T-lymphocyte subsets in acute illness

Effects of human immunodeficiency virus status on symptom severity in influenza-like illness in an otherwise healthy adult outpatient cohort

The impact of HIV on influenza-like illness (ILI) has been incompletely described in the era of combination antiretroviral therapy, particularly in the post-H1N1 pandemic period. This analysis informs on ILI in an otherwise healthy, predominantly outpatient cohort of adults with HIV in the USA. From September 2010 to March 2015, this multisite observational cohort study enrolled otherwise healthy adults presenting to a participating US military medical center with ILI, a subset of whom were HIV positive. Demographics, clinical data, and self-reported symptom severity were ascertained, and enrollees completed a daily symptom diary for up to 10 days. 510 men were included in the analysis; 50 (9.8%) were HIV positive. Subjects with HIV were older and less likely to be on active duty. Rhinovirus and influenza A were the most commonly identified pathogens. Moderate–severe diarrhea (p<0.001) and fatigue (p=0.01) were more frequently reported by HIV-positive men. HIV positivity was associated with higher gastrointestinal scores, but not other measures of ILI symptom severity, after controlling for age, race, military status, and influenza season. Few were hospitalized. HIV-positive subjects had more influenza B (p=0.04) and were more likely to receive antivirals (32% vs 6%, p<0.01). Antiviral use was not significantly associated with symptom scores when accounting for potential confounders. In this predominantly outpatient cohort of adult men, HIV had minimal impact on ILI symptom severity. Despite similar illness severity, a higher percentage of subjects with HIV reported undergoing antiviral treatment for ILI, likely reflecting differences in prescribing practices.Trial registration number: NCT01021098.

Care of Critically Ill Patients with Human Immunodeficiency Virus

Care of patients with human immunodeficiency virus (HIV) infection in the intensive care unit (ICU) has changed dramatically since the infection was first recognized in the United States in 1981. The purpose of this review is to describe the current important aspects of care of patients with HIV infection in the ICU, with a primary focus on the United States and developed countries. The epidemiology and initial approach to diagnosis and treatment of HIV (including the newest antiretroviral guidelines), common syndromes and their management in the ICU, and typical comorbidities and opportunistic infections of patients with HIV infection are discussed.

Experience of SARS-CoV-2 infection in two kidney transplant recipients living with HIV-1 infection

There is still no consensus on the optimal management of COVID-19 within the general population due to the emerging evidence base. High-risk groups, including kidney transplant recipients living with HIV present unique additional challenges. Here we discuss two kidney transplant recipients living with HIV with SARS-CoV-2 infection and their clinical course, and review the existing literature for this subset of challenging patients.

Association between CD4 T cell counts and the immune status among adult critically ill HIV-negative patients in intensive care units in Uganda

Background: Cluster of differentiation 4 (CD4) T cells play a central role in regulation of adaptive T cell-mediated immune responses. Low CD4 T cell counts are not routinely reported as a marker of immune deficiency among HIV-negative individuals, as is the norm among their HIV positive counterparts. Despite evidence of mortality rates as high as 40% among Ugandan critically ill HIV-negative patients, the use of CD4 T cell counts as a measure of the immune status has never been explored among this population. This study assessed the immune status of adult critically ill HIV-negative patients admitted to Ugandan intensive care units (ICUs) using CD4 T cell count as a surrogate marker. Methods: A multicentre prospective cohort was conducted between 1st August 2017 and 1st March 2018 at four Ugandan ICUs. A total of 130 critically ill HIV negative patients were consecutively enrolled into the study. Data on sociodemographics, clinical characteristics, critical illness scores, CD4 T cell counts were obtained at baseline and mortality at day 28. Results: The mean age of patients was 45± 18 years (mean±SD) and majority (60.8%) were male. After a 28-day follow up, 71 [54.6%, 95% CI (45.9-63.3)] were found to have CD4 counts less than 500 cells/mm³, which were not found to be significantly associated with mortality at day 28, OR (95%) 1 (0.4-2.4), p = 0.093. CD4 cell count receiver operator characteristic curve (ROC) area was 0.5195, comparable to APACHE II ROC area 0.5426 for predicting 24-hour mortality. Conclusions: CD4 T cell counts were generally low among HIV-negative critically ill patients. Low CD4 T cells did not predict ICU mortality at day 28. CD4 T cell counts were not found to be inferior to APACHE II score in predicting 24 hour ICU mortality.

