Immunological Profile of HTLV-1 in Pediatric Patients - European Medical Journal

Immunological Profile of HTLV-1 in Pediatric Patients

Authors:
Diana MC Donneys,1,2 Ingara C James,1,2 Herney Garcia,3 *Juan P Rojas1,2,4-7
  • 1. Department of Pediatrics, Universidad Libre Cali, Colombia
  • 2. Member of the Pediatric Research Group (GRINPED)
  • 3. Division of Urology/Urooncology, Department of Surgery, School of Medicine Universidad del Valle, Cali, Colombia
  • 4. Hospital Universitario del Valle Evaristo García, Cali, Colombia
  • 5. Epidemiology, Universidad Libre, Cali, Colombia
  • 6. Fundación Universitaria San Martín, Cali, Colombia
  • 7. Pontificia Universidad Javeriana, Cali, Colombia
*Correspondence to [email protected]
Disclosure:

The authors declare no conflicts of interest.

Citation:
Microbiol Infect Dis AMJ. ;2[1]:66-69. https://doi.org/10.33590/microbiolinfectdisam/NAYU1648.
Keywords:
Cellular immunity, human T lymphotropic virus type 1 (HTLV-1), humoral immunity, retroviridae.

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.

INTRODUCTION

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with significant immunological dysregulation and oncogenesis.1 It is highly endemic in South America, notably in Brazil, Peru, and Colombia, affecting primarily individuals of indigenous and African descent.2 In children, HTLV-1 often presents with dermatologic manifestations, respiratory diseases, opportunistic co-infections, and autoimmune disorders.3 The virus primarily targets CD4+ T lymphocytes but can also infect CD8+ T cells, B cells, and other immune cell types.4 Transmission occurs mainly through prolonged breastfeeding, sexual contact, blood transfusions, and needle sharing.5 This study aims to describe the immunological profile of pediatric patients diagnosed with HTLV-1 in Cali, Colombia, focusing on cellular and humoral responses.

METHODS

This observational, descriptive, and retrospective cross-sectional study was conducted at a pediatric referral center from January 2017–March 2021. Nineteen pediatric patients with confirmed HTLV-1 infection were included. The median age at diagnosis was 94 months, with school-age children representing the largest group (52.6%). The analysis involved lymphocyte subpopulations (CD4+, CD8+, CD19+, CD3+) and serum immunoglobulin levels (IgA, IgG, IgM, IgE), interpreted according to age-specific reference values. Data were collected from medical records and analyzed using IBM® SPSS® Statistics 22 (Armonk, New York).

RESULTS

Of the 19 patients, 57.9% were male, and 84.2% were affiliated with the subsidized health insurance system. Malnutrition was observed in 52.6% of the cases, suggesting a potential risk factor for immune dysfunction. No cases of HIV co-infection were found. Cellular immunity analysis in six patients revealed that 50% had elevated B lymphocytes (CD19), while CD4+ and CD8+ T cell counts were within normal ranges for most patients. Regarding humoral immunity, 16 patients were evaluated, with elevated IgA, IgG, and IgE levels in over half of the patients, while IgM was normal in 81.3% of cases (Table 1). The increase in immunoglobulin levels, particularly IgE and IgA, was associated with elevated CD19+ B lymphocytes, suggesting a link between B cell activation and polyclonal hypergammaglobulinemia.

Table 1: Clinical characteristics and immunological profile of patients with HTLV-1 in the present study.
F: female; M: male.

DISCUSSION

The findings indicate that immunosuppression in pediatric HTLV-1 patients is not related to reduced lymphocyte subpopulations but may be mediated by cytokine dysregulation and viral regulatory proteins that interfere with immune signaling.4 This immune dysregulation contributes to increased susceptibility to opportunistic infections such as Strongyloides stercoralis, Aspergillus fumigatus, and Mycobacterium tuberculosis.6 Pulmonary infections, including tuberculosis and aspergillosis, along with dermatological conditions like infective dermatitis, were common opportunistic manifestations.7 The male predominance observed contrasts with studies reporting a higher prevalence in females.8 Consistent with prior research, this study identified polyclonal hypergammaglobulinemia rather than lymphopenia, reflecting an aberrant but functional immune response.9 Additionally, the elevated immunoglobulin levels and B lymphocytes suggest a possible link to immune system overstimulation rather than depletion.10

CONCLUSION

Pediatric patients with HTLV-1 infection exhibit elevated B lymphocytes and immunoglobulin levels, indicating immune dysregulation driven by cytokine alterations rather than lymphocyte depletion.2 Enhanced monitoring for opportunistic infections and regular immunological assessments are recommended to improve outcomes. Future studies should focus on understanding immune activation mechanisms and developing therapeutic interventions that address pediatric HTLV-1 infection.5

References
Vásquez P. HTLV-I (Human T- cell lymphotropic virus), algo que decir? Rev Chil Infect. 2003;20 (Suppl 1):S34-7. Kannagi M et al. Impact of host immunity on HTLV-1 pathogenesis: potential of Tax-targeted immunotherapy against ATL. Retrovirology. 2019;16(1):23. Futsch N et al. HTLV-1, the other pathogenic yet neglected human retrovirus: from transmission to therapeutic treatment. Viruses. 2017;10(1):1. Sanchez-Palacios C et al. Seroprevalence and risk factors for human T-cell lymphotropic virus (HTLV-I) infection among ethnically and geographically diverse Peruvian women. Int J Infect Dis. 2003;7(2):132-7. Mosquera Herrera CE et al. Infección por el Virus Linfotrópico de Células T Humano HTLV-1 y Paraparesia Espástica Tropical en Ecuador: Paradigma de Enfermedad Tropical Desatendida. Rev Ecuat Neurol. 2019;28(2):71-4. Fuzii HT et al. Immunopathogenesis of HTLV-1-assoaciated myelopathy/tropical spastic paraparesis (HAM/TSP). Life Sci. 2014;104(1-2):9-14. Gotuzzo Herencia E et al. Veinte años de investigación sobre HTLV-1 y sus complicaciones médicas en el Perú: perspectivas generales. Acta Med Per. 2010;27(3):196. Paiva AM et al. Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring. Sci Rep. 2018;DOI:10.1038/s41598-018-25939-y. Mejía-Mertel J et al. Clinical profile of human T-lymphotropic virus type I: a forgotten infection in pediatrics. Revista Infectio. 2021;25(1):28-32. James IC et al. Case series: pediatric human T-lymphotropic virus type 1 and its clinical expression. Front Trop Dis. 2022;DOI:10.3389/fitd.2021.824067.

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