This invention relates to a method of treating patients suffering from immunodeficiency, both in the treatment and prophylaxis of opportunistic diseases, and to compositions for use in the method.

Within the immune system of humans and other warm-blooded animals are two types of white blood cells, the B-cells and T-cells. B-cells make antibodies which are released into the bloodstream and designed to combat antigenic materials, such as invading organisms. T-cells are divided into helpers (inducers) and suppressors (cytotoxics) which mediate in the defense mechanisms brought into play against the invading organisms.

Normally, there are twice as many helper T-cells as suppressor T-cells. ie. a normal ratio of 2:1.

Patients suffering from severe immunological abnormalities, for example patients suffering from AIDS, some cancers, leukemia etc, and also patients undergoing immunosuppressive regimes, for example patients undergoing transplant surgery, have a drastically lower T-cell population.

Patients undergoing immunosuppressive treatment must be carefully isolated and are always in danger of contracting viral or bacterial infections. AIDS patients suffer from a range of opportunistic infections and other diseases, in particular Pneumocystis carvnii infections. Kaposi's sarcoma etc.

At the moment, no effective treatment is available in order to eradicate or prevent opportunistic infections, except antibiotic regimes which have limited success.

Lactic acid producing bacteria are well known. They have been widely used in the acid-preservation of foodstuffs, for example as silage. The addition of lactobacilli to the diet, particularly L.bul aricus and its analogues in such foods as live yoghurt, has long been known as a method of improving health generally and in overcoming undesirable gut infections, in particular. Bacteria of this type are also recognised as an effective treatment for Candida infections of the mouth.

I have now discovered that a suitable combination of strains of lactic acid producing bacteria, when fed in relatively high quantities to immuno-suppressed patients, can provide excellent prophylaxis against opportunistic infections and also an effective treatment of existing conditions.

According to the invention there is provided a method of treatment of an immuno-depressed patient, in particularly a patient suffering from Aquired Immunodefficiency Syndrome (AIDS) to prevent or diminish opportunistic diseases, comprising subjecting the gastrointestinal tract of the patient to a combination of bacterial strains selected from vigorous strains of lactic acid producing bacteria, in particular strains of Lactobacillus and Streptococcus, especially L.plantarum. L. acidophilus. S. lactis. S. faecium and S. faecalis. Some species of Streptococcus are alternatively classified as Enterococcus and thus some deposied strains of S. faecium and S. faecalis are referred to as E. faecium and E. faecalis.

In general, at least two strains should be simultaneously administered, and preferably three or more strains e.g. 6-12 strains. The strains should be vigorous strains so that they quickly and thoroughly colonise the gastrointestinal tract. Some strains of S. faecalis are particularly virulent and would be unsuitable in cases where contact with the bloodstream might occur, eg. those with intestinal lesions or internal Kaposi's sarcoma.

A particularly useful combination comprises S. lactis. L. plantarum and S. faecium. A typical daily dose 10 to 10 bacteria, or more. e.g. at least

5x10 bacteria, can be administered. Bacteria of this type are non-toxic and can be easily rendered palatable. The bacteria can be provided as a dry mixture incorporating a carrier and nutrient, but alternatively liquid or semi-solid preparations may be obtained in the manner of yoghurt. For preference a combination of the strains, as dry cells can be prepared in combination with a carrier/nutrient. In a prefered embodiment, a composition comprises whey solids, sugars, and preferably, amylases. Such a composition can be prepared by cultivating each individual strain separately in an appropriate medium and separating the cells by conventional means, eg. centrifugation, lyophilising the cells and then mixing them together in combination with the carrier, eg. whey powder and fructose.

The level and extent of dosage will depend on the degree of vigour of the strains used. Particularly vigorous strains are obtainable from culture collections such as ATCC and NCIB or from commercial sources such as Cernitin SA, Lugano, and the AFRC. Maidenhead, Berks. Suitable bacteria for use in accordance with the present invention include Lactobacillus acidophilus. strain DeLatte. NCIB 40084. and Enterococcus faecium (deposited as Lactobacillus pian arum, strain DeLatte). NCIB 40085. deposited with the National Collection of Industrial & Marine Bacteria. Aberdeen on 16th November 1988.

However, the only essential difference between vigorous and less vigorous strains is that with vigorous strains dosage can be discontinued after an initial period for colonising the gastrointestinal tract, with periodic top-up doses, whereas with less vigorous strains continuous daily dosage is recommended. It is particularly desirable that strains used are derived from human hosts, ie. bacteria of human gut origin. Indeed, it can be advantageous to use strains isolated from the gut of the patient.

The mode of action of the bacterial mixture used according to this invention is only partly understood. While I do not wish to be bound by theoretical considerations, I believe that the composition actually exhibits an immunostimulant activity on the patient, encouraging the formation of T-cells and other factors in the immunological response mechanism. Evidence for the activity of such compositions is based on the following experience.

The choice of a model animal for testing medicaments for an immunostimulant activity is difficult. However, there is evidence to suggest that farmed mink can be used as such a model. The commercially farmed mink tends to be a particularly inbred animal which is highly susceptible to disease. A particular problem is the viral infection known as Aleutian Disease which produces a decreased

T-cell response rather similar to that found in AIDS. (see, for example. Perryman, et al. J. Immunology. Vol 115. no 1. 1975, 22-27: and Henson et al, American J. Pathology, vol 71, no 3. 1973, 345-348). My own experiments have shown that mink fed with silage produced using the bacteria used according to the invention remain healthy and thrive in comparison with mink fed an ordinary diet. There is a distinct decrease in mortality and, in particular, a reduced incidence of Aleutian Disease (AD) .