A prospective study on the outcome of human immunodeficiency virus-infected patients requiring mechanical ventilation in a high-burden setting

BACKGROUND

There is a paucity of data on the mortality of patients admitted to the intensive care unit (ICU), despite the fact that human immunodeficiency virus (HIV)-related diseases represent a significant burden to health care resources particularly in sub-Saharan Africa.

AIM

To describe the outcome and prognostic factors of HIV-infected patients requiring mechanical ventilation in an ICU.

DESIGN

Prospective observational study.

METHODS

All 54 patients (34.8 ± 10.4 years, 38 females) admitted with confirmed HIV from October 2012 until May 2013 were enrolled. Disease severity was graded according to APACHEII score. Admission diagnoses, clinical features and laboratory investigations, complications and outcomes were recorded.

RESULTS

The mean length of ICU stay was 11.0 days (range: 1-49 days), and 33 patients survived (ICU mortality: 38.9%). The in-hospital mortality at 30 days was 48.1%. ICU mortality was associated with an AIDS-defining diagnosis (OR = 7.97, P = 0.003). Non-survivors had higher APACHEII scores (25.8 vs. 18.6, P = 0.001) and lower mean admission CD4 counts (102.5 vs. 225.2, P = 0.014). Multiple logistical regression analysis confirmed the independent predictive value of WHO stage 4 disease (P = 0.008), lower mean CD4 count on admission (P = 0.057) and higher APACHEII score (P = 0.010) on ICU mortality, and WHO stage 4 (P = 0.007) and higher APACHE II score (P = 0.003) on 30-day mortality.

CONCLUSIONS

The ICU mortality of mechanically ventilated HIV-positive patients was high. WHO stage 4 disease and a higher APACHEII score were predictive of both ICU and 30-day mortality, whereas a low CD4 count on admission was associated with ICU mortality.

Implementation and Operational Research: Effects of CD4 Monitoring Frequency on Clinical End Points in Clinically Stable HIV-Infected Patients With Viral Suppression

BACKGROUND

Current treatment guidelines for HIV infection recommend routine CD4 lymphocyte (CD4) count monitoring in patients with viral suppression. This may have a limited impact on influencing care as clinically meaningful CD4 decline rarely occurs during viral suppression.

METHODS

In a regional HIV observational cohort in the Asia-Pacific region, patients with viral suppression (2 consecutive viral loads <400 copies/mL) and a CD4 count ≥200 cells per microliter who had CD4 testing 6 monthly were analyzed. Main study end points were occurrence of 1 CD4 count <200 cells per microliter (single CD4 <200) and 2 CD4 counts <200 cells per microliter within a 6-month period (confirmed CD4 <200). A comparison of time with single and confirmed CD4 <200 with biannual or annual CD4 assessment was performed by generating a hypothetical group comprising the same patients with annual CD4 testing by removing every second CD4 count.

RESULTS

Among 1538 patients, the rate of single CD4 <200 was 3.45/100 patient-years and of confirmed CD4 <200 was 0.77/100 patient-years. During 5 years of viral suppression, patients with baseline CD4 200-249 cells per microliter were significantly more likely to experience confirmed CD4 <200 compared with patients with higher baseline CD4 [hazard ratio, 55.47 (95% confidence interval: 7.36 to 418.20), P < 0.001 versus baseline CD4 ≥500 cells/μL]. Cumulative probabilities of confirmed CD4 <200 was also higher in patients with baseline CD4 200-249 cells per microliter compared with patients with higher baseline CD4. There was no significant difference in time to confirmed CD4 <200 between biannual and annual CD4 measurement (P = 0.336).

CONCLUSIONS

Annual CD4 monitoring in virally suppressed HIV patients with a baseline CD4 ≥250 cells per microliter may be sufficient for clinical management.

The Impact of HCV Infection Duration on HIV Disease Progression and Response to cART amongst HIV Seroconverters in the UK

Introduction

The effect of HCV infection on HIV disease progression remains unclear; the effect of HCV infection duration on HIV disease progression is unknown.

Methods

We used data from a cohort of HIV seroconverters to investigate the effect of HCV infection duration on time from HIV seroconversion to CD4 <350cells/mm³, AIDS or death, censoring at the earlier of cART initiation or last clinic visit, adjusting for confounders and splitting data into follow up periods from HIV seroconversion (<2, 2–4 and >4 years). We additionally compared CD4 cell decline following HCV infection to that of mono-infected individuals with similar HIV infection duration by fitting a random effects model. In a separate analysis, we used linear mixed models to we examine the effect of HCV infection and its duration on CD4 increase over 48 weeks following cART.

