Serum immunoglobulin and complement levels in tropical pulmonary eosinophilia, and their correlation with primary and their relapsing stages of the illness

Reduced IgG levels found during acute eosinophilic pneumonia, which normalize during recovery from disease

Clinically there are several different types of eosinophilic pneumonia (EP), but other than for tropical pulmonary eosinophilia, the humoral immune response between different types of EP, such as acute eosinophilic pneumonia (AEP), chronic EP, drug-induced EP, allergic bronchopulmonary aspergillosis, and Churg-Strauss syndrome, has not been examined. Immunoglobulin G (IgG) and E (IgE) serum concentrations were analyzed in patients with EP, or bacterial pneumonia, and in age-matched controls. Patients with AEP had lower IgG levels than the age-matched controls. Serum IgG levels in patients with AEP were significantly lower than in patients with other types EP or bacterial pneumonia. IgG2 and IgG4 were also significantly decreased in AEP, compared to age-matched controls. In AEP, the serum IgG levels were significantly decreased during active disease and increased during remission, but the serum IgE levels did not change significantly, indicating a decrease in serum IgG is a common feature of AEP. Low IgG levels were significantly correlated with serum surfactant protein D and absolute eosinophil counts in the bronchoalveolar lavage fluid of patients with AEP. This is the first reported study of immunoglobulin levels in AEP. The pathogenesis of AEP might negatively affect serum IgG levels, but not IgE levels. The present findings might indicate that serum IgG reflects the inflammatory response in AEP.

Alpha 1-antitrypsin in tropical pulmonary eosinophilia

Serum alpha-antitrypsin (A1AT) was measured in 36 patients (group A) with tropical pulmonary eosinophilia (TPE) and 30 patients with pulmonary eosinophilia with associated worm infestation (group B). Serum A1AT level was also measured in 42 healthy subjects (group C). In 28 patients (group A, 15 and group B, 13), the serum A1AT level was below 60 percent of the mean A1AT value of the control group. The A1AT-deficient patients had a more severe form of illness with recurrence and relapse, and they were generally refractory to treatment. In these deficient patients, a significant negative correlation (p < 0.02) between A1AT and absolute blood eosinophil counts (AEC) was observed. In 21 patients (group A, B and group B, 13), the effect of therapy with either diethylcarbamazine or deworming or both was observed. This showed a significant posttreatment rise of A1AT level with a significant fall in AEC (p < 0.02) as compared to their respective pretreatment levels. Serum A1AT levels in either or both parents of 11 patients (group A, 5 and group B, 6) were found to be within normal levels. The significant rise in A1AT levels with a significant fall in AEC levels in the patients following therapy and the absence of A1AT deficiency in the parents examined indicate that the A1AT deficiency observed in TPE is probably acquired.

Breakdown product of factor B as an index of complement activation in lepromatous leprosy and its relation with bacillary load

Serum complement profile studied in 50 lepromatous leprosy patients with various bacillary loads demonstrated significantly decreased C3 levels in patients with high bacteriological index (2+ to 4+) as compared with those with lesser bacterial load. In contrast, mean serum levels of C1q and C4 components remained unchanged. The concentration of factor B breakdown product (Ba) and its ratio to factor B increased with the bacterial density and more so in patients with erythema nodosum leprosum. A significant negative correlation was found between serum C3 and Ba levels in most lepromatous patients. Analysis of the data suggested the alternative pathway as the possible mechanism of complement activation in lepromatous leprosy.

Alterations in blood eosinophil morphology, binding capacity for complexed IgG and kinetics in patients with tropical (filarial) eosinophilia

As the significance of the eosinophilia which is found in some patients with chronic filarial infections is unknown, blood eosinophils were studied in seven patients with tropical (filarial) eosinophilia who had blood eosinophil counts between 5.2 and 56.6 x 10(9)/l. In six of these patients over 20% of the eosinophils were vacuolated, and degranulated eosinophils were found in the three patients with the most severe illness. In four patients serum eosinophil cationic protein levels were raised, and serial studies in two showed that they returned to normal after treatment with diethylcarbamazine. In addition, an increased proportion of eosinophils in these patients were able to bind to complexed IgG suggesting that they were responding to stimuli in the blood, and in one patient the blood eosinophil half-time clearance was prolonged. Labelled cells were cleared into the spleen, liver and bone marrow. These findings support the hypothesis that in patients with tropical (filarial) eosinophilia, blood eosinophils are induced to release their granule constituents into the circulation. It is suggested that these secretion products may interact with microfilariae, and may give rise to some of the clinical features of chronic filarial infections.