A dramatic example of the effect on AD is as follows. In the winter of 1988-89 a mink farm in Holland had a sever outbreak of AD with 900 animals infected. Instead of requiring an immediate slaughter of all the animals, the veterinary surgeon agreed to the administration of a mixture of lactic acid producing bacteria according to the invention. The bacteria were administered at a higher dose per kg body weight than that used for humans, because the mink has a particularly short digestive tract. The dosage was 4 kg of the bacteria/carrier mixture per 1000 kg wet fodder. After a regime of 3 months the condition of animals had improved remarkably. Before, the animals had poor appetites, low fertility, poor condition and growth and many died. After treatment of 900 animals. 884 survived (over 99%). They had very good appetites (eating 260-280g food per day - more than had previously been

known in the farm), good fertility, weight, colour and general health. Autopsies showed (as compared with sick animals) regenerated liver and kidneys, good fur, low fat and cholesterol deposits in the arterial system.

Tests in humans with AIDS have been equally exciting. In twelve cases patients with severe AIDS conditions, typically with Kaposi sarcoma, herpes, diarrhea, candidiasis and Pneumocvstis carvnii infection (PCP), were started on regime of about 10 cfu of mixed bacteria per day. After four to six months the conditions of eleven had improved from severely ill with a prognosis of a few days to a few months left, to a condition of increased weight, few or no opportunistic infections, good appetite and energy and a prognosis of at least 6 months to 1 year. One patient with terminal AIDS died early in the treatment. In general, weight gains of from 5 to 15 kg were noted. One of the eleven had been taking AZT (zidovudine) but stopped during the period of treatment. It should be noted that although the patients feel, and obviously are, much better, their T4 cell count remains very low.

Based on this evidence, I believe it is the case that humans with immunodeficient conditions, especially AIDS, will benefit by the proposed invention.

As well as oral administration of the bacteria as described above, it is most beneficial for the colon to be directly colonised by irrigation and anal administration e.g. by enema. A typical formulation for this use comprises the dried bacterial cells in-a water- soluble or dispersible carrier, e.g. a sugar such as glucose.

While undergoing treatment of this type, it is recommended that the patient should observe a diet free from meat, cheese, animal fat, eggs, and poultry, and instead eat a diet based on a high fibre, rich in vitamins A and C. especially including vegetables from the brassica family, garlic, fish and fish oil. It is also desirable that the patient undertakes as much physical exercise as his condition permits.

The following examples illustrate compositions according to the invention.

Example 1

A dry powdered product has the following bacterial cell content by weight:

S. faecium SF-68 25%

S. faecalis TH69(ATCC-31663) 25%

L. plantarum W26TKS1 25%

S. lactis (ATCC-11007) 12.5%

L. acidophilus (NCL-84) 12.5%

This bacterial mixture is combined with a carrier based on acid whey and fructose to a total of 5-10% by weight of the total weight of bacteria.

S. faecium SF-68 is available from Cernitin SA, Lugano L. plantarum W26TKS1 is available from the AFRC, Institute for Grassland and Animal Production. Hurley. Maidenhead. Berks. UK.

Although other strains producing high levels of amino acids could be substituted. L. acidopholus could be replaced by L. bulqaricus.

Example 2 Oral Composition

by weight

E. faecium NCIB 11181 (human origin) 10%

E. faecium NCIB 10415 10%

E. faecalis NCIB 8275 (human origin) 10%

S. lactis NCIB 6681 10%

L. plantarum NCIB 8030 25%

L. acidophilus NCIB 8690 (human saliva origin) 5%

L. fermentum NCIB 2797 (infant human origin) 10%

Micrococcus luteus NCIB 8553 5%

L. casei NCIB 8010 (similar to NCIB 8030) 5%

L. delbrueckii NCIB 8130 (similar to NCIB 6681) 5%

L. amylophilus NCIB 11546 5%

carrier as for Example 1.

The dried product contains about 3 x 10 cells per gram. Oral dose 3 x lOg per day.

Example 3 Colonic irriσant

by weight E. faecium NCIB 11181 25%

S. lactis NCIB 6681 25%

L. plantarum NCIB 8030 25%

L. fermentum NCIB 2797 25%

carrier: glucose

The dry product contains about 3 x 10 9 cells per gram. Dose : 3g per irrigation mixed with water (ad lib) 3 hours before use.

Suggested regime: 2-3 irrigations per week.

11 Example 4 A pacticulary preferred composition contains

Bacteria:

S. lactis NCIB 6681 E E.. ffaaeecciiuuim NCIB 40085 E E.. ffaaeecciiuuim NCIB 11181 L L.. ppllaannttaairum NCIB 7220 L L.. ffeerrmmeemntum NCIB 2797 ( (o0r1 : LL.. aacciidoplilus NCIB 40084) E. faecalis NCIB 8275 * E. coli B NCIB 8545 *

* These strains should not be used for patients with Kaposi sarcoma. β in approximately equal amounts to a total of 10 x 10

9 -l . . . . to 10 x 10 cfu.g ; in the following composition:

by weight glucose monohydrate 27.4% precooked wheat 50.0% malt enzymes 10.0% herbal demulcents etc 2.6% bacteria + starter 10.0% 100.0%

A dosage of 3 x 5 ml spoons per day provides from 10 x 10 ⁹ to 10 x 10 ¹⁰ cfu.