Results

Of 1655 individuals, 97 (5.9%) were HCV co-infected. HCV<1 year was associated with a higher risk of endpoint in each follow-up period from HIV seroconversion (HR [95% CI] 2.58 [1.51, 4.41], p = 0.001; 3.80 [1.20, 12.03], p = 0.023; 2.03 [0.88, 4.71], p = 0.098 for <2, 2–4 and >4 years respectively), compared to mono-infected individuals. However, we found no evidence of an association for those with HCV>2 years (all p>0.89). Individuals experienced a somewhat greater decrease in CD4 count following HCV infection lasting 13 months, relative to individuals with HIV alone, (estimate = -3.33, 95% CI [-7.29, 0.63] cells/mm³ per month, p = 0.099). Of 1502 initiating cART, 106 (7.1%) were HCV co-infected, with no evidence of HCV duration at cART being associated with immunological response (p = 0.45).

Conclusions

The impact of HCV co-infection on HIV disease progression appears to be restricted to the first year after HCV infection.

Burden of tuberculosis in intensive care units in Cape Town, South Africa, and assessment of the accuracy and effect on patient outcomes of the Xpert MTB/RIF test on tracheal aspirate samples for diagnosis of pulmonary tuberculosis: a prospective burden of disease study with a nested randomised controlled trial

BACKGROUND

There are few prospective data about the incidence and mortality associated with pulmonary tuberculosis in intensive care units (ICUs), and none on the accuracy and clinical effect of the Xpert-MTB/RIF assay in this setting. We aimed to measure the frequency of culture-positive tuberculosis in ICUs in Cape Town, South Africa and to assess the performance and effect on patient outcomes of Xpert MTB/RIF versus smear microscopy for diagnosis of tuberculosis.

METHODS

We did a prospective burden of disease study with a randomised controlled substudy at the ICUs of four hospitals in Cape Town. Mechanically ventilated adults (≥18 years) with suspected pulmonary tuberculosis admitted between Aug 1, 2010, and July 31, 2013 (irrespective of the reason for admission), were prospectively investigated by culture, and by Xpert-MTB/RIF testing or smear microscopy, of tracheal aspirate samples. In the substudy, patients were randomly assigned (1:1), via a computer-generated allocation list, to smear microscopy or Xpert MTB/RIF. Participants, caregivers, and outcome assessors were not masked to group assignment. Only the laboratory staff were blinded to the clinical details of the participants. In November, 2012, Xpert MTB/RIF was adopted as the initial diagnostic test for respiratory samples in Western Cape province. Thereafter, patients received Xpert MTB/MIF and culture as standard of care. For the whole study cohort, the primary outcome was the frequency of bacteriologically confirmed tuberculosis. The primary endpoint of the randomised substudy was the proportion of culture-positive patients on treatment at 48 h after enrolment. The randomised substudy is registered with ClinicalTrials.gov, number NCT01530568.

FINDINGS

We investigated 341 patients for suspected pulmonary tuberculosis out of a total of 2309 ICU admissions. 46 (15%) of 317 patients included in the final analysis had a positive test for tuberculosis (Xpert MTB/RIF or culture). Culture-positive patients who failed to initiate treatment (adjusted HR 4·49, 95% CI 1·45-13·89) or who received inotropes (4·33, 1·49-12·60) were more likely to die. However, tuberculosis status was not associated with 28-day or 90-day mortality. In the substudy, we randomly assigned 115 patients to smear microscopy and 111 to Xpert MTB/RIF. Smear microscopy detected six (43%) of 14 culture-positive patients, and Xpert MTB/RIF detected 11 (100%) of 11 culture-positive patients (p=0·002). The proportion of culture-positive patients on treatment at 48 h was higher in the Xpert MTB/RIF group than in the smear microscopy group (11 [92%] of 12 vs nine [53%] of 17; p=0·043), although use of Xpert MTB/RIF had no effect on mortality or other patient outcomes.

INTERPRETATION

Tuberculosis is fairly common in ICUs in high-burden settings, and clinicians should screen and test patients for tuberculosis with Xpert MTB/RIF where available. This test improves diagnostic yield and rates of treatment initiation, and reduces unnecessary treatment, but might not increase the total number of patients on treatment when empirical treatment is widely used. A suspected diagnosis of pulmonary tuberculosis should not exclude patients from ICU care in resource-limited settings because mortality is unaffected by the presence of this disease.

