This study set out to investigate the influence of emergency major abdominal surgery on CD4 count among HIV positive patients. We found that major surgery did not significantly reduce CD4 count.
The exact mechanism of CD4 reduction is said to be due to several factors; cell lysis, autoimmune mechanism, anergy, effect of super antigens, apoptosis and virus specific immune responses .
Auto immune responses may be evoked by shared structural homology between MHC class II molecules and cellular humoral immune responses directed towards HIV proteins which cross react against self HLA antigens on T cells causing immune destruction.
The role of anergy in CD4 dysfunction is by binding of the glycoprotein 120 to CD4.
Molecules causing them to be refractory to further stimulation and destruction by HIV.
Super antigens are microbial or viral antigens capable of activation of many T-cells, in HIV infection; they render T-cells more susceptible to HIV.
All these factors are worsened by stress which is caused by surgical trauma. Other factors like infection and use of steroids can also trigger these factors.
The CD4 cell counts were generally lower in the HIV infected group than in the HIV uninfected group.
The high values of the CD4 count even in the HIV positive i.e. higher than 200 cells/ml the AIDS defining level of CD4 by WHO, can explain the finding that surgery had no statistically significant effect of reduction in CD4 as the pre-operative CD4 levels were high (347 cells/ml).
The blood for CD4 test was taken between 7 pm and 11 pm to cater for the diurnal variation. The CD4 reduction was transient in our study with CD4 levels rising to above pre-operative values on the 7th POD in both the HIV positive and negative patients. This was similar to previous studies by Rahal , where it lasted 8 days, Bolla and Tuzzato  where it lasted 8 days and Johanna  where CD4 returned to baseline value between 6th and 8th post-operative days.
Surgery and anesthesia cause T-cell apoptosis which is said to be only transient lasting up to 5 days .
In our study emergency major surgery caused transient reduction in CD4 because within seven days the levels had risen to above pre-operative values. In a study by Ramon , CD4 drop persisted for only two days after which there was a rise. This was independent of the type of operation done. The reduction is said to be because stimulation and production of T-cells is reduced in the immediate post-operative period causing a CD4 drop. The rise in CD4 later occurs when stimulation & production increase.
Women showed a greater CD4 cell reduction than men in our study unlike in a study by Wichmann where men suffered longer lasting depression of CD4 than women of about 5 days while the depression in the women the CD4 depression lasted only 2 days .
In our study, the men had a better rise in CD4 count on 7th POD than the women who instead had a reduction. This could be due to the fact that women tend to have other factors affecting their CD4 changes, like the menstrual cycle alone is said to have an effect on women’s CD4 count variations, . Use of oral contraception’s also affects the CD4 count changes in women. Probably a combination of these factors could have caused these changes.
The CD4 reductions after surgery were highest in the HIV negatives than positives on 1st POD which was unexpected as the HIV infection itself reduces the CD4 count. This could be explained by the different operations in the two groups as the greatest drop in CD4 count was different for different operations. It could also be due to the many factors causing CD4 variation. CD4 levels are said to vary by about 25% even in HIV negative patients .
Available information suggests that HIV positive patients should have a higher reduction in CD4 count because of the effect of the disease itself in addition to the other factors affecting CD4 count .
CD4 rise was more in the HIV negative patients in this study between 1st and the 7th POD and pre-operative to 7th POD as expected (p > 0.05). In comparison, a study by Rahal  also showed that surgery does not affect immune function adversely in HIV-infected patients, as judged by CD4 cell counts or viral titers which were also done in their study.
In the Rahal study, of the 17 patients with CD4 cell counts >500/mm3 prior to surgery, 64.7% had unchanged counts after surgery (95% confidence interval [CI] 32.9%, 81.6%), whereas 35.2% of patients had lower CD4 counts after surgery (95% CI 14.2%, 61.7%).
Most patients in this study were in the (20–40) age group and most of HIV positive patients were in the same age group. This is expected as this is the most sexually active of the three categories of age in the study <20, 20–40 and >40. The general age range of the patients in the study was 10 years to 82 years with a median age of 35 years.
There were more males than females in the study and most of the patients in the study were married. The commonest operations in the study were appendectomy then sigmoidectomy for both groups which is almost similar to the study by Rahal  were the commonest operation was also appendectomy followed by hernia repair for that study. Other studies vary in scope of procedures done [14, 15].
It would be expected that the reduction in the HIV positives be greater. This may be due to hyper stimulation of immune cells in the presence of infection in the HIV positives.
But in the same group the HIV negative show a better rise in CD4 between 1st to the 7th POD and a much greater rise than the HIV positives between pre-operative period to the 7th post-operative day. This shows that their immune system recovered better than that of the HIV positive patients which is an expected finding.
Prevailing literature on effects of splenectomy on CD4 count suggests that splenectomy causes an abrupt and prolonged increase in CD4 cell count . However in our study the 3 patients who had splenectomy who were all HIV negative had a marked fall in CD4 count by 1st POD (Table 3), with a small rise between 1st to 7th POD and a fall between pre-operative to 7th POD. This may be due to other stresses as all these patients were trauma patients with multiple injuries. It could be also due to the fact that CD4% as opposed to CD4 cell count is more accurate in assessment of asplenic patients .
This study wasn’t without limitations. There were several confounders not controlled for the clinical staging of HIV was not done, the period of starvation was not considered. Perhaps some HIV negatives were in the window period and should have been in the positives group. The indications of surgery were taken together; owing to small numbers meaningful stratification wasn’t possible. These limitations could have been controlled for to some extent by the selection process (which was random) and the comparison of the two groups showed comparability (insignificant p-values) for some important variables such as age, occupation and haemoglobin. The state of receiving HAART or being HAART naive was not considered. Over all we believe that our findings support the policy that HIV positivity alone should not deter or defer surgery when it clearly indicated, similar to cacala’s findings .