, and elicitation of anti-KD-247 idiotype antibody was suggested. All monkeys given KD-247 exhibited striking postinfection protection against both CD4 T-cell loss in various lymphoid tissues and atrophic changes in organs compared with control group animals treated with normal human immunoglobulin G. The KD-247-treated groups were also partially protected against plasma viral load elevation in peripheral blood samples, although the complete protection previously reported with preadministration of this mAb was not achieved.

CONCLUSION

Postinfection passive transfer of humanized mAb KD-247 with strong neutralizing capacity against challenged virus simian/human immunodeficiency virus-C2/1 protected CD4 T cells in lymphoid organs.

Reactive lymphadenopathy in Ugandan patients and its relationship to EBV and HIV infection

In Uganda, a large number of biopsied enlarged lymph nodes is diagnosed as reactive lymphoid hyperplasia (RLH) not indicative of a specific etiologic agent. The aim of this study was to examine the spectrum of RLH in lymph node biopsies in Ugandan patients and their possible association with HIV and EBV infection. Ninety biopsies were retrieved and included in the study. The predominant RLH type was follicular, found in 45 (50.0%) of the cases. Positive staining for LMP-1 was found in six cases (6.7%), EBNA-1 in 36 cases (40.0%) and HIV1-p24 in 15 cases (16.7%), respectively. A combination of EBV and HIV positivity was found in 46 (52.2%) of the cases. EBV infection was associated with hyperplastic germinal centers (p<0.01). HIV1-p24 positive staining was associated with follicle fragmentation (p<0.01) but not hyperplastic GC (p=0.08). In conclusion, RLH in Ugandan patients is frequently associated with EBV and HIV infection. The histologic features of the lymph nodes are not specific for any individual infection, but a high number of EBV-positive cases are associated with hyperplastic GC, and follicular fragmentation is characteristic of HIV infection.