FUNDING

European and Developing Countries Clinical Trials Partnership, South African Medical Research Council, and the Discovery Foundation.

Management of persons infected with human immunodeficiency virus requiring admission to the intensive care unit

Rates of admission to the intensive care unit (ICU) for persons infected with human immunodeficiency virus (HIV) remain relatively unchanged in the modern era despite advances in antiretroviral therapy (ART) and improvements in ICU survival. Critical care may be required for patients with HIV because of severe opportunistic infections or malignancy, antiretroviral drug toxicity, or critical illness seemingly unrelated to HIV, and each of these scenarios may present different management challenges. In this article, the epidemiology of HIV-related ICU admission is reviewed and key management issues are discussed.

False positive HIV diagnoses in resource limited settings: operational lessons learned for HIV programmes

BACKGROUND

Access to HIV diagnosis is life-saving; however the use of rapid diagnostic tests in combination is vulnerable to wrongly diagnosing HIV infection when both screening tests give a false positive result. Misclassification of HIV patients can also occur due to poor quality control, administrative errors and lack of supervision and training of staff. Médecins Sans Frontières discovered in 2004 that HIV negative individuals were enrolled in some HIV programmes. This paper describes the result of an audit of three sites to review testing practices, implement improved testing algorithms and offer re-testing to clients enrolled in the HIV clinic.

FINDINGS

In the Democratic Republic of Congo (DRC), Burundi and Ethiopia patients were identified for HIV retesting. In total, 44 false-positive patients were identified in HIV programmes in DRC, two in Burundi and seven in Ethiopia. Some of those identified had been abandoned by partners or started on anti-retroviral therapy or prophylaxis. Despite potential damage to programme reputations, no impact in terms of testing uptake occurred with mean monthly testing volumes stable after introduction of re-testing. In order to prevent the problem, training, supervision and quality control of testing procedures were strengthened. A simple and feasible confirmation test was added to the test algorithm. Prevalence of false positives after introducing the changes varied from zero percent (95% CI 0%-8.2%) to 10.3 percent (95% CI: 7.2%-14.1%) in Burundi and DRC respectively.

CONCLUSION

False HIV diagnoses were found in a variety of programme settings and had devastating individual consequences. We re-tested individuals in our programmes while instituting improved testing procedures without a negative impact on test uptake. Considering the importance of correct diagnosis to the individual, as well as the resources needed to care for someone with HIV, it is critical to ensure that all patients registered in HIV programmes are accurately diagnosed.

Is frequent CD4+ T-lymphocyte count monitoring necessary for persons with counts >=300 cells/μL and HIV-1 suppression?

Among patients infected with human immunodeficiency virus (HIV), those with HIV-1 RNA <200 copies/mL and CD4 counts ≥300 cells/µL had a 97.1% probability of maintaining durable CD4 ≥200 cells/µL for 4 years. When non-HIV causes of CD4 lymphopenia were excluded, the probability rose to 99.2%. Our data support less frequent CD4 monitoring during viral suppression.

Use of the relationship between absolute lymphocyte count and CD4 count to improve earlier consideration of pneumocystis pneumonia in HIV-positive emergency department patients with pneumonia

BACKGROUND

The ability to accurately assess the level of immunosuppression in HIV+ patients in the emergency department (ED) is often limited and can affect management of these patients.

OBJECTIVE

To evaluate the relationship between the absolute lymphocyte count (ALC) and CD4 count in HIV patients admitted through the ED with pneumonia and how utilization of this relationship may affect early consideration and evaluation of Pneumocystis jiroveci pneumonia (PCP).

METHODS

Retrospective multicenter 5-year study of HIV+ patients with an ICD-9 diagnosis of pneumonia. Included patients had an ALC measured on ED presentation and a CD4 count measured in < 24 h. A receiver operator curve (ROC), decision plot analysis, and McNemar test of proportions were used to characterize the relationship between study variables.

