HIV-infected individuals are co-infected with Mycobacterium tuberculosis. Tuberculosis (TB)remains a major challenge to global public health. In addition to HIV infection, other factors that contribute to susceptibility and progression of TB have not been well defined. It has been suggested that susceptibility to TB is associated with host immune response and could be influenced by environmental and genetic factors or by gene-environment interactions. Human Immunodeficiency Virus (HIV) disease is characterized by a progressive deterioration in immune function. Interventions that offset this impairment have the potential to slow HIV disease progression and improve quality of life. The latter has become increasingly important in the face of HIV infection becoming a chronic disease in those with access to anti-retroviral therapy (ART)(I) 25(OH) D has been shown to downregulate the pro-inflammatory response and therefore may help to protect the host against increased lung pathology induced by exacerbated inflammation¹.It also has anti-microbial effects By inducing activation macrophages². A seminal paper in Science demonstrated the link between 25(OH) D and IFN-g induced macrophage antimicrobial responses^3. The majority of studies analyzing the role of 25(OH) D in TB have shown an association between low 25(OH) D and susceptibility to active TB disease^4-7. However, there are still discrepancies interms of genetic predisposition^8,9 and serum levels in TB and non-TB subjects^10,11. This is likely due to geographic location, exposure to sunlight, genetic differences, cultural practices, religion and the presence of other disease conditions¹². Most previous vitamin D studies in HIV-positive patients are observational, and associations are based on a single measurement per patient. Moreover, only a few studies in HIV-positive patients have addressed the effect of vitamin D supplementation through a nutritional intervention trial with a placebo- or non-supplemented control group^3,4.

AIM Association of vitamin D level with disease severity (as detected by CD4 cell count.)

This observational study recruited a total of 60 subjects, split evenly between two groups: 30 cases of HIV with tuberculosis (Group A) and 30 cases of HIV without tuberculosis (Group B). The subjects were selected from those attending the outpatient clinic and those admitted to the Department of General Medicine at SMS Medical College and its affiliated hospitals. Before inclusion in the study, each subject provided informed consent and met specific inclusion and exclusion criteria. They were informed about the study's purpose and procedures, and written consent was obtained from all participants.Baseline clinical characteristics, including demographic, clinical, and biochemical data, were collected for each subject. This included detailed personal and family medical histories.

Table 1 Distribution of patients according to age and gender.

The study revealed that most male patients (50.7%) were aged 31-40, with 22.38% falling between 20-30 years. Among females, 33.3% were aged 31-40, and 30.3% were aged 41-50. The average age was 36.2 years for males and 40.28 years for females.

Table 2: Distribution of patients according to occupation

In our study we found that 28% patients were non working female followed by 20% patients of private sectors in group A. In group B, 32% patients were house wife followed by 16% patients of private sector. 

Table 3 Distribution of patients according to CD4 Count

The mean CD4 count for Group A was 328.3 cells/cumm, for Group B it was 379.04 cells/cumm, and for the entire study population, it was 353.67 cells/cumm. Group B had a significantly higher CD4 count compared to Group A, with a p-value of 0.03, indicating a significant difference between the groups (p < 0.05).

Table 4 Distribution of patients according to CD4 count.

In our study, 48% of patients in Group A had a CD4 count less than 200, followed by 28% with a count between 200-500. In Group B, 56% of patients had a CD4 count between 200-500, followed by 26% with less than 200 CD4 count. The p-value was 0.03, indicating a significant difference between the groups (p < 0.05).

Table 5 Distribution of patients according to WHO staging.

In our study, 66% of patients in Group A were at WHO staging 3, followed by 24% at staging 4. In Group B, 70% were at staging 3, and 26% were at staging 4.(p > 0.05).

Table 6 Correlation of CD4 count and WHO staging with Vitamin D level.

