Profound reduction of CD4+ lymphocytes without HIV infection: two cases from the horn of Africa

HIV False-Positive Test in the Setting of CD4 Lymphocytopenia

In 2016, we implemented a non-targeted Emergency Department (ED)-based HIV screening program at our academic medical center following revised CDC guidelines utilizing the Abbott Alinity 4th generation HIV-1/2 antigen (Ag)/antibody (Ab) immunoassay (Abbott Laboratories, Abbott Park, IL). Following the CDC algorithm, after reactive fourth-generation testing, HIV-1/2 Ab testing is conducted. Patients undergoing acute seroconversion (acutes) may express p24 Ag but have a negative confirmatory Ab test. Acutes have the same laboratory signature during the ED encounter as those that are false positive (False +), and the two patient groups are denoted as "equivocals" until viral load testing specifies a definitive HIV status. Among False + patients (Ab/Ag positive, Ab negative, viral load undetectable), there have been limited studies on those also demonstrating a reduction in CD4+ count, an uncommon phenomenon known as "idiopathic CD4 lymphocytopenia." We review a patient with a reactive fourth-generation HIV Ab/p24 Ag test on two separate occasions. Despite lymphopenia with a reduced CD4 count, his symptoms resolved, and an RNA PCR test did not detect any presence of HIV (False +). This patient was unique as False + patient with p24 Ag reactive, as well as a coincidental low CD4 count in the absence of HIV infection. A low CD4 count is often a sign of significant HIV infection.

Fatal dermatophytic pseudomycetoma in a patient with non-HIV CD4 lymphocytopenia

Dermatophytic pseudomycetoma is a rare invasive infection, involving both immunocompetent and immunocompromised individuals. Since the discovery of inherited immune disorders such as the impairment of CARD9 gene, extended dermatophyte infections are mostly ascribed to any of these host factors. This study is to present and explore the potential causes in a fatal dermatophytic pseudomycetoma patient. We present a chronic and deep pseudomycetoma caused by the common dermatophyte Microsporum canis which ultimately led to the death of the patient. Mycological examination, genetic studies and host immune responses against fungi were performed to explore the potential factors. The patient had decreased lymphocyte counts with significantly reduced CD4⁺ T cells, although all currently known genetic parameters proved to be normal. Through functional studies, we demonstrated that peripheral blood mononuclear cells from the patient showed severe impairment of adaptive cytokine production upon fungus-specific stimulation, whereas innate immune responses were partially defective. This is, to our knowledge, the first report of fatal dermatophytic pseudomycetoma in a patient with non-HIV CD4 lymphocytopenia, which highlights the importance of screening for immune deficiencies in patients with deep dermatophytosis.

Severe Pneumocystis jirovecii pneumonia in an idiopathic CD4+ lymphocytopenia patient: case report and review of the literature

INTRODUCTION

When diagnosing Pneumocystis jirovecii pneumonia (PJP), the clinical suspicion must be confirmed by laboratory tests. PJP is rarely described in patients with idiopathic CD4⁺ lymphocytopenia (ICL), a rare T-cell deficiency of unknown origin with persistently low levels of CD4⁺ T-cells (<300 µl^-1 or <20 % of total lymphocytes) but repeated negative human immunodeficiency virus (HIV) tests. We retrospectively analysed a case of an ICL patient with severe PJP associated with multiple opportunistic infections (OIs). We also reviewed the literature since 1986.

CASE PRESENTATION

A laboratory-confirmed case of PJP associated with invasive candidiasis and cytomegalovirus infection was reported in an ICL patient. Despite early treatment, the patient died of respiratory failure under polymicrobial pneumonia. According to the literature, the mortality rate of ICL patients is 10.4 % (33/316). In ICL patients, the risk of OI is 83.2 % (263/316), with viral infections being the most prevalent (58.2 %, 184/316), followed by fungal infections (52.2 %, 165/316) and mycobacterial infections (15.5 %, 49/316). Dysimmunity is reported in 15.5 % (49/316) of ICL patients. Among the fungal infections, cryptococcal infections are the most prevalent (24.1 %, 76/316), followed by candidiasis (15.5 %, 49/316) and PJP (7.9 %, 25/316).

CONCLUSIONS

The high risk of OIs underlines the importance of more vigorous preventative actions in hospitals. The response to therapy and the detection of early relapse of PJP may be monitored by several laboratory tests including quantitative PCR. It is essential to treat the ICL and to follow the guidelines concerning therapy and prophylaxis of OIs as given to HIV patients.