RESULTS

Six hundred eighty six patients were enrolled, 23.2% (95% confidence interval [CI] 20.2-26.1) were diagnosed with PCP. The geometric mean CD4 count and ALC were 81 and 1089, respectively. The correlation between ALC and CD4 was r = 0.60 (95% CI 0.55-65, p < 0.01). The ROC was 0.78 (0.75-0.82). An ALC < 1700 cells/mm(3) had a sensitivity of 84% (95% CI 80-87) and specificity of 55% (95% CI 48-70) for a CD4 < 200 cells/mm(3). An ALC threshold of 1700 cells/mm(3) would have identified 86% of patients with PCP but falsely identified 2.5 patients without PCP for every one accurately identified.

CONCLUSION

The ALC threshold of 1700 cells/mm(3) retains significant discriminatory value and would moderately improve identification of patients with a CD4 < 200 cells/mm(3) but is not likely to be reliable as the sole method of early recognition and evaluation of PCP.

Immunological and molecular epidemiological characteristics of acute and fulminant viral hepatitis A

BACKGROUND

Hepatitis A virus is an infection of liver; it is hyperendemic in vast areas of the world including India. In most cases it causes an acute self limited illness but rarely fulminant. There is growing concern about change in pattern from asymptomatic childhood infection to an increased incidence of symptomatic disease in the adult population.

OBJECTIVE

In-depth analysis of immunological, viral quantification and genotype of acute and fulminant hepatitis A virus.

METHODS

Serum samples obtained from 1009 cases of suspected acute viral hepatitis was employed for different biochemical and serological examination. RNA was extracted from blood serum, reverse transcribed into cDNA and amplified using nested PCR for viral quantification, sequencing and genotyping. Immunological cell count from freshly collected whole blood was carried out by fluorescence activated cell sorter.

RESULTS

Fulminant hepatitis A was mostly detected with other hepatic viruses. CD8+ T cells count increases in fulminant hepatitis to a significantly high level (P = 0.005) compared to normal healthy control. The immunological helper/suppressor (CD4+/CD8+) ratio of fulminant hepatitis was significantly lower compared to acute cases. The serologically positive patients were confirmed by RT-PCR and total of 72 (69.2%) were quantified and sequenced. The average quantitative viral load of fulminant cases was significantly higher (P < 0.05). There was similar genotypic distribution in both acute and fulminant category, with predominance of genotype IIIA (70%) compared to IA (30%).

CONCLUSIONS

Immunological factors in combination with viral load defines the severity of the fulminant hepatitis A. Phylogenetic analysis of acute and fulminant hepatitis A confirmed genotypes IIIA as predominant against IA with no preference of disease severity.

Biphasic onset of splenic apoptosis following hemorrhagic shock: critical implications for Bax, Bcl-2, and Mcl-1 proteins

Introduction

The innate immune response to trauma hemorrhage involves inflammatory mediators, thus promoting cellular dysfunction as well as cell death in diverse tissues. These effects ultimately bear the risk of post-traumatic complications such as organ dysfunction, multiple organ failure, or adult respiratory distress syndrome. In this study, a murine model of resuscitated hemorrhagic shock (HS) was used to determine the apoptosis in spleen as a marker of cellular injury and reduced immune functions.

Methods

Male C57BL-6 mice were subjected to sham operation or resuscitated HS. At t = 0 hours, t = 24 hours, and t = 72 hours, mice were euthanized and the spleens were removed and evaluated for apoptotic changes via DNA fragmentation, caspase activities, and activation of both extrinsic and intrinsic apoptotic pathways. Spleens from untreated mice were used as control samples.

Results

HS was associated with distinct lymphocytopenia as early as t = 0 hours after hemorrhage without regaining baseline levels within the consecutive 72 hours when compared with sham and control groups. A rapid activation of splenic apoptosis in HS mice was observed at t = 0 hours and t = 72 hours after hemorrhage and predominantly confirmed by increased DNA fragmentation, elevated caspase-3/7, caspase-8, and caspase-9 activities, and enhanced expression of intrinsic mitochondrial proteins. Accordingly, mitochondrial pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins were inversely expressed within the 72-hour observation period, thereby supporting significant pro-apoptotic changes. Solely at t = 24 hours, expression of the anti-apoptotic Mcl-1 protein shows a significant increase when compared with sham-operated and control animals. Furthermore, expression of extrinsic death receptors were only slightly increased.

Conclusion

Our data suggest that HS induces apoptotic changes in spleen through a biphasic caspase-dependent mechanism and imply a detrimental imbalance of pro- and anti-apoptotic mitochondrial proteins Bax, Bcl-2, and Mcl-1, thereby promoting post-traumatic immunosuppression.