In our study, we observed an r-value of -0.01 for the correlation between Vitamin D and CD4 levels in Group A, and -0.23 in Group B. There was an inverse correlation between Vitamin D and CD4 count, (p > 0.05).Similarly, for the correlation between Vitamin D and WHO staging, we found an r-value of 0.17 for Group A and -0.1 for Group B. There was no significant difference between Vitamin D levels and WHO staging in either group (p > 0.05).

Image 1: Correlation of CD4 count with Vitamin D level.

Image 2: Correlation of WHO staging with Vitamin D level.

There are multiple direct immune mechanisms through which vitamin D deficiency may impair antimycobacterial immunity and increase the risk of tuberculosis reactivation or active primary infection. Vitamin D is required for an interferon-γ-mediated pathway in macrophages that leads to autophagy, phagosomal maturation, and other antimicrobial activities against M. tuberculosis¹³. Production of antimicrobial peptides, including cathelicidin and defensin β2, in macrophages when Toll-like receptors are stimulated by 1,25 (OH)2D^14,15. Furthermore, vitamin D also induces reactive nitrogen and oxygen intermediates, suppresses matrix metalloproteinase enzymes, and down regulates tryptophan-aspartate– containing coat protein, which can improve antimycobacterial immune responses^12,16,17. Vitamin D may also indirectly reduce the incidence of pulmonary tuberculosis by slowing HIV disease progression.

In our study we found that mean Vitamin D in group A was 20.33 Ng/dl and for group B it was 17.57 ng/dl. The p value was 0.04. There Was significant difference between these group as p value was <0.05. We also found that mean CD4 count for group A was 328.3 and for group B it was 379.04. The p value was 0.03. There was significant difference between These group as p value was <0.05.

 In our study 48% patients in group A Were of CD 4 count less than 200 followed by 28% patients with CD4 Count between 200-500. In group B 56% patients had CD4 count between 200-500 followed by 26% patients in less than 200 CD4 count. The p Value was 0.03. There was significant difference between these group as P value was <0.05.

In our study we found that 66% patients were of WHO staging 3 Followed by 24% patients of staging 4 in group A. In group B, 70% Patients were of WHO staging 3 and 26% patients of staging 4. There was No significant difference between these group as p value was >0.05. similarly,Yilma D et al¹⁷ found that individuals with WHO clinical stage IV and those who were on TB treatment at ART initiation had lower Serum 25(OH) D, but serum 25(OH)D was not associated with CD4 Count, viral load and serum CRP. The lower serum 25(OH)D in patients With WHO clinical stage IV disease and TB may be due to the reduced Dietary vitamin D intake because of the disease itself and/or due to Reduced exposure to sun because of their reduced mobility or Hospitalisation. Moreover, drugs used for TB treatment such as isoniazid And rifampicin may have contributed to the reduction in serum 25(OH)D, Because of their direct biological effects on the metabolism of vitamin D¹⁸R value for Vitamin D and CD4 level for group A and Group B was -0.01 and -0.23. We found that there was no significant Difference between Vitamin D levels and CD4 count in both the group as P value was >0.05.Musarurwa C et al¹⁶ conducted a study correlating gender, age, and CD4 count with vitamin D levels. They found that females had significantly higher median serum 25(OH)D concentrations compared to males, which contrasts with some reports of higher concentrations in males. Other studies have found no significant differences by gender. Musarurwa et al¹⁶ speculated that higher vitamin D levels in females might be linked to wasting, common in both PTB and HIV, as their female patients had slightly higher BMIs than males. This could imply that more vitamin D is stored in adipose tissue, which is then released during the wasting associated with HIV and/or active PTB.

Our findings, although differing from the commonly accepted link between serum vitamin D levels and PTB, align with several other studies of CD4 count , WHO staging report a connection between high serum 25(OH) D concentrations and increased PTB risk. This variation might be attributable to genetic factors, considering the complex and diverse roles of vitamin D. Therefore, genetic polymorphisms in the vitamin D receptor or in the various enzymes involved in vitamin D metabolism are promising areas for further investigation.

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