Enhanced in vivo protein synthesis in circulating immune cells of ICU patients

Insufficient function of the immune system contributes to a poor prognosis in intensive care unit (ICU) patients. However, the immune system function is not easily monitored and evaluated. In vivo protein synthesis determination in immune competent cells offers a possibility to quantify immunological activation. The aim of this descriptive study was to determine the in vivo fractional protein synthesis rate (FSR) in immune cells of ICU patients during the initial phase of the critical illness. Patients (n = 20) on ventilator treatment in the general ICU were studied during their first week of ICU stay. FSR was determined in circulating T lymphocytes, mononuclear cells, the whole population of blood leukocytes, and in stationary immune cells of palatine tonsils during a 90-min period by a flooding technique. Healthy, adult subjects (n = 11), scheduled for elective ear, nose, and throat surgery served as a control group. The FSR in leukocytes and mononuclear cells of ICU patients was higher compared with the control group. In contrast, the FSR of circulating T lymphocytes and of tonsillar cells was not different from that in the healthy subjects. In summary, the ICU patients showed a distinct polarization of metabolic responses during the initial phase of the critical illness. The in vivo rate of protein synthesis was high in the circulating mononuclear cells and leukocytes, reflecting enhanced metabolic activity in these cell populations. Determination of the in vivo protein synthesis rate may be used as a tool to obtain additional information on activation of the immune system.

Lymphocyte subsets and cytokines in ascitic fluid of decompensated cirrhotic patients with and without spontaneous ascites infection

BACKGROUND AND AIM

Spontaneous ascites infection is a frequently encountered and important complication of decompensated liver cirrhosis. The immune system plays an important role in the development or eradication of this infection. A number of compositional and functional alterations in immune system cells have been demonstrated in cirrhotic patients; however, there is a lack of knowledge about this issue in ascitic infections. The aim of the present study was to evaluate lymphocyte subsets and levels of some ascitic and lymphocytic intracytoplasmic cytokines in decompensated cirrhotic patients with or without spontaneous ascites infection.

METHODS

The study population consisted of 45 decompensated cirrhotic patients (32 men, 13 women) with different etiologies. Patients with ascitic polymorphonuclear leukocyte count > or =250/mm(3) and/or positive ascitic bacterial cultures were classified as the "infected group". Comparison was made between the infected and non-infected group for the following parameters: ascites leukocyte counts and differentiations; ascitic fluid protein; albumin levels and serum-ascites albumin gradients; flow cytometric detection of cell surface markers for ascitic T, B and natural killer lymphocytes; intracytoplasmic interleukin (IL)-2, IL-4, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma; levels of ascitic IL-8, IL-10, IL-12 and TNF-alpha; and soluble Fas antigen and soluble Fas ligand.

RESULTS

The CD4/CD8 ratio was significantly decreased and expression of T cell receptor-gammadelta was increased in the infected group. Furthermore, ascites TNF-alpha levels were also elevated in this group. Ascitic IL-8, IL-10, IL-12 and TNF-alpha levels were significantly higher in patients with positive ascitic bacterial culture.

CONCLUSIONS

These results suggest that a cytotoxic, especially Th1, immune response predominates in ascites infections. It also demonstrates that TNF-alpha might be involved in the pathogenesis of ascites infections.

Malaria chemoprophylaxis and the serologic response to measles and diphtheria-tetanus-whole-cell pertussis vaccines

Background

Acute malaria has been associated with a decreased antibody response to tetanus and diphtheria toxoids, meningococcal, salmonella, and Hib vaccines. Interest in giving malaria drug therapy and prevention at the time of childhood immunizations has increased greatly following recent trials of intermittent preventive therapy during infancy (IPTi), stimulating this re-analysis of unpublished data. The effect of malaria chemoprophylaxis on vaccine response was studied following administration of measles vaccines and diphtheria-tetanus-whole cell pertussis (DTP) vaccines.

Methods

In 1975, six villages divided into two groups of children ≤74 months of age from Burkina Faso, were assigned to receive amodiaquine hydrochloride chemoprophylaxis (CH+) every two weeks for seven months or no chemoprophylaxis (CH-). After five months, children in each group received either one dose of measles or two doses of DTP vaccines.

Results

For recipients of the measles vaccine, the seroconversion rates in CH+ and CH- children, respectively, were 93% and 96% (P > 0.05). The seroresponse rates in CH+ and CH- children respectively, were 73% and 86% for diphtheria (P > 0.05) and 77% and 91% for tetanus toxoid (P > 0.05). In a subset analysis, in which only children who strictly adhered to chemoprophylaxis criteria were included, there were, likewise, no significant differences in seroconversion or seroresponse for measles, diphtheria, or tetanus vaccines (P > 0.05). While analysis for pertussis showed a 43% (CH+) and 67% (CH-) response (P < 0.05), analyses using logistic regression to control for sex, age, chemoprophylaxis, weight-for-height Z-score, and pre-vaccination geometric mean titer (GMT), demonstrated that chemoprophylaxis was not associated with a significantly different conversion rate following DTP and measles vaccines. Seven months of chemoprophylaxis decreased significantly the malaria IFA and ELISA GMTs in the CH+ group.

Conclusion

Malaria chemoprophylaxis prior to vaccination in malaria endemic settings did not improve or impair immunogenicity of DTP and measles vaccines. This is the first human study to look at the association between malaria chemoprophylaxis and the serologic response to whole-cell pertussis vaccine.

CD4 T-lymphocyte subset counts in HIV-seropositive patients during the course of community-acquired pneumonia caused by Streptococcus pneumoniae

Total lymphocyte counts, CD4 T-lymphocyte counts and CD4/CD8 ratios were measured in 30 anti-retroviral-naive HIV-seropositive patients upon hospital admission for acute community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae, and again 1 month after resolution of infection. There was a significant depression of the total lymphocyte count (p < 0.005) and CD4 T-lymphocyte count (p < 0.001) in the acute stage of CAP caused by S. pneumoniae, with a subsequent increase in 90% (27/30) of cases after resolution of the infection. There was no significant difference in the CD4/CD8 T-lymphocyte ratio on admission compared with 1 month later (p 0.9).

Blood lymphocyte subsets in canine idiopathic pericardial effusion

The immunophenotype of peripheral blood lymphocytes was investigated in 23 dogs diagnosed with idiopathic pericardial effusion in order to provide information about a possible role of the immune system in this pathology. Flow cytometric analysis showed a significant reduction in nearly all lymphocyte subsets examined and a strong, significant (P < 0.001) reduction of the CD4 subset, which gave rise to a significantly lower CD4/CD8 ratio. Our data suggest that an imbalance in the immune system is present during the course of the disease, preferentially affecting the T helper cell response.

Clinical review: immunodepression in the surgical patient and increased susceptibility to infection

Several studies indicate that organ failure is the leading cause of death in surgical patients. An excessive inflammatory response followed by a dramatic paralysis of cell-mediated immunity following major surgery appears to be responsible for the increased susceptibility to subsequent sepsis. In view of this, most of the scientific and medical research has been directed towards measuring the progression and inter-relationship of mediators following major surgery. Furthermore, the effect of those mediators on cell-mediated immune responses has been studied. This article will focus on the effect of blood loss and surgical injury on cell-mediated immune responses in experimental studies utilizing models of trauma and hemorrhagic shock, which have defined effects on the immunoinflammatory response. Subsequently these findings will be correlated with data generated from surgical patients. The results of these studies may generate new approaches for the treatment of immunodepression following major surgery, thus reducing the susceptibility to infection and increasing the survival rate of the critical ill surgical patient.

Pneumocystis carinii pneumonia in a human immunodeficiency virus-uninfected patient with sickle cell crisis

Pneumocystis carinii pneumonia (PCP) usually occurs in the setting of preexisting immunosuppression. We present a case of PCP that occurred in an HIV-negative woman with severe sickle cell disease.

Role of CD4:CD8 ratio in predicting HIV co-infection in patients with newly diagnosed tuberculosis

Because of the clinical implications of Human Immunodeficiency Virus (HIV) status on treatment of tuberculosis (TB) and in view of the low percentage of patients in whom HIV testing is performed, we evaluated immunological features of 54 patients with newly diagnosed TB and its ability to predict HIV co-infection. All 54 patients had initially unknown HIV status and had no other Acquired Immunodeficiency Syndrome (AIDS) defining illnesses. Twenty-two patients were found to be HIV seropositive and 32 were seronegative. The median CD4 and CD8 counts were statistically different between the HIV seropositive and seronegative patients, however, there was overlap between the two groups. The median CD4:CD8 ratio was 0.17 in HIV seropositive patients and 1.95 in the seronegative patients and had minimal overlap (p < 0.0001). A CD4:CD8 ratio < or = 0.7 gave a sensitivity of 100%, specificity of 94%, positive-predictive value of 92% and a negative-predictive value of 100% in predicting HIV co-infection. In conclusion, HIV-co-infection in patients with newly diagnosed TB could be predicted on the basis of the CD4:CD8 ratio.

Premedication with clonidine does not attenuate suppression of certain lymphocyte subsets after surgery

Sixty-four patients undergoing elective major surgery were randomly assigned into a double-blinded, placebo-controlled, clinical trial to test the hypothesis that premedication with clonidine would attenuate postoperative reductions in circulating lymphocytes. The treatment group (n = 28) received a clonidine skin patch (0.3 mg/d) and a 0.6-mg oral loading dose 60-90 min before surgery. The control group (n = 36) received placebo patches and pills. Absolute blood levels of the following lymphocyte subsets were measured before induction of a standardized general anesthetic (baseline) and the morning after surgery: CD2, CD3, CD4, CD8, CD20, CD56, and the CD4:CD8 ratio. Significant decreases in lymphocyte subsets CD2, CD3, and CD4 were found in both groups; CD56 was significantly decreased only in the placebo group. However, the extent of lymphocyte depletion from baseline to Postoperative Day 1 between the clonidine and placebo groups was not different. Plasma concentrations of epinephrine, norepinephrine, and cortisol were measured from blood samples drawn at 8:00 AM on Postoperative Day 1. Plasma norepinephrine levels were significantly lower among patients who received clonidine. However, no significant differences were found in plasma epinephrine or cortisol levels between the clonidine and placebo groups. With a clinical dose, clonidine did not prevent postoperative lymphocyte depletion. alpha2-Agonists may not suppress adrenocortical stress responses sufficiently to prevent postoperative immune suppression.

IMPLICATIONS

Lymphocyte (white blood cell) counts often decrease after major surgery. We hypothesized that clonidine would reduce hormonal stress and blunt reductions in lymphocytes after major surgery. In a randomized trial, we found no differences from placebo in cortisol levels or lymphocyte changes. Lymphocyte levels did not predict infectious complications.

Changes in CD8 and CD4 lymphocyte subsets, T cell proliferation responses and non-survival in the very old: the Swedish longitudinal OCTO-immune study

Results from a previous longitudinal study indicated that a combination of high CD8 and low CD4 percentages and poor T cell proliferation in peripheral blood lymphocytes was associated with higher mortality in a subgroup of a sample of very old Swedish individuals. The present study examined whether those results could be confirmed at a subsequent 2-year time interval by investigating if additional individuals from the same original sample had developed the immune profile associated with higher mortality. Subgroups were formed by cluster analysis and similar to our previous results, this follow-up study identified a subgroup of subjects (n = 18) with an immune profile which again included high CD8, low CD4 percentages and poor mitogen response and was associated with higher mortality. Over the 2-year period 12 additional individuals: (1) Developed this immune profile; and (2) Could be identified by changes in their CD4:CD8 ratios which progressively decreased over the study period. These results confirm our original study and indicate that in this very old sample, over a subsequent 2 year period, additional individuals moved into the cluster at risk for higher mortality.

Lymphocyte function in wound healing and following injury

BACKGROUND

Injury activates a cascade of local and systemic immune responses.

METHODS

A literature review was undertaken of lymphocyte function in wound healing and following injury.

RESULTS

Lymphocytes are not required for the initiation of wound healing, but an intact cellular immune response is essential for a normal outcome of tissue repair. Injury affects lymphocyte immune mechanisms leading to generalized immunosuppression which, in turn, increases host susceptibility to infection and sepsis. Although the exact origin of post-traumatic immunosuppression remains unknown, stress hormones and immunosuppressive factors, such as inflammatory cytokines, prostaglandin E2 and nitric oxide, affect lymphocyte function adversely. Post-traumatic impairment of T lymphocyte immune function is reflected in decreased lymphocyte numbers, as well as altered T cell phenotype and activity. Antibody-producing B lymphocytes are variably affected by injury, probably secondary to alterations of T lymphocyte function, as a result of their close interaction with helper T cells. Therapeutic modulation of the host immune response may include non-specific and specific interventions to improve overall defence mechanisms.

CONCLUSION

Early resuscitation to restore lymphocyte function after injury is important for tissue repair and the prevention of immunosuppression.